How a random sampling regime could help detect COVID and highlight infection hotspots


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Stephen John Haslett, Massey University and Richard Arnold, Te Herenga Waka — Victoria University of WellingtonFor the detection of community transmission of COVID-19, New Zealand currently relies on contact tracing, testing of self-selected people with symptoms and those with permission to travel between different alert levels, and surveillance testing of staff at businesses permitted to operate in higher alert levels.

Surveillance testing has picked up cases before they knew they were contacts of another infected person. But people who are only tested after they feel unwell may have already passed the virus on to several others. Others who have COVID-19 may not display symptoms.

As a supplement to current testing, we suggest a sound, properly designed random sampling regime of certain areas or workplaces to provide a cost-effective way to determine, with known probability, if there is any COVID-19 in a specified area or group.

The critical point is that such COVID Clearance Check surveys must be random.

Continued wastewater testing, contact tracing and community testing stations remain critically important. But they don’t provide any measures of accuracy because currently they don’t incorporate formal sampling designs.

Probability theory behind random sampling

A statistically designed random sampling scheme, based on as few as 100 people or households from key sub-populations, would give a very high probability of detecting if there are any COVID-19 cases. However, to determine this probability, it is critical the sampling is random.

Geographical locations could include certain neighbourhoods and wastewater catchment areas. Workplace sampling could focus on large businesses, rest homes, hospitals and prisons.

COVID Clearance Checks based on random sampling could shorten lockdowns, lessen social impact, save money and support businesses. Once Aotearoa’s borders reopen, they would provide critical information of known accuracy about infection hotspots.




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The formal sampling scheme is based on probability theory, which provides the mathematical connection between COVID prevalence (p₀), sample size (n) and the probability of detecting the virus in the subpopulation (p).

Unless a subpopulation is very small, its size has little effect on the sample size required. For a simple random sample, which selects people or households essentially independently and with equal probability, the probability of detecting COVID is:

p = 1-(1-p₀)ⁿ

For example, for a 3% prevalence of COVID and a random sample of 100, the chance of detecting the virus is over 95%. A larger sample would be required to detect COVID at lower prevalence, for clustered random sampling schemes, or for higher levels of detection probability.

Instead of simple random sampling of households, systematic sampling (which selects households at a fixed interval in a list or along a route) could be used to simplify fieldwork without loss of accuracy.

Survey design and structured fieldwork would provide the mechanism for implementing the random selection of people and safe work conditions for the sampling team. For random sampling, this is now feasible because saliva tests have recently been approved by the Ministry of Health.

Using self-administered saliva tests would reduce close contact between field staff and household members, minimising the risk of spread.

A rapid antigen testing kit
New Zealand has approved the use of rapid antigen testing as a screening tool to protect critical worksites.
Phil Walter/Getty Images

How it would work

Examples where a COVID Clearance Check survey would be useful include towns or city suburbs, and households in catchment areas with positive wastewater results. Sampling areas around MIQ facilities, but not including them, would provide information on possible community transmission.

As a first step, the Ministry of Health would identify particular areas or groups of interest, and then randomly select a sample within it, using statistically sound methods, to ensure every person had a known non-zero chance of being included.

For area sampling, having pre-notified residents, field staff would drop off saliva tests at each sampled household. Household tests would then be collected, either for separate individuals or combined, using set safety protocols.




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Any selected households which do not return test results would be contacted again to reduce non-response bias. Any detected cases would bring other current control mechanisms into play.

Detecting all cases in an area is different and more difficult than detecting whether there are any cases. Cases detected by COVID Clearance Check sampling provide a searchlight rather than fully illuminating the situation. Finding all cases would require much larger sample sizes, which is why such checks supplement rather than replace current surveillance methods.

Using well-designed and implemented random sampling schemes can be an effective, rapid and low-cost way of assessing whether there are any community cases, without testing thousands of people who are not necessarily those of greatest interest. When useful, such surveys can be repeated, using another sample from the same area or group.

As we are now all realising, keeping COVID-19 out of Aotearoa cannot be a long-term plan. Once vaccination rates are high and borders begin to reopen, COVID Clearance Checks using random sampling to monitor possible hotspots will become increasingly useful, even necessary, for surveillance.


Alistair Gray, at Statistics Research Associates, is also a member of the Ministry of Health COVID-19 Expert Advisory Network and has collaborated with us on this article.The Conversation

Stephen John Haslett, Emeritus Professor of Statistics, Massey University and Richard Arnold, Professor of Statistics and Data Science, Te Herenga Waka — Victoria University of Wellington

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia must get serious about airborne infection transmission. Here’s what we need to do


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Lidia Morawska, Queensland University of TechnologyAustralia is now in the grip of its second winter marred by the pandemic, with crippling lockdowns in multiple cities.

Earlier this month, the federal government announced a four-stage plan to bring the country back to something resembling normality. Acknowledging it will be impossible to eradicate COVID-19 completely, the plan focuses on a variety of steps — most notably vaccination — to enable the country to live with the virus.

However, if we want this plan to work, there’s one crucial control measure yet to be considered: protection against airborne transmission of the infection in public indoor spaces.

We need to modernise our indoor environments to protect Australians from respiratory infections, and more broadly, from all indoor air hazards. This includes indoor exposure to pollution originating from outdoors, such as bushfire smoke.

The evidence is in

The body of scientific evidence pointing to airborne transmission as the key route by which SARS-CoV-2 spreads is now overwhelming.

Put simply, over the past 18 months, we have come to understand most people become infected with the virus that causes COVID-19 by inhaling it from shared air. The risk is predominantly indoors.

Consequently, every public building should have control measures in place to provide adequate ventilation.

But this information hasn’t been communicated to Australians — many of whom remain focused on hand washing and cleaning surfaces. These are good practices, but because SARS-CoV-2 spreads predominantly through the air, they likely provide only a marginal contribution to infection control.

A waiter wipes down a table in a cafe.
Surfaces don’t appear to be a major source of SARS-CoV-2 transmission.
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While the World Health Organization has recently released a roadmap to improve indoor ventilation in the context of COVID-19, many Australian public spaces are significantly under-ventilated.

We don’t know exactly what proportion of infections would be prevented by improving ventilation in public places, but the evidence indicates this could drastically reduce the risk.




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So how do we do it?

Appropriate building engineering controls include sufficient and effective ventilation, possibly enhanced by particle filtration and air disinfection systems. It’s also important to avoid recirculating air, as well as overcrowding.

We have the technology to make these changes, and these are things that can often be implemented at low cost. But for this to happen, Australia must first recognise the significant contribution these measures make to infection control. I propose the following solutions.

1. Establish a national regulatory group for clean indoor air

This is an issue that will require co-operation across various areas of government. The establishment of a national regulatory group — led by the federal government working with the states and territories through the national cabinet — would provide a platform for the relevant ministries to cooperate on this matter.

The key goal should be the explicit inclusion of protection against indoor air hazards (including airborne infection control) in the statements of purpose and definitions of all relevant Australian building design and engineering standards, regulations, and codes.




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2. Provide financial support

It will be important to establish a national fund enabling the rollout of indoor environment modernisation measures addressing both immediate emergencies, such as COVID-19, as well as a long-term transition process.

Over a period of years, all new buildings would ideally be designed to ensure good indoor air quality, while existing buildings would be retrofitted with the same objective.

3. Create a communication campaign

The Australian government should set up a communication campaign to educate people on the risks of shared air, and on how to improve ventilation.

Steps people can take themselves to improve ventilation include opening windows, and raising the issue with those responsible for the space if they feel ventilation is inadequate.

A woman sits next to an open window.
Opening windows is one way to improve ventilation.
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Yes, it might sound daunting. But it’s possible

At first, it may appear to be a huge task to ensure clean indoor air to the entire country. Is it possible?

Perhaps the same questions were asked by Britons when in the 19th Century, Sir Edwin Chadwick was tasked by the British government with investigating clean water supply and centralised sewage systems.

His recommendations in 1842 changed the approach to sanitation in Britain, and ultimately the world, creating enormous public health benefits and corresponding economic dividends through health-care savings.

We cannot imagine now what it would be like to live without clean water flowing from our taps.

What we need is a similar “revolution” in Australia regarding clean indoor air — one that future generations will rightly regard as a baseline standard for the built environment.

Australia already has sophisticated building infrastructure and public health regulatory frameworks to support the required advances. These will require modernisation, but it’s far from a case of building from nothing.




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Numerous expert Australian colleagues and myself would be pleased to offer our assistance to make this dream an Australian reality.

Importantly, in this crucial period while we wait for high levels of vaccination, addressing ventilation could be the difference between recurring lockdowns or enjoying a COVID-free life.The Conversation

Lidia Morawska, Professor, Science and Engineering Faculty; Director, International Laboratory for Air Quality and Health (WHO CC for Air Quality and Health); Director – Australia, Australia – China Centre for Air Quality Science and Management (ACC-AQSM), Queensland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Can I get coronavirus from mail or package deliveries? Should I disinfect my phone?



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Euan Tovey, University of Sydney

According to Google Trends, the top two most searched terms about mobile phones this week in Australia were “how to disinfect phone” and “how to clean your phone.”

And the third most-searched “can I get coronavirus from…?”-style question in the past week in Australia was “can you get coronavirus from mail?” (If you were wondering, “can you get coronavirus from food?” was number one, followed by “can you get coronavirus twice?”)

In short, many Australians are wondering what role phones and mail and/or package deliveries may play in the risk of coronavirus transmission.

To better understand the risk, and what you can do to reduce it, it helps to think about how your phone or mail might come into contact with coronavirus – and what the evidence says about how long it lives on various surfaces.




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What do we know about how long the coronavirus can survive on a phone or mail?

Not a whole lot yet.

There has been some general media reporting on the role that surfaces play in the transmission of this coronavirus, termed SARS-CoV-2. That’s the disease that causes COVID-19.

But the main peer-reviewed journal paper on this topic was published about a week ago by the New England Journal of Medicine.

That paper found:

SARS-CoV-2 was more stable on plastic and stainless steel than on copper and cardboard, and viable virus was detected up to 72 hours after application to these surfaces.

It also noted:

On copper, no viable SARS-CoV-2 was measured after 4 hours […] On cardboard, no viable SARS-CoV-2 was measured after 24 hours.

These might be underestimates. The virus may survive even longer on these surfaces, depending on conditions. That’s because these studies looked at how long the virus would survive when in a “buffer” (a solution in which viruses live in the lab). In real life, they would be in mucous and would be more stable.

The fact that the viruses seemed to last longest on plastic is something of a worry and means that, on phones, the virus could potentially last for days.

It is important to remember this is a new virus and we don’t yet have all the data. New findings are emerging every day.

It’s also possible that, in reality, the virus may last longer on phones than indicated in the recent lab experiments.

CDC data published yesterday detected the faint genetic signature of viruses (viral RNA) which had survived 17 days on surfaces in cruise ships. That doesn’t mean infectious virus particles were found after 17 days – only a part of the virus was detected in this study – but it does suggest there may be some cause for concern regarding how long this coronavirus can last on surfaces. More research is required on this question.

Ideally, you should be cleaning your phones, tablets and keyboards with alcohol wipes – if you can get them.
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How might virus particles end up on a phone?

Talking on the phone generates an invisible spray of airborne droplets. A person with COVID-19 can have a lot of virus in the mucous at the back of their throat, so they’re likely spraying the virus on their phone every time they make a call.

If an infected person hands their phone to someone else, the virus could transfer to the new person’s fingertips, and then into their body if they touch their mouth, eyes or nose. (And remember, not every infected person displays the classic symptoms of fever and cough, and may be infectious before symptoms show).

It’s also possible there is an oral-faecal route for transmission of coronavirus. This coronavirus is often detected in faeces.

That means, for example, that tiny particles of poo generated by flushing a toilet could settle on a toothbrush, on a phone brought into the bathroom or on surfaces/food in an adjoining room. They could then end up in your mouth. At the moment this has not been shown, but it is certainly possible. SARS was sometimes spread by this route.

That’s why frequent handwashing with soap is so crucial.

What about mail?

It is technically possible a package or mail coming to your house is contaminated with virus picked up somewhere along the way by people handling or coughing on it. I think, though, the infection risk is very low because, as the New England Journal of Medicine study found, the survival time on cardboard is thought to be around one day.

And unlike plastic surfaces, cardboard is porous. That means a droplet would probably penetrate into the material and may not be so easily picked up when you touch the package.

The survival time on cardboard is thought to be one day.
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What can I do to reduce my risk?

For starters, do the obvious things: wash hands frequently, reduce your contact with others (and if you do see other people, stay at least 1.5 metres apart, particularly if you are talking). Definitely don’t go out at all if you’re unwell.

Keep your phone to yourself. I’d be very reluctant to share my own phone with anyone right now, especially if they seem unwell.

It’s not clear what role children play in the transmission of this coronavirus but, just in case, children should be washing hands before they touch their parents’ phones. That said, it seems more likely at present that adults give it to children than the other way round.

Ideally, you should be cleaning your phones, tablets and keyboards with alcohol wipes (which need to be around 70% alcohol). They are quite effective at deactivating viruses (if somewhat hard to get now). Most baby wipes only have a low percentage of alcohol so are less effective but just the wiping would help remove virus particles.

In the worst case scenario, you can try using a damp cloth with a small amount of soap and water to clean your phone – but don’t let water get inside your phone and wreck it.

When it comes to mail and package deliveries, try to keep apart from the delivery person. Many delivery people are already forgoing the customary signature on the tablet, meaning you don’t have to touch a device or e-stylus that many others have already handled. You could consider wiping down a package before opening it, and washing your hands well after disposing of the packaging.

At the end of the day, the risk is never zero, and the world is a nightmare if you go too far down this route of worrying about every single surface.




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The Conversation


Euan Tovey, Associate Professor & Principal Research Fellow in Medicine, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How to flatten the curve of coronavirus, a mathematician explains



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Andrew Black, University of Adelaide; Dennis Liu, University of Adelaide, and Lewis Mitchell, University of Adelaide

People travelling into Australia will now have to self-isolate for 14 days – one of a range of measures announced at the weekend by Prime Minister Scott Morrison, with the aim of slowing the spread of the coronavirus and easing the stress on hospital beds.

This general concept of slowing the virus’s spread has been termed “flattening the curve” by epidemiologists – experts who study how often diseases occur in different populations, and why. The term has become widespread on social media as the public is encouraged to practise “social distancing”.

But how does social distancing help to flatten the curve? We can explain by referring to what mathematicians call “exponential growth”.

Exponential growth

In the early stages of an epidemic, when most people are susceptible to infection, mathematicians can model a disease’s spread from person to person as essentially a random “branching process”.

This diagram shows the number of cases, over time, in a branching process with exponential growth. Author Provided.

If one infected person infects two others on average, the number of infected people doubles each generation. This compounding is known as exponential growth.

Of course, an infected person is not definitely going to infect others. There are many factors affecting the likelihood of infection. In a pandemic, the growth rate depends on the average number of people one person can infect, and the time it takes for those people to become infectious themselves.




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Research suggests the number of confirmed COVID-19 cases is growing exponentially worldwide with the number doubling about every six days

Exponential growth models closely match reality when starting with a small number of infected individuals in a large population, such as when the virus first emerged in Wuhan, or when it arrived in Italy or Iran.

But it’s not a good model once a large number of people have been infected. This is because the chance of an infected person contacting a susceptible person declines, simply because there are fewer susceptible people around, and a growing fraction of people have recovered and developed some level of immunity.

Eventually, the chances of an infected person contacting a susceptible person becomes low enough that the rate of infection decreases, leading to fewer cases and eventually, the end of the viral spread.

Flatten the curve

Health authorities around the world have been unable to completely prevent COVID-19’s spread. If cases double every six days, then hospitals, and intensive care units (ICUs) in particular, will be quickly overwhelmed, leaving patients without the necessary care.

But the growth rate can be slowed by reducing the average number of cases that a single case gives rise to.

In doing so, the same number of people will probably be infected, and the epidemic will last longer, but the number of severe cases will be spread out. This means that if you plot a graph of the number of cases over time, the rising and falling curve is longer but its peak is lower. By “flattening the curve” in this way, ICUs will be less likely to run out of capacity.

Flattening the curve is another way of saying slowing the spread. The epidemic is lengthened, but we reduce the number of severe cases, causing less burden on public health systems. The Conversation/CC BY ND

As there is currently no vaccine or specific drug for COVID-19, the only ways we can reduce transmission is through good hygiene, isolating suspected cases, and by social distancing measures such as cancelling large events and closing schools.

Avoid “super-spreaders”

Of course, the situation is not quite as straightforward as a simple branching process. Some people interact more than others, and might come into contact with many different groups.




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Mathematicians model these connections as a social network, such as the one below. Infected people are red nodes, and susceptible people are blue. The large node in the middle of the diagram is a super-spreader, a person who connects with many others, and thus has more potential to spread the disease.

This graph shows how an epidemic might spread across a network over time. Blue dots are susceptible individuals, while red dots are infected people. Two dots are connected by a line if they are in contact with each other, and the more contacts a person has, the bigger their dot is on the network. Author provided

Interventions help remove nodes and break connections.

In the diagram above, the large, highly connected central node would be the best one to remove to break connections. This is why it’s a good idea to avoid large public gatherings during the COVID-19 outbreak.

Mathematical simulations of social distancing have shown how breaking the network apart helps flatten the curve of infection.

How maths is helping

How much social distancing is required to flatten the curve enough to stop hospitals being overwhelmed? Is it enough to quarantine people who have been in contact with confirmed cases? Do we need widespread closure of events, schools and workplaces?

Answers to these questions require mathematical modelling.

We are still in the early stages of the COVID-19 outbreak and there is great uncertainty about the characteristics of this virus. To accurately forecast COVID-19’s growth, the underlying dynamics of transmission need to be determined.

These are driven by factors including:

  • How many people on average does an individual infect? (the “reproduction number” which, according to the World Health Organisation, is currently between 1.4–2.5 people)
  • How long until the onset of symptoms? (the “incubation period”, which is estimated to be 5.1 days)
  • What proportion of transmission occurs prior to the onset of symptoms, if any?

As such data is collected and integrated into models over the coming months, we will be better placed to offer accurate predictions about the course of COVID-19.

Until then, it’s better to err on the side of caution and take swift action to slow transmission, rather than risk a spike in cases, and put strain on our health system.The Conversation

Andrew Black, Lecturer in Applied Mathematics, University of Adelaide; Dennis Liu, PhD Candidate, University of Adelaide, and Lewis Mitchell, Senior Lecturer in Applied Mathematics, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Here’s what you need to know about melioidosis, the deadly infection that can spread after floods



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People typically become sick between one and 21 days after being infected.
Goran Jakus/Shutterstock

Sanjaya Senanayake, Australian National University

The devastating Townsville floods have receded but the clean up is being complicated by the appearance of a serious bacterial infection known as melioidosis. One person has died from melioidosis and nine others have been diagnosed with the disease over the past week.

The bacteria that causes the disease, Burkholderia pseudomallei, is a hardy bug that lives around 30cm deep in clay soil. Events that disturb the soil, such as heavy rains and floods, bring B. pseudomallei to the surface, where it can enter the body through through a small break in the skin (that a person may not even be aware of), or by other means.

Melioidosis may cause an ulcer at that site, and from there, spread to multiple sites in the body via the bloodstream. Alternatively, the bacterium can be inhaled, after which it travels to the lungs, and again may spread via the bloodstream. Less commonly, it’s ingested.




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Melioidosis was first identified in the early 20th century among drug users in Myanmar. These days, cases tend to concentrate in Southeast Asia and the top end of northern Australia.

What are the symptoms?

Melioidosis can cause a variety of symptoms, but often presents as a non-specific flu-like illness with fever, headache, cough, shortness of breath, disorientation, and pain in the stomach, muscles or joints.

People with underlying conditions that impair their immune system – such as diabetes, chronic kidney or lung disease, and alcohol use disorder – are more likely to become sick from the infection.

The majority of healthy people infected by melioidosis won’t have any symptoms, but just because you’re healthy, doesn’t mean you’re immune: around 20% of people who become acutely ill with melioidosis have no identifiable risk factors.

People typically become sick between one and 21 days after being infected. But in a minority of cases, this incubation period can be much longer, with one case occurring after 62 years.

How does it make you sick?

While most people who are sick with melioidosis will have an acute illness, lasting a short time, a small number can have a grumbling infection persisting for months.

One of the most common manifestations of melioidosis is infection of the lungs (pneumonia), which can occur either via infection through the skin, or inhalation of B. pseudomallei.

The challenges in treating this organism, though, arise from its ability to form large pockets of pus (abscesses) in virtually any part of the body. Abscesses can be harder to treat with antibiotics alone and may also require drainage by a surgeon or radiologist.

How is it treated?

Thankfully, a number of antibiotics can kill B. pseudomallei. Those recovering from the infection will need to take antibiotics for at least three months to cure it completely.

If you think you might have melioidosis, seek medical attention immediately. A prompt clinical assessment will determine the level of care you need, and allow antibiotic therapy to be started in a timely manner.

Your blood and any obviously infected body fluids (sputum, pus, and so on) will also be tested for B. pseudomallei or other pathogens that may be causing the illness.

While cleaning up after these floods, make sure you wear gloves and boots to minimise the risk of infection through breaks in the skin. This especially applies to people at highest risk of developing melioidosis, namely those with diabetes, alcohol use disorder, chronic kidney disease, and lung disease.




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The Conversation


Sanjaya Senanayake, Associate Professor of Medicine, Infectious Diseases Physician, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Most people don’t benefit from vaccination, but we still need it to prevent infections



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Everyone has to be vaccinated for immunisation programs to work.
from http://www.shutterstock.com

Allen Cheng, Monash University

A recent article in The Conversation questioned whether we should all get flu vaccinations, given 99 people would have to go through vaccination for one case of flu to be prevented.

But this position ignores the purpose of immunisation programs: whole populations of people need to take part for just a small number to benefit. So how do we decide what’s worth it and what’s not?




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Decision-making in public health

When we consider a treatment for a patient, such as antibiotics for an infection, we first consider the evidence on the benefits and potential harms of treatment. Ideally, this is based on clinical trials, where we assume the proportion of people in the trial who respond represents the chance an individual patient will respond to treatment.

This evidence is then weighed up with the individual patient. What are the treatment options? What do they prefer? Are there factors that might make this patient more likely to respond or have side effects? Is there a treatment alternative they would be more likely to take?

In public health, the framework is the same but the “patient” is different – we are delivering an intervention for a whole population or group rather than a single individual.

We first consider the efficacy of the intervention as demonstrated in clinical trials or other types of studies. We then look at which groups in the population might benefit the most (such as the zoster vaccine, given routinely to adults over 70 years as this group has a high rate of shingles), and for whom the harms will be the least (such as the rotavirus vaccine, which is given before the age of six months to reduce the risk of intussusception, a serious bowel complication).

Compared to many other public health programs, immunisation is a targeted intervention and clinical trials tell us they work. But programs still need to target broad groups, defined by age or other broad risk factors, such as chronic medical conditions or pregnancy.




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Risks and benefits of interventions

When considering vaccination programs, safety is very important, as a vaccine is being given to a generally healthy population to prevent a disease that may be uncommon, even if serious.

For example, the lifetime risk of cervical cancer is one in 166 women, meaning one woman in 166 is diagnosed with this cancer. So even if the human papillomavirus (HPV) vaccine was completely effective at preventing cancer, 165 of 166 women vaccinated would not benefit. Clearly, if we could work out who that one woman was who would get cancer, we could just vaccinate her, but unfortunately we can’t.

It’s only acceptable to vaccinate large groups if clinically important side effects are low. For the HPV vaccine, anaphylaxis (a serious allergic reaction) has been reported, but occurs at a rate of approximately one in 380,000 doses.

An even more extreme case is meningococcal vaccination. Before vaccination, the incidence of meningococcal serogroup C (a particular type of this bacterium) infection in children aged one to four years old was around 2.5 per 100,000 children, or 7.5 cases for 100,000 children over three years.

Vaccination has almost eliminated infection with this strain (although other serotypes still cause meningococcal disease). But this means 13,332 of 13,333 children didn’t benefit from vaccination. Again, this is only acceptable if the rate of important side effects is low. Studies in the US have not found any significant side effects following routine use of meningococcal vaccines.

This is not to say there are no side effects from vaccines, but that the potential side effects of vaccines need to be weighed up against the benefit.

For example, Guillain Barre syndrome is a serious neurological complication of influenza vaccination as well as a number of different infections.

But studies have estimated the risk of this complication as being around one per million vaccination doses, which is much smaller than the risk of Guillain Barre syndrome following influenza infection (roughly one in 60,000 infections). And that’s before taking into account the benefit of preventing other complications of influenza.




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High schools are bigger, so immunisation is easier than at primary schools.
from http://www.shutterstock.com

What other factors need to be considered?

We also need to consider access, uptake and how a health intervention will be delivered, whether through general practices, council programs, pharmacies or school-based programs.

Equity issues must also be kept in mind: will this close the gap in Indigenous health or other disadvantaged populations? Will immunisation benefit more than the individual? What is the likely future incidence (the “epidemic curve”) of the infection in the absence of vaccination?

A current example is meningococcal W disease, which is a new strain of this bacteria in Australia. Although this currently affects individuals in all age groups, many state governments have implemented vaccination programs in adolescents.

This is because young adults in their late teens and early 20s carry the bacteria more than any other group, so vaccinating them will reduce transmission of this strain more generally.

But it’s difficult to get large cohorts of this age group together to deliver the vaccine. It’s much easier if the program targets slightly younger children who are still at school (who, of course, will soon enter the higher risk age group).

In rolling out this vaccine program, even factors such as the size of schools (it is easier to vaccinate children at high schools rather than primary schools, as they are larger), the timing of exams, holidays and religious considerations (such as Ramadan) are also taken into account.




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For government, cost effectiveness is an important consideration when making decisions on the use of taxpayer dollars. This has been an issue when considering meningococcal B vaccine. As this is a relatively expensive vaccine, the Pharmaceutical Benefits Advisory Committee has found this not to be cost effective.

This is not to say that meningococcal B disease isn’t serious, or that the vaccine isn’t effective. It’s simply that the cost of the vaccine is so high, it’s felt there are better uses for the funding that could save lives elsewhere.

While this might seem to be a rather hard-headed decision, this approach frees up funding for other interventions such as expensive cancer treatments, primary care programs or other public health interventions.

Why is this important?

When we treat a disease, we expect most people will benefit from the treatment. As an example, without antibiotics, the death rate of pneumonia was more than 80%; with antibiotics, less than 20%.

The ConversationHowever, vaccination programs aim to prevent disease in whole populations. So even if it seems as though many people are having to take part to prevent disease in a small proportion, this small proportion may represent hundreds or thousands of cases of disease in the community.

Allen Cheng, Professor in Infectious Diseases Epidemiology, Monash University

This article was originally published on The Conversation. Read the original article.

Egyptian Couple Shot by Muslim Extremists Undaunted in Ministry


Left for dead, Christians offer to drop charges if allowed to construct church building.

CAIRO, Egypt, June 9 (CDN) — Rasha Samir was sure her husband, Ephraim Shehata, was dead.

He was covered with blood, had two bullets inside him and was lying facedown in the dust of a dirt road. Samir was lying on top of him doing her best to shelter him from the onslaught of approaching gunmen.

With arms outstretched, the men surrounded Samir and Shehata and pumped off round after round at the couple. Seconds before, Samir could hear her husband mumbling Bible verses. But one bullet had pierced his neck, and now he wasn’t moving. In a blind terror, Samir tried desperately to stop her panicked breathing and convincingly lie still, hoping the gunmen would go away.

Finally, the gunfire stopped and one of the men spoke. “Let’s go. They’re dead.”

 

‘Break the Hearts’

On the afternoon of Feb. 27, lay pastor Shehata and his wife Samir were ambushed on a desolate street by a group of Islamic gunmen outside the village of Teleda in Upper Egypt.

The attack was meant to “break the hearts of the Christians” in the area, Samir said.

The attackers shot Shehata twice, once in the stomach through the back, and once in the neck. They shot Samir in the arm. Both survived the attack, but Shehata is still in the midst of a difficult recovery. The shooters have since been arrested and are in jail awaiting trial. A trial cannot begin until Shehata has recovered enough to attend court proceedings.

Despite this trauma, being left with debilitating injuries, more than 85,000 Egyptian pounds (US$14,855) in medical bills and possible long-term unemployment, Shehata is willing to drop all criminal charges against his attackers – and avoid what could be a very embarrassing trial for the nation – if the government will stop blocking Shehata from constructing a church building.

Before Shehata was shot, one of the attackers pushed him off his motorcycle and told him he was going to teach him a lesson about “running around” or being an active Christian.

Because of his ministry, the 34-year-old Shehata, a Coptic Orthodox Christian, was arguably the most visible Christian in his community. When he wasn’t working as a lab technician or attending legal classes at a local college, he was going door-to-door among Christians to encourage them in any way he could. He also ran a community center and medical clinic out of a converted two-bedroom apartment. His main goal, he said, was to “help Christians be strong in their faith.”

The center, open now for five years, provided much-needed basic medical services for surrounding residents for free, irrespective of their religion. The center also provided sewing training and a worksite for Christian women so they could gain extra income. Before the center was open in its present location, he ran similar services out of a relative’s apartment.

“We teach them something that can help them with the future, and when they get married they can have some way to work and it will help them get money for their families,” Shehata said.

Additionally, the center was used to teach hygiene and sanitation basics to area residents, a vital service to a community that uses well water that is often polluted or full of diseases. Along with these services, Shehata and his wife ran several development projects, repairing the roofs of shelters for poor people, installing plumbing, toilets and electrical systems. The center also distributed free food to the elderly and the infirm.

The center has been run by donations and nominal fees used to pay the rent for the apartment. Shehata has continued to run the programs as aggressively as he can, but he said that even before the shooting that the center was barely scraping by.

“We have no money to build or improve anything,” he said. “We have a safe, but no money to put in it.”

 

Tense Atmosphere

In the weeks before the shooting, Teleda and the surrounding villages were gripped with fear.

Christians in the community had been receiving death threats by phone after a Muslim man died during an attack on a Christian couple. On Feb. 2, a group of men in nearby Samalout tried to abduct a Coptic woman from a three-wheeled motorcycle her husband was driving. The husband, Zarif Elia, punched one of the attackers in the nose. The Muslim, Basem Abul-Eid, dropped dead on the spot.

Elia was arrested and charged with murder. An autopsy later revealed that the man died of a heart attack, but local Muslims were incensed.

Already in the spotlight for his ministry activities, Shehata heightened his profile when he warned government officials that Christians were going to be attacked, as they had been in Farshout and Nag Hammadi the previous month. He also gave an interview to a human rights activist that was posted on numerous Coptic websites. Because of this, government troops were deployed to the town, and extremists were unable to take revenge on local Christians – but only after almost the
entire Christian community was placed under house arrest.

“They chose me,” Shehata said, “Because they thought I was the one serving everybody, and I was the one who wrote the government telling them that Muslims were going to set fire to the Christian houses because of the death.”

Because of his busy schedule, Shehata and Samir, 27, were only able to spend Fridays and part of every Saturday together in a village in Samalut, where Shehata lives. Every Saturday after seeing Samir, Shehata would drive her back through Teleda to the village where she lives, close to her family. Samalut is a town approximately 105 kilometers (65 miles) south of Cairo.

On the afternoon of Feb. 27, Shehata and his wife were on a motorcycle on a desolate stretch of hard-packed dirt road. Other than a few scattered farming structures, there was nothing near the road but the Nile River on one side, and open fields dotted with palm trees on the other.

Shehata approached a torn-up section of the road and slowed down. A man walked up to the vehicle carrying a big wooden stick and forced him to stop. Shehata asked the man what was wrong, but he only pushed Shehata off the motorcycle and told him, “I’m going to stop you from running around,” Samir recounted.

Shehata asked the man to let Samir go. “Whatever you are going to do, do it to me,” he told the man.

The man didn’t listen and began hitting Shehata on the leg with the stick. As Shehata stumbled, Samir screamed for the man to leave them alone. The man lifted the stick again, clubbed Shehata once more on the leg and knocked him to the ground. As Shehata struggled to get up, the man took out a pistol, leveled it at Shehata’s back and squeezed the trigger.

Samir started praying and screaming Jesus’ name. The man turned toward her, raised the pistol once more, squeezed off another round, and shot Samir in the arm. Samir looked around and saw a few men running toward her, but her heart sank when she realized they had come not to help them but to join the assault.

Samir jumped on top of Shehata, rolled on to her back and started begging her attackers for their lives, but the men, now four in all, kept firing. Bullets were flying everywhere.

“I was scared. I thought I was going to die and that the angels were going to come and get our spirits,” Samir said. “I started praying, ‘Please God, forgive me, I’m a sinner and I am going to die.’”

Samir decided to play dead. She leaned back toward her husband, closed her eyes, went limp and tried to stop breathing. She said she felt that Shehata was dying underneath her.

“I could hear him saying some of the Scriptures, the one about the righteous thief [saying] ‘Remember me when you enter Paradise,’” she said. “Then a bullet went through his neck, and he stopped saying anything.”

Samir has no way of knowing how much time passed, but eventually the firing stopped. After she heard one of the shooters say, “Let’s go, they’re dead,” moments later she opened her eyes and the men were gone. When she lifted her head, she heard her husband moan.

 

Unlikely Survival

When Shehata arrived at the hospital, his doctors didn’t think he would survive. He had lost a tremendous amount of blood, a bullet had split his kidney in two, and the other bullet was lodged in his neck, leaving him partially paralyzed.

His heartbeat was so faint it couldn’t be detected. He was also riddled with a seemingly limitless supply of bullet fragments throughout his body.

Samir, though seriously injured, had fared much better than Shehata. The bullet went into her arm but otherwise left her uninjured. When she was shot, Samir was wearing a maternity coat. She wasn’t pregnant, but the couple had bought the coat in hopes she soon would be. Samir said she thinks the gunman who shot her thought he had hit her body, instead of just her arm.

The church leadership in Samalut was quickly informed about the shooting and summoned the best doctors they could, who quickly traveled to help Shehata and Samir. By chance, the hospital had a large supply of blood matching Shehata’s blood type because of an elective surgical procedure that was cancelled. The bullets were removed, and his kidney was repaired. The doctors however, were forced to leave many of the bullet fragments in Shehata’s body.

As difficult as it was to piece Shehata’s broken body back together, it paled in comparison with the recovery he had to suffer through. He endured multiple surgeries and was near death several times during his 70 days of hospitalization.

Early on, Shehata was struck with a massive infection. Also, because part of his internal tissue was cut off from its blood supply, it literally started to rot inside him. He began to swell and was in agony.

“I was screaming, and they brought the doctors,” Shehata said. The doctors decided to operate immediately.

When a surgeon removed one of the clamps holding Shehata’s abdomen together, the intense pressure popped off most of the other clamps. Surgeons removed some stomach tissue, part of his colon and more than a liter of infectious liquid.

Shehata could not eat normally and lost 35 kilograms (approximately 77 lbs.). He also couldn’t evacuate his bowels for at least 11 days, his wife said.

Despite the doctors’ best efforts, infections continued to rage through Shehata’s body, accompanied by alarming spikes in body temperature.

Eventually, doctors sent him to a hospital in Cairo, where he spent a week under treatment. A doctor there prescribed a different regimen of antibiotics that successfully fought the infection and returned Shehata’s body temperature to normal.

Shehata is recovering at home now, but he still has a host of medical problems. He has to take a massive amount of painkillers and is essentially bedridden. He cannot walk without assistance, is unable to move the fingers on his left hand and cannot eat solid food. In approximately two months he will undergo yet another surgery that, if all goes well, will allow him to use the bathroom normally.

“Even now I can’t walk properly, and I can’t lift my leg more than 10 or 20 centimeters. I need someone to help me just to pull up my underwear,” Shehata said. “I can move my arm, but I can’t move my fingers.”

Samir does not complain about her condition or that of Shehata. Instead, she sees the fact that she and her husband are even alive as a testament to God’s faithfulness. She said she thinks God allowed them to be struck with the bullets that injured them but pushed away the bullets that would have killed them.

“There were lots of bullets being shot, but they didn’t hit us, only three or four,” she said. “Where are the others?”

Even in the brutal process of recovery, Samir found cause for thanks. In the beginning, Shehata couldn’t move his left arm, but now he can. “Thank God and thank Jesus, it was His blessing to us,” Samir said. “We were kind of dead, now we are alive."

Still, Samir admits that sometimes her faith waivers. She is facing the possibility that Shehata might not work for some time, if ever. The couple owes the 85,000 Egyptian pounds (US$14,855) in medical bills, and continuing their ministry at the center and in the surrounding villages will be difficult at best.

“I am scared now, more so than during the shooting,” she said. “Ephraim said do not be afraid, it is supposed to make us stronger.”

So Samir prays for strength for her husband to heal and for patience. In the meantime, she said she looks forward to the day when the struggles from the shooting are over and she can look back and see how God used it to shape them.

“There is a great work the Lord is doing in our lives, we may not know what the reason is now, but maybe some day we will,” Samir said.

 

Government Opposition

For the past 10 years, Shehata has tried to erect a church building, or at a minimum a house, that he could use as a dedicated community center. But local Muslims and Egypt’s State Security Investigations (SSI) agency have blocked him every step of the way. He had, until the shooting happened, all but given up on constructing the church building.

On numerous occasions, Shehata has been stopped from holding group prayer meetings after people complained to the SSI. In one incident, a man paid by a land owner to watch a piece of property near the community center complained to the SSI that Shehata was holding prayer meetings at the facility. The SSI made Shehata sign papers stating he wouldn’t hold prayer meetings at the center.

At one time, Shehata had hoped to build a house to use as a community center on property that had been given to him for that purpose. Residents spread a rumor that he was actually erecting a church building, and police massed at the property to prevent him from doing any construction.

There is no church in the town where Shehata lives or in the surrounding villages. Shehata admits he would like to put up a church building on the donated property but says it is impossible, so he doesn’t even try.

In Egypt constructing or even repairing a church building can only be done after a complex government approval process. In effect, it makes it impossible to build a place for Christian worship. By comparison, the construction of mosques is encouraged through a system of subsidies.

“It is not allowed to build a church in Egypt,” Shehata said. “We can’t build a house. We can’t build a community center. And we can’t build a church.”

Because of this, Shehata and his wife organize transportation from surrounding villages to St. Mark’s Cathedral in Samalut for Friday services and sacraments. Because of the lack of transportation options, the congregants are forced to ride in a dozen open-top cattle cars.

“We take them not in proper cars or micro-buses, but trucks – the same trucks we use to move animals,” he said.

The trip is dangerous. A year ago a man fell out of one of the trucks onto the road and died. Shehata said bluntly that Christians are dying in Egypt because the government won’t allow them to construct church buildings.

“I feel upset about the man who died on the way going to church,” he said.

 

Church-for-Charges Swap

The shooters who attacked Shehata and Samir are in jail awaiting trial. The couple has identified each of the men, but even if they hadn’t, finding them for arrest was not a difficult task. The village the attackers came from erupted in celebration when they heard the pastor and his wife were dead.

Shehata now sees the shooting as a horrible incident that can be turned to the good of the believers he serves. He said he finds it particularly frustrating that numerous mosques have sprouted up in his community and surrounding areas during the 10 years he has been prevented from putting up a church building, or even a house. There are two mosques alone on the street of the man who died while being trucked to church services, he said.

Shehata has decided to forgo justice in pursuit of an opportunity to finally construct a church building. He has approached the SSI through church leaders, saying that if he is allowed to construct a church building, then he will take no part in the criminal prosecution of the shooters.

“I have told the security forces through the priests that I will drop the case if they can let us build the church on the piece of land,” he said.

The proposal isn’t without possibilities. His trial has the potential of being internationally embarrassing. It raises questions about fairness in Egyptian society during an upcoming presidential election that will be watched by the world.

Regardless of what happens, Shehata said all he wants is peace and for the rights of Christians to be respected. He said that in Egypt, Christians have less value than the “birds of the air” mentioned in the Bible. According to Luke 12:6, five sparrows sold for two pennies in ancient times.

“We are not to be killed like birds, slaughtered,” he said. “We are human.”

Report from Compass Direct News

Iranian Authorities Release Assyrian Pastor on Bail


Accused of ‘converting Muslims,’ church leader faces trial – and threat of murder.

ISTANBUL, April 5 (CDN) — An Assyrian pastor the Iranian government accused of “converting Muslims” has been released from prison on bail and is awaiting trial.

The Rev. Wilson Issavi, 65, was released from Dastgard prison in Isfahan last week. Conflicting reports indicated Issavi was released sometime between Sunday (March 28) and Tuesday morning (March 30).

On Feb. 2, State Security Investigations (SSI) agents arrested Issavi shortly after he finished a house meeting at a friend’s home in Isfahan. Along with the accusation of “converting Muslims,” the pastor is charged with not co-operating with police, presumably for continuing to hold such house meetings after police sealed the Evangelical Church of Kermanshah and ordered him not to reopen it.

After his arrest, Issavi was held at an unmarked prison facility in Isfahan and apparently tortured, according to a Christian woman who fled Iran and knows Issavi and his family. The Christian woman, who requested anonymity for security reasons, said Issavi’s wife, Medline Nazanin, visited the pastor at the unmarked facility. Nazanin said it was obvious Issavi had been tortured, the Christian told Compass.

Issavi’s confinement cells were so filthy he contracted a life-threatening infection, Nazanin told the Christian woman.

“They took him to the hospital and then returned him back to the prison,” the woman said.

Friends of Issavi added that he is still dealing with the lingering effects of the infection.

During Issavi’s imprisonment, authorities threatened to execute him, sources close to the case said. The joy of Issavi’s family at his release was tinged with fear as they waited in agony for the possibility of him being killed by Islamic extremists, as is common in Iran when Christians are detained for religious reasons and then released.

“Sometimes they release you just to kill you,” the Christian source said.

Issavi has not been informed of his trial date.

Issavi’s friend said that low-key ethnic Christians, such as the Assyrians, are largely unbothered for long periods of time. Active Christians are treated differently.

“When you start evangelizing, then you are in real trouble,” she said.

Iranian authorities have set up a video camera outside Issavi’s church to monitor anyone going in or out of the building, according to the pastor’s friend.

Issavi was one of a few Christians in leadership positions arrested in Isfahan in February during what some Middle Eastern experts described as a crackdown on area church leadership.

Isfahan, a city of more than 1.5 million people located 208 miles (335 kilometers) south of Tehran, has been the site of other anti-Christian persecution. In an incident in July 2008, two Christians died as a result of injuries received from police who were breaking up a house meeting.

On Feb. 28, Isfahan resident Hamid Shafiee and his wife Reyhaneh Aghajary, both converts from Islam and house church leaders, were arrested at their home.

Police handcuffed, beat and pepper-sprayed Aghajary and then took her to prison. Her husband Shafiee, who was away from the house when police arrived, was arrested an hour later when he returned to the house. Approximately 20 police officers raided the home, seizing Bibles, CDs, photographs, computers, telephones, personal items and other literature.

The couple is still being held. Other details about their detainment are unknown.

Three Christians Released

Elsewhere, three Christians arrested on Dec. 24, 2009 have been released, according to Farsi Christian News Network (FCNN).

Maryam Jalili, Mitra Zahmati, and Farzan Matin were initially arrested along with 12 other Christians at a home in Varamin. Eventually they were transferred to Tehran’s notorious Evin Prison, though the other 12 prisoners were conditionally released on Jan. 4. 

Jalili, Zahmati and Matin were freed on March 17, though terms of their release were unclear. Jalili is married and has two children.

Iran has a longstanding history of religious repression. Shia Islam is the official state religion and is ensconced as such in Iran’s constitution. Every year since 1999, the U.S. Secretary of State has designated Iran as a “Country of Particular Concern” for its persecution of Christians and other religious minorities.

According to the 2009 International Religious Freedom Report issued by the U.S. Department of State, persecution of Christians and other religious minorities in Iran continued to get significantly worse.

“Christians, particularly evangelicals, continued to be subject to harassment and close surveillance,” the report states. “The government vigilantly enforced its prohibition on proselytizing by closely monitoring the activities of evangelical Christians, discouraging Muslims from entering church premises, closing churches, and arresting Christian converts.”

Report from Compass Direct News 

Iranian Christian was arrested and took to unknown place


Farsi Christian News Network (FCNN), reports that at 8 am on December 16, 2009, several security officers entered the home of Hamideh Najafi, a Christian lady who resides in the city of Mashhad, and not only searched her home thoroughly, but also arrested and took her away to an unknown location.

According to this news three security officers, two female and one male, who carried an order for arrest from the Revolutionary Court of Mashhad, entered the home of this lady and after searching the her home seized her personal belongings along with books, CDs, and hand painted portraits of Jesus Christ that were hanging on her walls. According to these officers the existence of these pictures will be sufficient evidence that would convict her in court.

Even though Mashhad is the birthplace of Ayatollah Khamenei, the supreme leader of the Islamic Republic, and is considered one of the holiest centers of the Shiite faith (Ghom being the other center in Iran) and also a center of pilgrimage and theological schools, in the recent years there have been significant growth of the underground home based churches.

Mashhad is an ultra-religious city where Rev. Hossein Soodmand, one of the recent Martyrs of the church in Iran was executed on December 3, 1990 at the Mashhad prison and was buried in a trash dump site outside of the city.

According to FCNN, after 10 days of her arrest there has been no telephone contact or visitation granted to the family of Hamideh.

Despite the worries about her well-being and the location of her detention, coupled with her husband’s frantic efforts to contact the Revolutionary Court of Mashhad in order to have information as to the nature of the charges against Hamideh, unfortunately as of now the officials have refused to provide any answers or information. When her husband finally decided to retain a lawyer in order to investigate his wife’s condition, the court officials notified him that the accusations were political in nature and she would be charged for contacting foreign Christian television networks.

This incident is based on the yet-to-be-defined laws of the Islamic Republic of Iran regarding what constitutes a political crime and calling a religious television program does not constitute a political crime.

Its is probable that Hamideh Najafi is currently being held at a detention center on the Vakil Abbad Blvd., next to the Mashhad prison, in order to be fully interrogated and confessions be obtained for future court trial.

She has a 10 years old daughter that is currently suffering from a severe kidney and bladder infection that only her mother is capable of nursing her. According to news received this little girl’s condition, due to missing her mother and being away from her, is not well at all and during the last 10 days, she has not been able to attend school.

The Committee of Christian Activists of the Human Rights in Iran, not only expresses its serious concerns regarding the condition of this Christian woman and the baseless accusations of political crimes that have been filed against her, but it is equally worried about the physical and psychological condition of the 10 years old daughter of Hamideh Najafi who needs her mother, and demands an immediate investigation and speedy freedom of this Christian lady.

Report from the Christian Telegraph