Media hype and increased testing: this year’s flu numbers are high, but there’s more to the story

Posted on July 25, 2019 by particularkev

The media suggests we’re in the midst of a horror flu season, but there are nuances to consider.
From shutterstock.com

Over recent months, the news has been saturated with headlines claiming we’re experiencing a “killer flu season”. Researchers watching laboratory data are using the term “flunami”.

Data suggests this is a serious year for the flu, with a higher number of cases, hospitalisations and deaths recorded than at the same time point in previous years. But there’s more to the story.

Increased testing for influenza and a very early start to the flu season have driven these high figures. Meanwhile, we’ve seen heightened community awareness and concern as the media continue to report on the high numbers of flu cases.

Increased concern leads to increased testing

Tragically, influenza causes deaths every year, including among infants and healthy young people. This still comes as a surprise to many. News coverage of these deaths presents human stories that make the risk feel real and threatening.

We can see the impact of this by looking at the trends in Google searches for “flu deaths” and “flu symptoms” in Australia this year. The steep rise is closely aligned with media reporting of deaths from early May.

The Google search interest in deaths in 2019 dwarfs the 2017 interest, when media reports of influenza deaths appeared more sporadically.

The fear of a uniquely severe and dangerous flu season leads more people to go to their GP or emergency department for an assessment if they’re experiencing flu-like symptoms. In turn, it may also lead more doctors to test for influenza, resulting in increased influenza counts.

Every Monday morning in winter our Flutracking survey asks around 45,000 Australians about their influenza-like symptoms (fever and cough). We also ask ill Flutrackers if their doctor tested them for influenza.

Every year, more and more Flutrackers answer yes. Comparing the percentage of Flutrackers with cough and fever who reported being tested for influenza during April and May increased markedly from 2016, with a very significant increase in 2019.

The season is earlier, but it’s not more severe

Since at least 2011, there has been an increasing summer to autumn blip in influenza activity. That trend has been particularly pronounced this year.

Systems like Flutracking are showing higher levels of influenza-like illness for this time of year, but the figures are not nearly as high as the typical August to September peak seen over the last five years.

Flutracking is not perfect, tracking only “influenza-like” symptoms. Influenza surveillance relies on multiple imperfect streams of data; each contribute to our understanding of the whole picture.

Another system providing objective information on the severity of influenza is the New South Wales death registration data. It showed a few unseasonal spikes in February and March, but is otherwise low and around half the rate we see in the middle of a typical influenza season.

Hospitalisation rates for influenza are high across many hospitals for this time of year, and some may approach peak winter rates seen in 2017. But looking at the proportion of patients admitted to hospital with the flu requiring intensive care, there’s no indication the early influenza season is deadlier than usual.

The simplest way to describe the season is early, but average so far. The rates of influenza are high for this time of year, but the illness is no more severe compared to the typical peak we see in the middle of winter.

Comparing 2019 to 2018, which was a very mild year, further exaggerates the difference.

So when will it end?

In describing the season as “early”, the question arises as to how long it will last. No one knows. The dynamics of an influenza season are a mix of the particular strains circulating, underlying population immunity to the circulating strains from past infection or immunisation, levels of population density and interactions, and weather – all highly unpredictable factors.

If there is no change in the circulating strains then it’s possible the number of susceptible people in the community could be exhausted and the influenza season could “burn out”. If not, it could be a big year for influenza.

Note that this is a broad brush overview of a large country. Western Australia appears to be having a different experience this year with very high rates of laboratory notifications and influenza related hospitalisations. After experiencing a series of mild influenza seasons it may now have a much larger pool of people susceptible to influenza infection.

How worried should you be?

So far, the season is early but average. It’s not the worst flu season on record and not a “flunami”.

Is there any harm in the media being hyperbolic about the nature of each flu season? Some see no downside in using media interest as an opportunity to educate the public about influenza or promote research.

At the same time, there is a danger in tying reasonable public health advice to unreliable interpretations of what is actually happening. Crying wolf may undermine trust in public health messaging.

Hopefully, the messages around flu remain clear. You don’t want to get influenza, and if you do get it, you don’t want to spread it to other people. Immunisation, hand hygiene, anti-viral treatment and staying home if ill can all help.

If you would like to help Flutracking track the flu near you, you can join at Flutracking.net.

Sandra Carlson, the Flutracking senior analyst, contributed to this article.

Craig Dalton, Conjoint Senior Lecturer School of Medicine and Public Health, University of Newcastle

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

Hand sanitisers in public won’t wipe out the flu but they might help reduce its spread

Posted on July 19, 2019 by particularkev

It’s quicker to use hand sanitiser than soap and water, which means people might be more likely to use it.
Shutterstock

Trent Yarwood, The University of Queensland

This year’s flu season is off to an early start, with 144,000 confirmed cases so far in 2019. That’s more than twice as many confirmed cases of the flu than for all of 2018 (58,000), and almost as many as the 2017 horror flu season (251,000).

The number of cases so far this year, including more than 231 deaths nationwide, led the NSW opposition health spokesperson to call for hand sanitisers in public spaces to help slow the spread.

Influenza spreads via droplets from coughing and sneezing, which is why it’s a good idea to catch your cough. But coughing into your hand can leave flu virus on your hands, which is why we recommend coughing into your elbow or sleeve and washing your hands afterwards.

Along with getting vaccinated and staying home if you’re sick, washing your hands is the best defence against getting the flu.

If the government can make this easier by providing hand sanitisers in public places, it may be worth the investment. It won’t solve our flu problem but it might be an important tool in the toolbox of measures to reduce its spread.

What does the research say?

The scientific literature on hand sanitisers isn’t so clear-cut.

A 2019 study in university colleges showed the use of hand hygiene and face masks didn’t protect against flu any better than mask use alone. But unlike some other countries, Australia doesn’t have a strong habit of mask use when people are unwell, so this may not be very helpful to us.

A 2014 study in New Zealand schools showed that providing sanitiser didn’t reduce the rate of absenteeism from school either.

While these studies make it sound like hand sanitiser is not very effective, that’s not the end of the story.

Other studies show a positive effect – a 16% reduction in respiratory illness in one and a 21% reduction in another. For some infections, the evidence is even stronger – for example, gastroenteritis, most of which is also viral.

However, few of these studies showing the benefits of hand sanitisers were done during a large disease outbreak, which means the potential benefit may be even greater.

Not all influenza-like illness is caused by the flu – it can be other viruses as well, so the estimates are a bit rubbery at best. Hand sanitiser trials which look at influenza-like illness or respiratory infections generally are more likely to show benefits than those that just look for influenza – meaning good hand hygiene prevents other infections as well.

If you have the flu, the best place to be is at home.
Tero Vesalainen/Shutterstock

Lessons from hospitals

Although preventing infection in hospitals is not the same as doing it in the community, there are two important lessons from hospital infection control.

First, in hospital hand-hygiene programs, hand sanitiser is more effective than soap-and-water hand-washing, provided your hands aren’t visibly dirty.

This is partly because of the rapid effect of the alcohol, but mostly because it’s much quicker and therefore more likely that staff will use it.

The second important point from hand hygiene and other areas of hospital infection control is that introducing a “bundle” of strategies usually reduces healthcare-associated infection rates – even when the individual parts of these bundles don’t show benefits alone.

This could be because the individual effect sizes are too small, or that change in practice highlights a “safety culture”.

Sanitisers can be one of many strategies

Installing hand rub in public areas won’t solve this year’s flu outbreak by itself. But it can be part of a bundle of strategies – as long as the dispensers are kept topped up.

And it’s certainly a safe intervention – despite some desperate hysteria about the safety of hand gels, or the risk of people drinking them, there is little evidence this actually occurs in reality.

Hand sanitiser is also likely to be easier to implement than fixing the much larger social problem of Australians going to work when they’re sick. This may be because of inadequate sick leave, concerns about “letting the team down”, or other logistical problems such as child-care.

Get your flu vaccine – even now it’s still not too late – and get it for your kids as well, for their sake as well as your own.

Remember to stay home if you’re unwell, and always to cough into your sleeve. And don’t forget to clean your hands – even if the government doesn’t end up making it easier for you.

Trent Yarwood, Infectious Diseases Physician, Senior Lecturer, James Cook University and, The University of Queensland

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

It’s a bad year for flu, but it’s too early to call it the worst ever – 5 charts on the 2019 season so far

Posted on July 17, 2019 by particularkev

The impact of the flu on a population can be measured by looking at figures including cases, hospitalisations and deaths.
From shutterstock.com

Ian Barr, WHO Collaborating Centre for Reference and Research on Influenza

From early this year it’s been apparent the 2019 Australian influenza “season” was going to be different. Normally, the flu season coincides with the winter months of July and August, sometimes stretching to September and October.

But this year, things have happened much earlier, with a record number of influenza cases reported in summer and autumn.

So what’s been happening, and is it really as bad as the media have been reporting? Here we look at some of the latest data on cases and their outcomes to see if it is indeed “a horror flu season”.

The impact of influenza on the community is measured in several ways. The most basic measure is to simply count the number of cases of people presenting to their GP with influenza-like illness.

Sometimes the doctor will take a swab, and these are tested in the laboratory to confirm that influenza virus is present (it’s possible another respiratory virus or bacteria might be causing the flu-like symptoms).

Cases of influenza-like illness were increasing in early March, peaked in early June, and are now decreasing. Laboratory confirmed cases (the results of which we see in the above chart) show a similar trend. We haven’t included July in this chart because it’s not finished yet, but we’re still seeing a high number of cases into July.

Compared to previous years, 2019 looks like a big year with more than 120,000 cases of lab confirmed influenza up to the end of June. But it’s not nearly as bad as 2017, which had more than 250,000 cases reported to the National Notifiable Diseases Surveillance System (NNDSS) by the end of the year. As this season occurred much later than 2019’s, 2017 had only 24,000 cases reported up to July 7.

The good news is that as the 2019 season started earlier, it’s also likely to finish earlier than usual. This is because once the main influenza season starts, it usually ends around 12-16 weeks later, when the number of susceptible people drops below the level required to maintain efficient circulation.

FluCAN (via Department of Health Influenza Surveillance Report), CC BY-ND

Another measure of how severe the influenza season is can be gauged by the number of hospitalisations, including admissions to ICU (intensive care units).

Hospital admissions show from April 1 to June 30 this year, there have been 1,309 admissions to the Australian sentinel surveillance hospitals (a number of hospitals where flu admissions are tracked each year).

This figure is much higher than previous years at the same time point. In 2018, there were 90 admissions, and in 2017, 311. But in 2017 the season arrived much later and more seriously and ultimately resulted in 3,969 admissions for that year.

It’s also useful to look at the proportion of people attending hospital with influenza infections who are admitted directly to ICU. In 2019 it’s been 6.7% of admissions compared to 2018 (a mild influenza year) with 8.1% of admissions, and 2017 (a very severe year) with 8.9% of admissions.

The 2019 ICU rate is at the lower end of historical figures which range from 8.7% in 2015 to 14.2% in 2013. By this measure, the 2019 season is of a similar severity to that seen in previous seasons and is therefore not exceptional.

While hospital admissions can be measured relatively easily, measuring deaths due to influenza is more complicated for a few reasons. The flu often paves the way for secondary bacterial infections, like pneumonia, which can lead to hospitalisation and death, particularly in the elderly. When this happens, it can be difficult to link death directly to an earlier influenza infection.

And, death data is often very delayed. So readily available death data collected by the NNDSS is considered a significant underestimate of the actual number.

To the end of June 2019, there were 231 influenza-related deaths reported to the NNDSS. Virtually all of these were due to the influenza A strain. They spanned all ages, but most deaths were in the elderly (80 years and older).

This compares to 24 and 21 deaths over the same period in 2018 and 2017 respectively. But these figures grew to 55 deaths and 598 deaths reported by the end of 2018 and 2017 respectively.

Clearly 2019 is more severe than 2018, based on the measures detailed above, but at this stage it looks like it will be less severe than 2017. However, we’ll need to wait for a number of weeks yet to be sure.

When we look at what’s happened in each state of Australia so far this year, we see some interesting differences in how the season has played out. Most states began to see significant rises in cases in April, while South Australia had already peaked in April and this number of cases was maintained into May. This means that most other states still have a number of weeks of influenza circulation to endure.

People of all ages are susceptible to influenza, and this is reflected in the wide range of ages at which people are infected. Young children (especially those under 10 years of age) and the elderly (especially those over 80 years of age) are more susceptible, and are often more severely affected by influenza infections – as are pregnant women.

Interestingly, different types of influenza affect different age groups, with influenza B and influenza A(H1N1) more common in the young and influenza A(H3N2) more common in the elderly.

At this stage we can conclude that the 2019 influenza season is quite different to our usual seasons and overall, is likely to be one of the more severe seasons seen in the last 20 years.

So while 2019 doesn’t appear to be the worst season we’ve ever seen – that’s likely to remain with 2017 – it may well run a close second place. But we’ll have to wait another month or two before we can be sure.

Ian Barr, Deputy Director, WHO Collaborating Centre for Reference and Research on Influenza

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

The 2019 flu shot isn’t perfect – but it’s still our best defence against influenza

Posted on July 13, 2019 by particularkev

Early indications are that the vaccine has been a reasonably good match in the 2019 season.
Shutterstock

Lauren Bloomfield, Edith Cowan University

Over recent months, reports of “a horror flu season” causing serious illness and death have dominated the headlines.

The high number of cases has led some people to question the effectiveness of the flu vaccine, and whether it’s worth getting if it doesn’t guarantee you won’t get the flu.

The flu vaccine is designed to cover the strains of the flu anticipated to circulate during the season. But even with the most sophisticated scientific processes, determining the right strains to include in the vaccine isn’t 100% foolproof.

Sometimes the virus undergoes major genetic changes or “mutations” in a relatively short space of time. Reports of a “mutant strain” this year means there’s concern some people might catch a strain the vaccine hasn’t protected against.

It’s too soon to tell the full extent of the effects of this mutation on how well the vaccine has worked. But the 2019 vaccine is showing early signs of being a good match for the common strains of the flu circulating this season.

What’s in a name?

Influenza or “flu” isn’t just one virus; different strains circulate each season.

Flu viruses that cause seasonal epidemics in humans fit under one of two major groups: influenza A or B.

Most flu vaccines protect against four strains of influenza.
Image Point Fr/Shutterstock

Influenza A is further broken down into strains or subtypes based on surface proteins called hemagglutinin (H) and neuraminidase (N).

We’re currently concerned about two subtypes which cause outbreaks in humans: A/H1N1pdm09 and A/H3N2.

Influenza B viruses are similarly categorised into strains based on two distinct lineages: B/Yamagata and B/Victoria.

Understanding the circulating strains is important because it gives us clues as to which age groups will likely be worst affected. Influenza A/H3, for example, has historically been associated with higher rates of disease in people aged 65 and over.

But the circulating strains are also important because they inform how the vaccine will be developed. A good match between the vaccine strains and what is circulating will mean the vaccine offers the best possible protection.

So how do we decide which flu strains are covered by the vaccine?

Every year, a new vaccine is produced to cover the strains that are predicted to be circulating in the northern and southern hemispheres. The World Health Organisation (WHO) uses a range of measures to determine which strains should be included in the vaccine.

Many of us who were vaccinated this year would have received a quadrivalent vaccine. This means it covered four strains in total: two strains of influenza A, and two strains of influenza B.

People aged 65 and over are offered a “high-dose” trivalent vaccine, which covers both A strains, and one B strain.

The Australian Influenza Vaccine Committee (AIVC) reviews the results and makes recommendations for the Australian vaccine, which in 2019 covered the following strains:

an A/Michigan/45/2015 (H1N1)pdm09-like virus
an A/Switzerland/8060/2017 (H3N2)-like virus
a B/Colorado/06/2017-like virus (Victoria lineage) – not included in the trivalent vaccine recommendation
a B/Phuket/3073/2013-like virus (Yamagata lineage).

Do we always get it right?

The basic premise of forecasting is that it’s a “best guess”. It’s a highly educated guess, based on analysis and evaluation, but it’s not a guarantee.

The effectiveness of a vaccine depends on a number of factors, only some of which are within our control. While the choice for the vaccine is made on the best evidence available at the time, the viruses circulating in the population undergo changes as they replicate, known as antigenic “drift” and “shift”.

Flu viruses change every year so researchers have to make an educated guess about which ones might circulate.
Image Point Fr/Shutterstock

If the changes are only small, we can still get good cross-protection.

Less frequently, a big genetic “shift” happens. If this occurs after vaccine development has started and the strains have been chosen, we are dealing with a so-called “mutant flu” and the vaccine will likely not be a good match.

So is this year’s vaccine is working?

Data available for this year are showing the majority of influenza cases in Australia have been influenza A – with some states reporting more H3N2 than H1N1, and others reporting a more even mix of both.

The WHO Collaborating Centre in Victoria is also reporting that the majority of specimens of all four strains they’ve tested this year appear to be similar to the vaccine strains.

While early indications are that the vaccine has been a good match in the 2019 season, the WHO Collaborating Centre has also recently confirmed there has been a mutation in the A/H3N2 strain this season.

It’s not clear yet if this mutation will have a significant impact on vaccine effectiveness, but it may at least partially explain the high case numbers we’ve seen so far.

Large vaccine effectiveness studies done at the end of the flu season will help assess the impact of this mutation. In the meantime, a mismatch on only one strain means the vaccine will still provide reasonable protection against other circulating strains.

It’s still worth being vaccinated

In the same way wearing a seat belt is no guarantee we won’t be injured in a car accident, a flu vaccine is no guarantee we won’t develop influenza this season.

A person’s underlying susceptibility, due to factors such as their age and health, will also influence how well a vaccine works.

But the flu shot remains a safe and reasonably effective strategy to reduce your risk of serious illness.

While flu epidemics remain complex, advice to prevent flu transmission remains simple. Regularly washing our hands, covering our mouth when we cough or sneeze, and staying home when we’re unwell are things we can all do to help stop the spread.

Lauren Bloomfield, Lecturer, School of Medical and Health Sciences, Edith Cowan University

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

You can’t get influenza from a flu shot – here’s how it works

Posted on June 27, 2019 by particularkev

You might feel a bit off after your flu shot but this doesn’t last long.
Rawpixel.com/Shutterstock

Allen Cheng, Monash University and Katherine Kedzierska, University of Melbourne

Influenza is a moving target for vaccines. Each year, up to four different strains circulate, and they are constantly evolving to escape our immune system.

So rather than childhood jabs giving long lasting immunity, we need annual flu shots to provide optimal protection against influenza.

But while you might sometimes get sick after having a flu shot, it’s a myth that having a flu shot can give you the flu.

A quick history of the flu vaccine

Influenza vaccines were first developed in the 1930s and 1940s, starting with the isolation of the influenza virus.

Back then, we learned there were many different influenza strains. To be effective, early research showed the vaccine needed to be matched to the circulating strains, and to be able to stimulate a response from the immune system.

The process to produce modern influenza vaccines now occurs on a much more refined and industrial scale. Hundreds of thousands of influenza viruses are collected by hundreds of national influenza centres around the world.

From these, four strains are selected for the annual flu vaccine, based on the viruses that are circulating at that time, how well the vaccines activate the immune system, how the strains are evolving, and the effectiveness of previous vaccines.

Modern flu vaccine development is slow and labour-intensive process.
hotsum/Shutterstock

Most modern vaccines are manufactured by growing large quantities of live virus – mostly in chicken eggs or less commonly animal cells – which are then purified, deactivated and split into smaller components. These vaccines are inactive and cannot replicate.

There are also two new “enhanced” vaccines that are used in older people, who don’t tend to respond as strongly to vaccines: Fluzone High Dose and Fluad, which is designed to better stimulate immunity and draw immune cells to the site of vaccination.

How the immune system fights the flu

The human immune system has several strategies to protect against infection. For viral infections such as influenza, the key strategy is known as adaptive immunity. This part of the immune system can “remember” previous exposure to pathogens.

When you get an influenza infection, the virus enters and hijacks the machinery of the host cell to replicate itself, before releasing these copies to infect more cells.

T lymphocyte cells of the immune system can recognise this viral incursion. T cells protect against further spread of the virus by activating pathways that cause infected cells to trigger a “suicide” process.

Another strategy the body uses is to produce antibodies, which are molecules produced by B cells that recognise components of the viral capsule. These antibodies work by sticking to the surface of the influenza virus to prevent it spreading and facilitating disposal.

Flu shots help mount a quicker defence

On a first exposure to a pathogen, our B cells take at least two weeks to ramp up production of antibodies. However, on subsequent challenges, antibody production occurs much more quickly.

Influenza vaccines harness this arm of the immune system, known as “humoral” immunity. By “practising” on viral components, vaccines allow the immune system to react more quickly and effectively when faced with the real virus.

The flu shot takes about two weeks to start protecting you against influenza.
DonyaHHI/Shutterstock

So why do you sometimes get sick after a flu shot?

There are several reasons why you might feel a bit off after getting your flu shot.

First, your flu shot only protects you against influenza and not other respiratory illness which might causes similar cold or flu symptoms. This includes RSV (respiratory syncytial virus), which is common in late autumn and early winter.

Second, stimulating the immune system can result in symptoms similar to that of influenza, although much milder and short-lived. These include local inflammation (redness, pain or swelling at the site of the vaccine) and more general symptoms (fever, aches and pains, tiredness).

Third, vaccine-induced protection isn’t complete. In some years, the vaccine is not well matched to circulating strains. Usually this is due to mutations that may develop in circulating strains after the vaccine strains are selected.

The flu vaccine also doesn’t “kick in” for two weeks after vaccine administration. In some people, particularly those who are older and those who have weakened immune systems, antibody production is not as strong, and the level of protection is lower.

Despite this, studies have consistently shown that vaccinated people are less likely to get influenza or complications from the flu than those who aren’t vaccinated.

A better way to protect against the flu

A problem with current vaccines is the reliance on eggs, which results in a relatively slow and labour-intensive production process.

Current work is aiming to speed up this process by using different technologies so that vaccine manufacturers can react more quickly to changes in circulating viruses.

The “holy grail” for influenza vaccines is to stimulate an effective immune response to a component of influenza that doesn’t change each year, so annual vaccination is not required.

These efforts have proved elusive so far.

A better strategy might be to harness T cell immunity. Recent work has shown that a type of T cell, known as “killer” T cells, can recognise other parts of the influenza virus, and therefore can provide broad protection against seasonal and pandemic strains.

But while we wait for a better alternative, getting an annual flu shot is the best way to avoid the flu.

Allen Cheng, Professor in Infectious Diseases Epidemiology, Monash University and Katherine Kedzierska, Academic, Microbiology and Immunology, University of Melbourne

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

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Tag Archives: influenza

Media hype and increased testing: this year’s flu numbers are high, but there’s more to the story

Increased concern leads to increased testing

The season is earlier, but it’s not more severe

So when will it end?

How worried should you be?

Hand sanitisers in public won’t wipe out the flu but they might help reduce its spread

What does the research say?

Lessons from hospitals

Sanitisers can be one of many strategies

It’s a bad year for flu, but it’s too early to call it the worst ever – 5 charts on the 2019 season so far

The 2019 flu shot isn’t perfect – but it’s still our best defence against influenza

What’s in a name?

So how do we decide which flu strains are covered by the vaccine?

Do we always get it right?

So is this year’s vaccine is working?

It’s still worth being vaccinated

You can’t get influenza from a flu shot – here’s how it works

A quick history of the flu vaccine

How the immune system fights the flu

Flu shots help mount a quicker defence

So why do you sometimes get sick after a flu shot?

A better way to protect against the flu

Random Thoughts

Sharing my thoughts with the world from a Particular Baptist perspective

Increased concern leads to increased testing

The season is earlier, but it’s not more severe

So when will it end?

How worried should you be?

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What does the research say?

Lessons from hospitals

Sanitisers can be one of many strategies

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What’s in a name?

So how do we decide which flu strains are covered by the vaccine?

Do we always get it right?

So is this year’s vaccine is working?

It’s still worth being vaccinated

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A quick history of the flu vaccine

How the immune system fights the flu

Flu shots help mount a quicker defence

So why do you sometimes get sick after a flu shot?

A better way to protect against the flu

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