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



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

Craig Dalton, University of Newcastle

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.




Read more:
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


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.




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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.




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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.




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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.The Conversation

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



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.




Read more:
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


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.




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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.




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


The Conversation


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



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).




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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.




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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).




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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.




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Here’s why the 2017 flu season was so bad


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.The Conversation

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



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.




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When’s the best time to get your flu shot?


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.




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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.




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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.




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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.The Conversation

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


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.




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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.




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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.




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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.




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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.




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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.The Conversation

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.

Sick with the flu? Here’s why you feel so bad



You might feel terrible. But your runny nose, sore throat and aches are signs your body is fighting the flu virus. And that’s a good thing.
from www.shutterstock.com

Stephen Turner, Monash University

“You never forget the flu”. This is the title of the Victorian health department’s current campaign, which highlights people’s recollections of having the flu.

‘The flu knocked me out for weeks’, part of the Victorian health department’s winter flu campaign.
Vic Dept Health & Human Services

Phrases include “I’ll never forget the pain of the fever”, “the flu flattened me”, “the flu knocked me out for weeks”.

This gives the impression that when you have the flu, you know you have it. What makes the flu so memorable is the severe symptoms. These include fever, aches and pains, a sore throat, runny nose, cough, and feeling weak and lethargic.

But what causes the flu? And why are the symptoms so severe?




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What causes the flu?

Influenza is caused by a virus, a small microbe that needs to enter our cells to replicate and produce more viruses. The influenza virus infects cells that line our airways and so is easily transmitted via the spread of droplets released when we sneeze or cough.

Coughs, sneezes and the other symptoms we feel after getting the flu, are largely due to our bodies fighting the infection.




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The immune response is a double-edge sword

When you are infected with the flu virus, your innate immune system kicks in. Special receptors recognise unique parts of the virus, triggering an alarm system to alert our bodies that an infection is under way.

This produces a rapid but non-specific response — inflammation.




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Inflammation results from the action of small proteins called cytokines. A primary role of cytokines is to act locally in the lung to help limit the initial infection taking hold.

They can also make their way into the circulation, becoming systemic (widespread in the body) and act as a “call to arms” by alerting the rest of the immune system there is an infection.

Unfortunately, your body’s inflammatory response, while trying to fight your infection, results in the flu symptoms we experience.

Inflammation can trigger increased mucus production. Mucus (or phlegm) is a sticky substance that helps capture virus in the lungs and upper airways. The increased amount of mucus in the airways can trigger coughing and/or sneezing, and can lead to a runny nose. This helps expel the virus from our body before it can infect other airway cells.




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Inflammation also results in an increase in body temperature or fever, which creates an inhospitable environment for the flu virus to replicate.

While an increased body temperature helps fight the infection, it also results in you feeling colder than usual. That’s because you feel a greater temperature difference between your body and the outside environment.

This can induce rapid muscle contractions in an effort to heat you up. This is why you can feel like you can’t stop shivering while at the same time burning up.




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Finally, some of these inflammatory molecules act directly on infected cells to stop the virus replicating. They can do this by either interfering with the replication process directly, or alternatively, by actually killing the infected cell.

One of these factors is tumour necrosis factor alpha (TNF-alpha). While its actions limit where the flu virus can replicate, its side effects include fever, loss of appetite and aching joints and muscles.

Calling in the big guns

Inflammation induced by the innate response also helps alert the adaptive immune system that there is an infection.

While innate immunity provides an immediate, albeit non-specific, response to viral infection, it is the adaptive immune response that can efficiently clear the infection.

The adaptive immune system consists of specialised white blood cells called T and B cells that when activated provide a highly specific response to infection.

Your flu symptoms are likely the result of your body fighting off infection with the the tiny flu virus.
from www.shutterstock.com

Activation of flu-specific T and B cells in tissues called lymph nodes results in the generation of hundreds of thousands of clones, all specific for the flu virus. These can migrate into the lungs and specifically target the virus and its ability to replicate.

This enormous expansion of T and B cell numbers in response to infection results in swelling of the lymph nodes, which you can feel under your armpits or chin, and which can become sore.

Flu-specific T cells are also a source of the inflammatory molecule TNF-alpha and help fight influenza infection by killing off virus-infected cells. Both actions can contribute to the flu symptoms.

Why can flu become a serious problem?

Our ability to see off a flu infection requires a coordinated response from both our innate and adaptive immune responses.

If our immune system function is diminished for some reason, then it can prolong infection, lead to more extensive damage to the lung and extended symptoms. This can then result in secondary bacterial infections, leading to pneumonia, hospitalisation and eventually death.

Then there are people whose immune system doesn’t work work so efficiently who are particularly susceptible to the flu and its complications. These include:

  • the very young, whose immune system is still yet to mature
  • the elderly, whose immune system function wanes with age
  • people with other conditions where immune function might be compromised, or be taking medication that might suppress the immune system.

Preventing the flu

Washing your hands and covering your mouth when coughing and sneezing are simple things we can all do to reduce the chance of catching the flu in the first place.

And getting the flu vaccine activates your adaptive immune response to induce the sort of immunity efficient at protecting us from infection.

With the flu season well under way, prevention is our best bet that you won’t be saying “Remember the time I got the flu”.




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The Conversation


Stephen Turner, Professor, viral immunology, Monash University

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

When’s the best time to get your flu shot?



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What goes up must come down, and that includes the protection the flu vaccine offers against influenza.
Irina Bg/Shutterstock

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

When most of us get the flu, we spend three or four days on the couch feeling miserable, then we bounce back pretty quickly. But others have more severe symptoms and need to be hospitalised because they’re at risk of life-threatening complications. Some people even die from the flu.

The size and impact of influenza seasons varies from year to year. In 2017, Australia had its worst flu season for 20 years, with at least 1,255 lives lost. The 2018 season was relatively mild, but it doesn’t seem to have ever ended – cases have been reported throughout summer and into autumn 2019.

The best way to protect against influenza is to get a flu vaccine each year. It’s not as effective as some other vaccines, but it reduces your risk of getting the flu by around 60%.




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Protection often will have begun to wane four or five months later, so getting vaccinated in mid to late May, or even early June, will give you better protection at the height of the flu season. But there are number of factors to consider before deciding when to get your flu shot.

Remind me, why get a flu shot each year?

Influenza viruses change each year and the vaccine is updated to keep up with these changes. This year, for example, the vaccine protects against two different strains than the 2018 vaccine.

Our body’s immune response to the vaccine also wanes over time. So even if you were vaccinated last winter, you may no longer be fully protected 18 months later, depending on your age and your response to the last vaccination.

When does the flu vax become available?

Influenza vaccines are usually available in early April, or even in March; though you’ll generally have to pay full price for early access, even if you’re eligible for a free flu vaccine later.

In mid-April, stock starts arriving at GP clinics and pharmacies for the government’s immunisation program, which offers free flu vaccines for those most at risk of complications from influenza. This includes:

  • all Aboriginal and Torres Strait Islander people aged six months and over
  • pregnant women (during any stage of pregnancy)
  • all people aged 65 years and over
  • people aged six months and over with medical conditions which increase the risk of complications following influenza infections.



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In addition, most states in Australia offer free vaccination to all other children from six months of age to five years of age.

For those not eligible for the free vaccine, influenza vaccines are available through pharmacies and GPs for between A$10 and A$25 (plus the cost of a consultation if your GP doesn’t bulk bill), or via workplace programs.

The 2018 flu season was mild but there have been more cases of influenza over summer than usual.
kurhan/Shuttestock

Is it good to get in early?

Getting a vaccine immediately after it becomes available will ensure you don’t miss out if there’s a vaccine shortage. And it will protect against the “summer flus” we’ve been seeing over the last few months, which are circulating earlier than normal.

But there is a potential downside. Protection against influenza peaks one to two months after you have your vaccine, and then declines. This rate of decline varies from person to person, by age, and by influenza strain.

The flu season usually reaches its peak in August or sometimes even September. So if you’re vaccinated in early April, four to five months will have passed by the time you reach the peak virus months, and you will have lower levels of protection.




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There are few good quality studies across all ages to measure this rate of decline accurately, although a study from 2015 showed that the measurable antibody responses to the influenza vaccine components reduced slowly.

Another study from 2014 showed the vaccine was less effective in people vaccinated three or more months earlier, adding to the evidence that protection wanes over time.

When is too late for the flu shot?

If you delay your decision to be vaccinated until July or August, when the flu season is well underway, your chance of becoming infected will significantly increase.

Mid to late May or early in June is the sweet spot between trying to maximise your protective levels of antibodies generated by vaccination and getting vaccinated before there are significant levels of influenza virus circulating.

It’s better to be vaccinated early than not at all.
DonyaHHI/Shutterstock

Remember, it takes seven to ten days from the time of your flu shot for the vaccine to begin to be fully effective.

Getting vaccinated in late May or early June should provide good levels of protection during the peak of the influenza season and may even last through to November, by which time the influenza season has usually finished.

Vaccinate kids a month earlier

Vaccination timing is a little different for children. Those aged six months to nine years who haven’t been vaccinated against influenza before need two doses of vaccine, four weeks apart. So they will need to start their vaccination program a month earlier than adults and the elderly.




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So if you want to get vaccinated in 2019, there’s no need to rush, and in fact May or even early June might be a better time to be vaccinated. But it’s better to be vaccinated early than not at all.

Your GP or pharmacist will advise you on the most appropriate vaccine and the best timing for you.The Conversation

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.

Health Check: how long should you stay away when you have a cold or the flu?



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Symptoms of the flu generally develop more quickly and are more severe than the common cold.
By txking/Shutterstock

Nadia Charania, Auckland University of Technology

Most adults get around two to three colds a year, and children get even more. In terms of the flu, there are around 3-5 million severe cases of influenza worldwide each year and 290,000 to 650,000 deaths.

The symptoms of a cold and the flu are similar, so it’s hard to tell the difference. But the flu is usually more severe and develops more quickly than a cold.

Colds and flus can be easily passed from person to person through the air, when an infected person coughs or sneezes, and touch, when a person touches an infected surface or object like doorknobs and light switches.

So what’s the difference between colds and flus, and how long should you stay away?

Colds

Cold symptoms include a sore throat, cough, runny or stuffy nose, tiredness and headache.

Most people become contagious with cold symptoms one to two days after exposure to a cold virus. These symptoms usually peak two to four days later. The common cold usually lasts about ten days.




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There is nothing you can take to shorten the duration of a cold, and most people will get better without needing to see a doctor. But some over-the-counter medications can help alleviate the symptoms. These include anti-inflammatories (to reduce inflammation or swelling), analgesics (to reduce pain), antipyretics (to reduce fever) and decongestants (to relieve nasal congestion).

But be careful you follow the instructions and recommended dosage for these medications. A recent study of US adults who used paracetamol, the active ingredient in many cold and flu medicines, found 6.3% of users exceeded the maximum recommended daily dose. This mostly occurred during the cold and flu season.

For your own and others’ health, the best place for you to be when you’re sick is at home.
Shutterstock

Natural products such as vitamin C and echinacea are sometimes recommended to prevent and treat a cold, but there is limited evidence to support their effectiveness.

The flu

Common symptoms of the flu include fever (a temperature of 38°C or higher), cough, chills, sore throat, headache, runny or stuffy nose, tiredness and muscle aches.

An infected person can spread the flu for five to seven days after becoming infected. The infectious period can begin 24 hours before the onset of symptoms. This means you can spread the flu without even knowing you’re sick.

Influenza viruses can cause mild to severe illness in people of all ages. Most people will fully recover within one to two weeks and won’t require any medical attention. Similar to a cold, people can take some over-the-counter medications and other remedies to help alleviate symptoms.




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But some people can become acutely unwell with the flu. They may require antiviral medication and, in severe cases, hospitalisation. Those at high risk include pregnant women, children, the elderly, and people with certain medical conditions such as HIV/AIDS, asthma, diabetes and heart and lung diseases.

The flu virus strains that circulate usually change every year, so the best way to prevent getting the flu is to get the annual flu vaccine. The vaccine is moderately effective and recommended for adults and children over the age of six months. Some common side effects may occur, such as temporary soreness, redness and swelling at the injection site, fever, headache, muscle aches and nausea.

Wash with soap for at least 20 seconds to kill the germs.
Shutterstock/Alexander Raths

Avoid passing it on

If you feel unwell, stay home from work or school and rest (and get plenty of fluids) until you feel better. If you’ve had a fever, stay home for at least 24 hours after the fever has broken.

When you go back to work or school, you may still be infectious, so avoid passing the virus on by:

  • regularly washing your hands with soap and water for at least 20 seconds and drying them properly – if soap and water are not available, use an alcohol-based hand sanitiser

  • practising good cough and sneeze etiquette: cover your mouth and nose with a tissue or your upper shirtsleeve when you cough or sneeze, and throw away used tissues immediately

  • not touching your eyes, nose and mouth

  • The Conversationfrequently cleaning the surfaces and objects you’ve touched.

Nadia Charania, Senior Lecturer, Public Health, Auckland University of Technology

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

Health Check: should I take vitamin C or other supplements for my cold?



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Once you have a cold, taking vitamin C supplements won’t do anything.
From shutterstock.com

Clare Collins, University of Newcastle

Last week I had a shocking cold. Blocked nose, sore throat, and feeling poorly. This made me think about the countless vitamins and supplements on the market that promise to ease symptoms of a cold, help you recover faster, and reduce your chance of getting another cold.

When it comes to the common cold (also called upper respiratory tract infections) there is no magic cure (I wish) but some supplements may deliver very minor improvements. Here is what the latest research evidence says.




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Vitamin C

For the average person, taking vitamin C does not reduce the number of colds you get, or the severity of your cold.

In terms of how long your cold lasts, some studies have looked at people taking vitamin C every day, while others have focused on participants taking it once they develop a cold.

In 30 studies comparing the length of colds in people regularly taking at least 200 milligrams of vitamin C daily, there was a consistent reduction in the duration of common cold symptoms.

However, the effect was small and equates to about half a day less in adults, and half to one day less in children. These types of studies also found a very minor reduction in the amount of time needed off work or school.

Among studies where vitamin C was only started once a cold had developed, there was no difference in duration or severity of a cold.

There are some risks to taking vitamin C supplements. They can increase the risk of kidney stones in men, and shouldn’t be taken by people with the iron storage disease haemochromatosis, as vitamin C increases iron absorption.




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Special considerations

Although in the general population vitamin C has no impact on the number of colds people get, there is an exception. For people who are very physically active – such as marathon runners, skiers and soldiers exercising in very cold conditions – vitamin C halved their chance of getting a cold.

Many people take vitamin C supplements in hope it will treat their cold.
From shutterstock.com

A few studies have also found some benefit from vitamin C supplements of at least 200 milligrams a day for preventing colds among those with pneumonia.

However, taking vitamin E supplements in combination with a high intake of vitamin C from food markedly increased the risk of pneumonia.

Zinc

A review of studies testing zinc supplements in healthy adults found starting daily supplements of at least 75 milligrams within 24 hours of the onset of a cold shortened the duration by up to two days or by about one-third. It made no difference to the severity of the cold.

There was some variability in the results across trials, with insufficient evidence related to preventing colds. Researchers suggested that for some people, the side effects such as nausea or a bad taste from zinc lozenges might outweigh the benefits.

Take care to stop zinc supplements as soon as your cold resolves because taking too much zinc can trigger a copper deficiency leading to anaemia, low white blood cell count, and memory problems.

Garlic

Only one study has tested the impact of garlic on the common cold. Researchers asked 146 people to take garlic supplements or a placebo daily for 12 weeks. They then tallied the number and duration of their colds.

The group that took garlic reported fewer colds than those who took the placebo. The duration of colds was the same in both groups, but some people had an adverse reaction to the garlic, such as a rash, or found the garlic odour unpleasant.

Because there is only one trial, we need to be cautious about recommending garlic to prevent or treat colds. We also need to be cautious about interpreting the results because the colds were tracked using self-report, which could be biased.




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Probiotics

In a review of 13 trials of probiotic supplements that included more than 3,700 children, adults and older adults, those taking supplements were less likely to get a cold.

Their colds were also likely to be of shorter duration and less severe, in terms of the number of school or work days missed.

There is some evidence that probiotics, which can be found in yoghurt, may reduce the incidence of colds.
From shutterstock.com

Most supplements were milk-based products such as yoghurt. Only three studies used powders, while two used capsules.

The quality of the all the probiotic studies, however, was very poor, with bias and limitations. This means the results need to be interpreted with caution.

Echinacea

Echinacea is a group of flowering plants commonly found in North America. These days you can buy echinacea products in capsules, tablets or drops.

A review of echinacea products found they provide no benefit in treating colds. However, the authors indicated some echinacea products may possibly have a weak benefit, and further research is needed.

Chicken soup

Yep, I’ve saved the best until last.

In a novel experiment on 15 healthy adults, researchers measured the participants’ nasal mucus flow velocity – our ability to break down and expel mucus to breathe more clearly. They tested how runny participants’ noses were after sipping either hot water, hot chicken soup or cold water, or sucking them through a straw.

Sipping hot water or chicken soup made participants’ noses run more than cold water, but sipping chicken soup worked the best. The researchers attributed this to the chicken soup stimulating smell and/or taste receptors, which then increased nasal mucus flow.

Another study on chicken soup found it can help fight infection and recovery from respiratory tract infections.

The ConversationOther researchers have shown comfort foods, such as chicken soup, can help us feel better.

Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle

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

A strong immune system helps ward off colds and flus, but it’s not the only factor



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Winter bugs are impossible to escape.
Shutterstock

Hui-Fern Koay, University of Melbourne and Jesseka Chadderton, University of Melbourne

It’s peak flu season. You’re cold, rugged up and squashed on public transport or in the lift at work. You hear a hacking cough, or feel the droplets of a sneeze land on your neck. Will this turn into your third cold this year?

No matter how much we try to minimise our exposure to respiratory viruses, it’s far more difficult in winter when we spend so much time in close proximity to other people.

On top of this, viruses tend to be more stable in colder and drier conditions, which means they stick around longer.




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The common cold is caused by more than 200 different viruses, the most common of which are rhinoviruses (rhino meaning nose). Rhinovirus infections tend to be mild; you might get a sore throat and a head cold lasting just a few days.

Influenza, or the flu, is generally caused by type A or B influenza viruses. The flu is far more aggressive and often includes a fever, fatigue and body aches, in addition to all the classic cold symptoms.

The flu tends to be more severe than the common cold.
healthdirect

When it comes to getting sick, there’s always an element of bad luck involved. And some people, particularly those with young children or public transport commuters, are likely to come into contact with more viruses.

But you may have noticed that illness often strikes when you’re stressed at work, not sleeping properly, or you’ve been out partying a little too much. The health of our immune system plays an important role in determining how we can defend against invading cold and flu viruses.

How the immune system fights viruses

Your skin and saliva are key barriers to infection and form part of your immune system, along with cells in every tissue of your body, including your blood and your brain.

Some of these cells migrate around to fight infection at specific sites, such as a wound graze. Other cells reside in one tissue and regulate your body’s natural state of health by monitoring and helping with the healing process.

The cells that make up your immune system need energy too, and when you’re low on juice, they’ll be on low-battery mode. This is when our natural immune defences are weakened and normally innocuous bugs can begin to cause strife.

Our immune system requires a lot of energy to defend our bodies. Feeling tired and achy, overheating, and glands swelling are all signs that our immune system is busy fighting something.




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Boosting our natural defence system

Our immune system has evolved to naturally detect and eliminate viral infections. And we can actively strengthen our immunity and natural defences by looking after ourselves. This means:

  • getting adequate sleep. Sleep deprivation increases the hormone cortisol, which suppresses immune function when its levels are elevated

  • exercising, which helps the lymphatic system, where our immune cells circulate, and lowers levels of stress hormones

  • eating well and drinking enough water. Your immune system needs energy and nutrients obtainable from food. And staying well hydrated helps the body to flush out toxins

Good food feeds your immune system.
Anna Pelzer
  • not smoking. Smoking, or even secondary smoke, damages our lungs and increases the vulnerability of our respiratory system to infection.



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Educating our immune system

Natural defences aren’t always enough to keep us safe and we need the help of flu vaccinations.

Vaccines are designed to educate an army of B and T cells which make up your adaptive immune system. This arm of your immune system learns by exposure and provides long-term immunity.

These T and B cells need a bit of time from the initial influenza exposure before they can be activated. This activation lag time is when you feel the brunt of the flu infection: lethargy, body aches, extreme fatigue and unable to get off the couch for a day or two.

To overcome this delay and protect people before they are exposed to potentially harmful flu strains, flu vaccination introduces fragments of the influenza virus into the body, which acts like prior exposure to the bug (without actual infection).

You can still get the flu if you’ve been vaccinated but you might not get as sick.
VGstockstudio/Shutterstock

Seasonal vaccines are designed to match currently circulating strains and target those strains before you’re infected.

You can still catch the influenza virus if you are vaccinated. But because of this pre-education, the symptoms will likely be milder. The immune system has been trained and the army of B and T cells can move into action quicker.

Already have a cold or the flu?

If you’ve been sniffling and sneezing your way through winter, be comforted by the fact that these bugs are strengthening your immune system. Our body remembers the particular strain of rhinovirus or influenza we get, so it can recognise and mount a stronger defence if we encounter it again.


The Conversation


Read more:
Explainer: what’s new about the 2018 flu vaccines, and who should get one?


Hui-Fern Koay, Research Fellow in Immunology, University of Melbourne and Jesseka Chadderton, PhD Candidate, University of Melbourne

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