Speaking to Vaccines Today from the 4th ESWI Influenza Conference, Dr Arnold Monto, Professor of Epidemiology at the School of Public Health, University of Michigan, said the impact of flu remains widely underestimated.
“One common misconception is that flu is not a serious disease; that it is just like the common cold. In fact, influenza causes the hospitalisation of a significant number of people,” he said.
Dr Monto, who chaired a session focusing on Misconceptions in Flu at the ESWI conference, said it is often presumed that older people are the ones who end up in intensive care due to severe bouts of flu, but young children are also at risk.
“It affects young and old, we see it every year during flu season,” he said.
Dr Monto said misconceptions about the safety and effectiveness of the flu vaccine also persist. “The vaccine doesn’t cause the flu. Most [influenza] vaccines are inactivated so they cannot cause flu. We commonly get sore arms after the injection but that doesn’t last more than a half a day or so.”
He acknowledged that rare side-effects can occur but “they are outweighed by the benefit of the flu vaccine”.
Questions are frequently raised as to the effectiveness of influenza vaccination, with some patients suffering flu-like symptoms during flu season despite being immunised.
This, says Dr Monto, arises because the vaccine protects against the most common flu viruses in circulation but it does not prevent infection with other pathogens.
“A lot of other things out there resemble flu so when someone who has been vaccinated comes down with a respiratory illness during the winter they suspect it must be caused by a flu virus – even though this may not be the case,” he explained.
In addition, it is accepted that existing flu vaccines are less effective in the elderly population than in younger adults.
“It’s not a perfect vaccine which is why we are working on a new one. We’ve got a good vaccine which provides enough protection to make it worth being immunised. The current vaccine was actually developed by the military in the 1940s but there has been little investment – until relatively recently – in developing a new one.”
The fact that older people might not be as well protected by the flu vaccine as younger people was one of several factors which led the United States to recommend that everyone have a flu shot ahead of the winter flu season.
Immunising the vast majority of the population can help contain the spread of flu viruses which reduces the risk to older people as well as protecting babies younger than six months who cannot be vaccinated.
He added that US authorities now recommend universal flu vaccination because the proportion of the population falling into at-risk groups – such as older people and babies, as well as those who care for them – became so large and complex that it made sense to cover the whole population.
“It got to point where 70% of people were recommended to have the shot so it seemed better just to make a clear recommendation for everyone to be protected. The side effects of the vaccine are rare and the benefits are clear,” Dr Monto said.
One of the arguments made against universal flu vaccine coverage was that it would lead to an increase in serious adverse events. Critics pointed to a spike in Guillain–Barré syndrome (GBS) during the US swine flu outbreak in 1976.
Dr Monto said cases of GBS are extremely rare in the population and it remains unclear whether flu vaccines cause an increase in cases, despite a great deal of research and disease surveillance.
“My own view is that we may never really know if there was a connection because it’s such a rare condition. During the 2009 pandemic, when millions of people were vaccinated, we didn’t see any increase in GBS. It’s very fortunate that we have set up a network to look for GBS because now we can be convinced that it is not a problem. ”
However, authorities in Sweden, Finland and elsewhere reported a number of cases of narcolepsy after the H1N1 pandemic – a rare sleep disorder – but Monto said no causal link has been proven. “Again, it’s such a rare disorder that a small number of additional cases can look like a spike but we may never know for sure what caused this,” he added.
Dr Monto said the 2009 flu pandemic could be suppressing vaccine uptake in Europe in a way that has not been a problem in the US. The American public generally views the pandemic response to have been a success, whereas Europeans typically complain that the threat of H1N1 was overblown.
“In the US – and in my own hometown – we got H1N1 early. Infections were common and some cases were very very severe. Intensive care units were filling up, our local hospital ran out of ventilators, vacation time for nurses was cancelled, and schools were closed. There was a lot of uncertainty but the disease was contained. That’s what made it different to Europe where it wasn’t seen as an immediate and serious threat,” he said.
Given all the misconceptions that surround flu, how can these be addressed? Patience, says Dr Monto, is the key.
“We’ve been trying to address these misunderstandings over a number of years. One of the best ways to do this is to diagnose flu. If physicians recognise it more – rather than just having public health people talking about it – then the message may work through to the overall population.”
He says the public has a broadly favourable view of the flu vaccine but scientists should do more to make their voices heard.
“The real challenge now is that we have a small but very vocal group who are against vaccination of any kind. The internet can be seen as a problem but we need to get ourselves out there – in the media and on the internet. Reputable journalists can help but scientists should not feel as though they can leave communication to others,” Dr Monto stresses.
“There are so many sources of misinformation as well as information. For me, the people who have a lot of time on their hands may not be the ones we should be listening to.”