Flu jab is not a 'waste of time'

Crabsallover comment: As the Public Health England Press Release says 'The research, based on the results from 1,314 patients presenting in primary care across the UK, found that vaccine effectiveness in preventing laboratory confirmed influenza was estimated to be 3% overall. This compares to approximately 50% vaccine effectiveness that has typically been seen in the UK over recent years.'

PHE also says" In the UK, influenza A(H3N2) is the predominant subtype circulating this season to date, and H3N2 viruses similar to A/Texas/50/2012 are the strains that the vaccine currently protects against. Analysis conducted by PHE has shown a large proportion of flu viruses circulating have shown evidence of either antigenic or genetic drift from A/Texas/50/2012, and were similar to another H3N2 strain; A/Switzerland/9715293/2013. The A/Switzerland/9715293/2013 strain has been recommended for inclusion in the southern hemisphere influenza vaccine to be used in 2015.'

source: http://en.wikipedia.org/wiki/File:InfluenzaNomenclatureDiagram.svg

and
'The World Health Organization monitors influenza globally and each year recommends the strains of flu virus that should be included in the flu vaccine for the forthcoming flu season. It takes from February through to August / September to produce sufficient quantities of the flu vaccine. If a change in the virus is detected once production has started it is not possible to change it.  Throughout the last decade, there has generally been a good match between the strains of flu in the vaccine and those that subsequently circulate, so it’s crucial that these results do not discourage people in at-risk groups from having flu vaccination now, or in the future.'

Interesting comparison of what is in seasonal H3N2 flu vaccines.

Friday February 6 2015

This year’s flu jab may still protect against other strains

“Flu jab given to millions is 'useless',” and "Flu jab is a waste of time," are the irresponsible headlines in The Daily Telegraph and the Daily Mail.

While recent research shows that the currentseasonal flu vaccine only has 3% protection against the main circulating strain – A(H3N2) – in adults, it can still protect against other strains.

Both papers also ignore the fact that another version of the flu vaccine, in the form of a nasal spray designed forvulnerable children, is also available.

Discouraging parents of vulnerable children from getting vaccinated could increase the risk of serious childhood illnesses and possible hospitalisation.

Why is the flu vaccine not working?

There are many strains of the influenza virus and each one can mutate. It takes time to develop and produce vaccines against them. Global surveillance is used to predict which strains are likely to be circulating the following winter, and in February the World Health Organization (WHO) announces which strains the flu vaccine should cover. Last year, it decided to cover three flu varieties:

• Influenza A (H1N1), also known as “swine flu"
• Influenza A (H3N2)
• Influenza B

In March, the WHO Global Influenza Surveillance and Response System detected a new strain of influenza A (H3N2), but this was too late to change the production of the vaccine.

It was also not known whether this particular strain would be the predominant strain this winter, which it has been, and so the vaccine is not effective against it.

‘A Jack Bauer car chase’

“Trying to predict which seasonal flu vaccine to produce each year must be a bit like a Jack Bauer [hero of the TV thriller series '24'] car chase in Los Angeles.

“At any intersection, the fugitive has three choices of direction. Bauer can’t catch up, and he doesn’t know the ultimate destination, so he has to try to guess the likeliest turns, and place his limited team in side streets where they’re most likely to block the fugitive, to slow him down or capture him. Even with Jack Bauer’s experience, this is bound to prove somewhat hit and miss.”

Dr Michael Skinner, Reader in Virology, Imperial College London (and fan of ‘24’).

How effective is it?

The vaccine is effective against the other strains of influenza, but not the new strain of influenza A (H3N2). The mid-season vaccine effectiveness rate is just 3.4%. Vaccination against this new strain and other possible mutations will be considered at the WHO meeting this February for next winter.

Reactions to the news

Dr Michael Skinner, Reader in Virology, Imperial College London said: “The current type of seasonal influenza vaccine is, at the moment, the best we have. Annually it saves tens of thousands of lives. Unusually, but not uniquely, this year one (H3N2) of the four targeted viruses ‘drifted’ (mutated) in an unanticipated direction after the vaccine was formulated for production, so that the vaccine offers little protection against the drifted H3N2.

"Even so, the vaccine still protects against the other three components (pre- and post-2009 H1N1 and B). And it does at least stop the virus drifting back along the path that had been predicted. To describe it as ‘useless’ would be misguided.”

Should you still get the jab?

The other strains can still cause infection so the vaccine is still recommended for pregnant women, people aged over 65 and those with any of the following conditions:

• chronic (long-term) respiratory disease, such as asthma (that requires inhaled or tablet steroid treatment or has led to hospital admission in the past), chronic obstructive pulmonary disease (COPD) or bronchitis 
• chronic heart disease, such as heart failure 
• chronic kidney disease 
• chronic liver disease, such as hepatitis 
• chronic neurological conditions, such as Parkinson's diseaseor motor neurone disease 
• diabetes
• problems with your spleen – for example, sickle cell disease, or if you have had your spleen removed 
• a weakened immune system due to conditions such as HIV and AIDS, or as a result of medication such as steroid tablets orchemotherapy

When to visit your GP

If you are otherwise fit and healthy, there is usually no need to visit your GP if you have flu-like symptoms.

The best remedy is to rest at home, keep warm and drink plenty of water to avoid dehydration.

You can take paracetamol or ibuprofen to lower a high temperature and relieve aches.

If you are in any of the high risk groups listed above then you should visit your GP.

Depending on your circumstances, your GP may recommend a short course of antiviral medication, such as Tamiflu (oseltamivir). 

Antivirals are not used for everyone with flu because this would lead to further mutations in the viruses and drug resistance, making them ineffective.

If you suspect you have the flu it is important to take steps to prevent it spreading; especially to one or more of the vulnerable groups listed above.

Always:

• make sure you wash your hands regularly with soap and water
• clean surfaces such as your keyboard, telephone and door handles regularly to get rid of germs
• use tissues to cover your mouth and nose when you cough or sneeze
• put used tissues in a bin as soon as possible

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Analysis by 

Edited by NHS Choices

Links to the headlines

Flu jab given to millions is 'useless'. The Daily Telegraph, February 6 2015

Flu jab is a waste of time for 97% of patients: Vaccine developed only a year ago no longer 'matches' because the virus has mutated so much. Daily Mail, February 6 2015

Flu vaccine 'barely effective' against main viral strain. BBC News, February 5 2015

Useless flu jab blamed for surge in death toll. Daily Express, February 6 2015

Current winter flu jab works in only 3% of cases. ITV News, February 6 2015

Flu vaccine gives only ‘low protection’ in UK this winter, experts warn. The Guardian, February 5 2015

Flu jab given to millions offers almost no protection. The Times, February 6 2015

Flu Jab Found To Work In Just 3% Of Cases. Sky News, February 6 2015

Links to the science

Pebody RG, Warburton F, Ellis J, et al. Low effectiveness of seasonal influenza vaccine in preventing laboratory-confirmed influenza in primary care in the United Kingdom: 2014/15 mid-season results. Eurosurveillance. Published online February 5 2014

Further reading

Public Health England. Flu vaccine shows low effectiveness against the main circulating strain seen so far this season – Press Release. February 5 2015

reposted (unedited) from: http://www.nhs.uk/news/2015/02February/Pages/Flu-jab-is-not-a-waste-of-time.aspx

crabsallover highlights, key points, comments / links.

Flu jab "may cut" stroke risk by a quarter

A recent report has revealed that people who have the seasonal flu jab are 24% less likely to suffer a stroke, according to The Daily Telegraph

The report is based on the results of a large study, which used the GP database for England and Wales to access data on almost 50,000 people who had suffered a stroke or transient ischaemic attack (TIA or a so-called “mini” stroke) over an eight-year period. Researchers then matched them to a person of the same age and gender who had attended the GP around the same time (these people are known as the “controls”). They then compared how likely they were to have been given the seasonal flu vaccine before the date of the stroke or TIA.

They found that slightly more controls had received the flu vaccine before the date: 50.8%, compared to 50.6% of people who had had a stroke or TIA. This meant that, overall, having the flu vaccine reduced the risk of a person having a stroke by about a quarter (there was no link with TIAs).

The research benefits from a large quantity of reliable data, with a number of health and lifestyle factors that may have influenced the results also adjusted.

It is plausible that a link exists between the protection against flu strains the vaccine provides and the risk of having a stroke.

The researchers summarise by saying they “reinforce current recommendations for annual influenza vaccination” with “potential added benefit for stroke prevention”.

Where did the story come from?

The study was carried out by researchers from the University of Lincoln and University of Nottingham, and was funded by the National Institute for Health Research.

The study was published in the peer reviewed journal Vaccine.

The Daily Telegraph and The Independent’s reporting of the study was accurate.

What kind of research was this?

This was a case-control study, which aimed to see if the influenza or pneumococcal vaccination might prevent a stroke. Some previous research studies have suggested that respiratory infections, such as the flu, may be associated with a stroke.

They cite a number of studies that have found there is an increased likelihood of respiratory symptoms in the weeks prior to having a stroke. However, other observational studies failed to find any significant link.

Due to this inconsistent evidence, the researchers aimed to investigate this further themselves, using data for thousands of people stored on the UK General Practice research database.

They identified people who had suffered a stroke or TIA and a matched group of people without, examining if they had been given the seasonal flu jab or the pneumococcal vaccine.

The pneumococcal vaccine is part of the child vaccination programme. It is also offered as a one-off jab to all adults over the age of 65 and to younger adults that have a heightened risk of infection (such as those with weakened immune systems). The vaccine protects them against infection with the bacteria Streptococcus pneumonia, which can cause pneumonia and other severe infections.

What did the research involve?

The researchers used the General Practice Research Database (now called the Clinical Practice Research Datalink, CPRD), which contains anonymised data for over 5% of the population of England and Wales. The database codes for vaccinations, diseases and health behaviours using a validated coding system. They used the eight-year period 2001-9 to identify adults coded for stroke or TIA (“case”). Each case was randomly matched to a control of the same age and gender who attended a general practice at the same time. They excluded cases and controls with a previous diagnosis of stroke or TIA.

They looked for vaccinations recorded prior to the ”index” date, when the stoke or TIA was recorded. Because the influenza vaccine is seasonal, the researchers looked to see if the vaccine was given in the same seasonal year (September 1 to August 31 the following year) and whether given “early” (between September 1 and November 15) or “late” (November 16 to February 28), and the time elapsed since last influenza vaccination (defined as 0 to 3, 3 to 6, 6 to 12, or more than 12 months before the index date). Pneumococcal vaccination was defined as vaccination at any time before the index date, as it is given as a one-off vaccine.

The researchers looked at the odds for cases and controls given either or both vaccines.

They adjusted their analyses for potential confounders, including cardiovascular risk factors, current medications, number of cormorbid medical illnesses, lifestyle factors (such as whether a person smokes) and the number of GP consultations and home visit requests. 

What were the basic results?

The researchers identified 47,011 cases (comprising 26,784 cases of stroke and 20,227 cases of TIA), with the same number of matched controls.

Very slightly more controls than cases had received the flu vaccine in the same season as the index date: 50.8% of controls compared to 50.6% of cases. After adjusting for the measured confounders, this meant that having an influenza vaccine within the same season as the index date was associated with a 24% reduction in the risk of a stroke (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.72 to 0.80).

Further adjustment for body mass index (BMI), cholesterol and blood pressure slightly reduced the risk association, such that the risk reduction was only 19%, but still remained statistically significant(OR 0.81, 95% CI 0.77 to 0.85).

Reduction in the risk of a stroke was greatest when the vaccine had been given within three months of the index date (22% reduction), reducing to 11% reduced risk when the vaccine had been given between three and 12 months of the index date.

However, the flu vaccine only seemed to protect against a stroke if given early in the flu season: September to mid-November (26% risk reduction, OR 0.74, 95% CI 0.70 to 0.78). Giving the vaccine late in the flu season (mid-November to February) did not result in a significantly reduced risk.

Flu vaccine was not significantly associated with being at risk of TIA. Neither was pneumococcal vaccination significantly associated with being at risk of a stroke or TIA.

How did the researchers interpret the results?

The researchers conclude that: “Influenza vaccination was associated with a 24% reduction in risk of having a stroke, but not TIA. Pneumococcal vaccination was not associated with reduced risk of a stroke or TIA. This has important implications for the potential benefits of an influenza vaccine.”

Conclusion

This research finds that, overall, having the flu vaccine reduced the risk of a person experiencing a stroke by about 25%. The reduction in risk seemed to be greatest within the first three months of vaccination, but remained for up to 12 months.  However, the effect lasted only if the vaccine was given early in the flu season (September to mid-November); giving the vaccine late in the flu season (mid-November to February) was not associated with significantly reduced risk.

The research benefits from using data coded within the General Practice Research Database for England and Wales for almost 50,000 people with stroke or TIA, matched by age and gender to the same number of controls who had attended the GP at the same time. There is still potential for missing or miscoded information in the database, but overall the data is thought to be fairly reliable.

They also adjusted their analyses for a large number of potential confounders. The researchers say there is still the potential for what they call “healthy vaccine” bias, with healthier people more likely to be vaccinated, and are perhaps less likely to have a stroke.

The findings support previous studies, which the researchers say have suggested an association between recent respiratory illness and risk of a stroke; they have also studied findings that influenza vaccination may offer protection against another heart attacks. However, the biological mechanisms by which respiratory infections or influenza might precipitate cardiovascular events is unknown. It is also unknown if the findings could apply to younger people at risk.

In summary, it is plausible that there could be a link between the protection the flu vaccine gives against flu strains and a risk of suffering a stroke in the same season.

The purpose of the seasonal influenza vaccine is to protect against respiratory illness, not to offer possible protection against a stroke. However, the researchers “reinforce current recommendations for annual influenza vaccination” and that there is “the potential added benefit of stroke prevention”.

Even if the link between the flu jab and reduced stroke risk is unproven, it is always a good idea to get the jab if you are in one of the groups recommended to receive it. This is if you are:

• 65 years of age or over 
• pregnant
• have a long-term (chronic) medical condition such as asthma or diabetes
• living in a long-stay residential care home or other long-stay care facility
• receive a carer's allowance, or you are the main carer for an elderly or disabled person whose welfare may be at risk if you fall ill
• a healthcare worker with direct patient contact or a social care worker

Read more on who should get the flu jab.

Analysis by Bazian. Edited by NHS Choices. 

Follow Behind the Headlines on Twitter. 
Join the Healthy Evidence forum.

Links to the headlines

Flu jab could cut risk of stroke by quarter. The Daily Telegraph, February 20 2014

Winter flu jab may reduce stroke risk by up to a quarter. The Independent, February 20 2014

Links to the science

Siriwardena AN, Asghar Z, Coupland CA. Influenza and pneumococcal vaccination and risk of stroke or transient ischaemic attack—Matched case control study. Vaccine. Published online January 28 2014

reposted from: http://www.nhs.uk/news/2014/02February/Pages/Flu-jab-may-cut-stroke-risk-by-a-quarter.aspx

crabsallover highlights, key points, comments / links.

Claims flu jab is a 'waste of money' misleading

reposted from: http://www.nhs.uk/news/2012/11November/Pages/Claims-flu-jab-is-waste-of-money-misleading.aspx

crabsallover highlights, key points, comments / links.

Thu Nov 22, 2012 10:51 Share

As flu season approaches, claims that the flu vaccine is a 'waste of money' are being widely reported. The Daily Telegraph declares that 'flu vaccine effectiveness [is] exaggerated,' while the Daily Mail claims that 'flu jabs are a 'waste' of taxpayer's money.'

Both headlines are exaggerations based loosely on a new report from researchers at the University of Minnesota.

While the news stories go on to offer measured coverage of the report, the suggestion that the vaccine is of limited effectiveness in older people and a 'waste of money' is spurious and misleading when read out of context in the headlines.

The report by a team of researchers at the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota covers multiple aspects of the flu vaccine in the US. It includes evidence of the vaccine's effectiveness, research and development efforts, vaccine production, and policy surrounding who gets the vaccine.

While the flu vaccine is not 100% effective, the flu vaccination programme in the UK has proven effective at preventing deaths. Claims that the flu vaccine is in some way over-hyped are based on the report's finding that the perceived level of effectiveness may be putting vaccine manufacturers off investing in research into new types of flu vaccine.

Multiple strains of the flu virus may be circulating in any given year. Current efforts to prepare for and combat flu epidemics include the widespread production and use of a yearly flu vaccine. This vaccine is developed to protect against three strains of the virus that experts predict will circulate during the upcoming winter flu season.

How effective is the flu vaccine?

The UK Department of Health (DH) reports that the current trivalent inactivated influenza vaccine (the seasonal flu jab) has an overall efficacy, or success rate, of 59% among adults aged 18 to 65 years. Protection may be lower in the elderly. The type of flu vaccine recommended for children (a 'live' vaccine as opposed to an inactivated vaccine) is thought to be more effective, with a reported efficacy of 83% for children. The DH figures correspond with those reported in the current CIDRAP report.

Who produced the report?

The report was produced by the Center for Infectious Disease Research and Policy (CIDRAP). CIDRAP is a research unit based at the University of Minnesota in the US, which says it aims to "prevent illness and death from infectious diseases through epidemiological research".

CIDRAP carried out an extensive review of flu vaccine efforts. The report authors reviewed studies published between 1967 and 2012 that looked into the effectiveness of flu vaccination. This report covers:

• the scientific basis of the vaccine, including research and development, and the safety and effectiveness of the annual vaccine
• the implementation of annual vaccination programmes, including the financing, manufacturing and distribution of the flu jab
• policy and communication regarding the annual flu jab, including details on public education programmes, acceptance of the jab among patients, and public policy surrounding the vaccine

What were the main findings of the report?

The CIDRAP review reports 10 key findings, only some of which feature in current media coverage.

The report says that the current flu vaccine offers "substantially lower" protection than that offered by most routinely recommended vaccines. However, the report has concluded that during some flu seasons, the jab offers substantially more protection for most people compared with not being vaccinated at all.

It says that for one form of the vaccine (trivalent inactivated influenza vaccine, or TIV) the evidence surrounding protection varied:

• among children aged of 2-17, they found inconsistent evidence of vaccine protection
• among healthy adults (aged 18-64), the vaccine offered moderate protection (approximately 59%).
• there was limited evidence of TIV effectiveness for people over the age of 65

For the other type of vaccine (live attenuated influenza vaccine, or LAIV), CIDRAP found:

• evidence of high protection (approximately 83%) among children aged six months to seven years
• a lack of evidence for protection among people aged 8-59
• limited evidence among adults over the age of 60

The review found that commonly cited figures regarding flu vaccine effectiveness are largely based on studies with poor methodology, and studies employing better methods have not reported protection levels as high. The authors suggest that this perception of vaccine effectiveness prevents research into the development of highly effective vaccines.

Over the last 50 years in the US the groups of people recommended to receive the annual flu jab have expanded beyond those at high risk of complication. The study authors report that these recommendations were often based on professional judgement and not scientific evidence.

New approaches to flu vaccine development may offer increased protection against seasonal flu, but more research support is needed to determine whether these approaches could result in "game-changing vaccines".

The media did not cover the report findings concerning vaccine policy, financing, production and distribution.

What recommendations did the report make?

The CIDRAP report recommends:

• Research efforts should focus on developing new "game-changing" vaccines that offer high levels of protection against both seasonal and pandemic flu. These vaccines should show increased effectiveness for populations at high risk of severe illness or death, while maintaining at least the same levels of safety as current vaccines.
• Estimates of current flu jab effectiveness based on methodologically strong research should be used in all vaccine policy. The authors recommend that international standards for determining vaccine effectiveness are developed so that all policy is based on the same quality level of evidence.
• Vaccines against pandemic flu should achieve high levels of protection, be based on new international standards of effectiveness, and be available in the quantity necessary to protect populations around the world either before or during the early stages of a new pandemic.
• New regulatory, investment and production strategies should be developed to support the development of highly effective flu vaccines.
• The US should take on a leadership role in developing new vaccines, and the World Health Organisation (WHO) and other international agencies and governments should support this US-led effort.
• New international standards of evaluating vaccine effectiveness should be used to assess whether vaccines offer good value for money.

These are broad recommendations and it is unclear at this point how and whether they will be implemented.

How accurate was the media's coverage of the report?

The media coverage of this report in the UK was poor for two main reasons:

• there was no acknowledgment that this report was primarily aimed at a US readership and is based on the situation in that country
• all of the report's claims were taken at face value, with no attempt made at subjecting the claims to any kind of critical analysis

Due to both of these facts, there are a number of important points that need to be stressed:

• According to the CIDRAP, in the US the current recommendations for flu vaccination are that everyone over the age of six months is vaccinated. The same is not true in the UK, where only high-risk groups, such as pregnant women, are recommended that they receive the vaccine. These two different approaches to flu vaccination programmes may reflect different value for money, given the moderate effectiveness of the flu vaccine.
• The report states that the medical and health policy communities in the US tend to believe that the current flu vaccine is largely effective. They speculate that such beliefs could lead to "overselling" of the vaccine, despite evidence regarding its moderate effectiveness. The risk of such overselling may be lessened in the UK, as the   Department of Health is entirely transparent about the effectiveness of the flu vaccine and actually quote many of the statistics included in the CIDRAP report.
• The report makes repeated reference to the need to produce a "game-changing vaccine" – that is, a vaccine that can adapt to the flu virus' ability to mutate. But as yet there is no evidence that the production of such a vaccine is feasible, or whether such a vaccine would be safe and effective.
• The media makes repeated claims that the flu vaccine is "far less effective in the elderly". This is not actually an appropriate reflection of the review's findings. The review says that there is "limited evidence" surrounding the effectiveness of the vaccine in the elderly – this is not the same as "limited effectiveness" in this group. Absence of evidence is not the same as evidence of absence.

Overall, the report found that while the protection offered by the current annual flu jab is less than ideal when compared to other vaccines, for most people it is still better than not being vaccinated.

The report certainly does not conclude that flu vaccination be abandoned, or is a "waste of taxpayer's money".

But it does suggest that a new approach be taken to the development of the annual vaccine by both drug companies and governments, so that the protection it offers can be brought up to the standards we see with jabs for other diseases.

The report also recommends that more resources need to be put aside so that in the event of a future flu pandemic an appropriate vaccine can be produced quickly and distributed to the public.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.

Links To The Headlines

Flu jabs are a 'waste of taxpayer's money', claim scientists who say the benefits have been over-hyped. Daily Mail, November 21 2012

Flu vaccine effectiveness exaggerated, scientists claim. The Daily Telegraph, November 21 2012

Governments must be deadly serious regarding what they tell us. The Independent, November 20 2012

Links to the science

 http://www.cidrap.umn.edu/cidrap/files/80/ccivi%20report.pdf

Further reading

Center for Infectious Disease Research & Policy. The Compelling Need for Game-Changing Influenza Vaccines: An Analysis of the Influenza Vaccine Enterprise and Recommendations for the Future. Published online October 15 2012 http://www.cidrap.umn.edu/cidrap/files/80/ccivi%20report.pdf

Reducing Inflammation with statins, aspirin, flu jab cuts cancer and heart disease - David Agus

reposted from: http://www.youtube.com/watch?v=GZ6I3T1RAnQ&feature=relmfu

crabsallover highlights, key points, comments / links.




Reducing Inflammation with statins, aspirin, flu jab cuts cancer and heart disease - David Agus

Fever - we don't know if a fever is good or bad. But fever is caused by inflammation.

3:50s - 5:00 Statins block synthesis of LDL cholesterol, lowered death from heart disease and stroke
JUPITER trial (I assume Agus is talking about this trial) - statins reduced incidence of cancer by 40% in people who don't have high cholesterol, also delayed heart attack and stroke by 12 years. Statins work by reducing inflammation which reduces deposition of cholesterol and also reduces cancer.

5:40 how can we measure inflammation? Types of inflammation - some is causal, other is not. How to optimise bad inflammation?

6:40s - 7:15s Taking a flu jab not only reduces the chances of a nasty flu for 5 days but also reduces the chance of getting cancer or heart disease in 10 years time by reducing inflammation

Aspirin: 8.20s - aspirin reduces inflammation which reduces heart disease and cancer

Scientists warn about future flu strains

reposted from: http://www.nhs.uk/news/2011/03March/Pages/call-for-vaccination-against-h2n2-flu.aspx

crabsallover highlights, key points, comments / links.

Governments should start vaccinations against a lethal strain of the influenza virus circulating in birds and pigs, The Independent has reported.

The news is based on an article written by US vaccine researchers, who said that an old flu strain known as H2N2, which caused a pandemic in the 1950s and 60s, could easily start circulating again in humans. The researchers also conducted a small test of 90 people, which showed that people under the age of 50 have little or no immunity to the strain. They argue that creating a new vaccination programme to deal with this strain of flu could save lives by preventing a potential pandemic.

The emergence of different flu strains and the question of whether vaccines are needed against them is an important public health issue, particularly in light of the rapid spread of swine flu in 2009. However, it can be hard to initially tell how widely a new or re-emergent strain of flu will spread or how severely it will affect people. In the case of H2N2, the disease does not currently circulate in humans and any pre-emptive vaccine programme will need further investigation before it can be justified.

Where did the story come from?

The report was written by researchers working at the Vaccine Research Centre of the US National Institutes of Health. The researchers did not report any sources of external funding. The report was published in the peer-reviewed journal Nature.

The research article was faithfully reported by both the BBC andThe Independent. The BBC included comments from an independent UK expert, who questioned whether the public would want another vaccine against a disease that does not presently exist. The Independent’s headline, which stated that we should “vaccinate against killer flu virus now”, does not reflect the conclusion of the research article, which suggested we should examine the issue rather than begin vaccinations. In addition, it is not possible to tell whether the H2N2 flu virus would be likely to kill if it began circulating in a modern population.

What kind of report was this?

This commentary, written by vaccine researchers, argued that government regulatory authorities should plan for a vaccination programme against an old flu strain called H2N2. They warned that this strain is circulating in birds and pigs and could jump to humans, as the H1N1 swine flu strain did in 2009.

In their comment article, the researchers reported details of a small study they conducted, in which they tested 90 US residents for antibodies against the H2N2 flu strain. Their results suggested that people under the age of 50 have little or no immunity to the strain, while resistance dramatically increases in people older than 50. They say this pattern of immunity is similar to that found in H1N1.

What does the report say?

The researchers point out that the emergence of a new strain of the H1N1 virus in 2009 took the world by surprise. The public health community had assumed that any future pandemic flu strain would arise from a “major genetic reshuffling” of existing flu viruses to produce a new virus that had never circulated in humans before. As it turned out, the virus that emerged bore a remarkable resemblance to one that had already caused a pandemic 90 years earlier: H1N1 Spanish flu, which killed about 50 million people worldwide. A version of this virus had circulated in pigs for nearly a century and was able to eventually transfer back to humans and cause a new pandemic at a time when immunity levels had waned.

The authors of this comment article say that the unexpected origin of the H1N1 pandemic provides a “cautionary tale” for the public health community, and that the H2N2 strain constitutes a possible public health threat as it could re-emerge in a similar way. They argue that government regulatory agencies should develop a pre-emptive vaccine programme against H2N2.

The researchers draw a number of parallels between the H1N1 and H2N2 viruses. For example, they have both caused pandemics: from 1957 to 1968, an H2N2 strain caused 1–4 million deaths worldwide. Like the 1918 strain, the H2N2 virus has not circulated in humans for several decades but continues to do so among birds and pigs.

To examine people’s levels of immunity to this class of virus, between 2003 and 2007 the researchers tested stored blood samples for antibodies against H2N2 strains in a small cohort of 90 people in the US. The researchers admit that ideally the test needs to be repeated in several thousand individuals, but say their study suggests that people under the age of 50 have little or no immunity to H2N2, and immunity is far stronger in people over 50 (as was also the case for H1N1).

The researchers argue that governments should plan a pre-emptive vaccination programme to prevent the re-emergence of H2N2 in humans, perhaps based on the vaccine against H2N2 licensed for use against the 1957-68 pandemic. They suggest several possible strategies for doing this:

• Manufacture the vaccine licensed in 1957 and immunise enough of the world’s population to provide “herd immunity” to the rest (i.e. vaccinate a large enough proportion of people so that the virus cannot easily spread to non-vaccinated individuals).
• Stockpile the vaccine so supplies are ready in the event of an outbreak (which they point out would be more expensive and less effective than routine vaccination).
• Make “master lots” of H2N2 vaccine and increase production as soon as signs of an outbreak occur (they argue this would be cheaper but less effective than either of the above methods).

What do these researchers conclude?

The researchers looked at the pros and cons of developing a pre-pandemic vaccine, including cost, the obstacles to distributing vaccines internationally, potential public distrust of vaccines and the limitations that are placed on public health resources. However, they finally concluded that another major flu pandemic is likely to cost far more and create a far greater health burden than a pre-emptive vaccination programme.  Such a strategy would save lives and “spare the world a major public-health crisis”, they concluded.

Conclusion

The researchers raise important questions about the possibility of a future flu pandemic caused by the H2N2 virus, and about whether vaccination programme planning could be used to prevent it. However, many issues need further consideration, including a detailed assessment of the probability of the H2N2 strain jumping to humans, whether it would pose a serious health threat, how long it would take to emerge and which groups of people would be vulnerable. It is important to note that infection with the H1N1 virus, although dangerous for some population groups, did not make most people seriously ill.

As the researchers point out, there are concerns over whether it makes sense to expose individuals to vaccines for a virus that is not currently circulating in humans, although they say the previously licensed H2N2 vaccine has a proven safety and efficacy record. Also, the virus that might emerge in humans may have evolved or mutated to the point where the current H2N2 vaccine no longer provides immunity, although the researchers argue that this is unlikely. As the researchers note, more studies of the existing H2N2 vaccine would be required to confirm its safety and efficacy and to establish who to immunise and when.

The question of whether vaccines should be prepared against the possibility of new, emergent and sometimes dangerous strains of flu is an important public health issue, particularly given the nature of the 2009 swine flu pandemic, in which a new strain of the H1N1 virus emerged and spread quickly.

With new or re-emergent strains of flu, immunity levels are often low, and it can be difficult to initially tell how widely a new strain will spread, or how severely it will affect people. In the case of H2N2, the disease does not currently circulate in humans, so there is still uncertainty over whether it is necessary to plan a vaccine programme and whether existing vaccines would work against an emerging strain. It is also not clear whether the public would find it acceptable to receive or have the government fund a vaccine against a non-circulating disease.

While this research paper rightly argues that an H2N2 vaccination should be investigated, such an examination will need to be informed by evidence on the medical and logistic issues involved, particularly whether available vaccines would be likely to provide protection against future strains.

Links to the headlines

Call to vaccinate against possible H2N2 flu pandemic. BBC News, March 10
2011

Vaccinate against killer flu virus now, say experts. The Independent, March 10 2011

Links to the science

Nabel GJ, Wei CJ, Ledgerwood JE. Vaccinate for the next H2N2 pandemic now. Nature, 10 March 2011, volume: 471, Pages: 157–158

Seasonal Flu Vaccinations £12 from Bupa

http://www.bupa.co.uk/individuals/self-pay-treatments/flu-vaccinations_1 (accessed 7th October 2011)

venue

http://www.bupa.co.uk/facilitiesfinder/bupa-centres/southampton