Friday October 5 2012
Flu is highly infectious and is spread by coughs and sneezes
Britain is the 'most unhygienic nation' in the face of major flu outbreak, The Daily Telegraph tells us. Meanwhile, BBC News reveals that Britons ‘kissed through’ the swine flu pandemic of 2009-10.
The headlines are based on an international survey, carried out by telephone in 2010 (by which time swine flu was becoming much less common), involving five sets of 900 randomly selected people from the UK, US, Mexico, Argentina, and Japan.
The survey consisted of a range of questions designed to assess whether the people adopted well-established methods designed to prevent the spread of flu during an epidemic. These include, frequent washing of hands and avoiding close physical contact with others, such as hugging and kissing.
The researchers soon found a broadly consistent pattern – Mexican people were most likely to adopt these sorts of methods, while Brits were least likely to. For example, only 2% of the UK sample reported avoiding hugging or kissing family or friends, compared to 46% in Mexico who did take this precaution.
While not mentioned in the study, one possible reason that Mexico scored so highly is the fact that the swine flu pandemic originated there, and caused many deaths before being brought under control.
In contrast, the number of deaths in the UK was much lower. Also, after the initial shock, many sections of the media started running stories that UK health authorities were over-reacting to the threat of swine flu, which could have influenced public perception.
Ultimately, many of the differences seen may rest with different cultural values and practices between countries, and therefore, as the researchers conclude, strategies for behavioural recommendations in the event of future pandemics should be country specific.
Where did the story come from?
The study was carried out by researchers from Harvard School of Public Health and other institutions in the US, and was funded by the US Centers for Disease Control and Prevention and the National Public Health Information Coalition.
The study was published in the peer-reviewed medical journal The Lancet.
Generally the media reporting of these survey findings is well conducted, but the Daily Mail’s headline of ‘Britons are world’s worst flu-spreaders’ is both inaccurate and arguably a little unpatroic from the paper.
Admittedly, Britain did finish bottom of the list, but the list only involved five countries. It could well be the case that surveys in other Western European countries (where the public health impact of swine flu was similary modest) would have produced similar results.
What kind of research was this?
This was international cross-sectional research, involving telephone surveys conducted in five countries asking about health behaviours and preventative measures adopted by citizens during the 2009 swine flu pandemic.
The research involved large, random samples of 900 people from each country (911 in the US). This sample size is likely to give a fairly reliable representation of health behaviours adopted by the general population of these countries. However, even with this random sampling, the study design does have a number of inherent weaknesses.
It is possible that those who agreed to participate in the survey may have different health behaviours from those who did not choose to participate. For example, participants in the study may have been more conscious of hygiene than those who did not take part, so the proportions could actually be slight over-estimations of the hygiene practices of the population as a whole. However, given the wide range of the study (over 4,500 people from five different countries), the methods employed by the researchers were reasonable.
The study is valuable for informing public health organisations about how countries differed in their perceptions and reactions to nationally publicised measures to minimise the spread of illness during the 2009 flu pandemic. This information could inform future pandemic preparation efforts.
In the UK, much of the health advice given to the public during the swine flu epidemic was based on the principle of limiting the spread of infection by safely disposing of tissues and frequent washing of hands (the ‘Catch It, Bin It, Kill It’ campaign). The results of this study show that this proved to be reasonably effective (for example, 53% of people reported frequent hand washing). But if a future flu epidemic occurs, there may be a case for reviewing these findings and reinforcing other points of advice.
It is important to note that the study cannot tell us how effective each of these individual measures was at preventing the spread of the flu virus.
What did the research involve?
In 2010, researchers from the Harvard School of Public Health took telephone polls in five countries - Argentina, Japan, Mexico, the UK, and the US. They used sampling methods that were said to be consistent with the best practices of major polling efforts in each country. The researchers randomly selected participants via digit dial techniques – this is when a computer algorithm is used to randomly generate telephone numbers and is widely used by opinion pollsters and the like.
The researchers interviewed 900 adults from each country (911 in the US). This sample size was chosen because it would have sufficient range to detect differences between the countries.
Both holders of mobile phones and landline-only were represented. The researchers made sure that around 150 interviews were conducted via mobile for demographic reasons.
The questionnaires were developed and tested by the Harvard School of Public Health and included questions asking people whether or not they had adopted various prevention behaviours as a way of protecting themselves, or their family, from swine flu at any point during the pandemic.
This included hygiene behaviours including:
- personal protection (such as hand-washing, hand sanitisers, and the use of masks)
- social distancing behaviours (such as avoiding places where large numbers of people gather)
- taking steps to prevent the spread of infection (covering their mouth before coughing or sneezing)
- the uptake of vaccination
What were the basic results?
Overall, in all countries, personal protective behaviour such as washing hands more often or using sanitiser was adopted the most -far more than social distancing behaviours such as avoiding places where many people gather. However, perhaps surprisingly, there was wide variation in these practices across countries. The proportion of people reporting personal protection varied from 53% to 89% across countries, and from 11% to 69% for social distancing.
Generally, the UK tended to have the lowest proportion of people reporting the adoption of preventative behaviours during the pandemic. A sample of results are shown below which show the proportion of people in each country adopting the preventative behaviour described.
Personal protective behaviours
- More frequently washed hands or used hand sanitiser: Argentina 89%, Mexico 86%, Japan 72%, US 72%, UK 53%.
- More frequently cleaned or disinfected home or workspace: Mexico 77%, Argentina 76%, US 55% UK 34%, Japan 27%,
- More frequently covered mouth and nose with tissue when coughing or sneezing: Mexico 77%, Argentina 64%, US 61%, Japan 48%, UK 27%.
Social distancing behaviours
Limiting interactions with individuals:
- Took any steps to avoid being near someone who has influenza-like symptoms: US 56%, Mexico 53%, Argentina 43%, Japan 35%, UK 21%.
- Avoided hugging or kissing distant acquaintances: Mexico 56%, US 38%, Argentina 32%, UK 11%, Japan (not asked).
- Avoided hugging or kissing family or friends: Mexico 46%, US 21%, Argentina 19%, UK 2%, Japan (not asked due to cultural reasons).
Avoiding places with groups of people:
- Avoided places where many people gather, like shopping centres or sporting events: Mexico 69%, Argentina 61%, Japan 43%, US 28%, UK 11%.
- Avoided travelling long distances by aeroplane, train, or bus: Mexico 54%, Argentina 38%, Japan 25%, US 23%, UK 11%.
- Took public transportation less often: Mexico 51%, Argentina 35%, Japan 24%, US 16%, UK 11%.
- Got the vaccine: Mexico 33%, US 27%, Japan 25%, UK 19%, Argentina 16%.
Generally there was high public support for government recommendations to prevent spread, but again, UK support tended to be the lowest:
- Recommendation to avoid places where many people gather: Argentina 88%, Mexico 84%, Japan 81%, US 69%, UK 50%.
- Recommendation to close schools: Japan 90%, Argentina 82%, US 80%, Mexico 79%, UK 68%.
- Recommendation to wear a mask in public: Japan 91%, Mexico 88%, US 71%, Argentina 70%, UK 51%.
How did the researchers interpret the results?
The researchers conclude that ‘There is a need for country-specific approaches in pandemic policy planning that use both non-pharmaceutical [behavioural] approaches and vaccination’.
This large international survey finds that there was wide variation across countries in the personal and social protection strategies adopted by members of the public during the swine flu pandemic. Generally, the UK sample seemed to be the least likely to report taking up extra precautions to protect themselves or others against swine flu.
A strength of the study was that it included a large sample of 900 people from each of five countries, who were randomly sampled from telephone polls. As such, it may be considered to be fairly representative of the population as a whole. However, it must be remembered that although this was a random sample, in order to get 900 people they actually had to ask many more people. The sample for each of the countries represents 13% of those invited from Argentina, 15% in Japan, 12% in Mexico, 13% in the UK, and 21% from the US. Though, as the researchers say, this is similar to the participation rate in other surveys, it is possible that this small proportion of people who agreed to take part in the questionnaires may have had more health vigilant behaviour than those who declined. Therefore, it is possible the results could actually be an over-estimation.
It is important to remember that, as these behaviours were self-reported, we do not know how well they were actually adopted among individuals. For example, hand washing or sanitising practices may have been generally more rigorous among individuals in some countries than in others. There is also the possibility of recall bias, as the surveys were conducted in the year following the pandemic. Overall, the findings cannot tell us how effective these various strategies were, and which individual strategies are most effective at preventing spread of flu.
One potential explanation for higher preventative behaviour uptake in Mexico is that Mexico was the first country hit by swine flu. So the uncertainty and fear at this early stage of the pandemic may have caused more people to take preventative measures in this country than others further away, or where they did not have cases on their shores until sometime later.
In conclusion, it is not possible to say why the UK tended to report lower uptake of the various hygienic behaviours. However, it is possible that differences in the media portrayal of the threat of swine flu between the UK and other countries may have contributed to blasé (or perhaps stoical) British attitudes. Much of the UK reporting of the swine flu pandemic was excellent, being both measured and responsible. However, after the initial shock of the swine flu outbreak, attention moved on to other stories, such as whether the NHS was wasting money buying stocks of the antiviral drug Tamiflu.
As the researchers say, there are many factors that can affect behavioural adoption during a pandemic, and ultimately this is going to be influenced by the country’s culture, values and practices.
The researchers say that certain behaviours are more likely to be adopted than others in different countries. So the findings may help to guide country-specific planning approaches for future pandemics.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.