Would you wear a face mask in public during flu epidemic?
With the flu season in the southern hemisphere winter just over – Australia had a record number of laboratory confirmed cases (170,000) – we, in the northern hemisphere, are now bracing for our turn.
So what can we do to reduce our individual risk of contracting a bad flu this winter?
The flu strain A (H3N2) caused high numbers of hospital admissions in Australia, South Africa and Hong Kong, especially in older people. Yet, many of these had received a vaccine with a H3N2 component.
But it has now emerged that overall flu vaccine effectiveness in Australia between May and September was 33 per cent, with even lower rates of efficacy in the over 65s.
While we can’t be sure what strain of flu will emerge in Ireland in the coming weeks, there is concern because the H3N2 component of our current influenza vaccine is the same as that given to Australians in advance of their winter – with less than stellar results.
A repeat of this scenario here will place extreme pressure on our already struggling health system.
It is, of course, possible that our predominant influenza A virus will be of the H1N1 variety – it targets younger adults and causes fewer hospitalisations and deaths. And, reassuringly, one of the three components in the 2017/2018 flu vaccine is a strain of H1N1.
A blunt reality is that influenza strains can “drift” quite quickly, making the choice made by World Health Organisation experts in February nothing more than informed guesswork.
However, there is mounting concern that the decision made by WHO back then to use the same H3N2 version in last year and this year’s vaccine was a poor one – in other words, that the H3N2 component is unchanged, yet we know the virus is changing.
Does this mean that if you were immunised against flu last year there is no point in getting the same H3N2 shot this year? No, because you will benefit from the updated influenza B and A(H1N1) strains that are also in the vaccine.
And if H3N2 emerges as the big one in the weeks ahead, and you do come down with a dose, having the vaccine should result in a milder bout of flu than you might otherwise experience.
If the flu vaccine turns out to be less effective than we hope, what else can we do to protect ourselves?
Anti viral agents such as Tamiflu may help reduce the duration of influenza, but their benefit has recently been downgraded by the World Health Organisation due to uncertainty about their usefulness in reducing hospital admissions or on limiting the spread of influenza in an epidemic.
Which leaves us with a low-tech but effective intervention – hygiene.
Hand washing, face masks, and quarantine have been found to be very effective at protecting against acute respiratory infections.
Australian influenza experts, Prof Chris Del Mar and Dr Peter Collignon, writing in the British Medical Journal, ask: Why are these methods not canvassed as heavily as vaccination or antivirals?
“Social norms, though accepting
Hand washing, face masks, and quarantine have been found to be very effective at protecting against acute respiratory infections
of handwashing (or sterilisation in public places), mean that people baulk at wearing face masks (except in east-Asian countries such as Japan). Nor do such norms insist that people who are infectious stay away from work or school (instead, admiring them for “soldiering on”) or that mass gatherings (sports and cultural events) are cancelled,” they say.
Calling for greater support for sensible low technology policies, they point to one Australian state’s intention to install hand hygiene dispensers on trains, alongside a campaign to promote “cough into your elbow”.
“In the meantime it is clear that we need better vaccines, with better evaluation, and public awareness messages that promote mask wearing and hand hygiene,” the experts conclude.
Are you ready to swallow your pride and wear a surgical mask on the Dart or inter-city bus during a flu epidemic this winter?