Would you wear a face mask in pub­lic dur­ing flu epi­demic?

The Irish Times - Tuesday - Health - - Front Page - Muiris Hous­ton

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.

Guess­work

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?

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