Wednesday, September 13, 2017

UK: NHS Warns Of A Potentially Rough Flu Season Ahead

Credit NIAID


Although it is nearly impossible to know what kind of flu season we will see this winter, over the summer we've followed reports of severe (mostly H3N2) epidemics in Australia Hong Kong, Taiwan, and Southern China - all of which are suggestive that it might be the Northern Hemisphere's turn next.

Yesterday, after comments by Simon Stevens, head of their NHS, newspapers warned.
NHS fears the worst flu season in history 
NHS chief warns of severe winter flu outbreak after worst season on record in Australia

NHS bracing for the 'worst flu season in history'
Somewhat less hyperbolic is this report from the BBC. 

 NHS told to brace itself for bad flu season

12 September 2017 
Flu could put much more pressure than usual on GPs and hospitals this winter, health bosses are predicting.

It follows the worst outbreak in many years in Australia and New Zealand.

Speaking at a health conference in Manchester, NHS England chief executive Simon Stevens said the winter flu season there was a pointer to the pressure which could build up in the NHS this winter.

But he insisted measures were being taken to ensure the NHS was prepared.

Reports have suggested there has been close to double the amount of flu circulating in Australia this July and August - the country's core winter months - than the average over the previous five winters.

Mr Stevens said it had been a "heavy flu season" and many hospitals had struggled to cope, which should act as a warning to the health service and the need to get as many people as possible vaccinated.
(Continue . . . .)

While the seasonal flu shot has been reasonably effective against influenza B, and H1N1, it has struggled against the more genetically diverse H3N2 virus (see full discussion in The Enigmatic, Problematic H3N2 Influenza Virus).
Here in the United States, last winter we saw a modest level of protection (34%) against H3N2, according to the CDC's MMWR report of June 30th.

2016–17 Influenza Vaccine Effectiveness

Data collected through the U.S. Influenza Vaccine Effectiveness Network during November 28, 2016–April 14, 2017, indicate that influenza vaccination this season reduced the overall risk for influenza-associated medical visits by 42% (95% CI = 35%–48%). Vaccine effectiveness against the predominant influenza A(H3N2) viruses was 34% (95% CI = 24%–42%) and vaccine effectiveness against influenza B viruses was 56% (95% CI = 47%–64%).

This fall's northern hemisphere flu vaccine will use the same (A/Hong Kong/4801/2014-like) H3N2 virus as last year's formulation, but will add a new H1N1 strain (see NIAID Video: Antigenic Drift).

Over the past 9 months several new amino acid substitutions (including N121K) have turned up in H3N2 viruses in Hong Kong (and around the globe), which may further reduce this year's vaccine effectiveness (VE).  
We don't know, however, which strain of H3N2 will dominate the Northern Hemisphere this year, or how much of an impact (if any) these genetic changes will have on this year's VE. 

While the vaccine can’t promise 100% protection, it – along with practicing good flu hygiene (washing hands, covering coughs, & staying home if sick) – still remains your best strategy for avoiding the flu and staying healthy this winter.

And if an unusually severe H3N2 season does materialize this winter, you'll want every advantage you can get.


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