Another year

Influenza

Seasonal times bring seasonal infections, or not as in the case of Influenza this year. As has been the case for the last three years influenza activity has been very low, in fact for this year remarkably low and if past years are a reliable guide (they mostly are) then we are already through the peak month and the winter flu outbreak is already on the slide. The amazingly warm weather is certainly part of the reason for this but it seems also that the strains in circulation are relatively unchanged from previous years and are all well-matched by the current vaccine strains, unlike the situation last year where the H3 strains in the vaccine were poorly matched[1]  although that season too was very mild.  The majority of strains typed this year so far have been H1, essentially the pandemic strain from 2009 which seems have varied very little in recent years. We haven’t had a significant flu outbreak since 2010/11 but as noted previously in this blog the clock resets itself every year and a cold snap could change what has been, for the last few years, a relatively benign influenza season.

Ebola

Any review of the year for 2015 (they will be in the supplements at the coming weekend) would have to include the end of the Ebola outbreak. So much has been written on the outbreak that more seems pointless and there will be ample papers this year with official follow-up analysis such as the case fatality rate with time (remarkably similar from early in the epidemic to late as far as I can make out which suggests the treatment camps did not improve as time went on) and the outcome of clinical trials conducted while the epidemic was raging. Whatever these say, the subject has already gone from the headlines (graphic 1), predictable but still disappointing as it was historically significant for a number of reasons.

Others

If you strip out Ebola and Influenza then 2015 has been a relatively quiet year for virus infections (graphic 2), at least for those that might make headlines. They are all there of course causing routine

infections throughout the year, common cold, measles (still an issue in inner London), HIV, Herpes, norovirus, but nothing has really taken off this year and those associated with the winter season have been particularly quiet. Some of this is the result of other world events dominating the headlines but there too viruses are involved with increased incidences of a number of infections, including HIV and measles, in refugee populations displaced by the war in Syria. We must wait for the next year to see how serious these become and whether or not the El Nino effect that is giving the unseasonal weather will perturb virus dynamics (those transmitted by insect pests for example) later in the year.

[1] http://www.telegraph.co.uk/news/health/news/11393560/Flu-jab-given-to-millions-is-useless.html