I recently had my annual flu shot. Along with all the others who’ve received it, I’ll be hoping that it does the job of preventing me catching flu this winter – or at least reducing the severity of the disease if I do get it. Most years, it works, but occasionally things don’t go to plan. Winter 2014-2015’s vaccine was considerably less effective than usual and the flu caused 3,000 excess deaths per week in the UK alone in January 2015.
Annual flu vaccine design, manufacture and distribution involves a massive global undertaking but when it goes wrong the consequences can be serious, as we saw in early 2015. The reason this happens every few years is that the influenza virus has evolved to be a cunning vaccine-avoiding machine.
