We discussed at length the significance of influenza’s capacity to generate genetic variability, and it’s playing out currently this flu season. According to the United States Center for Disease Control and Prevention, the most common circulating flu strain last year was Influenza A H3N2. The vaccine was selected, and began to be prepared in February so there would be enough flu vaccine in time for the start of this flu season. While it’s never known exactly what strain of influenza will carry over from one season to the next, often times, the version seen towards the end of one season’s epidemic is present during the next years flu epidemic. Thus, a huge number of vaccines were made for this flu season to protect against this H3N2 strain. Unfortunately, only 6 weeks after the World Health Organization made its recommendations for this season's vaccine in the Northern Hemisphere, the scientific community detected a mutation.
It became very apparent that the mutated version of H3N2 would be more present based on surveillance of the virus in the southern hemisphere during our summer, but at that point it was too late to change the specificity of the vaccine. Experts are predicting a particularly sever flu season due to the antigenic drift of the H3N2 virus. However, the vaccine will still be somewhat effective and vaccination is still highly recommended.
- Eddie Irvine