Flu vaccine development is a challenge. Yonatan Grad, assistant professor of immunology and infectious diseases at Harvard T.H. Chan School of Public Health, told The Economist in a February 7, 2018 story that it can be difficult to predict when influenza pandemics will emerge, and consequently, which strains to target in the annual flu shot. In addition, he said that the current system of cultivating vaccines in chicken eggs may cause them to mutate to conditions inside the eggs, thus reducing the vaccines’ effectiveness. Researchers are working on other methods for developing vaccines, including utilizing different animal proteins or a genetically engineered live virus, and are also working to develop a universal flu vaccine.
The article notes that while this year’s flu vaccine has been less effective than usual against this season’s dominant H3N2 strain, it still cuts incidence, severity and transmission.
Read Economist article: Why the current flu crisis is so severe
Better late than never on vaccination, expert says (Interview with Yonatan Grad in Harvard Gazette)