Could the annual flu shot see big changes?

By Grace Materne

Most individuals will receive a flu shot annually without much thought; however, recent studies suggest an overwhelming need for flu vaccine research.  Traditionally, flu vaccines are manufactured by injecting the virus into chicken eggs and allowing it to replicate; the virus found in the fluid of the eggs can then be isolated and used in vaccines. A recent study examining the H3N2 subtype of influenza found that when replicating inside the chicken eggs, the influenza virus must adapt and mutate in order to grow in the new environment. In the case of the H3N2 subtype, however, the mutations during replication are causing vaccines to be only 33% effective. To further study the mutation, researchers use X-ray crystallography, a high-resolution imaging technique. The data indicates that while inside the chicken eggs, the H3N2 subtypes mutates the protein L194P on the hemagglutinin glycoprotein (HA). This mutation results in the human immune system being less effective in recognizing the virus. Thus, if a vaccine for H3N2 subtype contains the mutated protein, it will be unsuccessful in establishing immunity against this strain of influenza. Current research is investigating alternatives to the chicken egg test method and instead looking at the possibility of mammalian cells and recombinant HA protein vaccines.


Scripps Research Institute. "How flu shot manufacturing forces influenza to mutate: Egg-based production causes virus to target bird cells, making vaccine less effective." ScienceDaily. ScienceDaily, 30 October 2017. <>.