A Tale of Two Mutations: Beginning to Understand the Problems with Egg-Based Influenza Vaccines?
The majority of influenza vaccines are produced in embryonated eggs, but mutations occur as human influenza A(H3N2) viruses adapt to grow in eggs. This can alter virus antigenicity. Wu et al. (2019) reveal that there are two mutually exclusive pathways for egg adaptation, which has potential implications for future egg-based influenza vaccines.