Why This Flu Season Feels So Severe
The United States is experiencing one of its most intense flu seasons in the past 25 years, with millions of illnesses, tens of thousands of hospitalizations, and thousands of deaths reported so far. According to Prof. Yonatan Grad of the Department of Immunology and Infectious Diseases and Director of the Center for Communicable Disease Dynamics, several factors contribute to this surge: changes in circulating influenza strains, waning immunity from past infection and vaccination, and increased social interaction that facilitates virus spread.
This season has been dominated by the H3N2 influenza A subtype, which may cause more severe illness and differs antigenically from the strains included in this year’s vaccine. Although the vaccine may be a less perfect match, current evidence suggests it still induces some protective response, and it’s not too late to get vaccinated. Prof. Grad also stresses continuing respiratory virus precautions — such as masking, hand hygiene, and avoiding crowded, poorly ventilated spaces — to reduce transmission.
