Women experience side effects after vaccination more often than men: in 78.8% of cases, side effects after vaccination with Pfizer and Moderna were reported in middle-aged women, US Centers for Disease Control and Prevention (CDC) reported.

Most often, patients complained of a headache after vaccination (22.9%), dizziness (16.8%), and fatigue (16.8%). In more than 90% of cases, side effects were classified as not posing a threat to life and health. The average age of vaccinees who reported side effects is 42 years.

Post-vaccination anaphylactic reactions are also predominantly reported among women: all 19 cases in Pfizer and 44 out of 47 cases in Moderna.

CDC experts do not say what is the reason for this phenomenon. It is possible that women are simply more likely to report side effects, as they are thought to be more mindful of their health. Another explanation could be the stronger immune response in women.

Studies have shown that the level of neutralizing antibodies after vaccination against various infections in women is twice as high. It also develops stronger T-cell immunity in patients. This may be due to the effects of estrogen, which causes immune cells to produce more antibodies, while the male sex hormone testosterone is immunosuppressive.