Women tend to have a greater immune response to a flu vaccination compared to men, but their advantage largely disappears as they age and their estrogen levels decline, suggests a study from researchers at the Johns Hopkins Bloomberg School of Public Health.
The study was published July 12 in the journal npj Vaccines. The researchers evaluated responses to the flu vaccine in 50 adults age 18-45 years and to 95 adults age 65 and older, and found that the women in the younger group had a stronger immune response compared to the older women and all men. Experiments in mice yielded similar results, and suggested that estrogen — levels of which lessen with age in females — boosts females’ immune responses to flu vaccines, while testosterone lowers males’ responses. The scientists expect that their results will be generalizable to other vaccines.
“We need to consider tailoring vaccine formulations and dosages based on the sex of the vaccine recipient as well as their age,” says study senior author Dr. Sabra Klein, an associate professor in the Bloomberg School’s department of molecular microbiology and immunology.
Scientists have known that women tend to have stronger immune responses to vaccines, and also that the elderly tend to have weaker responses. Dr. Klein and colleagues in their study set out to get a better understanding of the interaction of these sex- and age-related differences.Friday Letter Submission, Publish on July 19