“We provide novel evidence of a potential connection between the baseline state of the immune system in the elderly and reduced responsiveness to vaccination,” coauthors Shankar Subramaniam of the University of California, San Diego, and Bali Pulendran of Emory University said in a press release. “By providing a more complete picture of how the immune system responds to vaccination, our findings may help guide the development of next-generation vaccines that offer long-lasting immunity and better protection of at-risk populations.”
The researchers combined their results on 212 vaccinated individuals with previously published data for 218 subjects, finding that, within a week of vaccination, young people had high levels of B cells, while elderly individuals had high levels of NK cells, as well as of monocytes, which trigger inflammatory responses. These differences corresponded with reduced vaccine-induced immune responses in the elderly a few weeks after the vaccine was given. Going back to samples taken before vaccination, the researchers found that high levels of B cells and low levels of monocytes and other inflammatory molecules could predict successful vaccine-induced immune protection. “This supports the concept that inflammatory responses at baseline may be detrimental to the induction of vaccine-induced antibody responses,” Subramaniam said in the statement.
Subramaniam hopes that the findings will be able to help researchers tailor future vaccines to the immune status of an individual. “Before I give a vaccine, can I look at your immune status and then tell you your immune status will be fantastic to this vaccine, or you’re not going to be responding greatly, so let’s hold off on giving you a vaccine,” he told The San Diego Union-Tribune.