Gene expression at play in age-dependent vaccine response

A new Yale School of Medicine study has answered the question of why younger bodies respond better to flu vaccines than older ones.

Researchers found that healthy older adults produced protective antibodies for the flu vaccine at a different rate than younger adults. Lower vaccine responsiveness in older adults is related to less effective immune responses. The results represent the first genome-wide analysis of age-dependent responses to the flu vaccine. The study was published in the journal Aging on Jan. 14.

The research was conducted with the hope that the genetic pathways that were identified could be future targets for therapies to improve responses for vaccination, particularly in older adults, said Albert Shaw, professor of medicine and senior author of the paper.

Even when the influenza vaccine is a good match for currently circulating strains of the virus, most vaccines are less effective for older adults, Shaw said. In fact, roughly 90 percent of deaths from influenza in the country occur in people older than 65, Shaw said.

Shaw said he and his team wanted to identify patterns of gene expression that were found in older and younger adults who showed excellent responses to vaccination and compare those patterns to those who had poor responses to vaccination.

They found specific patterns of gene expression that corresponded to antiviral responses, including those that reflected activities of cells that make protective antibodies against the influenza strain and vaccine, he said. Although antibodies were created about seven days after vaccination for young adults, for older adults, the timing varied, he added.

The studys findings were not news to representatives from leading vaccine development companies.

It is well known in our industry that the elderly mount less of an immune response to vaccination, said Charles Altman, head of medical affairs at BioCSL. If you look in any product label, you will find that.

Many manufacturers are trying to improve elderly response, but they face limited options for innovation due to regulations put forth by the World Health Organization, which makes a recommendation each year about which viral strains manufacturers can put in vaccines.

Because manufacturers are not allowed to modify which viral strains they use in their products, they can only vary a few factors, among them dosage and added adjuvants material added to vaccines to promote immune response Altman said. Therefore, the study has little practical relevancy for manufacturers like BioCSL.

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Gene expression at play in age-dependent vaccine response