Craig Boerner

The avian (bird) influenza vaccine creates a more robust immune response when paired with a potent ingredient known as an adjuvant, according to Vanderbilt University Medical Center (VUMC) research published in The Journal of Infectious Diseases.

Adjuvants are used to help some vaccines work better by creating a stronger immune response for people receiving the vaccine.

Avian influenza is a potential pandemic virus, so identifying the basic immune processes that govern how well individuals respond to influenza vaccination is important, according to senior author C. Buddy Creech, MD, MPH, director of the Vanderbilt Vaccine Research Program and Edie Carell Johnson Professor of Pediatrics.

“On its own, the vaccine does not generate a robust immune response, even with very high doses of the vaccine. However, when we add a potent adjuvant (in this case, AS03) to the avian flu vaccine, even small doses of the vaccine can be effective,” Creech said.

“This study, along with previously published work, gives us more insight into the biologic pathways that are needed to make an effective response to influenza vaccine,” he said.

Study authors recruited 20 healthy men and women ages 18-49 who were randomized to receive two doses of inactivated influenza A/H5N1 vaccine alone or with AS03 adjuvant one month apart.

Creech said there are some antigens, like on the surface of bird flu, that are not recognized as readily as others, so adjuvants are used to stimulate the immune response, which is particularly important for viruses that have pandemic potential.

A blood sample is usually required to gauge a person’s immune response to a vaccine, but in this study, researchers were able to predict who would be protected against a potential pandemic influenza virus by measuring byproducts of metabolism in the urine.

“Typically, to detect whether an individual has had an effective immune response to a vaccine requires collection of a blood sample to test antibody responses, which are not usually detectable until several weeks after a vaccine has been given,” said co-first author Leigh Howard, MD, MPH, assistant professor of Pediatric Infectious Diseases.

“Our findings mean that, in the near future, we may be able to identify individuals who have not responded well to an influenza vaccine with a simple urine sample. Additionally, we may be able to identify individuals with a weak immune response to the vaccine only a few days after vaccination, which may be helpful in designing strategies to provide extra protection for these individuals, such as additional vaccine doses or other mitigation measures.”