Immune Differences May Influence Flu Vaccine Effectiveness

Results of a recent study help to identify how differences in immune responses may be associated with the effectiveness of the seasonal flu vaccine.

Although previous research has found that the effectiveness of the flu vaccine differs between individuals based on various factors, including age, there is currently no method to allow for the prediction of its efficacy.
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To address this concern, researchers from the Mayo Clinic conducted a study in which 159 individuals aged 50 to 74 years old were given the influenza vaccine.1 Blood samples were collected before vaccination, as well as 3 and 28 days following vaccination. Using flow cytometry, the researchers analyzed these samples, examining the levels of several types of immune cells.

Overall, they found that the effectiveness of the influenza vaccine was associated with several immune cell parameters. Individuals with higher levels of antibody response to the vaccine at day 28 had higher levels of HLA-DR, a protein that serves as a marker for immune stimulation, on certain dendritic cells, cells that are responsible for coordinating immune responses. Prior to vaccination, these individuals also showed higher levels of B cells in the blood and higher concentrations of CD86, a protein involved in the activation of the immune system.

“These results show that individuals do exhibit meaningful differences in how their immune systems respond to vaccination against seasonal flu, which correlate to the level of immunity they show against flu after vaccination,” the researchers concluded. “Understanding more about how immune system function and response differs on an individual level will improve our ability to design and create more effective vaccines.”2

—Michael Potts

References:

  1. Kennedy RB, Simon WL, Gibson MJ, et al. The composition of immune cells serves as a predictor of adaptive immunity in a cohort of 50- to 74-year-old adults [published online May 17, 2016]. Immunology. doi:10.1111/imm.12599
  2. British Society for Immunology. Differences in individuals’ immune responses linked to flu vaccine [press release]. May 18, 2016. https://www.immunology.org/public-engagement/media16-immune-system-differences-vaccine-effectiveness.