Contributed by: Dr. Akilesh R & Dr. Tamhankar
A new study suggests antibiotics may hinder the effectiveness of flu vaccines!
In an earlier study involving humans, it was found that expression of the gene encoding TLR5 was correlated to increased antibody response weeks later. TLR5 encodes a protein that enables immune cells to sense flagellin, the main structural protein for the whips (flagella) many bacteria use to propel themselves.
“Our results suggest that the gut microbiome may be exerting a powerful effect on immunity to vaccination in humans, even immunity induced by a vaccine that is given at a distant site,” says Pulendran, Charles Howard Candler professor of pathology and laboratory medicine at Emory University School of Medicine and Yerkes National Primate Research Center.
Antibiotics may remove most of the gut bacteria which in turn may affect expression of genes encoding TLR5. In the current study on mice, they found that mice lacking TLR5 had diminished response to flu vaccine.
Viral infections in the upper respiratory tracts is common in winter and rainy seasons when flu also occurs. Antibiotics are often misused for treating these viral infections of the upper respiratory tract infections. It may happen that when gut bacteria are removed due to the effect of these antibiotics, flu vaccines given at this time, may have a reduced efficacy. This study may also explain the different responses to the same vaccine in different parts of the world.
To summarize, antibiotic treatment before or during vaccination may impair responses to certain vaccines in humans. The results may also help to explain why immunity induced by some vaccines varies in different parts of the world.
The study team is planning a study in humans shortly to confirm the findings in humans.
1. Jason Z. Oh et al. TLR5-Mediated Sensing of Gut Microbiota Is Necessary for Antibody Responses to Seasonal Influenza Vaccination. Immunity. Volume 41, Issue 3, p478–492, 18 September 2014.