Dr. Natalia Freund in her lab. Photo courtesy of Tel Aviv University
While stress improves antibody production after Covid-19 vaccination by 70%, it significantly reduces antibody diversity to protect against variants.
A significant link between behavioral stress and the effectiveness of vaccines was demonstrated for the first time, in a study published in Brain, Behavior, and Immunity by researchers at Tel Aviv University.
They found that acute stress in mice nine to 12 days after vaccination increases antibody response to the vaccine by 70 percent compared to a control group.
However, the diversity of antibodies in the stressed mice was reduced, resulting in diminished protection against the pathogen’s variants.
“The prevailing assumption is that the effectiveness of a vaccine is determined mainly by its own quality. However, over the years, professional literature has reported influences of other factors as well, such as the age, genetics, and microbiome of the outcomes of vaccination,” said clinical microbiologist and immunologist Natalia Freund, in whose lab the study was done by PhD student Noam Ben-Shalom.
“Our study was the first to investigate the possible effects of acute stress. We found that this mental state has a dramatic impact – not only on the vaccine’s effectiveness, but also on how it works,” said Freund.
The team gave mice two different vaccines: the model protein Ovalbumin and a fragment of the SARS-CoV-2 spike protein also used in the Covid-19 vaccine. Nine days later, just as the adaptive immunity became active and the production of antibodies began, the mice were subjected to a widely used behavioral paradigm simulating acute stress.
“Initially, we were surprised to find out that the response to the vaccine was much more effective in animals that had experienced stress,” Freund said.
“We would have assumed just the opposite – that stressful situations would have a negative impact on the immune system. Nevertheless, with both types of vaccines, we observed a stronger immune response after stress, both in the blood and in B cells [the lymphocytes that produce antibodies] derived from the spleen and lymph nodes of the immunized mice.”
