A meta-analysis of 13 studies examining the effectiveness of influenza vaccinations finds “a significant negative association between psychological stress and antibody responses” to the vaccine. This decreased effectiveness was seen in both elderly and youthful recipients of the purportedly protective injection.
Researchers led by Anette Fischer Pedersen of Denmark's University of Aarhus looked at 13 studies, which included a total of more than 1,150 participants. Five of them compared antibody levels of caregivers (whose stress levels tend to be higher) with non-caregivers; the others examined antibody responses to flu vaccine with self-reported stress levels or stress-producing life events.
The clear conclusion, as reported in the Journal Brain, Behavior and Immunity, is these vaccines are less effective on a stressed-out population.
A group of nursing students were randomly assigned to experimental and control groups. Their levels of stress, anxiety and depression were measured using standard techniques. Those in the experimental group then attended weekly 90-minute, meditation-based stress-reduction sessions.
After eight weeks, the experimental group had significantly lower stress and anxiety levels than the control group. However, there was no significant difference in their levels of depression, suggesting a different approach may be more effective for that particular condition.
Together, the studies suggest that Eastern and Western health-management techniques – so often perceived as in conflict – may in fact be complementary. It appears flu vaccines are most effective they are administered to people who have the sort of low stress levels produced by meditation.