Further to our most recent post about the likelihood that the frequency of adverse side effects may be attributable to the placebo effect (or more appropriately, the nocebo effect), here’s some more detail provided by reknowned placebo research Ted Kaptchuk, in an article from the Harvard Medical School, ‘Power of Placebo: Some COVID-19 vaccine reactions may result from placebo response’.

“Nonspecific symptoms like headache and fatigue—which we have shown to be particularly nocebo sensitive—are listed among the most common adverse reactions following COVID-19 vaccination in many information leaflets,” said senior author Ted Kaptchuk, HMS professor of medicine and director of the Program in Placebo Studies at Beth Israel Deaconess.

“Evidence suggests that this sort of information may cause people to misattribute common daily background sensations as arising from the vaccine or cause anxiety and worry that make people hyperalert to bodily feelings about adverse events,” he said.

Kaptchuk and colleagues are known for a large and growing body of evidence showing that full disclosure of placebo treatment, what he calls “open-label placebo,” can actually improve common chronic conditions without any nocebo effects. Kaptchuk believes it is ethically necessary to fully inform participants about the vaccines’ potential adverse reactions.

“Medicine is based on trust,” said Kaptchuk. “Our findings lead us to suggest that informing the public about the potential for nocebo responses could help reduce worries about COVID-19 vaccination, which might decrease vaccination hesitancy.”