More than two-thirds of the common side-effects people experience after a Covid jab can be attributed to a negative version of the placebo effect rather than the vaccine itself, researchers claim. In view of their results, the researchers argue that better public information about nocebo responses may improve Covid vaccine uptake by reducing the concerns that make some people hesitant. In each trial, those in the placebo arm were given injections of inactive salt solution instead of vaccine. The difference was even greater for local ailments, reaching 73% among those who had the vaccine and 12% in the placebo group. Overall, the researchers calculate that about two-thirds of common side-effects reported in Covid vaccine trials are driven by the nocebo effect, in particular headaches and fatigue, which many Covid vaccine leaflets list as the most common adverse reactions after a shot.

Source: The Guardian January 19, 2022 11:40 UTC