Headaches, fatigue, muscle pain… Perhaps have you felt these very side effects after the first, second, and even third dose of the Covid vaccine. You are not alone. An American study – conducted by scientists from the Boston hospital and Harvard – was issued this Thursday January 20, 2022, and explains effects felt are caused by the nocebo effect.
But what is the nocebo effect? The nocebo effect is the opposite of the placebo effect, leading some people to feel relief and a positive effect just by swallowing a medicine. On the contrary, the nocebo effect makes it that some people feel from the moment they take the medicine – or get the vaccine – all the side effects listed on the user instructions – and even if there is no active compound.
Based on the report of side effects from 45,000 people involved in 12 clinical trials about Covid vaccination, scientists running the study have separated a cohort into two parts: half of them got a real vaccine, the other a placebo.
The study shows that people given a placebo yet felt side effects in the days following the injection. Authors of the study consider 76% of side effects felt after the first dose of vaccine are caused by the nocebo effect, improved by anxiety and stress of patients to the idea of getting vaccinated. A stress that decreases with the second shot because, according to scientists, 52% of side effects felt after the second dose are caused by the nocebo effect.
