Last updated on 13.01.2021

Side effects & questions

Side effects

Vaccines are authorised by Swissmedic only if they are safe and effective. They are thoroughly tested to this end.

The risk of serious complications of an infection with coronavirus is many times higher than the likelihood of suffering severe side effects of the COVID-19 vaccination. In other words: it is the coronavirus that poses a threat, not the vaccination.

Side effects can occur with any vaccination, but serious side effects are clearly the exception.

Pfizer/BioNTech have tested the vaccine in a trial with 43,000 participants. Half of the tested individuals received the COVID-19 vaccine, while the other half received an inactive placebo. The side effects experienced by the study participants were those commonly seen with any vaccination. Aside from mild local reactions around the injection site, the following side effects were observed in those injected with the COVID-19 vaccine:

  • Fatigue
  • Headache
  • Muscle pain
  • Shivering
  • Fever

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These symptoms were short-lived. Four of the 43,000 or so study participants suffered severe side effects, including one case of temporary leg paralysis and one of cardiac arrhythmia. But such side effects occurred with equal frequency in both the vaccine and placebo groups, suggesting that the side effects were not caused by the vaccination.

Rare side effects, or those that occur after three months, have not yet been observed in the study. But the study results to date clearly demonstrate that the risks of coronavirus disease are much higher than the risks associated with the vaccine.

It is a similar story for the side-effects of the Moderna vaccine: half of the 30,000 or so people taking part in the trial were given the COVID-19 vaccine, while the other half received a placebo. Here too the symptoms were classic. In addition to minor reactions around the injection site, the following side-effects were observed:

  • Fatigue
  • Headache
  • Muscle pain
  • Joint pain
  • Shivering

Serious adverse side effects (for example heart attack, inflammation of the gall bladder and kidney stones) were reported as infrequently for trial subjects given the Moderna vaccine as for those who were not given a vaccine (0.6% in each case). In the trial there was no indication of these events having been triggered by the COVID-19 vaccination.

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