During the trials of the Pzifer vaccine, four cases of volunteers who suffered facial paralysis were detected. However, for the moment there is no evidence to link this with the administration of the vaccine.
Bell’s palsy is a disorder of the nerve that controls the muscles of the face, causing them to not be used properly. Usually it is usually a temporary ailment, and in this case the four volunteers have already recovered.

The fact that the four people affected with paralysis were in the group that had received the vaccine and not the placebo sounded the alarm. Despite this, the United States Food and Drug Administration (USFDA) reported that “Four cases in the vaccine group do not represent a higher frequency than expected in the general population.”
The number of people who suffered paralysis is within the normal rate of appearance of this condition in the population of a country. Therefore, according to the USFDA, what happened in the Pfizer trials “fits the expected history rate in the general population.”
Still, from the American organization Pfizer technicians have been warned to be alert and “monitor for Bell’s palsy with the deployment of the vaccine in larger populations.”