COVID-19 VACCINES: mRNA vaccines could cause face paralysis.

Back in December 2020, the U.S. Food and Drug Administration (USFDA) had issued a warning to health care workers, who administer the giving of both the Moderna and Pfizer vaccines to closely monitor the recipients for side effects such as Bell's Palsy. Among the 30,000 trial participants for Moderna, three of the persons who received the vaccine experienced Bell's Palsy. For the Pfizer vaccine, 43,000 persons were in their trial group, four of their participants who received the vaccine suffered from this side effect. 

What is Bell's Palsy?

According to the Mayo Clinic, Bell's palsy is a sudden freezing or weakness in a person's facial muscles that is usually temporary for most people. It's believed that it could be caused from either a viral infection or swelling and inflammation of the nerve that controls the muscles on one side of your face.

Even though there were four reported cases of Bell's palsy among Moderna's 30,000 trial participants, including three who got the vaccine, the FDA however said that "currently available information is insufficient to determine a causal relationship with the vaccine." 

The FDA's guidance for Moderna's vaccine which was issued on December 15, 2020 was similar to its guidance on Pfizer's vaccine a week earlier.

FDA Recommendations

U.S. Food and Drug Administration staff recommended monitoring people who get Pfizer or Moderna's Covid-19 vaccine shots for possible cases of Bell's palsy, saying it's not necessarily a side effect but worth watching out for after a handful of trial participants got the condition, which causes half of your face to droop.

The staff, which endorsed the emergency use of Moderna's coronavirus vaccine, said there wasn't enough data to tie the cases directly to the shots, but it warranted close scrutiny.

Two of the cases of Bell's palsy among Moderna's vaccine group have since "resolved" while one was still ongoing at the time of the report, the FDA staff said. The vaccinated participants experienced the paralysis between 22 days and 32 days following inoculation, they said.

The FDA's Vaccines and Related Biological Products Advisory Committee met on December 17, 2020 to review Moderna's vaccine. It had endorsed Pfizer's vaccine a week earlier, before the FDA granted formal authorization to begin its distribution. Health-care workers lined up at locations across the U.S. to get some of the first injections of Pfizer's vaccine on December 14.

Dr. Paul Offit, a voting member of the FDA's Vaccines and Related Biological Products Advisory Committee, had agreed that the condition was worth monitoring as the vaccines began to be rolled out. He however voted in favor of recommending Pfizer's vaccine.

When Merck submitted its data from its rotavirus vaccine trial, there were five cases of Kawasaki disease but none in the placebo group. That was "statistically significant" and caused Merck to change its label to note the cases.

While there was a small imbalance of cases in the vaccine group compared with the placebo, the FDA said it's not certain whether the drug contributed to the paralysis "because the number of cases was small and not more frequent than expected in the general population."

"There were no other notable patterns or numerical imbalances between treatment groups for specific categories of adverse events, including other neurologic, neuro-inflammatory, and thrombotic events, that would suggest a causal relationship to the Moderna COVID-19 vaccine," FDA staff wrote in the documents.

The FDA's guidance for Moderna's vaccine issued was similar to its recommendations for Pfizer's vaccine. U.S. Centers for Disease Control and Prevention officials said Pfizer's vaccine doesn't appear to cause the condition.

Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in an interview with JAMA on December 14 that the agency would be able to easily and quickly access data on Bell's palsy cases once the vaccines are administered.

"Our working hypothesis is this just was an imbalance in background rates like we've seen in other trials, but we'll make sure that we're going to actually query for that just to bring that question to close," Marks said.

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— CNBC's Berkeley Lovelace Jr. contributed to this report.

Source data: CNBC https://www.cnbc.com/amp/2020/12/15/fda-staff-recommends-watching-for-bells-palsy-in-moderna-and-pfizer-vaccine-recipients.html