No Link Between COVID-19 Vaccines and Bell’s Palsy, Research Confirms

Scientists continue to find no link between COVID-19 vaccination and several neurological conditions, according to a new study published in The BMJ. However, they did find a stronger association between COVID-19 infection and an increased risk of Bell’s palsy, encephalomyelitis, and Guillain-Barré syndrome.

The real-world evidence confirms the safety of COVID-19 vaccines which had initially come under scrutiny during clinical trials. Early reports from Pfizer and Moderna described seven cases of Bell’s palsy in people who received either vaccine. Additionally, some case reports point to Guillain-Barré syndrome (when your body attacks your nerves) as a potential rare side effect of the vaccines.

“In this observational study, they looked at cases for a long period of time in 9.2 billion doses,” Kiran Rajneesh, MD, director of the neurological pain division in The Ohio State University Wexner Medical Center, who was not involved in the study, told Verywell. “This is a huge sample size and strong data that makes the results more reassuring.”

No Link Between COVID-19 Vaccines and Neurological Side Effects

To investigate a potential link between COVID-19 vaccination and neurological side effects, the researchers tracked the health of over 8.3 million people who received one vaccine dose from AstraZeneca, Johnson & Johnson, Moderna, or Pfizer-BioNTech.

Among the vaccinated, there were over 594,000 people who had had a COVID-19 infection before receiving the first dose of the vaccine. The team also studied almost 736,000 unvaccinated individuals who were previously infected with COVID-19 illness and over 14 million people from the general population.

They calculated the likelihood of developing Bell’s palsy, encephalomyelitis, Guillain-Barré syndrome, or transverse myelitis 21 days after receiving the first vaccine dose or 90 days after testing positive for COVID-19 infection.

Results showed no safety signals—information of a new or previously known adverse event caused by a drug—between the mRNA COVID-19 vaccines and the risk of developing any of the four neurological conditions. Even though the AstraZeneca and Johnson & Johnson vaccines were not made with mRNA, the study also found no connection between these shots and developing neurological complications.

“Vaccines prepared using the previous technologies did not have the side effects that normally you would have expected in a very small percentage [of people],” Rajneesh explained. “Once again, it shows that we don’t have to worry about neurological [conditions] or complications in COVID-19 vaccines.”

However, in the two groups of people who previously had a COVID-19 infection, there was an increased risk of developing:

• Bell’s palsy
• Encephalomyelitis
• Guillain-Barré syndrome

Despite the large sample size, there were some limitations to the research. In the accompanying editorial to the study, a separate team of researchers points out that it is hard to detect small or moderate increases in neurological conditions after vaccination because it is already so rare to manifest one of these neurological side-effects.

Other than age, the authors also did not adjust for patient characteristics that may increase the risk of COVID-19 infection. For example, many people who experienced an infection were more likely to have more comorbidities than the general population.

How Does COVID Cause Neurological Issues?

Since the start of the pandemic, researchers have sought to understand how COVID-19 causes neurological complications post-infection. Rajneesh said the virus inflames or irritates the inner coating of blood vessels called the endothelium. Irritation of the endothelium may cause blood clots and strokes to occur, further damaging the brain. 

Rajneesh added that viruses have a propensity to attack nerve tissue, whether that’s in the brain or spine. Additionally, some viruses have a similar coating to our nerves, which is used to transmit information quickly in the brain. While most people fully recover from an infection, a minority of people remain hypersensitive in the brain.

“Even though you are virus-free, your body still thinks you have the virus because of the similar coating. Your immune cells then start attacking your own nervous system tissues and this gives you different manifestations,” Rajneesh explained. “Some of that is in this paper, such as Guillain-Barré syndrome or Bell’s palsy. What we’re seeing with this virus is similar to the overall pattern of how viruses behave in the nervous system acutely and the consequences after the infection is done and the virus is cleared.”

Get Vaccinated

Rajneesh said the probability of developing a vaccine reaction is very small. However, the real-world results show COVID-19 infection is much more dangerous and poses a greater risk of severe neurological complications.

There is a small percentage of patients who may experience some adverse side effects from vaccines because they are immunocompromised, have autoimmune conditions, or have a history of allergies to vaccines.

Because some COVID-19 vaccines are made differently, a healthcare provider can help you decide which vaccine might be better suited for you and which one will minimize the risk of an allergic reaction.

“We are still recommending these patients to get the vaccine after counseling and addressing their concerns,” Rajneesh said. “If you’re immunocompromised you are more predisposed to getting a COVID-19 infection and having a really severe infection.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.