Can the COVID-19 vaccine cause Bell’s palsy? Expert says it’s unlikely

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A new report from the Food and Drug Administration has sparked anxiety on social media about a form of temporary facial paralysis called Bell’s palsy, which several COVID-19 vaccine recipients have developed. But experts say the news isn’t reason to panic. Contrary to posts on Facebook implying the vaccine causes the condition, the FDA states clearly that a causal link has not been identified.

The paper, a 54-page briefing document released this week, reveals that four individuals in the Moderna trial— three of whom were given the vaccine — experienced Bell’s palsy. In an earlier briefing, the FDA noted that four candidates in Pfizer’s vaccine group also developed the condition. But an expert tells Yahoo Life that there’s a much better chance the condition is the result of other causes — and that even if it was linked to the vaccine, it can be treated successfully with steroids.

Here’s what you need to know.

The FDA says there is no evidence linking the COVID-19 to Bell's palsy. Here, an EMS worker gets the COVID-19 vaccine in Washington D.C. on Thursday. (Photo by Shawn Thew-Pool/Getty Images)
The FDA says there is no evidence linking the COVID-19 to Bell's palsy. Here, an EMS worker gets the COVID-19 vaccine in Washington D.C. on Thursday. (Photo: Shawn Thew-Pool/Getty Images)

Bell’s palsy comes on quickly, but typically only lasts a few weeks

The National Institutes of Health defines Bell’s palsy as a “form of temporary facial paralysis or weakness on one side of the face [that] results from dysfunction of cranial nerve VII (facial nerve).” The condition hinders an individual’s ability to perform typical facial functions such as blinking and smiling.

Dr. Leslie Kim, a double board-certified otolaryngologist and facial plastic surgeon at the Ohio State University Wexler Medical School, says she sees the condition fairly often. “It typically comes on very quickly, so most people will get it and within 24-48 hours, their face just drops on that side,” Kim tells Yahoo Life. “And most people, about 80 percent or more, start to improve as early as two to three weeks later.” In the vast majority of cases, Kim says, the condition will resolve completely but in rare situations, the nerve regenerates in an “imperfect” way causing what’s called synkinesis.

The exact cause is unknown, but doctors believe it’s triggered by a viral infection

Scientist seems to agree that the condition is caused by inflammation of the facial nerve, but there are multiple ideas about what’s fueling the inflammation. Kim says one leading theory is that it’s due to a “reactivation of the Herpes simplex virus” — which she describes as “the same one that causes cold sores.” A 2006 study published in Science Direct corroborated this, finding the herpes virus in the saliva of a third of patients with Bell’s palsy, but none in the control group.

Other studies have suggested it may be linked to other viral infections, not just herpes. The Mayo Clinic lists nine viruses that have been linked to Bell’s palsy, including influenza, hand-foot-and-mouth disease, chickenpox, respiratory illness and mumps.

Steroids are the best treatment, but antivirals are also sometimes prescribed

In many cases, Bell’s palsy will resolve on its own without treatment. But Kim says that the first line of defense for those who do visit an ER or primary care doctor are steroids. “The only treatment that we recommend is steroids,” says Kim. “Ideally you take them within 72 hours, and that's thought to shorten the time to recovery.” Antivirals are sometimes offered in addition to steroids, but the NIH says that with antivirals, “the benefit has not been clearly established.”

Certain conditions may put you at higher risk of developing it, including COVID-19

Kim says that there are certain risk factors linked to Bell’s palsy which may make individuals more likely to develop it. “What we know is that diabetes is a risk factor for Bell's palsy, as well as high blood pressure or hypertension,” she says. “If you have an upper respiratory infection, such as the flu or a sinus infection, you may be at higher risk, as well as if you are immunocompromised or pregnant.”

She notes that there’s also evidence that COVID-19 may become another risk factor for Bell’s palsy. “There are some reports that COVID itself increases the risk of Bell's palsy,” says Kim. One such study, published in the Journal of NeuroVirology in October, revealed eight COVID-19 patients who developed Bell’s palsy, three of them as the first symptom.

There is no evidence thus far that the COVID-19 vaccine causes Bell’s palsy

It is too soon to determine whether or not Pfizer or Moderna’s COVID-19 vaccines are linked to Bell’s palsy, but as an expert, Kim suspects they are not. “Bell’s palsy happens in about 15 to 30 per a hundred thousand people,” she says. “Moderna had three cases and Pfizer four, so technically speaking, we’re still within those numbers. At this point, it doesn’t seem any higher than the general population.”

She says that the debate over whether vaccines are linked to Bell’s palsy is a “very controversial one” but notes that it has been linked to a vaccine in the past — specifically a nasal spray flu vaccine that reportedly led to elevated cases of the condition. In a report on the matter, the World Health Organization determined that it was likely the “specific vaccine components” that caused it.

At the moment, given all of this, Kim isn’t concerned. “I certainly don't think at this point we can say it should be a deterrent to getting the vaccine,” says Kim. “It's just something to be aware of.”

For the latest coronavirus news and updates, follow along at According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.