Covid-19 vaccine linked to increased risk of facial paralysis: study

Scientists have found that vaccination against Covid-19 is associated with an increased risk of facial paralysis, with the risk being particularly high within 28 days of receiving the shot.

Facial paralysisalso known as Bell’s palsy, it leads to ephemeral weakness or paralysis of the facial muscles, which causes drooping of one side of the face and difficulty in facial expression. Although the exact cause of the disease is unknown, experts believe that certain viral infections, autoimmune mechanisms or vaccinations may be potential triggers.

Although pivotal clinical trials conducted during the development of Covid-19 vaccines have not identified any major safety concerns, there is an imbalance in the incidence of facial paralysis among vaccinated people compared to the general population. This prompted researchers to conduct large-scale studies test study of over 44 million patients in South Korea to investigate the risk of facial paralysis among people vaccinated against COVID-19.

The researchers checked a national database of people who had received more than one dose of a Covid-19 vaccine and were then diagnosed with facial palsy within 240 days of vaccination.

Comparing the incidence of facial paralysis between days 1 and 28 after vaccination with the follow-up window (the remainder of the 240-day follow-up period), the researchers noted that there were 5,211 cases in the risk window and 10,531 cases in the follow-up window. .

The study found a 12% augment in the risk of facial paralysis 1 to 28 days after receiving any dose of the Covid-19 vaccine. The researchers also noted that the risk increased regardless of whether a person received homologous or heterologous vaccines.

While the second dose showed a 7% higher risk, the combination of the first and second doses showed an 8% augment. However, there was no increased risk after the third dose.

“The risk of facial paralysis (FP) increased in the 28 days after vaccination, mainly after the first and second doses, and was observed with both mRNA and viral vaccines. Physicians should carefully assess the benefit-risk profile of FP associated with Covid-19 vaccines and monitor neurological symptoms post-vaccination,” the researchers wrote in: press release.

While the exact cause of facial paralysis following vaccination is unclear, researchers have suggested possible explanations.

One explanation is that mRNA vaccines employ lipid nanoparticles to deliver the SARS-CoV-2 spike antigen, which triggers an immune response that can lead to the release of pro-inflammatory cytokines. This reaction can damage the myelin sheath and potentially cause facial paralysis.

In the case of viral vector vaccines, their function is to produce antibodies against viral proteins. Because these antibodies are similar to proteins found in nerves, they can mistakenly attack myelin, causing nerve damage.

The researchers also noted that COVID-19 infection is associated with a higher risk of facial paralysis. Recent research suggests that this increased risk may be due to nerve compression resulting from inflammation caused by the virus.