A study notes that there is a “small increase” in the risk of facial paralysis associated with the CoronaVac vaccine against covid-19, although the benefits “far outweigh” the “very rare” risk of this effect, which in most of the cases is temporary and resolves itself.
The article published by The Lancet Infectious Diseases is the first large-scale analysis of the risk of Bell’s palsy after vaccination with the Chinese preparation CoronaVac or with that of Pfizer-Biontech (BNT162b2), for which data from the system were used. of Hong Kong Pharmacovigilance.
“Our study suggests a small increased risk of Bell’s palsy associated with vaccination with CoronaVac,” said study lead author Ian Chi Kei of the University of Hong Kong, cited by the journal.
However, “it remains a rare and mostly temporary adverse event. All the evidence obtained to date, from multiple studies, shows that the beneficial and protective effects “of inactivated-type covid-19 vaccines, such as CoronaVac” far outweigh any risks. “
Bell’s palsy is the sudden onset of a unilateral facial paralysis, which in most cases (70%) resolves on its own in six months without treatment, and the chance of recovery is even higher (90%) if patients receive early treatment with corticosteroids.
Cases of paralysis were included in the analysis if they occurred within 42 days of the first or second dose of the vaccine.
Between February 23 and May 4, 2021, 28 clinically confirmed cases of Bell’s palsy were identified among the 451,939 individuals who received at least a first dose of CoronaVac, equivalent to 3.61 cases per 100,000 doses administered.
For the BNT162b2 preparation, 16 cases were identified among the 537,205 individuals who received at least a first dose, which is equivalent to 2.04 cases per 100,000 doses.
Analyzing data from 2010-2020, the researchers estimated the risk of total Bell’s palsy in Hong Kong: about 27 cases per 100,000 people, per year. Global estimates range from 15 to 30 cases per 100,000 people a year.
Thus, the data indicated that receiving CoronaVac was associated with a 2.4 times higher risk of Bell’s palsy, whereas puncture with BNT162b2 was not associated with a significantly higher risk.
The authors note that they cannot conclude a causal relationship between Bell’s palsy and vaccination in any individual case from this study, and that the mechanism by which vaccination can – in very rare cases – cause Bell’s palsy remains unclear. be clear.
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