The risk of Bell's Palsy, a type of facial paralysis, is higher after Sinovac Biotech Ltd's Covid-19 vaccine CoronaVac, but should not be a deterrent to vaccination, according to a study published in the Lancet Infectious Diseases journal.

However, "the beneficial and protective effects of the inactivated Covid-19 vaccine far outweigh the risk of this generally self-limiting adverse event," the study said.

"Our findings suggest an overall increased risk of Bell's palsy after CoronaVac vaccination," it says.

The mechanism of Bell's palsy in patients after vaccination is unclear, the study acknowledges, calling for further investigation.