Neutralization of Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant by Sera From BNT162b2 or CoronaVac Vaccine Recipients

Omicron variant escapes neutralizing antibodies elicited by BNT162b2 or CoronaVac. The additional R346K mutation did not affect the neutralization susceptibility. Our data suggest that the omicron variant may be associated with lower COVID-19 vaccine effectiveness.