Third BNT162b2 Vaccination Neutralization of SARS-CoV-2 Omicron Infection

On November 26, 2021, the World Health Organization (WHO) named the B.1.1.529 (omicron) variant of severe acute respiratory syn­drome coronavirus 2 (SARS-CoV-2), first detect­ed in South Africa, as a variant. of concern.1 By November 29, 2021, three days after the an­nouncement by the WHO, cases of infection with the omicron variant had already been de­tected in many other countries. Whether the BNT162b2 vaccine (Pfizer­BioNTech), which was previously shown to have 950/o ycacוffeagainst coronavirus disease 2019 (Covid-19),2•3 will effectively neutralize infection with the omicron variant is unclear. We com­pared neutralization of omicron-infected cells in serum samples obtained from participants who had received two doses of vaccine with neut.ral­ization in samples obtained from participants who had received three doses.