Pfizer: Protection Against Omicron Variant ‘Improved’ After 3 Doses of COVID-19 Vaccine

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Three doses of the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) were shown to neutralize the Omicron variant of SARS-CoV-2, whereas 2 doses demonstrated significantly reduced neutralization titers in a preliminary laboratory study, the companies announced Wednesday.

The study compared the sera of people who received 2 or 3 doses of BNT162b2 against wild-type SARS-CoV-2 virus and the Omicron variant.

Results showed that sera from participants who received 2 doses experienced, on average, a more than a 25-fold reduction in neutralization titers against Omicron compared with the wild-type virus 3 weeks after the second dose, according to the December 8, 2021 press release.

However, sera collected from individuals 1 month after receiving a third dose neutralized the variant to levels comparable to the wild-type strain after 2 doses, and 2 doses still protected against more serious infections, reported Pfizer and BioNTech.

“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is improved with a third dose of our vaccine,” said Pfizer CEO Albert Bourla, PhD, in the release. “Ensuring as many people as possible are fully vaccinated with the first two-dose series and a booster remains the best course of action to prevent the spread of COVID-19.”

Although these findings are preliminary, Pfizer and BioNTech said they will continue to collect laboratory data and examine real-word effectiveness of BNT162b2, “to assess and confirm protection against Omicron and inform the most effective path forward.”

In November, Pfizer and BioNTech started to develop an Omicron-specific COVID-19 vaccine, a process which will continue in the event a modified vaccine is needed. If needed, the companies said they expect to have an Omicron-based vaccine ready by March 2022.