By IDSE News Staff
Results from an initial laboratory study demonstrate that serum antibodies induced by the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) neutralize the SARS-CoV-2 omicron variant after three doses.
Sera obtained from vaccinees one month after receiving the booster vaccination, which would be the third dose of vaccine, neutralized omicron to levels that are comparable to those observed for the wild-type SARS-CoV-2 spike protein after two doses, according to the companies.
To evaluate the effectiveness of BNT162b2 against the omicron variant, Pfizer and BioNTech tested a panel of human immune sera obtained from the blood of people who received two or three 30-mcg doses of BNT162b2 vaccine, using a pseudovirus neutralization test. The sera were collected from individuals three weeks after receiving the second dose or one month after receiving the third dose of the Pfizer-BioNTech COVID-19 vaccine.
Each serum sample was tested simultaneously for its neutralizing antibody titer against the wild-type SARS-CoV-2 spike protein and the omicron spike variant. The third dose significantly increased the neutralizing antibody titers against the omicron strain spike by 25-fold.
Neutralization against the omicron variant after three doses of BNT162b2 was comparable to the neutralization that was achieved against the wild-type strain observed in sera from individuals who received two doses of the companies’ COVID-19 vaccine: The geometric mean neutralizing antibody titers against the omicron variant measured in the samples was 154 (after three doses), compared with 398 against the delta variant (after three doses) and 155 against the ancestral strain (after two doses).
“Our preliminary, first dataset indicate that a third dose could still offer a sufficient level of protection from disease of any severity caused by the Omicron variant,” said Ugur Sahin, MD, the CEO and a co-founder of BioNTech. “Broad vaccination and booster campaigns around the world could help us to better protect people everywhere and to get through the winter season. We continue to work on an adapted vaccine which, we believe, will help to induce a high level of protection against
Omicron-induced COVID-19 disease as well as a prolonged protection compared to the current vaccine.”
Data on the persistence of neutralizing titers over time after a booster dose of BNT162b2 against the omicron variant will be collected, the companies said.
On Nov. 25, the companies started to develop an omicron-specific COVID-19 vaccine. The development will continue as planned in the event that a vaccine adaption is needed to increase the level and duration of protection against omicron, and could be read for deliveries within 100 days, pending regulatory approval, they said. The companies have also initiated clinical trials with variant-specific vaccines (alpha, beta, delta and alpha–delta mix); data from these studies will be submitted to regulatory agencies around the world to help accelerate the process of adapting the vaccine and gaining regulatory authorization/approval of an omicron-specific vaccine, if needed. The companies previously announced that they expect to produce 4 billion doses of BNT162b2 in 2022, and this capacity is not expected to change if an adapted vaccine is required.
—From company press materials
