Pfizer, BioNTech Say 3 Doses of COVID-19 Vaccine ‘Neutralize’ Omicron Variant

New data from Pfizer and BioNTech demonstrate that 3 doses of the COVID-19 vaccine successfully neutralize the Omicron variant, whereas 2 doses show significantly reduced neutralization titers, according to a press release.

The companies noted that these findings are from an initial laboratory study. Sera obtained from individuals who have been vaccinated 1 month after receiving the booster dose neutralized the Omicron variant to levels comparable to those observed for the wild-type SARS-CoV-2 spike protein after 2 doses.

“Although 2 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 Albert Bourla, DVM, PhD, chairman and CEO of Pfizer, in the press release. “Ensuring as many people as possible are fully vaccinated with the first 2 dose series and a booster remains the best course of action to prevent the spread of COVID-19.”

Importantly, the researchers found that sera from individuals who received 2 doses of the current COVID-19 vaccine exhibited, on average, more than a 25-fold reduction in neutralization titers against the Omicron variant compared to wild-type. This suggests that 2 doses of the vaccine may not be enough to protect against infection with the Omicron variant, according to Pfizer and BioNTech. However, because the vast majority of epitopes targeted by vaccine-induced T cells are not impacted by the mutations found in the Omicron variant, experts believe that vaccinated individuals may still be protected against severe disease.

More significant protection may be achieved with a third dose of the vaccine because data from additional studies suggest that a booster shot increases the antibody titers by 25-fold. According to the companies’ preliminary data, a third dose provides a similar level of neutralizing antibodies to Omicron as is observed after 2 doses against the wild-type and other variants that emerged before Omicron. These antibodies are associated with high efficacy against both the wild-type virus and the variants.

According to the press release, a third dose also strongly increases CD8 T cell levels against multiple spike protein epitopes, which correlate with the protection against severe disease. Compared to the wild-type virus, the majority of these epitopes remain unchanged in the Omicron spike variant.

“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, CEO and co-founder of BioNTech, in the press release. “Broad vaccination and booster campaigns around the world could help us to better protect people everywhere and to get through the winter season.”

Although these findings are preliminary, the companies are continuing to collect more laboratory data and evaluate real-world efficacy against the Omicron variant. On November 25, the companies began development of an Omicron-specific COVID-19 vaccine, which will continue as planned in the event that a vaccine adaption is necessary to increase the level and duration of protection against Omicron. First batches of the vaccine can be produced and are planned to be ready for deliveries within 100 days, pending regulatory approval.

“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,” Sahin said in the press release.

REFERENCE

Pfizer and BioNTech Provide Update on Omicron Variant. News release. Pfizer; December 8, 2021. Accessed December 8, 2021. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-provide-update-omicron-variant