Pfizer Inc. and BioNTech SE announced results from an initial laboratory study demonstrating 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 (third dose of BNT162b2 vaccine) neutralized the Omicron variant to levels that are comparable to those observed for the wild-type SARS-CoV-2 spike protein after two doses.
Sera from individuals who received two doses of the current COVID-19 vaccine did exhibit, on average, more than a 25-fold reduction in neutralization titers against the Omicron variant compared to wild-type, indicating that two doses of BNT162b2 may not be sufficient to protect against infection with the Omicron variant. However, as the vast majority of epitopes targeted by vaccine-induced T cells are not affected by the mutations in Omicron, the companies believe that vaccinated individuals may still be protected against severe forms of the disease and are closely monitoring real world effectiveness against Omicron, globally.
A more robust protection may be achieved by a third dose as data from additional studies of the companies indicate that a booster with the current COVID-19 vaccine from Pfizer and BioNTech 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 two doses against wild-type and other variants that emerged before Omicron. These antibody levels are associated with high efficacy against both the wild-type virus and these variants. A third dose also strongly increases CD8+ T cell levels against multiple spike protein epitopes which are considered to correlate with the protection against severe disease. Compared to the wild-type virus, the vast majority of these epitopes remain unchanged in the Omicron spike variant.
"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 maximized with a third dose of our vaccine," said Albert Bourla, Chairman and Chief Executive Officer, Pfizer. "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."
"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, M.D., CEO and 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."
While these results are preliminary, the companies will continue to collect more laboratory data and evaluate real-world effectiveness to assess and confirm protection against Omicron and inform the most effective path forward. On November 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. First batches of the Omicron-based vaccine can be produced and are planned to be ready for deliveries within 100 days, pending regulatory approval. Pfizer and BioNTech have tested other variant-specific vaccines that have produced very strong neutralization titers and a tolerable safety profile. Based on this experience the companies have high confidence that if needed they can deliver an Omicron-based vaccine in March 2022. The companies have also previously initiated clinical trials with variant-specific vaccines (Alpha, Beta, Delta & Alpha/Delta Mix) and 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 or approval of an Omicron-specific vaccine, if needed. The companies have previously announced that they expect to produce four billion doses of BNT162b2 in 2022, and this capacity is not expected to change if an adapted vaccine is required.