Pfizer and BioNTech Announce Preliminary Lab Data Showing Three Doses of Their mRNA Vaccine Neutralize Omicron Variant

Today, Pfizer and BioNTech announced preliminary laboratory study data. The study shows that serum antibodies induced after three doses of their mRNA COVID-19 vaccine can neutralize the latest Omicron variant. Moreover, one month after receiving the booster dose, the neutralizing ability of the serum against the Omicron variant remains comparable to the neutralization of the wild-type SARS-CoV-2 spike protein achieved by the standard two-dose regimen.

Since coming into the public eye, the Omicron variant has garnered global attention in just a few weeks. At the end of November, the World Health Organization noted that the emergence of this variant coincided with a surge in COVID-19 cases in South Africa. There is also evidence suggesting that this variant may increase the risk of reinfection with the coronavirus. For these reasons, the World Health Organization has classified it as a variant of concern, indicating that it may have higher transmissibility, potentially increase the risk of severe illness, or reduce the effectiveness of current diagnostics, vaccines, and therapies.

To evaluate the effectiveness of their vaccine against the Omicron variant, Pfizer and BioNTech obtained immune sera from a group of vaccinated individuals. For individuals who received only two doses, sera were collected three weeks after the second dose; for those who received an additional booster dose, sera were collected one month after the third dose.

These sera were simultaneously used for multiple neutralizing antibody titer tests: some targeting the spike protein of the wild-type SARS-CoV-2, while others targeting the spike protein of the Omicron variant. The tests utilized the pseudovirus neutralization method (pVNT).

Test results indicate that receiving only two doses of the vaccine may not be sufficient to protect against infection with the Omicron variant. Specifically, individuals who received only two doses showed a significant reduction in serum neutralization titers against the Omicron variant (compared to neutralization titers against the wild-type strain), with a decrease of up to 25-fold. However, the press release also noted that the Omicron variant did not affect most of the epitopes targeted by T cells induced by their vaccine. Therefore, the two companies believe that vaccinated individuals can still be protected and have a reduced risk of developing severe COVID-19. Of course, this requires further real-world evidence for validation.

In comparison, after the third vaccine dose, there was a notable increase in neutralizing antibody titers against the Omicron variant spike protein. Based on the preliminary data released today, the neutralization levels are equivalent to the serum neutralization levels against the wild-type coronavirus after two vaccine doses. Additionally, the third dose also boosts the levels of CD8-positive T cells, which target multiple epitopes on the spike protein and are considered to be associated with protection against severe COVID-19. Therefore, the press release suggests that a third vaccine dose may offer stronger protection.

▲Preliminary data from the laboratory study mentioned in the press release (Data source: Reference [1]; Table prepared by the WuXi AppTec content team)

"Although two doses of the vaccine may still provide protection against severe disease caused by the Omicron variant, these preliminary data suggest that a third dose offers even better protection," said Dr. Albert Bourla, CEO of Pfizer. "Ensuring that as many people as possible receive the full regimen of the initial two doses and the booster shot is one of the best strategies to prevent the spread of COVID-19."

"Our initial data from the first batch suggest that a third dose of the vaccine may still provide sufficient protection against any level of disease caused by the Omicron variant," said Dr. Ugur Sahin, CEO of BioNTech. "Widespread vaccination and booster programs globally will enable us to better protect people around the world through this winter. We will continue to develop an updated vaccine. We believe this vaccine can induce a higher level of protection against COVID-19 caused by the Omicron variant, and compared with the current vaccine, it can also offer longer-lasting protection."

The press releases from both companies also pointed out that these data are still very preliminary. Therefore, more evidence from laboratories and the real world is needed to evaluate and confirm the vaccine's efficacy against the Omicron variant and to find better solutions. We also look forward to the joint efforts of scientists around the world to control the spread of the Omicron variant as soon as possible, making the pandemic no longer a frightening threat.

References:

[1] Pfizer and BioNTech Provide Update on Omicron Variant, Retrieved December 8, 2021, from https://www.businesswire.com/news/home/20211208005542/en/

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