Pfizer’s preliminary laboratory studies have shown that the third booster dose increases the neutralizing antibody titers by 25-fold compared to two doses against the Omicron variant.
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Pfizer and BioNTech say three doses of their COVID-19 vaccine can neutralize the newly discovered Omicron variant of the SARS-CoV-2 virus. The announcement follows on the heels of reports that the new variant was able to partly evade destruction from two doses of the mRNA vaccine.
This morning, Pfizer’s preliminary laboratory studies have shown that the third booster dose of the vaccine increases the neutralizing antibody titers by 25-fold compared to two doses against the Omicron variant. Two doses of the vaccine show significantly reduced neutralization titers.
The company noted that two doses of the vaccine co-developed with Germany’s BioNTech may not be sufficient to protect against infection from the Omicron variant. However, the companies indicated that the majority of epitopes targeted by vaccine-induced T cells are not affected by the mutations in Omicron. That means that those who have only received two doses of the vaccine will still have protection against severe forms of the disease. The companies noted that the data is preliminary and will collect additional information to direct research. In the meantime, they are monitoring the real-world efficacy of the vaccine against the new variant.
As a result of the indication that two doses may still lead to illness, the companies noted that a booster shot could achieve more robust protection against COVID. Citing preliminary data, the two companies said a third dose can provide the same level of neutralizing antibodies to Omicron as is observed after two doses against wild-type and other variants. A third dose also strongly increases CD8+ T cell levels against multiple spike protein epitopes, which correlate with the protection against severe disease. When compared to the wild-type virus, the vast majority of these epitopes remain unchanged in the Omicron spike variant.
Albert Bourla, chairman and chief executive officer of Pfizer, said that it’s clear from the data that a booster dose of the mRNA vaccine improves protection against Omicron and other variants of the COVID-19 vaccine. Vaccination with two doses and a booster remains the best course of action to reduce the spread of COVID-19.
BioNTech CEO Ugur Sahin added that the first dataset from preliminary studies of the vaccine’s efficacy against Omicron confirms the added insurance a booster can provide.
“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 a statement.
The announcement from Pfizer and BioNTech comes days after a small study conducted in South Africa revealed a significant 40% reduction in neutralizing antibodies of patients who only received two doses of the mRNA vaccine. The study did not include patients who had received booster doses, The Hill reported. The study only included 12 people, half of whom were infected by the new variant. The Omicron variant was first discovered in South Africa about two weeks ago.
While a booster appears to offer significantly more protection against the new variant, as well as against the Delta variant that is still largely driving infection in the United States, Pfizer and BioNTech are rapidly developing a variant-specific vaccine to provide additional protection. The companies expect to have it available by March of 2022.
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