A preliminary study consisting of 12 patients has shown that the Pfizer vaccine offers some protection against the Omicron variant, The New York Times reported. The study conducted at the lab of Alex Sigal at the African Health Research Institute is not peer-reviewed.
The Omicron variant with an extensive set of mutations on its spike protein has been reported in 39 countries so far and in 20 states within the U.S. Interestingly, many countries have also reported infection in people who have not traveled abroad, indicating that the variant has been circulating undetected for a while. This has raised concerns if the variant can breakthrough even in vaccinated individuals.
Alex Sigal's lab in Durban, South Africa has worked tirelessly over the last two weeks to answer this question. Their study included 12 participants, all of whom had received the Pfizer vaccine. Six of them, however, received the vaccine after they had been infected with COVID, while the other six were never infected with COVID.
Sigal's lab grew the Omicron virus in the lab and then tested the antibodies derived from the participants against it. They found that the antibodies which worked well against other variants of Coronavirus fared quite poorly against the Omicron variant. The potency of the antibody reportedly dropped to 1/40 of the levels seen with previous variants.
However, antibodies of individuals who received the vaccine after a COVID infection fared better and offered better responses. This is because infected individuals produce higher levels of antibodies than those who are vaccinated but not infected, The New York Times reported. The team is yet to carry out this experiment in individuals who have received the booster dose but Sigal believes, with higher antibody levels, the response will be better.
Just be be clear on something as I'm still awake, this was better than I expected of Omicron. The fact that it still needs the ACE2 receptor and that escape is incomplete means its a tractable problem with the tools we got— Alex Sigal (@sigallab) December 7, 2021
BioNTech, the makers of the vaccine had said last week that they would need two to three weeks to determine if the variant could breakthrough in the vaccinated but these results are likely a precursor to what BioNTech will also find.