Pfizer and BioNTech said preliminary lab studies indicate that a third dose of their Covid-19 vaccine may be required to neutralize the omicron variant, which will hasten booster-shot drives around the world.

In people who received only two shots, researchers from the company discovered a 25-fold reduction in neutralizing antibody levels versus the variant when compared to the original strain of the virus. Boosting with an additional dose of the vaccine, on the other hand, increased antibodies against omicron 25-fold, resulting in a similar level of protective proteins as seen after the standard two doses, according to the vaccine partners in a statement.

According to the companies, the lab findings suggest that two doses of the vaccine "may not be sufficient" to protect against infection with the omicron strain. Along with enhancing the booster push, this may increase the likelihood that an omicron-targeted shot will be required in the future. Pfizer stated that this would be available in March.

Since omicron was discovered in southern Africa last month, uncertainty about vaccine efficacy has fueled market volatility and prompted travel restrictions. The study's findings boosted the US stock market, with S&P 500 futures up 0.2%. Pfizer shares rose 0.5% in New York pre-market trading, while BioNTech American depositary receipts rose 3%.

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The Pfizer-BioNTech findings supplement data from other studies attempting to assess the impact of omicron on vaccine protection. South African researchers discovered a 41-fold decrease in virus-blocking antibodies against omicron when compared to the strain that was circulating at the start of the pandemic. A German study discovered a 37-fold decrease in antibodies against omicron compared to the highly transmissible delta variant.

The companies said they'll be watching to see how quickly omicron immunity fades over time, even after a third dose. "It's clear from these preliminary data that protection improves with a third dose," said Pfizer CEO Albert Bourla in a statement.

Boosters could help people all over the world "get through the winter season" while the companies work on adapting the vaccine, according to BioNTech CEO Ugur Sahin. According to him, an adapted vaccine should provide "prolonged protection compared to the current vaccine."