Pfizer said Wednesday that a booster dose of its COVID-19 vaccine could provide important protection against the new omicron variant, even if the first two doses appear significantly less effective.
Pfizer and its partner BioNTech said that while two doses may not be protective enough to prevent infection, laboratory tests showed that the booster increased 25 times the levels of virus-fighting antibodies in humans.
Blood samples taken one month after the booster vaccination showed that in humans, levels of omicron-neutralizing antibodies were similar to the amounts that proved to be protective against earlier variants after two doses.
Scientists do not yet know how great the threat of the omicron variant is. The extra infectious delta variant is currently responsible for the majority of COVID-19 cases in the US and other countries.
But the omicron variant, discovered late last month, carries an unusually high number of mutations, and scientists are in a hurry to find out how easily it spreads, whether it causes more serious or milder illness than other types of coronavirus, and how much it can avoid infection. protection of previous vaccinations.
Pfizer’s results, published in a press release, are preliminary and have not yet been scientifically reviewed. But they are the first from a vaccine manufacturer to study whether the booster doses that health authorities are urging people to receive could really make a difference.
Scientists have suggested that the jump in antibody heights associated with a third dose of COVID-19 vaccine may be enough to counter any decrease in efficacy.
Pfizer and BioNTech are already working on an omicron vaccine in case it is needed.
Antibody levels predict how well a vaccine can prevent coronavirus infection, but they are just one layer of defense for the immune system. Pfizer said two doses of the vaccine should protect against serious illness because omicron mutations do not appear to interfere with one of these other defenses – T cells, which fight the virus after infection has begun.
“While two doses of the vaccine may still provide protection against severe disease caused by the Omicron strain, it is clear from this preliminary data that maximum protection is achieved with the third dose of our vaccine,” Pfizer CEO Albert Burla said in a statement.
Pfizer’s announcement had an immediate impact on the US markets. Futures, which indicated a lower open, changed course in seconds and turned solidly positive, with the Dow Jones jumping nearly 200 points.