NEW YORK, N.Y. — Pfizer announced Wednesday that data shows a third dose of its COVID-19 vaccine can “strongly” boost protection against the highly transmissible delta variant.
The pharmaceutical and biotechnology company made the announcement in a copy of its second-quarter results, which were expected to be discussed in a company earnings call.
Pfizer says its data suggests that after a third dose of its vaccine, the level of antibodies effective against the delta variant could be more than five times higher than after a second dose of the vaccine in people ages 18 to 55, and more than 11 times higher in people ages 65 to 85.
Pfizer also wrote that there’s an “estimated potential for up to 100-fold increase in delta neutralization post-dose three compared to pre-dose three.”
The information cited in the quarterly results has not yet been peer-reviewed or published.
Pfizer says federal regulators would determine whether a booster shot is needed and which populations it would recommend the third dose to.
Earlier this month, Pfizer said it would seek U.S. authorization for a third dose of its COVID-19 vaccine and that another shot could dramatically boost immunity and ward off the delta variant.
The delta variant is now the dominant strain in the U.S. and a recent rise in coronavirus cases is being attributed to its dominance in the country.
Despite the promising data released by Pfizer, it remains unclear if a third dose will be necessary because the current vaccines have shown to be effective at preventing serious illness.
A study published last week showed two doses of Pfizer or AstraZeneca’s vaccines are nearly as effective against the delta variant as they are against the previously dominant alpha variant, Reuters reports. The study found two doses of Pfizer’s shot were 88% effective at preventing symptomatic disease from the delta variant, compared to 93.7% against the alpha strain.