Covid19 Vaccine – Pfizer may require 3rd dose (booster shot)
The Pfizer-BioNTech Covid-19 vaccine, sold under the brand name ‘Comirnaty’, may require a third dose to work more effectively against the original strain of the coronavirus disease, news agencies reported on Friday morning, citing a statement from the companies from a day ago. The third Covid-19 shot is also expected to provide better protection against the Beta variant, first identified in South Africa, and the Delta variant, found in India, as per interim data from an ongoing trial into the vaccine.
Pfizer and BioNTech announced on Thursday that they would seek regulatory approval for the third dose of their Covid-19 vaccine, in view of the interim trial data which showed that a third dose can push antibody levels five to 10 times higher against the said variants of the coronavirus compared to the first two doses alone. This will, in effect, provide better protection than the current practice of administering two shots, the statement read.
The U.S. Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) said, however, in a joint statement that Americans who have been fully vaccinated do not need a booster COVID-19 shot at this time. Some scientists have also questioned the need for booster shots.
Pfizer’s chief scientific officer, Mikael Dolsten, said the recently reported dip in the vaccine’s effectiveness in Israel was mostly due to infections in people who had been vaccinated in January or February. The country’s health ministry said vaccine effectiveness in preventing both infection and symptomatic disease fell to 64% in June.
A study not yet released by the companies shows that a third dose of the Pfizer-BioNTech vaccine six months after the second dose protected people against the original strain of Covid-19 as well as the Beta variant.
After six months, the companies’ two-dose vaccine loses some of its ability to protect against getting Covid-19 and developing symptoms, although it continues to work well against preventing severe Covid-19, the companies said, referencing data from their studies and from the health ministry in Israel, which has a highly vaccinated population and has recently seen a wave of the Delta variant spread.
After taking the booster shot, antibodies against the original and Beta variants were “five to 10 times higher,” the companies said in a press release. The companies believe a booster shot would also increase protection against the Delta variant based on a Naturestudy which they said suggests that the two-dose vaccine is effective against the variant.