Pfizer announced Thursday that its COVID vaccine booster shot could further protect individuals from “all known variants” of COVID-19 – including. The booster shot is currently undergoing trials, the company said, and has shown “encouraging clinical trial data in a small number of participants in our study.”
Pfizer said the first two doses that patients received have elicited “strong immune responses” to the Delta variant, and that current studies are focused on whether the booster shot will further increase the response.
Experimental data have shown that when Pfizer boosters are given six months after the second dose, it has a “consistent tolerability profile”
While Pfizer believes the booster will be highly effective against COVID variants, the company said it is also developing an updated Pfizer-BioNtech COVID vaccine that will specifically target the Delta variant. mRNA for a new vaccine trial is already being prepared, the company said, and clinical trials are expected to begin in August pending approval.
“We have said and we continue to believe that it is likely, based on the overall data we have to date, that a third dose may be needed within six to 12 months of full vaccination,” said Pfizer. “While protection against severe disease remained high for a full six months, a decrease in efficacy against symptomatic disease is expected over time and the continued emergence of variants. Based on the overall information they have so far, Pfizer and BioNTech believe that a third dose may be beneficial in maintaining the highest levels of protection. “
However, the Centers for Disease Control and the FDA released a joint statement on Thursday stating that those who are fully vaccinated “do not need a booster shot at this time.”
“People who are fully vaccinated are protected from serious illness and death, including from the variants currently circulating in the country like Delta,” according to the statement. “People who have not been vaccinated remain at risk. Almost all COVID-19 hospitalizations and deaths are among those who have not been vaccinated.”
The federal agencies said they are involved in a “scientifically based, rigorous process” to look at, “whether or when” a booster would be needed.
“We will continue to review new data as it becomes available and will keep the public informed,” they said. “We are prepared for booster doses if and when science shows they are necessary.”
Dr. Sara Oliver of the CDC said in June that both Pfizer and Moderna have been working on boosters for their respective vaccines. Both companies, Oliver said, plan to release their survey data by the end of September.
Oliver also said that COVID vaccine boosters may only be needed for certain populations, including residents of long-term care facilities, adults 65 years or older, healthcare professionals and people with compromised immune systems.
In June, the FDA’s Dr. Doran Fink that the agency will not authorize emergency use of booster shots “just because data on safety and immunogenicity are available.”
“There would also be a need to determine the need for a modified COVID-19 vaccine and the selection of antigens for inclusion in that vaccine. And we expect this would be an international effort involving more public heath and regulatory authorities.”
Fink said the FDA will also be looking for an “immune-bridging approach” to ensure vaccines have the “expected effectiveness” and to “address potential future needs.”
The FDA will not approve additional vaccines without also having additional clinical data, Fink said, as is the case with the seasonal flu vaccine.
“We recognize that there is interest in ultimately moving to a paradigm where clinical data is not needed to support the approval of modified vaccines,” Fink said. “We do not believe that our current understanding of COVID-19, immunology, and vaccine protection mechanisms is entirely at a time when we can do so.”
Alexander Tin contributed to this report.