Pfizer Studying Effects of 3rd Dose of COVID-19 Vaccine

Pfizer Studying Effects of 3rd Dose of COVID-19 Vaccine
A pharmacist prepares a syringe with the Pfizer-BioNTech COVID-19 vaccine at a COVID-19 vaccination site in New York City, on Feb. 18, 2021. (AP Photo/Mary Altaffer)
Zachary Stieber
2/25/2021
Updated:
2/25/2021

Pfizer and its partner are conducting a new trial that will evaluate the effects of a third dose of their COVID-19 vaccine, in a bid to protect against the virus variants circulating around the world.

Pfizer and BioNTech’s vaccine is currently given in two doses spaced several weeks apart.

The phase 1/2/3 trial will study how patients react to a third dose and whether the additional dose better protects people against the CCP (Chinese Communist Party) virus, which causes COVID-19. People already participating in a phase 1 trial for the vaccine will be offered the chance to get a third dose 6 to 12 months after receiving the initial two-dose regimen.

“While we have not seen any evidence that the circulating variants result in a loss of protection provided by our vaccine, we are taking multiple steps to act decisively and be ready in case a strain becomes resistant to the protection afforded by the vaccine. This booster study is critical to understanding the safety of a third dose and immunity against circulating strains,” Albert Bourla, chairman and CEO of Pfizer, said in a statement.

“The flexibility of our proprietary mRNA vaccine platform allows us to technically develop booster vaccines within weeks, if needed. This regulatory pathway is already established for other infectious diseases like influenza. We take these steps in order to ensure a long-term immunity against the virus and its variants,” Ugur Sahin, CEO and co-founder of BioNTech, added.

Lilian Contreras (L) receives her second dose of the Pfizer-BioNTech COVID-19 vaccine during a mass vaccination event in the parking lot of Coors Field in Denver, on Feb. 20, 2021. (Michael Ciaglo/Getty Images)
Lilian Contreras (L) receives her second dose of the Pfizer-BioNTech COVID-19 vaccine during a mass vaccination event in the parking lot of Coors Field in Denver, on Feb. 20, 2021. (Michael Ciaglo/Getty Images)

The companies’ vaccine is one of only two authorized for use in the United States. Drug regulators authorized it in December 2020, along with a vaccine from Moderna.

Regulators are poised to greenlight a third option, a one-dose version from Johnson & Johnson, as soon as Feb. 27.

Different variants of the CCP virus have been spreading in the United States and elsewhere in recent weeks, including a variant that is believed to have originated in South Africa.

As of Feb. 23, officials had identified nearly 1,900 cases of the B117 variant across 45 states, 46 cases of the B1351 variant in 14 states, and five cases of the P1 variant in four states.

The Food and Drug Administration is developing updated guidelines for vaccine manufacturers and companies involved in producing therapeutics and tests as the United States faces different variants, Dr. Anthony Fauci, a top health adviser to President Joe Biden, told an online news conference this week.

The average number of daily new COVID-19 cases has been dropping in the United States. The figure dropped 74 percent since the peak seven-day average on Jan. 11 to 66,000, similar to the level seen last summer. Hospitalizations and deaths also have decreased dramatically in recent weeks.

The updated numbers came as more and more people get vaccinated, but officials are still urging Americans to stay cautious and consider continuing to avoid normal activities such as dining out.

“Even though we’re going way down on the decline ... we are still at an unacceptably high baseline level with a seven-day average being quite high,” Fauci said.