More Positive Data Released for Pfizer-BioNTech COVID-19 Vaccine

December 22, 2020 - A two-dose regimen of Pfizer and BioNTech’s mRNA COVID-19 vaccine, BNT162b2, elicited 95 percent protection against the coronavirus in individuals 16 years of age or older, according to a recent New England Journal of Medicine (NEJM) report.

Specifically, the vaccine met both primary efficacy endpoints, with a more than 99.99 percent probability of a true vaccine efficacy greater than 30 percent. 

Among the 36,523 participants who received BNT162b2 and had no existing or prior SARS-CoV-2 infection, there were eight cases of COVID-19 with onset seven days after the second dose of BNT162b2 and 162 cases among placebo recipients.  

Researchers highlighted that this case split corresponds to 95 percent vaccine efficiency. 

Additionally, researchers observed, out of participants with and without evidence of prior SARS-CoV-2 infection, nine cases of COVID-19 at least seven days after the second dose among individuals who received BNT162b2.

In contrast, there were 169 COVID-19 cases reported among placebo recipients, corresponding to 94.6 percent vaccine efficacy.

In the interval between the first and second doses, the observed vaccine efficacy against the coronavirus was 52 percent. In the first seven days after the second dose, the efficiency was 91 percent. 

Notably, researchers saw full efficacy against disease with onset at least seven days after the second dose.

“These results met our prespecified success criteria, which were to establish a probability above 98.6% of true vaccine efficacy being greater than 30%, and greatly exceeded the minimum FDA criteria for authorization,” researchers said in the report.

“The cumulative incidence of Covid-19 cases over time among placebo and vaccine recipients begins to diverge by 12 days after the first dose, 7 days after the estimated median viral incubation period of 5 days, indicating the early onset of a partially protective effect of immunization,” they continued. 

In the report, researchers uncovered safety and efficacy findings from the Phase 2/3 part of a global Phase 1/2/3 trial evaluating the safety, immunogenicity, and efficacy of 30 micrograms of BNT162b2.

Between July 27, 2020, and November 14, 2020, a total of 43,448 individuals 16 years of age or older were randomized at 152 sites worldwide and received one of two injections, BNT162b2 (21,720 individuals) or a placebo (21,728 individuals), both 21 days apart. 

The primary endpoint of the trial was systemic adverse events within seven days after the receipt of each dose of vaccine or placebo. Additionally, researchers looked at unsolicited adverse events over one month after the second dose and unsolicited serious adverse events through six months after the second dose. 

Younger vaccine recipients were more likely to report systemic adverse events from BNT162b2 compared to older recipients, and more often after the second dose than the first. 

The most common adverse events were fatigue and headache at 59 percent and 52 percent, respectively. There were severe systemic events in 0.9 percent or less of the study population. 

By the beginning of October, 37,706 participants in the study had a median of at least two months of safety data available after the second dose and contributed to the main data set in the report, researchers explained.

While this data does not address whether vaccination prevents asymptomatic infection, it does prove that coronavirus can be prevented by immunization.

Additionally, the data shows that RNA-based vaccines are a promising new approach for protecting individuals against infectious diseases and that a fast and efficient RNA-based vaccine can be developed with sufficient resources.  

Researchers also highlighted that the data set and trial results presented in the report are the basis for an application for FDA emergency use authorization.