Peer-reviewed findings from a multinational trial of Pfizer’s messenger RNA (mRNA) Covid-19 vaccine candidate confirmed previous reports of 95% protection against the disease, with a safety profile similar to other viral vaccines at 2 months.
The trial findings were published December 10 in the New England Journal of Medicine, as a U.S. Food and Drug Administration advisory panel met to consider approval of the Pfizer-BioNTech vaccine for immediate use under an emergency use authorization (EAU).
The approval would make the vaccine available for those at the front of the vaccination line — mostly healthcare workers and long-term care facility residents and staff — within a matter of days.
In all, roughly 21,700 study participants received the two-dose regimen of the mRNA vaccine BNT162b2 while a similar number received placebo shots — and, according to researchers, 8 cases of Covid-19 cropped up with onset at least 7 days after the second dose in the active vaccine group, while 162 cases were reported among those in the placebo arm of the study.
One participant in the active vaccine group and nine in the placebo group developed severe Covid-19.
“BNT162b2 was 95% effective in preventing Covid-19 (95% CI, 90.3-97.6),” wrote researchers Fernando P. Polack, MD, from Fundacion INFANT, Buenos Aires, and colleagues. “Similar vaccine efficacy (general 90% to 100%) was observed across subgroups defined by age, sex, race, ethnicity, baseline body mass index, and the presence of coexisting conditions.”
The investigators plan to continue to follow the study participants to obtain longer-term efficacy and safety data.
In an editorial published with the study, NEJM Editor-in-Chief Eric J. Rubin, MD, PhD, and deputy editor Dan L. Longo, MD, noted that while the trial was underpowered to adequately assess subgroup efficacy and important data have not yet been reported, the results “are impressive enough to hold up in any conceivable analysis.”
“This is a triumph,” they wrote. “Most vaccines have taken decades to develop, but this one is likely to move from conception to large-scale implementation within a year.”
They further noted that the viral sequencing which led to the development of the specific antiviral RNA sequence required for the vaccine was not known until January of 2020, when it was widely disseminated by the Chinese Center for Disease Control and Prevention.
“There is a lot of credit to go around: to the scientists who shared data and who developed the underlying methods and implemented them to create a vaccine, to the clinical trialists who performed high-quality work in the setting of a health emergency, to the thousands of participants who volunteered to take part in the trial, and to the governments that helped create performance standards and a market for the vaccine,” Rubin and Longo wrote.
Rubin and Longo concluded that while the logistical challenges related to manufacturing and vaccine delivery remain daunting, “the remarkable level of safety and efficacy the vaccine has demonstrated thus far make this a problem that we should welcome solving. What appears to be a dramatic success for vaccination holds the promise of saving uncounted lives and giving us a pathway out of what has been a global disaster.”
BNT162b2 is a “lipid nanoparticle-formulated, nucleoside-modified RNA vaccine that encodes a prefusion stabilized, membrane-anchored SARS-CoV-2 full-length spike protein,” the study group wrote.
The trial data reported in NEJM included 43,548 participants age 16 years and older randomized in a 1:1 ratio to receive two doses, 21 days apart, of either placebo or the BNT162b2 vaccine (30 μg per dose).
Primary end points included efficacy against laboratory-confirmed Covid-19 and safety. The safety profile of the mRNA vaccine was characterized by short-term, mild-to-moderate pain at the injection site, fatigue, and headache.
The incidence of serious adverse events was found to be low and was similar in the active vaccine and placebo groups.
“The vaccine met both primary efficacy end points, with more than a 99.99% probability of a true vaccine efficacy greater than 30%. 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,” the researchers wrote.
The report did not include data on children younger than age 16 years or pregnant women. The researchers noted that additional data on adolescents between the ages of 12 and 15 years will soon be reported, “and additional studies are planned to evaluate BNT162b2 in pregnant women, children younger than 12 years, and those in special risk groups, such as immunocompromised persons,” they added.
“Although the vaccine can be stored for up to 5 days at standard refrigerator temperatures once ready for use, very cold temperatures are required for shipping and longer storage,” Polack and colleagues noted. “The current cold storage requirement may be alleviated by ongoing stability studies and formulation optimization, which may also be described in subsequent reports.”
- Peer-reviewed findings from a multinational trial of Pfizer’s messenger RNA Covid-19 vaccine candidate confirm previous reports of a 95% protection against the disease, with a safety profile similar to other viral vaccines at 2 months.
- The vaccine met both primary efficacy end points, with more than a 99.99% probability of a true vaccine efficacy greater than 30%.
Salynn Boyles, Contributing Writer, BreakingMED™
This trial was funded by BioNTech and Pfizer.
Lead researcher Fernando P. Polack reported Dr. Polack reports personal fees from Janssen, grants from Novavax, Inc., personal fees from Bavarian Nordic A/S, personal fees from Pfizer, personal fees from Sanofi, personal fees from Regeneron, personal fees from Merck, personal fees from Medimmune, personal fees from Virbio, personal fees from Arkbio, and personal fees from Daiichi Sankyo outside the submitted work.
Corresponding author Judity Absalon reported receiving personal fees from Pfizer Inc., outside the submitted work.
Cat ID: 926
Topic ID: 79,926,730,933,926,192,927,151,928,925,934
