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Pfizer’s COVID-19 vaccine 95% effective in final phase 3 results


After initial promising interim results on Nov. 9, Pfizer and BioNTech today announced that their mRNA vaccine, in development to prevent COVID-19, is 95% effective.

Final analysis of the randomized, phase 3 study of more than 43,000 people yielded 170 confirmed cases of COVID-19 – with 162 positive cases in the placebo group versus 8 in the BNT162b2 vaccine group.

Researchers reported 10 severe cases of COVID-19 in the trial, 9 of which occurred in the placebo group.

The study was ethnically diverse, and results were consistent across gender and age groups, with a 94% efficacy reported among participants aged older than 65 years.

Pfizer plans to file for an emergency-use authorization with the Food and Drug Administration “within days,” having now met all the FDA data endpoints, according to a news release from the two companies.

The vaccine was well tolerated with no serious safety concerns, the company stated. Two grade 3 adverse events were reported – fatigue in 3.8% of participants and headache in 2%.

The 95% efficacy places the Pfizer vaccine in the same neighborhood as the interim results of the Moderna vaccine, reported at 94.5%. Both products are two-dose mRNA vaccines.

As of Nov. 13, of 43,661 total participants in the Pfizer vaccine phase 3 trial, 41,135 received a second dose. The final results are based on two outcomes measured 7 days after the second dose: vaccine efficacy in people without prior SARS-CoV-2 infection as well as a secondary outcome in people both with and without prior SARS-CoV-2 infection.

The 95% vaccine efficacy was statistically significant, compared with placebo (P < .0001).

‘Historic 8-month journey’

The BNT162b2 vaccine candidate is a joint effort between Pfizer and BioNTech. “The study results mark an important step in this historic 8-month journey to bring forward a vaccine capable of helping to end this devastating pandemic,” Albert Bourla, DVM, PhD, Pfizer chairman and CEO, said in a statement. “With hundreds of thousands of people around the globe infected every day, we urgently need to get a safe and effective vaccine to the world.”

Ugur Sahin, MD, PhD, cofounder and CEO of BioNTech, added, “we are grateful that the first global trial to reach the final efficacy analysis mark indicates that a high rate of protection against COVID-19 can be achieved very fast after the first 30-mcg dose, underscoring the power of BNT162 in providing early protection.”

The two companies expect to produce up to 50 million vaccine doses in 2020 for global distribution. Projections for 2021 include up to 1.3 billion doses.

The companies also designed temperature-controlled thermal shipping containers with dry ice to maintain the required, approximate –70° C (–94° F) conditions. Clinicians can use the containers as temporary storage units for up to 15 days by replacing the dry ice.

This article first appeared on

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