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Pfizer's Vaccine 97% Effective at Preventing COVID-19 in Real-World Study

By Cory Renauer - Mar 11, 2021 at 12:24PM

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Results from Israel suggest the Pfizer-BioNTech vaccine works even better than its phase 3 trial results indicated.

A new analysis of COVID-19 statistics released on Thursday strongly suggests the COVID-19 vaccine from Pfizer (PFE 1.32%) and BioNTech (BNTX 5.69%) is even more effective in the real world than it appeared to be in clinical trials. 

The Israeli Ministry of Health (MoH) analyzed public health surveillance data over a seven-week period that ended on March 6. During that time, the Pfizer-BioNTech COVID-19 vaccine was the only COVID-19 vaccine available in that country. This gave the MoH a unique opportunity to, in effect, treat the country's immunization effort as if it were a gigantic clinical study.

Scientist with a microscope.

Image source: Getty Images.

Pfizer's vaccine did more than just clear the bar set by its impressive clinical trial results. According to the MoH analysis, the vaccine was at least 97% effective at preventing symptomatic disease, hospitalizations, and deaths. Notably, across the period of the study, more than 80% of people who tested positive for COVID-19 were infected with a more transmissible variant that first originated in the U.K. 

Unfortunately, the analysis can't tell us much about how long the Pfizer-BioNTech COVID-19 vaccine will protect people from getting infected. The analysis relied on data collected from patients at least two weeks after their second shot of the vaccine.

The MoH analysis didn't include many people whose infections were caused by B.1.351, a COVID-19 variant of concern that first appeared in South Africa, but a potential response to that one could be just around the corner. On Wednesday, Moderna (MRNA 4.42%) started a mid-stage clinical trial for a variant-specific booster shot called mRNA-1273.351.

It's too early for regulators to make any commitments, but there's a good chance the FDA will be willing to authorize strain-specific booster vaccines under the same relatively simple rules used to approve new strain-specific flu vaccines each year.

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Stocks Mentioned

Pfizer Inc. Stock Quote
Pfizer Inc.
$51.34 (1.32%) $0.67
Moderna, Inc. Stock Quote
Moderna, Inc.
$142.28 (4.42%) $6.02
BioNTech SE Stock Quote
BioNTech SE
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