Real-world data from 1.2 million people in Israel confirms that the Pfizer vaccine is 94 percent effective against COVID after the second dose.
It gives further hope that mass immunization will end the pandemic.
The vaccine also gives strong protection against the infection since it greatly reduces the chance of passing on the virus to others.
Dr Benjamin Neuman, a virologist from Texas A&M University, commented on this study:
“The fact that the vaccines worked so well in the real world… really does suggest that if the nations of the world can find the will, we now have the means to end COVID-19 forever.”
The research covers a period from December 2020 to February 2021 when a new SARS-CoV-2 variant was first seen in England and then was detected in different countries, including Israel.
To ensure the Pfizer vaccine’s reliability and its effectiveness on the new variant, every single vaccinated person was matched to an unvaccinated person who was in the control group.
The participants in the control group shared some similarities such as sex, geographic area, age, and medical conditions with those who had been vaccinated.
The results from 14 to 20 days after the first dose suggest at least a 57 percent effectiveness for symptomatic infection and 62 percent for severe COVID.
However, for the second dose seven days after injection the efficacy was increased to 94 percent for symptomatic COVID and 92 percent for severe disease.
Moreover, the outcomes from 7 days after the second dose suggest an 87 percent effectiveness against hospitalization.
Regarding different variants of the virus, the vaccine proved to be highly effective as those who received their second injection were 92 percent less likely to become infected with any strains of coronavirus than unvaccinated people.
Despite these promising outcomes, experts believe more evidence is needed due to participants not being tested systemically.
Dr Natalie Dean, a biostatistician at the University of Florida, explained:
“Unless you are testing everyone all the time, this will miss some infections.
Nailing down this number more precisely will require specialized study designs with frequent testing.”
However, she is sure that the vaccine provides strong protective benefit.
Another study suggests that a single shot of the Pfizer-BioNTech COVID-19 vaccine gives people 90 percent protection three weeks after injection.
The study was published in the New England Journal of Medicine (Dagan et al., 2021).