A coronavirus vaccine developed by Pfizer and BioNTech showed to drop symptomatic COVID-19 by 94%, per new research out of Israel. The peer-reviewed results offer a first look at effectiveness in real-world conditions, and showed consistency with high 95% vaccine efficacy reported during clinical trials.
Findings from the Clalit Research Institute, and contributing efforts from several U.S. universities, were published in the New England Journal of Medicine on Wednesday, stemming from about 1.2 million people in Israel. Half of the group was vaccinated from December into February, and the other half was not, serving as a control group.
A peer-reviewed study of a nationwide immunization effort is important to assess vaccine effectiveness in real-world, noncontrolled conditions compared to clinical trials, and account for difficulties maintaining the cold chain, vaccination schedule, and rolling the vaccine out among many more people of diverse populations, including those with chronic diseases, researchers wrote. Individuals aged under 16 were excluded, though Pfizer is currently running clinical trials in the 12-15 age group.
A week after two doses were administered, the team documented 87% effectiveness in dropping hospitalizations, a 92% cut in severe disease and 92% effectiveness for documented infection, compared to 14-20 days after an initial dose at 74%, 62% and 46%, respectively.
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"This study in a nationwide mass vaccination setting suggests that the BNT162b2 mRNA vaccine is effective for a wide range of Covid-19–related outcomes, a finding consistent with that of the randomized trial," the study reads.
The findings also suggest the vaccine afforded the same degree of protection for adults over 70 as younger groups. The U.S. Food and Drug Administration previously said it could not evaluate Pfizer’s vaccine effectiveness in certain populations at high risk of severe COVID-19 such as immunocompromised individuals, or in those who were previously infected with SARS-CoV-2.
On a separate note, the researchers said the vaccine is likely effective against a coronavirus variant first detected in the U.K., called B.1.1.7. While they couldn’t specify vaccine effectiveness against the variant, up to 80% of samples in Israel had the variant before data was collected, with study authors writing, "the plateau observed during the later periods in the cumulative incidence curve [on hospitalizations, deaths and more] for vaccinated persons suggests that the BNT162b2 vaccine is also effective for this variant." A separate variant first detected in South Africa was deemed "rare" during the early vaccination efforts in Israel.
Israel has been hailed for its speedy vaccination efforts and high uptake, with about one-third of its population now fully vaccinated.
"These results strengthen the expectation that newly approved vaccines can help to mitigate the profound global effects of the Covid-19 pandemic," study authors wrote.