Pfizer has not confirmed the authenticity of the study document. Its main authors are Sharon Alroy-Preis, head of public health at the Israeli Ministry of Health, and Eric Haas, researcher at the ministry. In addition, the study was conducted by a team of eight Pfizer researchers, including epidemiologists Farid Khan and John McLaughlin and the company’s global medical lead for covidial vaccines, David Swerdlow, a previously infectious disease expert. with the United States Centers for Disease Control and Prevention.
The research represents the first joint report from the Department of Health and Pfizer since they reached an agreement earlier this year for Israel to share immunization data in exchange for a steady supply of doses.
The cooperation is part of a larger effort by Pfizer to track how its vaccine, named Comirnaty, works in large populations. The company told the MIT Technology Review earlier this week that it was studying “the effectiveness of the vaccine in the real world at several locations around the world, including Israel,” and “in particular looking at real-world data from ‘Israel to understand any potential impact of the covid-19 vaccine from emerging variants. Pfizer’s vaccine, like Moderna’s, another mRNA vaccine licensed in the United States and Europe, uses two injections of Messenger RNA carrying information about the virus to train people’s immune systems to recognize and fight infection
The new findings are broadly consistent with separate announcements made in recent days by two of Israel’s major healthcare organizations, Maccabi Healthcare Services and Clalit Health Services, which together treat 80 percent of Israelis.
On February 14, Ran Balicer, head of innovation and research at Clalit, Israel’s largest HMO, mentionned that the evidence collected from 1.2 million members “shows unequivocally that Pfizer’s coronavirus vaccine is extremely effective in the real world one week after the second dose.”
Other analyzes suggest that serious infections and deaths fell among older Israelis, who received the vaccine first, but not among those under 44 who were not vaccinated.
The Israeli report describes observations made over three weeks in January and February when researchers were able to compare the health records of unvaccinated people and people who had received their second injection more than a week before. They then compared the groups for five covid-19 outcomes: infection, symptoms, hospitalizations, critical hospitalization, and death. The unpublished study indicates that the vaccine was about 93% effective in preventing symptomatic covid-19. Pfizer and its partner, German biotech company BioNTech, found 95% efficacy in their clinical trials conducted in 2020. The nationwide study was also able to show that hospitalizations and deaths fell by similar amounts in the vaccinated group.
Because Israel tests people fairly comprehensively, researchers were also able to estimate the vaccine to be 89.4% effective in preventing any detectable infection, including asymptomatic infections.
The new finding suggests that the vaccine could strongly suppress transmission of the virus between people and could help end the outbreak, a possibility Pfizer and Israeli researchers say are watching closely. “Israel offers a unique opportunity to observe the nationwide impact of an increasing prevalence of immunity on Sars-Cov-2 transmission,” the authors wrote. Eric Topol, a doctor with Scripps Research in California, who reviewed the document, said that “the blocking of infections here is testament to the impact of the vaccine on asymptomatic transmission, which we are not sure about.