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Pfizer and BioNTech said they are working on a real-world analysis of data from Israel.
The Pfizer Inc. and BioNTech SE Covid-19 vaccine appeared to prevent the vast majority of recipients in Israel from becoming infected, providing the first real-world indication that immunization will slow transmission of the coronavirus.
The vaccine, which is being rolled out in a national immunization program that began Dec. 20, was 89.4% effective in preventing laboratory-confirmed infections, according to a copy of a draft post that was posted on Twitter and confirmed. a person familiar with the work. The companies worked with the Israeli Ministry of Health on the preliminary observational analysis, which was not peer-reviewed. Some scientists questioned its accuracy.
The results, also reported in Der Spiegel, are the latest in a series of positive data to come out of Israel, which has given more Covid vaccines per capita than anywhere else in the world. Almost half of the population has received at least one dose of vaccine. Separately, Israeli authorities said Saturday that the Pfizer-BioNTech injection was 99% effective in preventing deaths from the virus.
A nurse administers the Pfizer-BioNTech vaccine at McLeod Health Clarendon Hospital in South Carolina.
If confirmed, early results from laboratory-tested infections are encouraging because they indicate that the vaccine can also prevent asymptomatic carriers from spreading the virus that causes Covid-19. That has not been clear because clinical trials that tested the safety and efficacy of vaccines focused on the ability to stop symptomatic infections.
Group immunity
“This is the data that we need to see to estimate the potential for achieving herd immunity with vaccines,” Raina MacIntyre, a professor of biosafety at the University of New South Wales in Sydney, said in an email Monday. “However, we need to be able to see the data published in a peer-reviewed journal and to be able to analyze the data in detail.”
Pfizer and BioNTech said they are working on a real-world analysis of the Israel data, which will be shared as soon as it is complete. Spokesmen declined to comment on unpublished data.
The study was not designed to accurately measure a reduction in SARS-CoV-2 transmission because it used data from national tests without taking into account differences in testing rates between vaccinated and unvaccinated people, said Zoe McLaren, associate professor. in the school of public education. policy of the University of Maryland in Baltimore County.
“The main result exaggerates the reduction in transmission from the Pfizer vaccine,” McLaren said in an email.
The study compares the number of reported cases between those who had been fully vaccinated and those who had not been vaccinated, but vaccinated people are less likely to be tested, so the data will not count cases, especially asymptomatic ones, in this group said. .
‘I need more evidence’
“That means the true reduction in transmission is less than the 89.4% estimate,” McLaren said. “How much lower? We need more evidence to know for sure. But hopefully, once we take bias into account, we still find that this vaccine reduces transmission. And that would be very good news.”
Approximately 80% of SARS-CoV-2 cases in Israel during the study time period, January 17 to February 6, were caused by the most transmissible strain first identified in the UK. Israel’s vaccination campaign began just before the variant called B.1.1.7 emerged, fueling infections and leading to a third lockdown on January 8.
As of February 6, approximately 27% of people 15 years and older in Israel were fully vaccinated, and the Pfizer-BioNTech vaccine was the only vaccine available in the country at the time. People were considered fully vaccinated and included in the analysis if the data collected was more than seven days after receiving their second dose.
Based on the infectivity of SARS-CoV-2, a vaccine that is 89% effective in preventing infection is likely to be effective in eliminating Covid-19 in a population in which high vaccination coverage is achieved, Helen said. Petousis-Harris, a vaccinologist at the University of Auckland.
The elimination of Covid-19 will depend on the possible “reservoirs” of SARS-CoV-2 in animals, genetic changes in the virus that could allow it to escape the immunity induced by the vaccine and the ability to stop transmission worldwide, said Petousis-Harris, co-leader of the Global Vaccine Data Network, a multinational group that collaborates on vaccine safety studies.
