An Israeli health worker from Maccabi Healthcare Services is preparing to administer a dose of Pfizer-BioNtech vaccine on February 24, 2021 in Tel Aviv.
Jack Guez | AFP | Getty Images
Data from Israel, which vaccinated the vast majority of its elderly population with the Pfizer Covid-19 vaccine, indicate that mass vaccinations have prevented people from becoming seriously ill, according to a new study by the Centers for Disease Control and Prevention .
While clinical trials have found that the Pfizer-BioNTech vaccine is 95% effective in preventing Covid-19, the Israeli data provide an early look at how effective the vaccine is in an uncontrolled, real-world environment.
The study, published Friday in the CDC’s weekly report on morbidity and mortality, found that among the most vaccinated part of the Israeli population, the percentage of patients in need of ventilation dropped dramatically, indicating a decrease in serious illness.
“Together, these results indicate a reduced dose of severe COVID-19 after vaccination,” wrote researchers at Ben Gurion University of the Negev, Tel Aviv University and Maccabi Healthcare Services.
Israel launched its national vaccination campaign in December to prioritize people aged 60 and over, health workers and people with poor conditions. According to the researchers, 84% of the population aged 70 and older were fully immunized by February with the Pfizer-BioNTech two-shot vaccine. Only 10% of the population under 50 were vaccinated by the same time, the researchers said.
The researchers compared the number of Covid-19 patients 70 years and older who needed a mechanical ventilator with those younger than 50 who needed a ventilator. The researchers said they use the need for a ventilator, a medical tool used to help patients breathe, to measure severe Covid-19.
Between October and February, the number of patients aged 70 and older who needed a ventilator decreased. At the same time, the number of people under 50, a population that is not usually vaccinated, who need a ventilator, has increased, the study found. The country began delivering shots to mostly elderly people on December 20, with a second shot three weeks later.
The researchers noted some limitations of the study. On January 8, weeks after the start of the vaccination campaign, Israel implemented a strict national home order, which could lead to a decrease in seriously ill patients in need of ventilators. The introduction of new variants of the coronavirus could also have affected the data.
According to the researchers, their findings are preliminary, “important evidence of the effectiveness of vaccines in preventing serious cases of COVID-19 at the national level in Israel.”
“Receiving COVID-19 vaccines by eligible individuals can help limit the spread of disease and potentially reduce the incidence of serious diseases,” they write.