An Israeli health worker from Maccabi Healthcare Services is preparing to administer a dose of the Pfizer-BioNtech vaccine on February 24, 2021 in Tel Aviv.
Jack Guez | AFP | Getty Images
Data from Israel, which vaccinated the overwhelming majority of its elderly population with the Pfizer Covid-19 vaccine, suggests that mass vaccination has prevented people from becoming seriously ill, according to a new study by the Center for Disease Control and Prevention.
While clinical trials have found that the Pfizer-BioNTech vaccine is 95% effective in preventing Covid-19, Israeli data provides an initial glimpse of how effective the vaccine is in a real, uncontrolled environment.
The study, which was published Friday in the CDC’s Morbidity and Mortality Weekly Report, found that among the most vaccinated part of the Israeli population, the percentage of patients needing ventilation has dropped dramatically, suggesting a reduction in serious illness.
“Taken together, these results suggest reduced rates of severe COVID-19 after vaccination,” wrote researchers at Ben Gurion University in Negev, Tel-Aviv University and Maccabi Health Services.
Israel launched its national vaccination campaign in December prioritizing people aged 60 and over, health professionals and people with comorbidities. In February, the researchers said, 84% of the population aged 70 and older had been fully immunized with the Pfizer-BioNTech dual vaccine. Only 10% of the population under 50 was vaccinated at the same time, the researchers said.
The researchers compared the number of Covid-19 patients aged 70 and over who needed a mechanical ventilator with those under 50 who needed a ventilator. The researchers said they used the need for a ventilator, a medical instrument used to help patients breathe, to measure severe Covid-19.
Between October and February, the number of patients aged 70 and over who needed a ventilator dropped. At the same time, the number of people under 50, a population that was not usually vaccinated, who needed a ventilator increased, the study found. The country started administering injections to older people on December 20, with a second round of injections three weeks later.
The researchers noted some limitations of the study. Israel implemented a strict national order to stay home on January 8, weeks after the vaccination campaign began, which could have led to a reduction in the number of critically ill patients who would need ventilators. The introduction of new variants of the coronavirus may also have affected the data, they said.
The researchers said their findings are preliminary, “important evidence of the vaccine’s effectiveness in preventing serious cases of COVID-19 at the national level in Israel”.
“Receiving COVID-19 vaccines by eligible people can help limit the spread of the disease and potentially reduce the occurrence of serious illnesses,” they wrote.