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 the elderly population with the Pfizer Covid-19 vaccine, suggests 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 Pfizer-BioNTech vaccine is 95% effective in preventing Covid-19, Israeli data provide a brief look at the vaccine’s effectiveness in an uncontrolled real-world setting.
The study, which was published Friday in the CDC’s weekly report on morbidity and mortality, found that among the most vaccinated Israeli population, the percentage of patients in need of ventilation fell sharply, suggesting a reduction in severe disease.
“Taken together, these results suggest low rates of severe COVID-19 after vaccination,” wrote researchers at Ben Gurion University in the Negev, Tel Aviv University and Maccabi Healthcare Services.
Israel launched its national vaccination campaign in December, giving priority to people over the age of 60, health workers and people with comorbid conditions. By February, the researchers said, 84 percent of the population aged 70 and over had been completely immunized with the Pfizer-BioNTech two-shot vaccine. Only 10 percent of the population under the age of 50 had been vaccinated at the same time, the researchers said.
The researchers compared the number of patients with Covid-19 aged 70 and over who needed a mechanical ventilator with those under the age of 50 who needed a ventilator. The researchers said they used the need for a ventilator, a medical tool used to help patients breathe, to measure Covid-19 severely.
Between October and February, the number of patients aged 70 and over who needed a ventilator decreased. At the same time, the number of people under the age of 50, a population that was generally not vaccinated, that needed a fan, has increased, the study found. The country began firing mainly on the elderly on December 20, with a second round of shootings three weeks later.
The researchers noted some limitations of the study. Israel implemented a strict national order of residence at home on January 8, weeks after the start of the vaccination campaign, which could have led to a decrease in seriously ill patients who needed ventilators. The introduction of new variants of the coronavirus could also have affected the data, they said.
The researchers said their findings were preliminary, “important evidence of the effectiveness of vaccines in preventing severe cases of COVID-19 nationwide in Israel.”
“Receiving COVID-19 vaccines by eligible individuals can help limit the spread of the disease and reduce the potential for severe disease,” they wrote.