The recent large-scale trial by an Israeli HMO reveals that a fourth dose reduces both the likelihood of infection and severe sickness, since omicron’s BA.2 variation is causing a jump in COVID-19 infections.
Separate studies published Saturday by Israel’s two leading health-care providers suggest that the fourth vaccine dosage considerably reduces the risk of dying from COVID-19 when compared to three doses of the vaccine.
Clalit Health Services, Israel’s largest health maintenance organization, found that a fourth vaccine reduces both the risk of infection and the danger of severe illness, whereas Maccabi Healthcare Services found that a fourth vaccine reduces both the risk of infection and the risk of severe disease.
As omicron’s BA, these results are especially important. COVID-19 omicron’s BA.2 variant infections are rising in the US, UK and many other nations.
Clalit’s research included 563,465 adults aged 60 to 100 who had received three vaccination doses. They were separated into two groups: those who decided to receive a fourth dose and those who did not. A fourth vaccine was given to 58 percent of the individuals.
The researchers analyzed the mortality rate in the two populations between January 10, roughly a week after the fourth dose was approved, and February 20. 232 persons died in the group that received only three doses throughout this time, compared to 92 in the group that received four doses.
The statistics reveal that the fourth immunization reduces the risk of dying from the coronavirus by 78 percent in older persons, according to the researchers.
Clalit’s research has not yet been peer-reviewed, but it is now being considered for publication in a journal. Clalit’s Community Medicine Division collaborated on the study alongside Ben-Gurion University of the Negev’s Faculty of Health Sciences and Sapir Academic College’s Maximizing Health Outcomes Research Lab.
Dr. Doron Netzer, the chairman of the Community Medicine Division, said the discoveries are significant because the omicron type is thought to produce very moderate disease, thus no further immunization is required.
“The results of the study show that the fourth dose is significantly associated with a reduced risk of mortality from coronavirus, including from omicron,” he said.
Maccabi’s study looked at the vaccination’s effectiveness for nine weeks, from January to March, among roughly 100,000 Maccabi members aged 60 and up who received three doses of the vaccine. It was discovered that the fourth dose was 73 percent more efficient than the first three in preventing serious sickness. However, only about 1% of those who had at least three doses of the vaccine developed severe COVID-19.
The results also demonstrated that the fourth dose was effective against coronavirus infection. According to the study, the chance of being ill drops by 64 percent three weeks after receiving the fourth vaccine compared to individuals who received only three doses. However, 10 weeks after receiving the fourth vaccine, the reduction in risk lowers to 29 percent, showing that the additional protection it provides wears off faster than the third dosage.
KSM, the Maccabi Research and Innovation Center, completed the research, which is currently undergoing peer review.
More research over a longer time period, according to the researchers, is needed to evaluate the length of protection conferred by the fourth dose over time. More research could be done to see how re-exposure to the same vaccine affects protection against various variations, they said.
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