A new Israeli study found that a fourth dose of the Pfizer/BioNTech coronavirus vaccine offered significant protection against the infection for elderly individuals but noted that its effects waned quickly.

The study that was published on Tuesday in the New England Journal of Medicine observed and reviewed the health records of more than 1.25 million vaccinated individuals in Israel. The people included in the study were aged 60 years or older and were monitored from January to March 2022, the period when the Omicron variant was the dominant strain.

Second COVID-19 Booster Shot

The researchers found that the rate of severe COVID-19 infection in the fourth week after a fourth dose of the vaccine was much lower compared to people who only got three doses. The numbers varied by a factor of 3.5.

Furthermore, they found that the protection offered by the second booster shot against severe illness did not seem to wane in the six weeks following the fourth shot. However, the study was not conducted long enough to determine exactly how long the protection provided lasts, as per CNN.

However, protection from infection provided by the fourth dose waned after just four weeks despite shielding an individual from severe illness. The results of the research come before a meeting by the U.S. Food and Drug Administration (FDA) on Wednesday.

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Officials will discuss the need for additional booster shots which comes a week after the United States authorized a second booster dose for individuals 50 years and older. The decision is being discussed amid the spread of the BA.2 subvariant of the coronavirus.

According to Reuters, European health ministers have encouraged the bloc's government to support the fourth dose for people aged over 60. In Asia, on the other hand, South Korea has begun handing out fourth doses of the coronavirus vaccines in February. Singapore has also announced that they plan to provide second booster shots for people aged 80 and older.

Spread of the Omicron Variant

The Israeli researchers wrote that for confirmed infection, a second booster shot appeared to provide only short-term protection. Discussions for a fourth vaccine dose have intensified amid the rapid spread of the Omicron variant which sometimes can evade a human's body immune defenses.

The FDA also authorized an mRNA booster for adults who have already received two doses of the Johnson & Johnson vaccine. However, many believe that support for another vaccine shot will be hard to acquire as 66% of Americans have already been vaccinated and only 30% have received their first booster shot.

While it was obvious that the Omicron variant has reduced the effectiveness of the coronavirus vaccines, data on the benefits of a second booster remain limited. Israeli researchers conducted another study previously and found that older adults who received a second booster shot were 78% less likely to die of COVID-19 than individuals who only received one booster dose. However, the study was not published in a scientific journal and it received criticism from scientists who cited its methodology, the New York Times reported.

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