Study in Israel will test the effectiveness of 4th dose of vaccine

An Israeli hospital on Monday began a study to test the safety and effectiveness of a fourth dose of a Covid-19 vaccine, as health officials continued to deliberate on rolling out a fourth vaccine for those with vulnerable people across the country.

Officials at Sheba Medical Center near Tel Aviv said their study was the first of its kind in the world and involved giving an additional injection to 150 medical staff who had received a third dose of the Pfizer vaccine. BioNTech at least four months ago. .

Actions taken in Israel, one of the early leaders in Covid vaccinations, are being watched closely as governments around the world struggle to deal with the rapidly spreading Omicron variant, which is leading to record numbers of new infections in parts of the United States, Europe and other places. Even though some studies suggest Omicron infections are milder than those caused by other variants, flare-ups are already spreading health systems, and experts warn it could lead to many more deaths.

With studies showing that Covid vaccines still protect people against serious diseases from Omicron, a panel of medical experts advising the Israeli government last week recommended that health officials offer a fourth injection to people aged 60. years and older, for those with lower immunity and for medical care. workers.

The proposal is awaiting formal approval from the Ministry of Health, but questions have been raised as to whether the recommendation was premature given the lack of data on the effects of a fourth injection. It was not clear whether the ministry would wait for the results of the hospital study before making its recommendation.

The advisory group acknowledged uncertainty about Omicron’s effects, but pointed to evidence of decreased immunity in people who were among the first to receive a third dose in August. Israeli data showed a doubling in the rate of infection with the then-dominant Delta variant among the 60-and-over age group within four or five months of the third stroke.

Israel, a relatively small country with an efficient public health system, has been a leader in introducing the first round of Covid vaccinations and later in administering boosters, putting it in a position to assess early how well the injections work and how quickly the protection wears off. .

Most of the advisory group argued that the potential benefits of a fourth dose outweighed the risks and that there was no time to waste making decisions to protect the most vulnerable. But other experts have argued that not enough is known about the effects of a fourth injection, and some scientists have raised concerns that too many injections could cause some kind of fatigue. immune system, compromising the body’s ability to fight the virus, especially in older people.

A senior health ministry official said last week the ministry would collect more data from other countries, particularly on the risk of severe Omicron disease in the elderly, before deciding to offer a fourth dose. and to whom.

On Monday, a second ministry official said a decision could be made in a few days. Both officials requested anonymity to comment on the process.

Also on Monday, Israel’s health ministry formally accepted another of the advisory board’s recommendations, shortening the period between receiving a third booster after the second vaccine to three months instead of five months.

“Now, in light of the Omicron wave, there is an increased need to increase the level of immunity of the general population as quickly as possible,” the ministry said in a statement, noting that other countries Europe had done the same.

Most of the Israeli population has received at least two doses, but about one million eligible citizens have yet to receive a third booster, out of a total population of nine million.

Sara H. Byrd