Is it necessary to start a fourth dose of the vaccine? The Israeli experience: useful for the elderly

Speaking recently about the need to promote a fourth dose of the new crown vaccine, Zhang Wenhong, director of the Infection Department at Huashan Hospital affiliated to Shanghai Fudan University, said that the Israeli experience could be taken into account. He said, "Both Israel and Singapore have recently been laying out the fourth dose of the shot, and our country will consider the fourth dose of vaccination subsequently."

In January this year, Israel, which is riding high on vaccination, was again the first in the world to start offering a fourth dose of the new crown vaccine to people aged 60 and above. But unlike the rapid rollout of the first three doses of the vaccine, the fourth dose was controversial from the start, with many, including experts, arguing that it was not necessary.

As the fourth dose of the vaccine has been rolled out in Europe and the US, more scientists have joined the heated debate. But the latest news from Israel may help to ease the debate. An Israeli study has shown that for the elderly or those with immune deficiencies, a fourth dose is not only useful but also life-saving: those who received a fourth dose of the vaccine had a 78% lower mortality rate compared to those who received three doses.

Dr Jing Song, a scientist in residence at the Benaroya Research Institute in the US and a doctor of immunology at the Hebrew University of Jerusalem in Israel, told Business First that the average person may not need to go for a fourth dose, but for older people who need priority protection, the fourth dose is crucial.

Reducing mortality in the elderly

covid

Arnon Gutfeld, an 82-year-old professor emeritus at Tel Aviv University in Israel, told China Business that as soon as the Israeli Ministry of Health announced in January that the fourth dose would be administered, he rushed to get it. He said that the fourth dose is now well accepted among the elderly in Israel and that many people have received it.

The latest figures that have come out support his view, and Professor Gutfeld said he was pleased to see that older Israelis are making the right choice. Clalit, Israel's largest health service, in conjunction with other research institutions, has announced that after following 560,000 older people over the age of 60, it found a significant 78% reduction in mortality after a fourth dose of the vaccine, compared to those who received only three doses.

The study surveyed 560,000 older people, with a median age of 73 years and 53% women. Of these, 330,000 were vaccinated with the fourth dose and 92 died of disease (due to infection with the new crown), while as a control, 235,000 were not vaccinated with the fourth dose and 232 died of disease.

Ronen Arbel, the Sapir College researcher who led the study, said the main conclusion of the study was that a fourth dose of the vaccine could save lives. He said that while it was difficult to estimate how many people would be saved by a fourth dose globally, hundreds of lives could have been saved in Israel alone.

In January, Israel had the highest per capita infection rate in the world at 0.6 per cent per day, and elderly Israelis were fully exposed to the risk of contracting the new coronavirus. This scenario also lends credibility to the study.

Due to the transmission characteristics of the Omicron strain and Israel's relaxed epidemic control, 3.88 million cases of infection have accumulated in the country's population of more than 9 million. According to outbreak data released by the Israeli Ministry of Health on the 28th, the country has seen 9,857 new confirmed cases of the new crown in the past 24 hours. The cumulative number of deaths is 10,485.

Albel stressed that the fourth dose may not be satisfactory in preventing infection due to the more infectious strain of Omicron, but it is outstanding in preventing serious and fatal cases.

He suggested that other countries could begin to consider administering the fourth dose to immune vulnerable groups. However, he also noted that the global inequity in vaccine distribution remains unresolved and that many places are not yet in a position to roll out a third or fourth dose.

According to a study conducted on 17 March at the Sheba Medical Centre in Israel, a fourth dose of the vaccine is "minimally effective" against the new coronavirus.

Dr. Gili Regev-Yochay, director of the infection prevention and control department at Sheba Medical Centre, said that 270 of the approximately 600 participants in the trial received a fourth dose of either the Pfizer or Modena vaccine. Their levels of both immunoglobulin G (IgG) antibodies and neutralising antibodies were largely similar to those measured one month after the third dose of the vaccine.

This result suggests that for healthy young people who had received three doses of the vaccine, the effect of the fourth dose was not significant and provided only "mild protection" against symptomatic infection.