Indoor masks remain as Israel discovers new COVID strain and reproduction rate creeps up again

A fourth shot of the mRNA COVID-19 vaccine offers low efficacy and may even largely fail to prevent virus carriers from being infectious, according to an Israeli study published in The New England Journal of Medicine on March 16.

The study, conducted by Sheba Medical Center, compared a fourth shot taken by healthcare workers to those who have had just a third shot.

“Along with previous data showing the superiority of a third dose to a second dose, our results suggest that maximal immunogenicity of mRNA vaccines is achieved after three doses and that antibody levels can be restored by a fourth dose,” the study concluded. “Furthermore, we observed low vaccine efficacy against infections in health care workers, as well as relatively high viral loads suggesting that those who were infected were infectious. Thus, a fourth vaccination of healthy young health care workers may have only marginal benefits. Older and vulnerable populations were not assessed.”

The study claims that the fourth dose is “immunogenic, safe, and somewhat efficacious (primarily against symptomatic disease).”

“A comparison of the initial response to the fourth dose with the peak response to a third dose did not show substantial differences in humoral response or in levels of omicron-specific neutralizing antibodies,” the study noted.

Prof. Gili Regev-Yochay said that from the 270 participants – out of 600 total – who received a fourth dose of either the Pfizer or Moderna vaccine, “we found no differences, both in terms of IgG antibody levels and in terms of neutralizing antibody levels, which reached a level similar to that measured a month after the third dose was administered.”

Some 737,472 Israelis have taken the fourth shot since Israel offered the extra booster in December.

Regev-Yochay had previously mentioned the initial outcome of the study in January. At the time she said “we see many infected with Omicron who received the fourth dose. Granted, a bit less than in the control group, but still a lot of infections.”

The study comes as Israel has discovered a new strain of the Omicron variant – dubbed BA.1 and BA.2.

“This variant is still unknown around the world,” the Health Ministry said in a statement. “The two cases of the combined strain, which have been discovered so far, suffered from mild symptoms of fever, headaches and muscle dystrophy, and do not require a special medical response.”

The media is already ballyhooing a “sixth wave” as the reproduction number of those tested creeps up toward 1.

Prime Minister Naftali Bennett and Health Minister Nitzan Horowitz decided on Wednesday to extend the indoor mask mandate, including for schoolchildren who must be masked in the classroom. They also ordered that public information efforts to encourage vaccinations continue and they will assess whether Israel has enough vaccines and medicine in stock “in preparation for the possibility of a severe corona strain, if detected,” according to a statement from prime minister's foreign media adviser.

“During the discussion, the data on the infection rate in Israel was presented, as well as the infection rate in the world, with an emphasis on the focal points of the outbreak in China in general and in Hong Kong in particular. In addition, the information available at this stage regarding the BA2 corona strain and the combined strain was also presented,” the statement said. 

The Green Passport has been canceled in most venues, but remains in place at nursing homes in order to protect the elderly.

This article was updated on Mar. 20 at 11:07 am.