Pfizer’s vaccine only partially protects against omicrons, initial study shows

The omicron variant of the coronavirus may partially escape the protection of the Covid vaccine from Pfizer and its partner BioNTech, said on Tuesday (7) the head of research at a laboratory at the African Institute for Health Research, in South Africa.

Alex Sigal, a professor at the institute, said on Twitter that there was “a very big drop” in the neutralization of the omicron variant compared to an earlier strain of Covid.

The laboratory tested the blood of 12 people who were vaccinated with the immunizer from Pfizer/BioNTech, according to a text posted on the laboratory’s website. Preliminary data from the document have not yet been reviewed by other scientists.

According to the paper, a 41-fold decline in neutralizing antibody levels against the omicron variant was observed.

Blood from five out of six people previously infected with Covid-19 and who had been vaccinated, however, still neutralized the omicron variant, the text also says — suggesting that booster doses may be able to curb the disease.

Sigal said on Twitter that the number should be adjusted after his lab does more experiments.

Although neutralizing antibodies are an indicator of the immune response, scientists believe that other cell types, such as B and T, are also stimulated by vaccines and help protect against the effects of the coronavirus.

The omicron variant, first detected in southern Africa last month, has set off alarms around the world of yet another outbreak of infections, with more than two dozen countries, from Japan to the United States, reporting cases.

The World Health Organization on Nov. 26 named it a “variant of concern” but said there was no evidence to support the need for new vaccines specifically designed to deal with the omicron variant and its many mutations.

There is still no significant data on how the vaccines from Moderna, Janssen and other pharmaceutical companies behave in the face of the new variant. All manufacturers, including Pfizer, are expected to release their data within weeks.

The main specialist in infectious diseases of the United States, the physician Anthony Fauci, said on Tuesday (7) that the preliminary evidence indicates that the omicron variant of the coronavirus probably has a greater degree of transmissibility, but it is less severe.

He said the United States is testing to determine the protection of current vaccines against the strain, and expects results next week.

Umer Raffat, an analyst at Evercore ISI, rejects a conclusion based on a single study, noting that there was significant variability in the measurement of reduced antibody levels in previous laboratory studies.

“We will wait for further studies to form a mosaic,” he said.

_{Translated by Luiz Roberto M. Gonçalves}