South Africa Study, Complete Vaccine Recipient Blood And Ever Infected With COVID-19 Still Neutralizes Omicron Variant

JAKARTA - The Omicron variant of the coronavirus can partially evade protection from two doses of Pfizer BioNTech's COVID-19 vaccine, said the head of laboratory research at the Africa Health Research Institute in South Africa (South Africa), Tuesday.

However, studies show blood from people who have received two doses of the vaccine and had a previous infection, is mostly able to neutralize the variant, suggesting booster doses of the vaccine may help to fend off infection.

Alex Sigal, a professor at the African Institute of Health Research, said on Twitter there was a very large "reduction" in the neutralization of Omicron variants relative to previous COVID-19 strains.

The lab tested the blood of 12 people who had been vaccinated with two doses of the Pfizer/BioNTech vaccine, according to a manuscript posted on its lab website. However, the initial data in the manuscript has not been peer reviewed.

Blood from five of the six people who had been vaccinated and previously infected with COVID-19 still neutralized the Omicron variant, the manuscript said.

"This result is better than I expected. The more antibodies you get, the more likely you will be protected against Omicron," Sigal said on Twitter, citing Reuters Dec. 8.

He said the laboratory had not tested the variant against blood from people who had received the booster dose, as it was not yet available in South Africa.

According to the manuscript, the laboratory observed a 41-fold decrease in neutralizing antibody levels against the Omicron variant. Sigal said on Twitter the figure would likely be adjusted after his lab does more experiments.

While neutralizing antibodies are indicators of the body's immune response, scientists believe other cell types such as B cells and T cells are also stimulated by the vaccine and help protect against the effects of the coronavirus.

Preliminary data do not indicate that the vaccine is less able to prevent severe illness or death. While lab tests are ongoing, BioNTech CEO Ugur Sahin said last week, "we think it's likely people will have substantial protection against severe disease caused by Omicron."

The Omicron variant, first detected in southern Africa last month, has sparked alarm globally of another spike in infections, with more than two dozen countries from Japan to the United States reporting cases.

The World Health Organization (WHO) classified it on Nov. 26 as a "variant of concern," but said there was no evidence to support the need for a new vaccine specifically designed to address the Omicron variant with its multiple mutations.

There is no significant data yet on how vaccines from Moderna, Johnson & Johnson and other drugmakers hold up against the new variant. All manufacturers, including Pfizer and BioNTech, are expected to release their own data in a few weeks.

Meanwhile, BioNTech's Sahin told NBC News on Tuesday, the drugmaker has data coming Wednesday or Thursday regarding the new variant.

Yesterday, the leading US infectious disease expert Dr. Anthony Fauci said preliminary evidence suggests that the Omicron variant of the coronavirus may have a higher rate of transmission but is less severe.

He said the United States was conducting its own tests to determine current vaccine protection against the Omicron variant, expecting results to be obtained next week.

Separately, Umer Raffat, an analyst for Evercore ISI, cautions against reading too much into one study, noting there is significant variability in measuring the drop in antibody levels in previous laboratory studies.

"We are waiting for additional studies to draw the mosaic," he said.