Preliminary results from a South African study show that the Omicron variant reduced the levels of the Pfizer-BioNTech COVID-19 vaccine.
The first laboratory results show how a COVID-19 vaccine holds up. A group of researchers led by Africa Health Research Institute's Alex Sigal tested 14 blood samples from 12 people against a live sample of the Omicron variant. Six of the 12 people were previously exposed to a disease.
The scientists found a reduction in the levels of neutralizing antibodies compared to the original version of the virus.
Sigal wrote on the social networking site that Omicron did not evade vaccine protection completely. There are questions about whether booster shots will ward off disease or if new vaccines will eventually be required. It was a large drop in neutralization of Omicron.
Sigal said in an online presentation of his results on Tuesday that a good booster would decrease the chance of infections.
People who haven't had a booster should get one, and people who have been exposed should get one.
A group of researchers at Sweden's Karolinska Institutet disclosed their own findings that suggested a decline in antibody levels, after Sigal announced his team's results. The team found a seven-fold reduction in blood samples.
They used a fake version of Omicron that was made in a lab instead of the live one. The findings make Omicron worse than Delta, but it's not as extreme as we expected.
The Delta variant caused a 2- to 3-fold reduction in antibodies compared to the original virus, while theBeta variant caused a 7- to 8-fold reduction.
The results have not been published in a journal. The findings are likely to be adjusted as we do more experiments.
Pfizer's Chief Scientific Officer told Insider he was worried about a 10-fold reduction in antibody levels. He was concerned that current vaccines wouldn't offer enough protection and that an Omicron-specific shot would be needed.
"If we exceed a 10-fold drop in neutralization of Omicron, I think we are starting to enter the yellow to red zone, when your immunity is likely lowered and there's limited time after your boost until waning," he said.
Pfizer, Moderna, and Johnson & Johnson are working on Omicron-specific shots. An updated version could be ready to start mass-produced as soon as March 2022.
The South African study only looked at blood samples from people who got two shots of Pfizer's vaccine, not the people who got a booster shot. Five of the six blood samples came from people who had been exposed to Omicron and had high levels of neutralizing antibodies against it.
The researchers wrote that a previous infection followed by a vaccine or booster is likely to increase neutralization and give protection from severe disease.
It's not clear if Omicron will affect vaccine protection.
Despite drops in the levels of the vaccine's antibodies, the vaccine could still help prevent critical illness. B- and T-cells, which are part of the immune system, are activated by vaccines.
According to disease experts in South Africa, vaccines seem to reduce the risk of serious illness in Omicron cases.
Richard Friedland, chief executive officer of Netcare, which operates South Africa's largest private healthcare network, said on Friday that they are seeing breakthrough infections of people who have been vaccine free. It's mostly mild for healthcare workers who have had boosters.
Omicron has shown signs of being highly transmissible compared to other coronaviruses. The variant has spread to more than 40 countries since it was first detected.
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