Omicron Reduces Covid Antibody Protection in Small Study on Pfizer Vaccine


Nurse Mary Ezzat will give Jessica M. a booster dose of Pfizer COVID-19 at the UCI Medical Center in Orange, Calif., Thursday, August 19, 2021.

Jeff Gritchen | MediaNews Group | Orange County Register via Getty Images

South African scientists say the Covid-Omicron variant significantly reduces the antibody protection produced by Pfizer and BioNTech’s vaccine, despite people who have recovered from the virus and received a booster dose, according to a small preliminary study released Tuesday would likely have more protection from serious illnesses.

Prof. Alex Sigal of the Africa Health Research Institute and a team of scientists tested blood samples from 12 people who had previously been vaccinated with the Pfizer / BioNTech vaccine. In particular, they looked at how well the antibodies produced by the vaccine can neutralize the new variant – that is, block its ability to infect cells.

They found a 41-fold decrease in the antibody’s ability to neutralize the Omicron variant compared to the original virus, a dramatic decrease in its performance against the original ancestral strain as well as other variants, according to a preprint of the study that was not published ‘ has not yet been assessed. Vaccine-induced antibodies tripled in their ability to neutralize the former beta variant that previously dominated South Africa, suggesting that Omicron is much better at evading protection.

“The results that we present here with Omicron show a much more extensive escape” than the beta variant, the researchers wrote. “Previous infection followed by vaccination or booster will likely increase the level of neutralization and likely protect against serious illness in Omicron infection.”

The study tested 14 plasma samples from 12 vaccinated people, 6 of whom were previously infected. Scientists made their Covid research available prior to the extensive peer-reviewed process due to the urgency of the pandemic.

Dr. Paul Offit, a professor of pediatrics in the Department of Infectious Diseases at Philadelphia Children’s Hospital, told CNBC the data suggests that fully vaccinated individuals may be at higher risk of mild infection from Omicron compared to the earlier variants.

“I think there will still be protection against serious illnesses,” said Offit. “I think either a vaccination or a natural infection or both. You will be protected from serious illnesses.”

Albert Bourla, CEO of Pfizer, said Tuesday that the company could develop a vaccine that specifically targets Omicron by March 2022, if necessary. Bourla said it will be a few weeks before more definitive data are available on whether current vaccines offer adequate protection against the variant.

Pfizer’s CEO previously told CNBC that the protection offered by the company’s two-dose vaccine was likely to diminish somewhat in the face of Omicron.

The South African scientists also found that Omicron binds to the same receptor known as ACE2 to infect human lung cells that used previous variants.

Omicron, which was first identified in southern Africa, has dozens of mutations that make viruses generally more contagious. White House senior medical advisor Dr. Anthony Fauci told reporters during a Covid briefing at the White House Tuesday that data from South Africa on new omicron infections “clearly suggests a high level of transmissibility”.

Fauci said Tuesday it was too early to draw conclusions about whether Omicron causes more serious illnesses, although he said over the weekend that the first reports were encouraging.

The South African Medical Research Council found in a report released on Saturday that most patients admitted to hospital in Pretoria with Covid did not need supplemental oxygen, as was common in previous waves of infection. According to the report, many patients in the Covid wards were actually hospitalized for other reasons.

Pfizer’s CEO said Tuesday that a variant that spreads quickly but causes milder symptoms isn’t necessarily good news.

“I don’t think having something that is spreading quickly is good news,” Bourla told the Wall Street Journal during an interview at the newspaper’s CEO Council Summit. “Rapid spreading means that it will be in billions of people and another mutation could come. You don’t want that.”

– CNBC’s Meg Tirrell contributed to this report.