Pfizer-BioNTech COVID-19 Vaccine Less Effective Against Omicron: Companies

A vial of the Pfizer-BioNTech COVID-19 vaccine is seen in a file photograph. (Justin Sullivan/Getty Images)

The Pfizer-BioNTech COVID-19 vaccine is less effective against the Omicron virus variant than other strains of the CCP virus, the companies said Wednesday, citing interim results from a study they’re running.

Scientists found on average a more than 25-fold reduction in neutralizing antibodies against the Omicron variant compared to the wild type, “indicating that two doses of BNT162b2 may not be sufficient to protect against infection with the Omicron variant,” the companies said in a statement.

BNT162b2 is another name for the vaccine. The CCP (Chinese Communist Party) virus causes COVID-19.

Antibodies help protect people from COVID-19, along with T cells.

Testing was done on samples of immune sera drawn from people who had received two or three doses of the vaccine.

Most of the T cells triggered by the shot were not compromised by Omicron, according to the companies. That points to the shot holding up well against severe disease.

Additionally, Pfizer and BioNTech say the results show a booster dose, or a third dose, increased the antibodies by 25-fold, putting the protection back on the level of the primary regimen against earlier variants.

“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is improved with a third dose of our vaccine,” Pfizer CEO Albert Bourla said in a statement. “Ensuring as many people as possible are fully vaccinated with the first two dose series and a booster remains the best course of action to prevent the spread of COVID-19.”

The companies are working on an adapted vaccine that would target Omicron because of concerns the current formulation isn’t effective enough.

That updated shot “will help to induce a high level of protection against Omicron-induced COVID-19 disease as well as a prolonged protection compared to the current vaccine,” Dr. Ugur Sahin, BioNTech’s CEO, said.

The findings were not peer-reviewed and were criticized by some for lacking more detail.

A nurse fills up syringes for patients as they receive their COVID-19 booster vaccination during a Pfizer-BioNTech vaccination clinic in Southfield, Mich., on Sept. 29, 2021. (Emily Elconin/Reuters)

“We need to know how this differs by age, and by prior infection status. These data are 1 month after booster—what about 4 months after booster? How many times should we boost to increase neutralization if protection against severe disease is maintained?” Dr. Walid Gellad, professor of medicine at the University of Pittsburgh, wrote on Twitter.

Pfizer did not respond to a request for comment while BioNTech pointed to a press conference its CEO, Dr. Ugur Sahin, gave later in the day that did not answer the questions.

The Omicron variant was first identified in southern Africa last month. At least one sample on the continent dates back to October. The discovery led to travel bans because early data suggested the variant transmitted more easily than Delta, the dominant strain in many areas.

Experiments on the variant since then point to it transmitting more efficiently than Delta but also causing less severe disease. At the same time, the variant could better evade the immunity from vaccination and prior infection.

Pfizer and BioNTech’s release of laboratory data came hours after South Africa researchers said a small study showed the companies’ shot performed much worse against Omicron, and about a week after a study indicated Omicron also evaded natural immunity at a higher rate than the Delta and Beta strains.

Early studies by a Swedish team and a German team (pdf) also found a reduction in neutralizing antibodies among the vaccinated.