Pfizer shot elicits fewer antibodies for new variant
Scientists caution it remains to be seen what data means outside lab
Pfizer Inc. and BioNTech SE’s COVID-19 vaccine stimulated roughly two-thirds lower levels of neutralizing antibodies against the variant of the coronavirus first found in South Africa in a lab study.
The Pfizer results are part of tests of its vaccine against a labcreated virus that had all the mutations found in the South African variant, which is thought to spread faster than earlier versions. The study released Wednesday showed reduced neutralization of the virus variant, also known as B.1.351, by blood from people who had been immunized with the Pfizer-BioNTech vaccine. The companies expect their vaccine will still work against the variant.
All of the blood samples from vaccinated patients still showed significant levels of neutralizing antibody against B.1.351, the researchers said. The study was conducted by Pfizer, BioNTech and researchers at the University of Texas Medical Branch at Galveston and published in the New England Journal of Medicine.
A separate study by researchers from the National Institute of Allergy and Infectious Diseases and Moderna Inc. also looked at how that company’s vaccine performed against B.1.351 in the lab, and found a significant reduction in coronavirus-fighting antibodies. These neutralizing antibodies were reduced by a factor of 6.4, compared with levels produced against earlier versions of the virus, when the full group of B.1.351 mutations were examined.
What the lab data means in practice remains to be seen. “It is unclear what effect a reduction in neutralization by approximately two-thirds would have” on protection from COVID-19 caused by B.1.351, the Pfizer study concluded.
The mutant virus has become a stumbling block for vaccine campaigns, with South Africa halting the rollout of AstraZeneca PLC’s shot after a study showed it didn’t work as well in preventing mild illness involving the variant first identified there. AstraZeneca is working to revise its vaccine by fall, while Moderna Inc. is working on booster shots.
Pfizer and BioNTech said in a statement that there’s no realworld evidence that B.1.351 can elude their shot. Still, they said they’re getting ready to develop an updated vaccine or booster if need be. The partners said they’re also testing whether the vaccine works against a variant that has emerged in Brazil.
The findings shouldn’t stand in the way of South Africa using the Pfizer shots, according to the Africa Centres for Disease Control and Prevention. The government has ordered 20 million Pfizer vaccines.
Pfizer declined to comment further on the impact the lab study would have on the rollout of its inoculation in South Africa, referring to its statement. The World Health Organization said the data from the study needs to be scrutinized further before any decision is taken on the use of the shots.