(Reuters) – A laboratory study suggests South African variant of coronavirus may reduce antibody protection against Pfizer Inc / BioNTech SE vaccine by two-thirds and it is unclear whether the shot will be effective against the mutation, according to companies he said Wednesday.
The study found that the vaccine was still able to neutralize the virus and there is still no evidence from trials in people that the variant will reduce protection against the vaccine, the companies said.
Still, they are making investments and talking to regulators about developing an updated version of their mRNA vaccine or booster shot, if necessary.
For the study, scientists from companies and the medical branch of the University of Texas (UTMB) developed an engineering virus that contained the same mutations carried in the tip portion of the highly contagious coronavirus variant discovered in the South. -Africa, known as B.1.351. The ear, which the virus uses to enter human cells, is the main target of many COVID-19 vaccines.
The researchers tested the engineered virus against blood drawn from people who had been given the vaccine and found a two-thirds reduction in the level of neutralizing antibodies compared to its effect on the more common version of the vaccine. virus prevalent in trials in the United States.
His findings were published in the New England Journal of Medicine (NEJM).
As no benchmark has yet been established to determine what level of antibodies are needed to protect against the virus, it is unclear whether this two-thirds reduction will make the vaccine ineffective against the spreading variant. around the world.
However, UTMB professor and co-author of the UTMB study, Pei-Yong Shi, said he believes the Pfizer vaccine will likely be protective against the variant.
“We do not know what the minimum neutralizing number is. We don’t have that cut line, ”he said, adding that he suspects the observed immune response will likely be significantly above where it should be to provide protection.
This is because in clinical trials, both the Pfizer / BioNTech vaccine and a similar feature from Moderna Inc. conferred some protection after a single dose with an antibody response below the reduced levels caused by the southern variant. African in the laboratory study.
Even if the corresponding variant significantly reduces the effectiveness, the vaccine should help protect against serious illness and death, he noted. Health experts have said this is the most important factor in preventing stretched health systems from being overwhelmed.
More work needs to be done to understand whether the vaccine works against the South African variant, Shi said, including clinical trials and the development of protective correlates, benchmarks for determining what levels of antibodies are protective.
Pfizer and BioNTech said they were doing similar lab work to understand if their vaccine is effective against another variant found for the first time in Brazil.
Moderna on Wednesday published a correspondence with NEJM with similar data previously reported elsewhere showing a six-level drop in antibodies against the South African variant.
Moderna also said the actual effectiveness of her vaccine against the South African variant has not yet been determined. The company has previously said it believes the vaccine will work against the variant.
Reports by Michael Erman; Additional reports from Julie Steenhuysen in Chicago; Edited by Bill Berkrot