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By Michael Erman
Feb. 17 (Reuters) – A lab study suggests that the South African variant of the coronavirus could reduce the antibody protection of the Pfizer Inc / BioNTech SE vaccine by two-thirds, and it is not clear whether the vaccine will be effective against mutation, the companies said on Wednesday.
The study found that the vaccine was still able to neutralize the virus and there is no evidence yet from trials in people that the variant reduces vaccine protection, the companies said.
Still, they are making investments and discussing with regulators whether to develop an updated version of their mRNA vaccine or an injection vaccine, if necessary.
For the study, scientists from the business and medical branch of the University of Texas (UTMB) developed an engineered virus that contained the same mutations carried on the peak portion of the highly contagious coronavirus variant first discovered. times in South Africa, known as B.1.351. The peak, used by the virus to enter human cells, is the primary target of many COVID-19 vaccines.
The researchers tested the man-made virus against blood taken from people who had received the vaccine and found a two-thirds reduction in the level of neutralizing antibodies compared to its effect on the most common version of the virus prevalent in the trials. Americans.
Their results were published in the New England Journal of Medicine (NEJM).
Since there is no established benchmark yet to determine what level of antibodies is needed to protect against the virus, it is not known whether this two-thirds reduction will render the vaccine ineffective against the variant spreading worldwide. .
However, UTMB professor and study co-author Pei-Yong Shisaid believes the Pfizer vaccine will likely be protective against the variant.
“We don’t know what the minimum number of neutralizations is. We don’t have that cut-off line,” he said, adding that he suspects the observed immune response is probably well above what ‘it must be to provide protection.
Indeed, in clinical trials the Pfizer / BioNTech vaccine and a similar vaccine from Moderna Inc. conferred some protection after a single dose with an antibody reacting more slowly than the reduced levels caused by the South African variant in the laboratory study.
Even though the worrisome variant significantly reduces efficacy, the vaccine should still help protect against serious illness and death, he noted. Health experts said this was the most important factor in preventing stretched healthcare systems from being overwhelmed.
More work is needed to understand whether the vaccine works against the South African variant, Shi said, including clinical trials and the development of correlates of protection – the benchmarks for determining what levels of antibodies are protective.
Pfizer and BioNTech said they are doing similar lab work to determine if their vaccine is effective against another variant first found in Brazil.
Moderna published a correspondence in the NEJM on Wednesday with similar data previously disclosed elsewhere that showed six times lower antibody levels compared to the South African variant.
Moderna also said the actual effectiveness of its vaccine against the South African variant remains to be determined. The company has previously said it believes the vaccine will work against the variant (Reporting by Michael Erman; Additional reporting by JulieSteenhuysen in Chicago; Editing by Bill Berkrot)
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