Pfizer says the South African version could significantly reduce protection against vaccines

(Reuters) – A laboratory study suggests that the South African version of the coronavirus may reduce antibody protection from the Pfizer Inc / BioNTech SE vaccine by two-thirds and it is unclear whether the shot will be effective against the mutation. said Wednesday.

The study found that the vaccine was still able to neutralize the virus and there is still no evidence from studies in humans that the variant reduces vaccine protection, the companies said.

However, they are investing 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 University of Texas Medical Branch (UTMB) developed a projected virus that contained the same mutations carried on the tip portion of the highly contagious coronavirus variant first discovered in South Africa, known as the name of B.1.351. Peak, used by the virus to enter human cells, is the main target of many COVID-19 vaccines.

The researchers tested the virus projected against the blood taken from people who 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 US studies.

Their findings were published in the New England Journal of Medicine (NEJM).

As there is still no set benchmark to determine what level of antibodies are needed to protect against the virus, it is unclear whether the two-thirds reduction will make the vaccine ineffective against the worldwide spread.

However, UTMB professor and co-author of the study, Pei-Yong Shi, said he believes the Pfizer vaccine will likely be protective against the variant.

“We do not know what the minimum neutralization number is. We do not have this cutting line, “he said, adding that he suspected that the observed immune response was probably much higher than it should provide protection.

This is due to the fact that, in clinical trials, both the Pfizer / BioNTech vaccine and a similar vaccine from Moderna Inc. provided some protection after a single dose with a lower antibody response than the low levels caused by the southern variant. African in the laboratory study.

Even if the variant in question significantly reduces its effectiveness, the vaccine should help protect against severe disease and death, he said. Health experts say this is the most important factor in preventing widespread health 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 protective correlates – the benchmarks for determining what levels of antibodies are protective.

Pfizer and BioNTech said they are doing similar laboratory work to understand 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 revealed elsewhere, which showed a six-fold decrease in antibody levels compared to the South African variant.

Moderna also said that the real effectiveness of its vaccine against the South African variant is yet to be established. The company previously said it believes the vaccine will work against the variant.