Pfizer Coronavirus Vaccine Works on Variant Mutations in South Africa: Study

• In one study, the Pfizer and BioNTech vaccine worked against lab-made coronaviruses, similar to variants spreading in the UK and South Africa.
• Slight differences in how the vaccine behaved against mutations, compared to the original virus, were “unlikely to lead to a significant reduction” in efficacy.
• The Pfizer-BioNTech vaccine has not yet been tested against actual variants of the coronavirus.
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The COVID-19 vaccine co-developed by Pfizer and BioNTech works against lab-made coronaviruses that are similar to variants found in the UK and South Africa, the drugmakers said on Wednesday.

Studies by Pfizer and the University of Texas showed “small differences” in how the antibodies produced by Pfizer’s vaccine bind to and kill laboratory-made viruses, compared to their effectiveness against the virus. origin.

But these differences were “unlikely to lead to a significant reduction in vaccine effectiveness,” BioNTech said in a press release.

Pfizer and BioNTech’s vaccine was 95% effective in protecting against the original coronavirus in trials conducted in 2020.

In the new study, Pfizer tested three different “pseudoviruses” that it designed to have some of the mutations found in the UK and South Africa variants. The variant found in South Africa has a mutation called K417N which has been shown to escape antibodies in lab studies – the lab-made variant did not have this mutation.

Researchers at Pfizer looked at how antibodies work, which is one aspect of the immune system’s defense against the coronavirus. There is no agreement on how “protection against COVID-19” is defined, the study’s authors said in the article, acknowledging this as a weakness of the study.

The results come from a pre-printed study, and have yet to be published in a peer-reviewed journal for expert review.

The UK variant, B.1.1.7, has been found in several US states, as well as countries around the world. The variant found in South Africa, 501Y.V2, has not yet been identified in the United States.

Pfizer said on Jan.20 that it had tested its vaccine on the variant found in the UK and had worked in company-led lab studies, but this latest research was its first test against the southern variant. -african.

The sample size was small and the scientists had not performed any tests for statistical significance, which is one way the researchers assess whether the results may be due to chance.

Moderna announced on Monday that its vaccine was resistant to B.1.1.7, the variant found in the UK, but small-scale laboratory tests showed the shot worked less well against the variant found in South Africa, 501 .Y.V2.

“The gold standard” would be to test against the real variant

In the latest Pfizer study, scientists tested the pseudovirus against antibodies in 12 blood samples from people who had received two injections of Pfizer’s vaccine two or four weeks previously. They then examined the effectiveness of the antibodies against the pseudovirus variants, compared to the original strain.

“The gold standard would be to test antibodies against the variants themselves to understand how their unique constellation of mutations might affect natural immunity or protection against a vaccine,” said Dr. Jason McLellan, structural biologist at the ‘University of Texas at Austin, The Wall Street Journal. McLellan studied how coronavirus proteins interact with antibodies, but was not involved in the Pfizer study.

Rafael Casellas, a molecular immunologist at the National Institutes of Health (NIH), told the Journal that it was important to continue to monitor the coronavirus variants and assess whether vaccines and other treatments might need to be updated or if any booster injections would be required.

“We cannot take this virus lightly,” he said. “We just don’t have enough information, so we have to be careful.”

We don’t know how long immunity lasts after receiving a vaccine, whether for the coronavirus variants or for the original virus.

Pfizer said on Tuesday it was already working on booster shots that protect against variants of the coronavirus. Moderna said on Monday he would develop a new version of his COVID-19 shot to combat 501.Y.V2, the variant found in South Africa.

“Pfizer and BioNTech will continue to monitor emerging strains of SARS-CoV-2 and will continue to conduct studies to monitor the actual effectiveness of the vaccine,” the companies said.