In a study, Pfizer and BioNTech’s vaccine worked against lab-made coronaviruses similar to variants spreading in the UK and South Africa.
Small differences in how the vaccine performed against the mutations, versus the original virus, were “unlikely to lead to a significant reduction” in effectiveness.
The Pfizer-BioNTech vaccine hasn’t been tested yet against the real-life coronavirus variants.
The COVID-19 vaccine co-developed by Pfizer and BioNTech works against lab-made coronaviruses that are similar to the variants found in the UK and South Africa, the drugmakers announced Wednesday.
Studies conducted by Pfizer and the University of Texas showed “small differences” in how well antibodies produced by Pfizer’s vaccine bound to and killed the lab-made viruses, compared to how well they worked against the original virus.
But these differences were “unlikely to lead to a significant reduction in the effectiveness of the vaccine,” BioNTech said in a press release.
Pfizer and BioNTech’s vaccine was 95% effective at protecting against the original coronavirus in trials conducted in 2020.
In the new study, Pfizer tested three different “pseudoviruses” that it had engineered 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 that has been shown to evade antibodies in lab studies — the lab-made variant did not have this mutation.
The Pfizer researchers looked at how well antibodies worked, which is one aspect of the immune system’s defense against coronavirus. There is no agreement on how “protection against COVID-19” is defined, the study authors said in the paper, acknowledging this as a weakness of the study.
The results are from a preprint study, and are yet to be published in a peer-reviewed journal to be scrutinized by experts.
The variant found in the UK, 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 US.
Pfizer said on January 20 that it has tested its vaccine on the variant found in the UK, and it worked in company-run lab studies, but this latest research was its first test against the South Africa variant.