At a time when large-scale vaccination efforts have begun in various parts of the world, mutant variants of the SARS-CoV-2 virus – which causes COVID-19 – have cropped up. What is clear is that the virus’ mutations are more contagious than the original.
A pertinent question that arises is whether the different vaccines in use across the world can be effective against the mutant variants or not. All of the vaccines developed target the spike protein of the virus – the protein used to enter human cells. However, the mutant variants also have some changes in the spike protein as well.
Research about the same is beginning to come in, but with mixed results. While some researchers say that the current vaccines can be effective against the new variants, others say that may not be so.
The mutant strains of the virus – 501Y.V2, which was first detected in South Africa and B1.1.7, first found in the UK – have been studied by many groups. The research has primarily focused on how antibodies respond to the variants with and without vaccination. Antibodies are protein molecules in our immune system that target an invading pathogen (virus, bacteria, fungi or anything that can cause disease).
On January 19, a team of US researchers from the Howard Hughes Medical College, The Rockefeller University, reported that people who were administered either the Moderna or the Pfizer vaccine showed a modest drop in the potency of antibodies. These people were infected by the 501Y.V2 variant. The report was published in the pre-print server BioRxiv.
Similarly, a research group from the UK led by Ravindra Gupta at Cambridge University reported that people who received the Pfizer vaccine showed lowered effectiveness against the B1.1.7 variant. However, another research effort on the same lines, conducted by researchers from BioNTech – Pfizer’s partner in manufacturing the vaccine – reported that their vaccine was effective in fighting the mutant variant.
Soon, researchers at the bio-tech company Moderna in Cambridge, Massachusetts, also reported that their vaccine was effective in developing immunity against both, B1.1.7 and 501Y.V2. Their findings have been published in BioRxiv on January 25. However, notably, the study’s data set is very limited, consisting of only eight people who received two doses of the Moderna vaccine.
As a result, a judgment on the effectiveness of the vaccines remains quite elusive at this moment. Large cohort studies could be the only way to have more clarity on the topic.
Prof. Volker Thiel, who heads the Department of Virology at the University of Bern, Switzerland, shared similar concerns. According to him: “Although the vaccines target only the spike gene, they should still mount an immune response that is diverse enough that these new variants should be covered.” He, however, emphasised that more experimental studies were needed.
Most of the COVID-19 vaccines elicit a high amount of antibodies that are able to target different regions of the spike protein and so, some of these antibodies could have the ability to target variants of the novel coronavirus.
At the same time, there research shows that the antibodies generated in the body against the virus are less effective in neutralising the 501Y.V2 variant. This is primarily due to the mutations in the spike protein in the new variant. Certain mutations render the new variant the ability to escape an antibody attack. However, as pointed out by Prof. Thiel, aside from antibodies, there are other elements in the immune system which can facilitate the fight against the mutant variants.