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In the midst of a Delta-driven spike in several nations, the novel C.1.2 variety of Covid discovered in South Africa has become the latest cause for concern. According to scientists, the strain may be able to bypass antibodies that safeguard the body. Researchers from all over the world are racing to figure out why lineages discovered in the United Kingdom and South Africa spread so swiftly, and whether or not they may harm vaccines.

Scientists want to know why variations discovered in the United Kingdom and South Africa appear to be spreading so swiftly, and whether they could reduce the effectiveness of vaccines or override natural immunity, resulting in an outbreak of reinfections. 

"Many of us are scrambling to make sense of the new variants," says Jeremy Luban, a virologist at the University of Massachusetts Medical School in Worcester. "The million-dollar issue is what significance this will have for the effectiveness of vaccines that are now being administered."

The first lab results are trickling in and many more are expected in the coming days, as researchers rush to probe the viral variants and their constituent mutations in cell and animal models of SARS-CoV-2, and test them against antibodies elicited by vaccines and natural infections. A preprint published on 8 January 1 found that a mutation shared by both variants did not alter the activity of antibodies produced by people who received a vaccine developed by Pfizer and BioNTech. Data on other mutations and vaccines are expected soon.

Underlying truths

A team at the University of KwaZulu-Natal in Durban, South Africa, linked a fast-growing pandemic in the country's Eastern Cape Province to a coronavirus strain known as 501Y.V2. Although the UK and South African versions emerged independently, they share a number of changes in the coronavirus spike protein, which is used by the virus to identify and infect host cells and is also the primary target of human immune response.

Disentangling the consequences of the mutations that differentiate the UK and South African lineages from their near cousins is one challenge. The B.1.1.7 variant has eight modifications to the spike protein and several more in other genes; the 501Y.V2 variant from South Africa has up to nine changes to the spike protein. Luban describes figuring out specific factors that contribute to the variations' quick dissemination and other characteristics as an "enormous problem." "I don't believe there's a single mutation that's responsible for everything."

Antibody testing

The fear that the variations could compromise immune responses induced by vaccinations and past infection adds to the sense of urgency. The study discovered the minimal difference in the efficacy of antibodies created by 20 individuals against viruses harbouring the N501Y mutation compared to antibodies produced against viruses without the mutation, according to a preprint published on January 8th. The researchers are currently looking into the effects of further changes in the variants.

In a separate study, a team led by Menachery discovered that the 501Y mutation had no significant effect on the activity of neutralising antibodies in convalescent serum, which is the antibody-rich component of blood obtained from persons who have recovered from COVID infection. According to Menachery, who shared the findings on Twitter on December 22, the 501Y mutation is unlikely to affect immunity.

Immune Dodge

There is growing evidence that the E484K mutation allows the virus to evade immune responses in some persons. A team led by immunologist Rino Rappuoli at the Toscana Life Sciences Foundation in Siena, Italy, developed SARS-CoV-2 in the presence of modest quantities of one person's convalescent serum on December 28. The goal was to find viral alterations that could dodge the wide range of antibodies that are produced in response to infection.

However, the virus had picked up three modifications within 90 days that rendered it immune to the person's serum: one was the E484K mutation identified in the South African variety, and the others were N-terminal domain changes observed in both the South African and UK variants.

According to McLellan, this was startling because it suggested that the individual's whole antibody response against SARS-CoV-2 was focused against a little piece of the spike protein.

Final words

According to Jesse Bloom, a viral evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle, Washington, "a pressing question is whether such modifications would influence the real-world effectiveness of vaccines." On January 4th, his team showed that antibodies in people's convalescent sera can miss E484K and numerous other mutations to variable degrees.

To the extent these studies have been conducted and results known, it shall be said for certain that it would be foolish to lower the guard by not taking other preventive measures, such as wearing the masks and using the soaps and sanitizers. No time limit can be given to the people on when it would be safe to be without masks since the virus is undergoing mutations and effectiveness of vaccines would remain to be tested against new variants.