Vaccine progress depends on virus mutation

A study published in a medical journal has revealed that SARS-CoV-2, which causes Covid-19, has undergone multiple mutations in its “spike proteins”. This is the protein that gives the virus the ability to infiltrate the human cells. Once this occurs, the virus starts replicating, which leads to infection.

The paper published in Journal of Laboratory Physicians was based on an analysis of 1,604 spike proteins extracted from 1,325 complete genomes and 279 partial spike coding sequences of SARS-CoV-2 available at National Center for Biotechnology Information (NCBI) in the US till May 1.

Dr Sarman Singh, the lead author of the study, said they found 12 mutations in the spike proteins, six of which were novel mutations. “One deletion was also found in an Indian strain (MT012098.1). Deletion means change in the genetic structure of the virus. We don’t know how it will affect the virulence of the disease though,” he added.

The maximum genetic mutations were observed in spike proteins extracted from genomes of SARS-CoV-2 from the US, the experts said. “Viruses are known to mutate or change their genetic structure upon exposure to different environments. But in this case, the change is happening quite fast. We are not sure how it will affect the disease spread,” Singh said.

The others participants of the study included experts from Infectious Diseases and Immunity in Global Health Programme, Research Institute of McGill University Health Center, and McGill International TB Center, Canada. The study said spike protein was the major target for vaccine development, but several mutations were predicted in the antigenic epitopes across all genomes available globally.

“The emergence of various mutations within a short period might result in conformational changes in the protein structure, which suggests that developing a universal vaccine could be a challenging task,” the study added.
Mutation was also found in the antigens responsible for producing antibodies, indicating that the patients infected with the mutants would have very low or nil antibodies.

Recently, Hong Kong reported a case of re-infection due to Covid-19. Similar cases have also been documented in the US and India. “Even if a person gets Covid-19 again due to a mutated strain of the virus, the likelihood of severe symptoms would be less as seen in the patient in Hong Kong. This is because the antibodies against one strain of Covid-19 can offer protection against the mutated virus too. However, further scientific study and analysis is needed to ascertain this. The disease is new and we are still learning about it,” said a virologist from Maulana Azad Medical College.

In Delhi, the cases of Covid-19 had dipped significantly in July. However, it has started rising over the past few days. While lack of social discipline and opening of the economy are two key factors, many doctors said a mutation of the virus could also be behind it. “Multiple strains of the virus have been identified in the country, including the original one from Wuhan, China and the ones spreading in Europe,” said a doctor.
The World Health Organization does not expect widespread vaccinations against COVID-19 until the middle of next year, said a spokeswomen, stressing the importance of rigorous checks on their effectiveness and safety.