The Novel Coronavirus Variants and India's Uncertain Future - The Wire Science

The number of COVID-19 cases in India increased at a relatively slow pace after the first case was recorded on January 31, 2020.

While the state of Maharashtra dominates case counts at the moment, the numbers of infected all across India continue to rise inexorably, in the classic pattern of a second wave.

Antibodies, made by types of blood cells called B cells, are molecules that recognise and attach to parts of the virus.

Other cells called T cells seek out and destroy virus-infected cells, removing the source of infection.

This change can affect parts of the virus, altering the way the virus binds to the cells it infects.

Infections during this wave were dominated by a small number of variants that behaved roughly the same way, defining what is called a strain of the virus.

Extrapolating from the recent seroprevalence survey results, we can estimate that between 30-40% or so of India had been infected by the end of January 2021.

However the numbers of those infected should vary greatly across India.

The fraction of those with a prior infection is likely in the neighbourhood of 50% or more in major Indian cities while being at least 10-20% lower in rural India.

Such numbers would suggest that a large fraction of India still remains susceptible to infection by the original strain?

Why did cases begin to rise across India since the middle of February.

But even granted that much of India remained to be infected by January of 2021, would that account for the pace of the current rise.

Some variants are specific to regions of India, including one called B.1.36, found to be present in a good fraction of cases tested in Bengaluru.

The specific mutation carried by the B.1.36 variant, called N440K, is widespread in cases from the southern states.

The B.1.1.7 variant currently dominates new cases in Punjab.

Another variant, recently named B.1.617, figures prominently in the sudden increase of cases in Maharashtra.

That the circulation of the new, potentially more infectious variants is responsible for the spike in cases after January 2021 seems increasingly inescapable?

Here are some epidemiological questions to which we don’t know the answers: Has the B.1.617 variant spread more effectively in Maharashtra between February and now, replacing the older strain.

To what extent is this variant responsible for the spurt in cases outside that state?

Is the B.1.36 variant, prevalent in south India, also more transmissible than the original strain?

Does a prior infection with the original strain or a later vaccination protect substantially against an infection from the new variant.

Curbs on inter-state travel will help to restrict the spread of new and dangerous variants till measures are in place to deal with them?

But how is the balance between severe and mild disease shifted when someone already vaccinated is infected with the new variants.