Explainer: Are COVID-19 Mutant Strains Behind Current Second Wave?

The COVID-19 situation in India is nowhere near recovering. The last 24 hours have witnessed nearly 3 lakh new cases with over 2,000 deaths. Hospitals are running out of space, while many states, including the national capital, Delhi, are amidst a critical shortage of oxygen supply. 

While the health system is highly overburdened, there is also a huge gap in the scientific knowledge about the present surge, especially the virus and its mutations. Although aspects like the mutant variants circulating in India are known, several answers including how far these variants are responsible for the current surge, are yet unknown. There are also concerns of whether the mutant variants are deadlier.

Let’s take a few of these questions one by one. First, whether there exists a causality between COVID-19 surge in India and the variants.

Commenting on it, eminent immunologist Satyajit Rath, who is an adjunct faculty at IISER Pune, told NewsClick, “No, we cannot. In fact, we cannot even say with any confidence which variants are circulating to what extent in which part of India. There are quite a few examples of the B1617 strain in Maharashtra. But Punjab seems to have quite a bit of the B117 strain. Variants in the southern states seem to be yet different ones.”

He also added about the insufficiency of data, saying that, “However, virus sequencing is of yet not done from enough statistically reliable numbers of clinical samples for us to say anything more than these very vague statements. Hopefully this situation will change over the coming days and weeks, but there has been a relative failure to organise this major effort better in good time.”

Recently, an analysis by Indian scientists published in the website outbreak.info, said that the ‘double mutant’ variant in India is more than 60% prevalent in Maharashtra, one of the epicentres of the current wave. The double mutant variant is found to have emerged in India with two mutations in the genome of the novel coronavirus. So, the question that arises is from the analysis published in outbreak.info, is what can we gather in relation to the present COVID-19 situation of the country?

Rath commented on this saying, “There is increasing evidence that the current 'wave' is not uniform, with the same variant being prominently seen all over the country. Instead, there seem to be different variants and circumstances playing major local roles. Further, again, the sheer quantity of sequencing done so far is statistically quite inadequate for making robust quantitative estimates.”

The next important question is, previous studies show that the UK originating strain is more contagious whereas, the South Africa originating strain could evade antibody neutralisation. Do evading antibody neutralisation mean that a strain is deadlier? The science behind mutant strains and their possible behaviour are important to come to any conclusion about this.

Rath explained this as, “Almost all variants that have emerged so far are ones that allow the virus particle to stick better to cells. That makes them more easily transmittable, both between people and within an infected person from cell to cell. The highest estimate I have seen of the resultant increase in transmission between people is two-fold, which is neither trivial nor huge. The so-called antibody-evasion is also a matter of degree; it is not as if any of these variants are completely antibody-resistant. And it is quite unclear just how much re-infection, if any, is taking place with these variants. Also, it is useful to remember that 'immunity' is not simply a matter of neutralising antibodies, but that there are also T lymphocytes involved, and they are likely to recognise variants quite well, providing yet another layer of protective immunity. And finally, none of these issues, - better sticking, antibody evasion - necessarily make the variant strains 'deadlier' at all.”

“In fact, while there is some indication that the disease caused by the variants may look subtly different, there is as yet no reason to think that they are much more 'deadly'. While there is some evidence of small differences in disease severity, none of the variants actually cause a dramatically more severe disease. In general, SARS-CoV-2 is not actually a 'deadly' virus, it is killing one out of every 200--400 people infected, as compared to say, its relative, the MERS virus, which killed one out of every three people affected,” he added.

What India is seeing currently, is both an exponential rise in new COVID-19 cases and increased daily deaths. Also, there seems to be more patients in need of oxygen. So, the question arises that is it possible that combination of strains is leading to huge surge along with increase in critical patients? Whether the UK originating strain has more infectivity and the South Africa originating strain can cause disease severity? And when both are present in the country, the final outcome is an exponential rise in cases and also increase severity?

Answering these questions, Rath said that it can’t be correlated straightforwardly. He said, “All new variants, not just B117 (the 'UK strain', which is not what we should call it!), seem to be more sticky and therefore likely spread somewhat faster, as I pointed out earlier. But none of them seem to be causing more severe illness.”

“And in fact, India's current case load does not seem to be of more severe illness, but of higher numbers. So India's current numbers seem to be a convergence of diverse factors, with local variations,” he added highlighting the enormous increase in numbers in India.