Does India Have A Milder Epidemic? Not Really

It was around three months ago, in March, that the COVID-19 season properly began in India. Soon, the dizzying spiral in Italy had gripped the world바카라�s att­ention. Then, within days, that graph was replicating itself in the US. Naturally, the spectre of Covid effortlessly conquering new territories evoked fears.

But even by April, India바카라�s statistics were now­here near the worst-case scenario. The question naturally arose: was there something at work besides a stringent lockdown?

Nearly every possibility was speculated upon바카라�perhaps the virus was behaving differently here, maybe it was a milder 바카라�strain바카라�. Maybe there were different 바카라�strains바카라� in India itself....one thing in Gujarat, ano­ther in Gurgaon. The questions were not surprising: we knew little of the novel coronavirus, except that it was beset by signs of seemingly inexplicable randomness. So how do we begin to put the pieces of the puzzle together? We put the question to various experts.

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For a start, the actual spread of the disease across the world is itself an unravelling story. Russia, where they were making music videos celebrating the near-absence of COVID-19 in the initial days, is now a scare story (see Is Socialism the Vaccine?). And this is a strange, moving earthquake, one that has ser­ially found new epicentres: from Italy in spring, to Brazil now. The data dashboard maps out the curve so far바카라�over 66 lakh confirmed cases globally by the first week of June, out of which about 3.9 lakh people have died. And India has crossed 2.87 lakh cases, still with relatively fewer dea­ths바카라�8115바카라�than in many other countries. But the arc had begun to look ominous by May, in such a way as to almost completely negate the original question.

So no, it바카라�s no longer milder in the ordinary sense바카라�we바카라�ll have to wait for the final count and look at percentages to make a weaker claim at 바카라�mildness바카라�, if at all. And no, the heat certainly didn바카라�t kill the virus.

One way to navigate this warren of alleys is to try and mark out the actual presence of the virus, as opposed to official numbers. 바카라�Based on the results of seroprevalence studies conducted around the world, we now understand that the epidemic has spread far more widely throughout the (human) population than can be gleaned from case reports alone,바카라� says Jay Bhattacharya, professor of medicine at Stanford University. By seroprevalence, he바카라�s referring to the blood tests that look for antibodies바카라�the body바카라�s natural method of fighting an infection. It바카라�s a useful tool for epidemiologists to estimate what fraction of a population has already been exp­osed to the coronavirus. Last month, a Spanish antibody study indicated that 5 per cent of Spain바카라�s population has been aff­ected바카라�a figure that held up in a subsequent second round of survey. Sounds modest? Well, that바카라�s nearly 24 lakh people, over a third of the official world total. That may be the actual wingspan of the virus flying under the radar.

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And here? Well, the Indian Council for Medical Research (ICMR) too is currently carrying out a household-level antibody survey to estimate the prevalence of the infection in the country바카라�an ELISA test has been developed by the National Institute of Virology to look for Immunoglobulin G (IgG), a type of antibody. The survey across 69 districts in 21 states could potentially give us a richer, more finely-grained view of COVID-19바카라�s passage through India. ICMR favours repeated cross-sectional investigation to establish the actual trends in an evolving pandemic바카라�a kind of live cartography that maps the progress (or regress) of infection in specific districts which, when aggregated, offers us a country picture.

The spurt seen in the official count in recent weeks바카라�6,000+ cases being docked each day in the last week of May, almost touching 8,000+ as we closed off the month, then scaling 10,000 with a kind of sherpa-like tenacity a week later바카라�gives us a peek into the spread. But even that may be a fraction. Bhattacharya says various global studies indicate바카라�depending on the locality바카라�that, for every identified case, 바카라�somewhere between 10 and 500 people have been infected without being identified by healthcare systems as having the virus바카라�. By itself, the view that swab tests alone may not yield a true picture isn바카라�t new, because these tests, being time-consuming and expensive, have not cast their net wide enough, especially in India. But, on the other side, antibody survey findings too have been widely disputed바카라�even a paper Bhattacharya co-authored last month was criticised for its methodology (one of the early antibody surveys, it had looked at Santa Clara, California, as a case study).

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Then, the virus itself. Some pointers of how it spread around the world come from the genomic sequences various labs have decoded. About 40,000 sequences are currently available on the GSAID database, including some 400 from India, enabling researchers to piece together an evolutionary history, or the phylogenetic tree. All viruses mutate over time바카라�think of them as the typos they make as they replicate their RNA inside the host body바카라�s cells, which then get to be a new accepted spelling. The coronavirus is no exception. Researchers broadly group these variations into genetic lineages or clades. Globally, at least 10 clades have been identified, the A2a clade being the most common바카라�in India as well. But there바카라�s no evidence to say if any clade is less or more virulent than the other바카라�it바카라�s precisely such a claim that had come up last month from Gujarat.

All talk about some mutations being deadlier바카라�such as the allegedly more lethal D614G mutation바카라�or references to variable infectivity between the so-called 바카라�S strain바카라� and 바카라�L strain바카라� have now been given a quiet burial. Columbia virologist Vincent Racaniello summarised it with a headline to his blog post, 바카라�There is one, and only one strain of SARS-CoV-2바카라�. The more recent claim from Italy that COVID-19 was 바카라�weakening바카라� too has largely met the same fate. No serious study anywhere has yet found a significant mutation바카라�either heralding more virulence, or a weakening.

Epidemiologist Giridhara R. Babu of the Public Health Foundation of India sums it up thus: 바카라�What we definitely know is the genetic make-up of the virus is nearly the same all over the world.바카라� Another scientist working on vaccines says virus mutations don바카라�t present a significant issue to researchers like him바카라�바카라�the most important protein on the virus is the Spike protein and there is a mutation at a single position, but the rest of the Spike is pretty well-conserved in all the isolates that have been seen to date.바카라�

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That doesn바카라�t mean science stops looking. 바카라�We can바카라�t say yet if a strain is more virulent or not,바카라� says Rakesh Mishra, director, Centre for Cellular and Molecular Biology (CCMB), Hyderabad, offering a cautious margin note. 바카라�There are some mutations that look unique to our isolates, which is understandable.바카라� Last week, Mishra바카라�s centre바카라�along with its sister labs, the Institute of Genomics and Integrative Biology in Delhi and the Chandigarh-based Institute of Microbial Technology바카라�identified five clades that were circulating in India at the beginning of the outbreak. Among them was a new clade, which, the study claimed, hadn바카라�t been classified as such before. This new clade바카라�they named it A3i바카라�was mostly from the Telangana and Tamil Nadu region, and seen in some other South Asian countries, says Mishra.

Their next step will be to see if there바카라�s a link between the clades and patients바카라� clinical manifestations. 바카라�We want to see if there is a medical correlation,바카라� says Mishra. Meanwhile, genomic studies too are being planned to try and tease out a better understanding of the virus and disease progression. There are several questions here바카라�why are such a large number of patients asymptomatic, for instance. But alas, good science needs to be allowed to mature. 바카라�This patient-based gene study will take six months to a year...data generation takes time,바카라� says Mishra.

바카라�We certainly know more about the disease than we did at the beginning,바카라� says Gautam Menon of Ashoka University, which is currently building a long-term simulation model for the COVID-19 spread in India. 바카라�Our earlier estimates of the infection fatality rate were probably excessive, and we did not understand the importance of asymptomatic cases in driving transmission early enough.바카라� Even now, the question of how infectious asymptomatic people can be is open-ended (see Asymptomatic box). An ICMR study of testing data up to April 30 had found 28 per cent of 40,184 positive cases to be asymptomatic바카라�but these were only those who had direct contact with lab-confirmed cases.

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Throughout the world, the Covid virus is asymptomatic or mildly symptomatic in about 80 per cent of infected people. So what explains India바카라�s low uptake initially? 바카라�India바카라�s population structure probably offers clues,바카라� says virologist T. Jacob John. 바카라�Other countries have a larger representation of senior citizens than we have. We have a different population pyramid.바카라� But even though the 65+ age group made up only 6.18 per cent of India바카라�s population in 2018 (as against over 18 per cent in the UK and Italy), the sheer numbers are still large바카라�roughly over 83 million people. In the initial phase of the epidemic, says Babu, we were seeing the infection mostly in young people. 바카라�The moment it spreads to the elderly and more vulnerable, the picture will be the same as anywhere in the world,바카라� he had predicted in mid-May. Three weeks later, as India takes the fifth spot in the world, we바카라�re already there in a gross sense바카라�without the benefit of an age-wise mapping. The real challenge may be to stop this from becoming truly, chillingly Malthusian.  

Vox PoP

Sridhar Venkatapuram
Associate Professor, Global Health & Philosophy,  King바카라�s College London

Are we in an era of constant and regular viral attacks, since SARS? Is a bigger one lurking?

This is an opportunity for India to really understand that there have been outbreaks and epi­demics in India every year for decades. SARS, MERS, Ebola, COVID-19 are epidemics you are aware of because they worried people in rich countries. Globally, HIV caught people by surprise because most public health people in the 1970s believed infectious diseases were all under control in rich countries, and they were only a problem of poor countries. What we now know is that there are outbreaks around the world every year, and that some of them can become pandemics. This COVID-19 pandemic was expected, and unfortunately, it is not considered to be the worst pandemic that is possible. There are other, even more dangerous pandemics that are possible. Old infectious diseases can come back, and there are new ones coming more frequently. In fact, the WHO has a category called Disease X which stands for a new disease that we have no ideas about regarding its origin or make-up, and they have been preparing for what to do with that.