Is Covid-19 changing course from big cities to smaller towns and villages?

Two indicators--daily growth in stock of positive cases and a derived case positivity rate--show cases are rising fast in the rural, while the virus is becoming more ubiquitous in metros

Today is the 175th day since the first Covid-19 case was confirmed in India in a lab in Kerala. The patient was a student in Wuhan, the place where the virus originated. While the initial few cases in India were directly connected to foreign travel, it currently stands third among the most affected countries.

As it happened elsewhere, SARS-CoV2 made its impact felt in the biggest metropolitan regions in India: Mumbai, Ahmedabad, Chennai, and Delhi. The way it spread was not very different from UK (London) and US (New York, Chicago). 

But the pattern of Covid-19 spread now seems to be changing in India. Both, sparsely populated states such as Chhattisgarh, and densely populated and less economically integrated ones such as Bihar, are showing a faster growth in confirmed Covid-19 cases now. Within states, tier-2 cities are showing a faster spread than the state capitals in some cases. A lot of it is courtesy the rapid incorporation of faster and cheaper antibodies tests. 

This analysis is limited to the fact that a very small proportion—or just about one per cent—of the population has been tested in India. 

We look at the fortnightly progress of the epidemic in India in the following interactive map. 

Footnote: Data for Telangana not available. For some states, when the data for the exact middle of the month was not available, data for a preceding or succeeding date was used. For states with smaller stock of cases (most northeastern states), sudden reporting of cases distorts the data. Data for nearby days has been used in these cases. 

We find that Maharashtra and Gujarat showed a spurt in the number of confirmed cases in April and early May. In June, rapid spread was more strongly visible in eastern states. In early July, there was a resurgence in southern states. 

But in mid-July, the growth in the number of cases seems to have risen in multiple states, especially the big north Indian ones such as Madhya Pradesh, and Rajasthan. 

At the same time, the addition of new cases in hotspots such as Mumbai and Delhi is declining. Delhi and Mumbai now add less than 1,000 cases a day each. This figure is much lower than the 2,500 seen in the national capital on July 4, and the 1,400-odd observed in the financial capital. 

Why is this happening? 

There are several explanations to this, and all point to only one thing: we have to maintain social distancing outside our homes, and take more care in densely-populated areas. 

N K Arora, who leads the International Clinical Epidemiological Network, says that the spread in non-metros is happening in densely-populated clusters, be it in the village or otherwise. Clusters of peri-urban areas—pockets surrounding the cities—and villages with dense population are now picking up. 

“The speed of spread of the infection is highest in more densely-populated areas. It could be slums in cities, such as Dharavi in Mumbai, or even a densely-populated village in Bihar,” he tells Business Standard. 

“Even a household is a small cluster. And if you talk about villages, it is the nucleus of the village that has the bulk of the cases. This is how Covid-19 is spreading in India,” he says. 

There is also the statistical effect of having a lower base. Bihar has about 1,500 cases against Gujarat’s 13,000. If 150 new people get a confirmed infection, the former would show a growth of 10 per cent, while the latter, at just above 1 per cent. 

The growth rate in all states seems to have normalised now. 

But what, then, should be the policy response in a situation when the states which were not showing much spread, are now seeing a growth in cases similar to the kind leading states showed in the beginning? 

Similar to what Arora said, experts think that localised approaches can help, as wherever it is, the spread happens in clusters.

“We have to analyse clusters for spread, and then aim to achieve herd immunity at the cluster level, and not at the big city or the state level,” says Jayaprakash Muliyil, a renowned epidemiologist and scientific advisor on various governmental committees. 

Researchers concur that all the big spreads, irrespective of the state or the level of urbanisation, happen in clusters of closely packed households. 

The effect was more visible in cities initially, as cities are more networked, say some experts. They involve a large number people-to-people transactions on a particular day: this is how cities fundamentally are. 

“But at the same time, cities are the entities that learn very quickly,” says Luis Bettencourt, director at University of Chicago’s Mansueto Institution for Urban Innovation, and a researcher in complex systems and urbanisation tells Business Standard. 

“In cities, the political processes are stronger, and people get a sense of responsibility faster than in other areas,” he says. 

To some extent, this explains the control in new infections visible in Delhi and Mumbai.

Further, many towns are now speeding up the use of rapid antigen testing. These tests give results within a few hours and are cheap as well. 

Pune is one such example: the local body has ramped up the antigen testing numbers. Officials concerned with the testing feel that these tests are showing more positive results than what the RT-PCR tests show. 

Though they are less accurate, they are more inclined to give out “false positives” than “false negatives”. This means that they might show a non-exposed person as Covid-positive, but they are less likely to show an infected person as Covid-negative. 

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