COURTESY HT SEPT 19

Uneven spread in Delhi active cases

Abhishek Dey

abhishek.dey@hindustantimes.com

New Delhi : Delhi’s north-west and south-west districts together accounted for almost one in three active cases of Covid-19 in the Capital, which is seeing a surge in cases, albeit on the back of higher testing.

And Delhi’s most densely populated north-east district, which has around 40,000 people per sq km, has only 894 active cases, 2.87% of the total – the lowest among the city’s 11 districts.

Interestingly, according to district-wise data from Delhi’s second (August) sero-survey (antibody tests) — the break-up of the third survey is not available in the public domain — 29.6% of the population in the north-east district has been exposed to the virus, the same proportion as in the north-west.

That may likely mean that not enough testing is happening in north-east Delhi. District-wise testing numbers are not available.

The north-west district, which accounts for 16.3% (5,086) of the Capital’s active cases, and the south-west, which accounts for 13.3% (4,151) — all numbers are as of Wednesday when Delhi had 31,201 active cases — have a mix of planned residential areas and densely populated unplanned areas including unauthorised colonies, villages and slum clusters.

Prominent localities in these districts where a large number of Covid-19 cases have been identified – both clusters and isolated ones – include Pitampura, Ashok Vihar, sectors 14 to 18 of Rohini, Najafgarh and several sectors of the Dwarka sub-city, said officials in the revenue department citing details from geo-spatial to which only they have access. The two districts have 465 of Delhi’s 1751 containment zones as of Friday.

On Thursday, the data was discussed in a meeting of officials of the revenue and health departments, chaired by chief secretary Vijay Dev, said a senior government official who did not wish to be identified, adding that the agenda of the meeting was to find ways to understand patterns in the distribution of active Covid-19 cases across the city.

While district magistrate (north-west) Sandeep Mishra did not respond to calls and messages, district magistrate (south-west) Rahul Singh said: “We have aggressively scaled up testing, that is why the numbers are high, and we have also increased surveillance across the district. We are aggressively following the containment strategy under guidelines issued by the union government. The idea is to break the chain of transmission.”

West Delhi with 3,502 cases (11.22%) has the third highest load of active Covid-19 cases. It is followed by south Delhi’s 3,296 (10.56%) and south-east Delhi’s 2,935 (9.41%).

Dr Jugal Kishore, head of community medicines at Safdarjung Hospital and vice-president of the Indian Association of Epidemiologists, said: “In Delhi’s case, the transmission of the virus started from upscale colonies, with Covid-19 positive people returning from abroad and infecting others before they were detected. With time, the virus spread further and got into densely populated colonies. When cases peaked in June, densely populated low-income group localities and slums had emerged as threat points.”

Delhi overcame that first peak with aggressive testing and containment. But after falling for much of July and August, the number of new cases started climbing again.

“With tests being scaled up and more people from across different social classes coming out for getting themselves tested, cases once again have started to emerge in upper income group colonies too. Locality-based analysis of data would definitely help the government enhance their policies in terms of testing, surveillance, isolation and patient care,” added Kishore.

District officials in north-east Delhi claimed the spread of the virus took pace much later in the district — which is almost an entire lower-income group region — and by then there was already an uptick in cases in the south-east and south districts. “So, northeast Delhi learnt its lessons early, before things could go worse, and they scaled up surveillance before things went out of hand,” said a senior district official who did not wish to be identified. The district currently has only 57 containment zones.

Dr Lalit Kant, former head of the Division of Epidemiology & Communicable Diseases, the Indian Council of Medical Research (ICMR), said: “The numbers here (north-east Delhi) suggest that a large population in the densely populated north-east district were Covid-19 patients with no symptoms or mild symptoms. Fewer people got tested, so the figure of infections and active cases remains low. But the sero-survey findings later reveal that a large number of them had already been exposed to the virus by the time testing was scaled up.”

It may not be as straightforward as that, another expert suggested

Dr T Jacob John, former head of the virology department in Christian Medical College in Tamil Nadu’s Vellore, said, “Most interpretation of data at this juncture would be valid only for the time-being because things around the subject – and our knowledge of it – are still evolving. For instance, poorer and densely-populated neighbouring countries such as Pakistan and Bangladesh have had better numbers and ratios compared to India on several aspects. Similarly, Dharavi in Mumbai, which had once emerged as a hotspot, currently has lower number of active cases than many upscale neighbourhoods in Mumbai. North-east Delhi could be a similar case. We need more time and studies in this to ascertain cause and effect relationships and to validate such trends scientifically.”

Delhi government spokespersons did not comment on the matter