New Delhi: Delhi has witnessed a declining trend in terms of Covid-19 numbers in a span of one month. From positivity rate, daily moving average to case fatality — all have registered a decline between 22 June and 22 July.
The number of new cases in the national capital has also been decreasing for the last few days. On 21 July, Delhi recorded 1,349 cases, while the numbers were 1,227 and 1,041 on 22 July and 23 July, respectively.
On 20 July, Delhi registered less than 1,000 new cases — 954 — for the first time in seven weeks. The last time the national capital saw less than 1,000 cases was on 1 June — 990 cases.
All these encouraging numbers gave rise to speculation if Delhi has flattened the Covid curve.
On 16 July, Chief Minister Arvind Kejriwal praised his government’s ‘Delhi model’, claiming that the city is now in a much better position than in June, when cases were surging daily.
Experts, however, say Delhi’s numbers, albeit encouraging, must be approached with caution, and that there’s no room for complacency.
Delhi’s declining trend
Before Delhi hit the 7-week low of daily cases on 20 July, government data analysed by ThePrint revealed that barring nine days (1-5 July and 7-10 July), cases remained below 2,000 throughout this month so far.
Data also revealed that Delhi’s daily moving average (an average of daily cases in every five days) has come down by half in July in comparison to June.
On 22 June, Delhi’s daily moving average was 2,909 cases, while on 22 July, the daily moving average was down to 1,332 cases.
Case fatality rate too is down by almost half in one month — from 6.09 per cent on 22 June to 3.57 per cent on 23 July. Delhi’s positivity rate has gone down three times from 22.53 per cent to 6.91 per cent during the same period. Daily testing in the capital has, meanwhile, increased from 14,682 to 20,060 in the same time period.
‘Virus following natural course in Delhi’
Experts ThePrint spoke to said the decreasing Covid-19 cases might not necessarily mean that the peak is gone.
“In many pockets in India, cases are decreasing, but this does not mean the end of the epidemic. As of now, cases are reducing but that doesn’t mean the peak is gone, because we don’t know how the virus behaves,” said Dr A.M. Kadri, secretary-general, Indian Association of Preventive Social Medicine.
Experts also said the trend in Delhi is only following the natural course of the virus.
“Delhi has managed the healthcare system aspect of the epidemic, (but) not brought an end to the epidemic itself. Delhi, like the rest of the country, was caught unawares and the healthcare system was totally overwhelmed. Now, the virus is following its natural course in Delhi where it peaked three and a half weeks ago and now it is coming down,” said Dr T. Jacob John, former director-general, Indian Council of Medical Research.
Experts also said Delhi’s high testing should be approached with caution.
“The Delhi government changed testing rules several times. Any number that the government projects must include a revision with the false negatives numbers. But even if we include 18 per cent false negatives, still the slope is showing a downward trend in Delhi, so the main onslaught of the virus appears to have moved,” said Dr John.
The Delhi government claims that behind the declining cases is the focus on heightened testing. While government data revealed that daily testing has increased in one month, ThePrint reported how Delhi is conducting three times more rapid antigen tests than the more conclusive Real-Time-Polymerase Chain Reaction (RT-PCR) tests. Despite the spurt in testing, false negatives remain a worry.
After the results of the serological survey — conducted from 27 June to 10 July — came out on 21 July, revealing that 22.86 per cent of those surveyed had exposure to the novel coronavirus, the Delhi government said the next day it plans to conduct sero surveys every month.
In the survey, Central Delhi district recorded the highest infection prevalence at 27.86 per cent.
Talking to ThePrint, District Magistrate, Central Delhi, Nidhi Shrivastava said the district has high numbers due to a thorough surveillance system.
“We have made containment zones, micro containment zones as well as taped areas where we have found isolated cases outside the containment zones. In mid-June, we were reporting an average of 250-300 cases per day, but now we aren’t getting more than 50-70 cases per day due to our strict surveillance,” she said.
Rahul Singh, District Magistrate of South-West Delhi, where infection prevalence was 12.95 per cent, said the strategy was methodical isolation.
“We deployed 1,000 field warriors to heighten surveillance. All positive cases staying in dense colonies and JJ (jhuggi jhopri) clusters were moved to institutional centres and not advised home-isolation. Now 1,500 teachers are being trained for field surveillance. All such collective efforts have helped us keep the infection at the lowest,” he said.
Experts divided over herd immunity
Experts, however, are divided on this.
“The fact that nearly 23 per cent have been exposed and daily cases are declining implies government interventions are working. But we cannot depend on herd immunity and government interventions alone. People’s behaviour is an important factor,” said Dr Kadri.
Some experts claimed that the worst may be over for Delhi and large fluctuations are now unlikely.
“Sero survey shows that nearly one-fourth of Delhi has been exposed to the virus already. There has been no evidence of reinfection yet. We are moving towards herd immunity,” said Dr Sanjay Rai, professor, Community Medicine, All India Institute of Medical Sciences.
But it’s not certain if Delhi has flattened the Covid-19 curve.
Dr Preeti Kumar, vice-president for health systems support at the Public Health Foundation of India, said: “It’s too early to say that the peak is gone. Different states peak at different times and even best performing countries like South Korea have had flare-ups.”
Dr Kadri added, “Need to remember that sero survey too says 77 per cent are still susceptible to the virus. We can’t let complacency set in now.”