Even as the novel coronavirus cases in India cross 8 lakh, there is a glimmer of hope coming in from one of its worst-hit cities: Delhi.

After witnessing a single-day spike of almost 4,000 on 23 June, Delhi recorded only 1379 cases on 6 July - which made many people speculate about the capital having crossed its peak. But are we jumping the gun?

India vs Delhi: What the Graphs Show

A look at how daily COVID-19 cases in India and Delhi have progressed would show that Delhi witnessed a slump somewhere in July. In the first week of June, Delhi started witnessing a rising number of cases and deaths.

Throughout the second half of June, the city recorded more than 2,500 cases every single day - with over 3,000 cases on most days. The highest jump of 3,974 was recorded on 23 June (Figure 1).

While the cases ranged between 2,000 to 2,500 after that, the numbers on 6 July stood out. Delhi had only seen 1,379 cases in 24 hours - this low after almost a month. Moreover, the recoveries also increased substantially as the people who had been found infected two to three weeks ago, when Delhi was reporting high numbers, have now started to recover.

Meanwhile, India’s graph has shown an upward trend since the very beginning of the pandemic in the country (Figure 2).

Does the Number of Tests Have Something to Do With It?

The number of tests being conducted would invariably be an important factor in assessing whether a region is actually doing well. If the low numbers are a work of low testing, then there isn’t much to rejoice about - and the positivity rate becomes an important criterion.

To start off, Delhi has been conducting the most number of tests per million than all other states (Figure 3). Even before the end of June, Delhi was testing more than any other state in India at about 10,500 tests per million on May 31.

On 10 July, the city had tested 10,129 samples through RT-PCR tests and 12,832 rapid antigen tests - amounting to a total of 22,961 samples.

For the second half of June, the number of daily tests being conducted in Delhi has been provided regularly since the 18th, and the percentage of people testing positive on a single day ranged from 16% to 21% till 22nd. Out of a total of 384,696 tests conducted by 22 June, 62,655 had tested positive: positivity rate of 16.2%.

Does 23rd June offer an extraordinary scenario? Even though Delhi recorded its highest jump of 3,947 more cases that day, 16,952 tests were conducted - which isn’t unusually high (for instance, 18,105 samples were tested on 21 June, with 3,000 testing positive). Even though the number of tests wasn’t the maximum, the percentage of people testing positive remained high. Out of a cumulative 401,648 tests done so far, 66,602 (16.21%) had tested positive.

However, this rate fell consistently after this. On 6 July, when the lowest jump of 1379 cases was witnessed, only 9.9% of the total tests conducted in a day had tested positive. Out of a total of 657383 tests done by 6th, 100,823 had tested positive, with a 15.33% positivity rate.

Active cases began to plateau despite high testing from 16 June onwards and new cases began to sharply decline 23 June onwards.

As of today, Delhi’s test positivity rate is 14.6% - which shows it has been decreasing.

What Could Be Working in Delhi’s Favour?

In the beginning of May, the Delhi government had issued the protocol for home isolation in the city. By promoting and allowing patients with mild symptoms to stay at home, testing could be encouraged - which allowed identifying more and more people with the disease and tracing and their contacts.

Secondly, as already seen, Delhi has consistently been conducting more and more tests. With the introduction of rapid antigen test kits in mid-June, testing could be expanded and quicker results were enabled (even though the accuracy of these tests is questionable). While increased testing seemed to increase the number of cases, what it meant was that COVID positive patients were now being traced and isolated in a timely manner. The timely diagnosis could also have contributed to boost the daily recoveries significantly from an average of 400 a day till 8 June to 3,000 a day from 17 June. As a result, the ratio of recovered to total cases has risen from 42.7% on May 31 to  66.5% on June 30, at an average of 0.71% per day, The Wire reported.

Delhi has also ramped up its infrastructure and bed availability. An order passed by the government asked all private hospitals with more than 50 beds to reserve 40% of beds for treating COVID patients. By linking hotels, the number of beds in private hospitals went up from 5000 to 7000. Today, there are over 15,000 COVID beds in Delhi - with only about 38% of them occupied. Quarantine arrangements have also been made to accommodate more than 10,000 people with mild symptoms.

In a first, a ‘Plasma Bank’ has been set up by the government for patients to easily access convalescent plasma - an experimental treatment for COVID-19.

Has Delhi Crossed Its Peak? Too Soon To Say

The city has now been seeing more daily recoveries than new infections since a week (with a deviation of one day). If this trend continues, Delhi may have crossed its peak. Other states that have seen more recoveries than infections have not maintained the same for more than 2-3 days. On the other hand, in states like Maharashtra and Tamil Nadu, the new infections still exceed the daily recoveries, and a similar trend is being observed for the country in general as well, The Indian Express.

Speaking to FIT, Dr Shahid Jameel, a virologist & CEO of Wellcome Trust DBT India Alliance, spoke about the reliability of rapid antigen tests.

Here, we look for sensitivity (ability to pick up infected cases) and specificity (ability to exclude uninfected cases). The specificity of the antigen test is reportedly around 99%. That means a positive test result can be highly relied on to diagnose an infection. Sensitivity, on the other hand, is reported to be between 50-80%. That means the antigen test can miss several Covid19 cases.

Moreover, Delhi saw its share of erratic decisions and mismanagement of cases until last month - where people had to rush from one hospital to another to search for a bed. The government’s calls of reserving beds for Delhiites, or only testing symptomatic individuals (all of which was later overturned) were severely criticised. Reports of extremely critical patients losing their lives because of not receiving timely treatment, and alleged underreporting of deaths in the city - had all brought the government under the scanner.

With the new arrangements made and the increased testing, the situation is expected to improve - as it has been since a week. But a concerted effort to continue rigorous contact tracing would be required to make any real progress.