Indian Council of Medical Research maintained that amongst all Indian states, Karnataka conducted most tests of Covid-19 patients’ primary contacts, with an average of 93 compared to the national figure of 20.
The worst-hit states like Maharashtra and Delhi have tested only eight and nine contacts respectively on average.
The ICMR exercise was part of a larger study on ‘Laboratory surveillance for SARS-CoV-2 in India’. It has been released as a pre-print, Indian Express reported.
The study was conducted when India had not reported unprecedented number of cases of the coronavirus.
With the numbers surging, contact-tracing has been on the decline. Delhi Health Minister Satyendar Jain said last week that tracing was now being done only for immediate contacts of patients.
“Earlier, in one case, contact-tracing would be done for up to 600 people, and today, if we multiply 1,500 cases with 600, it gives us 9,00,000 people for contact-tracing,” he said.
Apart from Karnataka, states falling within the high-performance 75th percentile for contact-testing are Kerala and Tamil Nadu, with 40 and 44 contacts tested per COVID-positive person, Indian Express report added.
“Corrected for missing data from our sensitivity analysis, the average number of contacts tested per positive case was 20.4 at an all-India level and ranged from 6.6 in Chandigarh to 1387 in Tripura,” the study noted.
Which state fares well
Karnataka ranks high in terms of testing of only primary contacts, with 47 per case, compared to a national average of six. Delhi tested 2.1 primary contacts, Maharashtra 2.3 while Kerala and Tamil Nadu tested 11 and 14 primary contacts per positive case.
On testing of primary contacts, the study mentioned: “At the national level, the average number of contacts tested per laboratory-confirmed case was six. At the state level, the average number of contacts tested per positive case ranged from 1.3 in Jharkhand to 328 in Tripura.”
It further added: “Among the top 10 states/UTs, based on the reported number of Covid-19 cases, the average number of (primary) contacts tested per positive case was more than the national average in Tamil Nadu (14.4), Uttar Pradesh (9.8), Telangana (8.1), Andhra Pradesh (7.7), Madhya Pradesh (7.6) and Rajasthan (6.3).”
The study showed that the lowest rate of primary contact testing was reported from the states worst-hit by Covid-19.
11 per cent of all contacts testing positive in Maharashtra (13 per cent among primary contacts) and 9 per cent in Delhi (15 per cent of primary contacts). However, in Karnataka, 1 per cent of contacts tested positive (also 1 per cent of primary contacts) and in Kerala 2 per cent (3 per cent among primary contacts).
Despite nearly 70 per cent of the 3,092 active Covid-19 cases in Karnataka being new arrivals from other states, contact-tracing has managed to keep pace. As of Saturday, 35,552 primary and secondary contacts of Covid-19 cases were placed in quarantine in Karnataka. The state saw a surge of 70% in the number of cases due to fresh arrivals.