Rigorous contact tracing: Should Tamil Nadu follow the Kerala model?

Rigorous contact tracing, testing and people participation helped neighbouring State flatten curve even as cases spiked across India 

Published: 09th May 2020 06:04 AM  |   Last Updated: 09th May 2020 01:17 PM   |  A+A-

Traffic movement at Usman Road in Chennai's T Nagar during lockdown on Friday. (Photo | Martin Louis/EPS)

Express News Service

CHENNAI: Kerala was the first Indian State to report COVID-19 cases. When the outbreak began, it was leading the country in total number of cases. Yet, now the State has successfully managed to bring its tally to near zero. Kerala’s handling of the epidemic has become a global lesson in public health management. The ICMR has said that it would ‘continue referring to the Kerala model’.

In Tamil Nadu, meanwhile, the onset was delayed till the mass arrival of international passengers in March. On Friday, the State reported over 600 cases of which nearly 400 were in Chennai. Experts point out that if Tamil Nadu follows the ‘Kerala model’, it too can effectively contain the virus in due course. So what is the Kerala model?

The Kerala Model

The first step is rigorous contact tracing.

“For the 300 positive cases reported in Kerala in April, close to 1.75 lakh people were traced and quarantined,” says doctor Anup Warrier, a leading epidemiologist from Kerala.

The contact tracing was not simple. Professionals had to chart out route maps a positive patient could have taken, and follow it through with testing.

That is exactly what Kerala did in the case of the Wayanad truck driver, who belonged to the Koyambedu cluster.

According to a route map, when he tested positive, details of every single place he passed through, every single stop he made was traced out and recorded. This helped officials go back and find out the associated contacts of patients.

"Maybe not all contacts were traced, but a large number of them have been identified," says Anup. And that was possible not just because of contact tracing, but also because of rigorous testing. By the first week of April, Kerala had tested a substantial 14,000 samples. Tamil Nadu, where the number of cases were still low back then, had tested 5,305 samples.

Since then, Tamil Nadu has increased testing drastically and has now tested over 2 lakh people. Having contained the virus early, Kerala had to test only 500 persons per million population, compared to Tamil Nadu, which has tested 700 per million. Nevertheless, despite the early tracing, Kerala has gone into full surveillance mode now through sentinel surveillance, suggested by WHO, to be thorough.

“Sentinel surveillance means testing a random sample set of people, with the criteria being vulnerability and geographic location,” says Tamil Nadu-based virologist Jacob John. While this type of testing is best saved till the number of cases plummet, what Tamil Nadu needs to do now, John says, is to ensure diagnostics of symptoms and that people wear masks.

In Kerala, Anup says, people’s cooperation played a big role. “Except for very few instances, we did not see violation of lockdown norms. Most of the markets were closed while major markets were decentralised,’’ he said. In Tamil Nadu, in contrast, the Koyambedu cluster, the biggest one yet, started after one whole month into the lockdown.

While Kerala, being the first state in the country to handle the virus, had to figure out a lot on the go, other States have the opportunity to learn from its experiences and develop their own customised models, conclude experts.


Disclaimer : We respect your thoughts and views! But we need to be judicious while moderating your comments. All the comments will be moderated by the editorial. Abstain from posting comments that are obscene, defamatory or inflammatory, and do not indulge in personal attacks. Try to avoid outside hyperlinks inside the comment. Help us delete comments that do not follow these guidelines.

The views expressed in comments published on are those of the comment writers alone. They do not represent the views or opinions of or its staff, nor do they represent the views or opinions of The New Indian Express Group, or any entity of, or affiliated with, The New Indian Express Group. reserves the right to take any or all comments down at any time.

  • a.k.sehanobis

    Kerala has done well
    4 months ago reply
flipboard facebook twitter whatsapp