COVID-19: Rising Positivity Rate, Limited Testing, Many Unreported Cases in Tamil Nadu

The virulent Omicron variant has infected 85% of the patients in COVID-19 clusters, increasing the test positivity rate (TPR) in Tamil Nadu from 4.1 on January 6 to 11.3 on January 12.

The TPR of Chennai and Chengalpattu districts went above 20 as the state reported 17,934 cases on January 12.

Yet, the state barely increased testing from 1.28 lakhs to 1.56 lakhs in the same period.

Although the Omicron variant is fast spreading and the COVID-19 TPR has increased around three times, the state reported only a marginal increase in daily cases compared to the previous two weeks. This could likely be due to a disparity in the actual number of infected people than those reported.

MANY UNREPORTED CASES

The speed at which the COVID-19 is spreading has reduced compared to the previous week, at least as per the recorded cases. The cases increased four-fold from December 29 to January 4, and between January 6 to January 12, the increase was around 2.5 times.

Image credit: Prakash R

Tamil Nadu is steadily reporting only around 2,000 additional cases every other day.

"Yesterday, over 2,000 cases were reported, with 10,978 cases in Tamil Nadu. Even today, we expect new cases to be over 2,000," the state health minister said on January 9.

However, this does not necessarily indicate a flattening of the wave or drop in reproduction number or R-naught indicating a slow growth rate.

Dr J Amalorpavanathan, a member of the State Planning Commission, told NewsClick, "Many cases do not get reported as people are isolating and treating themselves. Many people also do not get tested worrying that they will be taken to the COVID camps."

However, he reiterated the importance of getting tested for COVID-19. He said, "It is necessary to report cases not only for data purposes but also to control the spread of the virus. Many people will not know the virulence of the virus and how to control its spread, so it is important to get tested and to follow protocol."

OMICRON CLUSTERS

A COVID-19 cluster of 58 students and staff members was reported at the Indian Institute of Technology, Madras. Similarly, 67 students in the Madras Institute of Technology and 12 in Madras Christian College also tested positive.

Additionally, 200 doctors and staff members tested positive for the infection at Vellore CMC Hospital on January 9.

However, the state has so far reported only 185 Omicron variant persons in total.

Clarifying the logic behind this, Dr Amalorpavanathan said, "The reported Omicron cases might be low, but what matters is the number of samples sent for testing and the percentage that tested positive for the Omicron variant. Supposing 400 samples were sent, and 350 were reported as Omicron, then it is understood that majority of the cases in the state are of the Omicron variant."

He added, "It is not necessary to send large samples; it will only take a lot of energy and manpower. Hence, it is better to focus on treatment at this moment."

The state has stopped sending samples for Omicron confirmation to the National Institute of Virology (NIV), and only samples from cluster areas are sent for variant confirmation.

TESTING REMAINS LIMITED

Tamil Nadu is making little effort to increase testing and contact tracing. Although experts have suggested that rapid antigen testing would be helpful, this is also not being considered.

With little push from the government, the public is also reluctant to get tested. Additionally, the Omicron variant is vastly mild, particularly on the vaccinated and partially vaccinated people.

Given the high limited sample load, Hugh TPR, the virulence of the Omicron variant, the public's reluctance to get tested, and the continuation of normal activities, there could be a vast disparity between the reported cases and actual numbers.

Moreover, the state has ruled out the possibility of a full lockdown in Tamil Nadu after the Pongal festival, citing that the economy and the livelihood of the people should not be affected.

All colleges (barring medical) will remain closed until January 31 as part of the restrictions due to the surge in Covid-19 cases.