Aggressive testing since mid-June in hotspot areas in Chennai and the 12-day lockdown that went into effect from June 19 helped sharply reduce daily fresh cases from its peak of about 2,000 to 1,100-1,200. But Tamil Nadu has not been able to reduce it any further. One of the main reasons: Absent boots on the ground to trace non-family contacts. But this may soon change.
Early in the course of COVID-19 pandemic in India, the number of fresh novel coronavirus cases reported daily from Kerala was worrying. As cases kept rising, Tamil Nadu appeared to have the virus spread in full control. The first biggest spike from a single cluster came from the infamous Tablighi Jamaat conference held in Nizamuddin, Delhi. Attendees of the conference, which was held in mid-March, fanned out to different parts of the country after the event. Tamil Nadu alone traced and tested 1,350 cases linked to the congregation. In all, 631 index cases and 719 contacts tested positive for the virus. The excellent contact tracing adopted by Tamil Nadu helped in tracing up to 17 contacts for every single case detected.
Even in the case of the largest cluster that originated at Koyambedu market — Asia’s largest wholesale hub for perishable products located in Chennai, which was kept open till May 5 even during the lockdown — contact tracing was good in the beginning. By the second week of May, 875 index cases were tracked and tested and 1,130 contacts tested positive for the virus. Cases from the cluster spread to several districts within the state and even to other neighbouring States. But the State’s ability to trace all the contacts of every primary case started floundering as about 50,000-1,00,000 people visited the market daily even during the lockdown.
Threw up its arms
Instead of revving up contact tracing in the State, whether connected with the Koyembedu cluster or not, the contact tracing initiative started losing steam. In retrospect, it looks like the State almost threw up its arms by mid-May. When the number of cases in the State is about 1,86,500 as on July 23, tracing all the contacts — family and non-family contacts — is far from ideal. There are no boots on the ground to trace non-family contacts in Chennai. The situation is no different in the rest of the State.
“As the cases started rising, due to excessive workload on the field staff, contact tracing in Chennai was restricted to just family members. And even there, the contacts are tested only if they show symptoms. It is difficult to keep pace with the contact tracing in a pandemic unless there are dedicated staff doing this task,” says Dr Prabhdeep Kaur, Deputy Director of ICMR’s National Institute of Epidemiology, Chennai and a member of the Tamil Nadu COVID-19 task force.
From up to 17 contacts traced for each primary case in the early days, the numbers have declined and that too only family contacts, according to Dr Kaur. Little wonder that despite increasing the number of fever clinics to about 500, aggressively testing since mid-June in hotspot areas in Chennai and notwithstanding the 12-day lockdown that went into effect from June 19, the number of fresh cases reported daily from the city still hovers around 1,100-1,200. Daily fresh cases dropped sharply from its peak of about 2,000 but the State has not been able to reduce it beyond 1,100-1,200 cases daily in Chennai.
What the WHO says
Even as recently as July 20, Director-General of World Health Organization Tedros A Ghebreyesus emphasised the importance of contact tracing. “So-called lockdown measures can help reduce transmission, but they cannot completely stop it. Contact tracing is essential for finding and isolating cases and identifying and quarantining their contacts. Mobile applications can support contact tracing, but nothing replaces boots on the ground – trained workers going door-to-door to find cases and contacts, and break the chains of transmission,” he says.
Reducing the turnaround time
There are a few challenges that need immediate attention if Tamil Nadu is intent on drastically reducing the daily fresh cases in Chennai. The top priority should be to shrink the turnaround time from testing to communicating the test result from the current over 48 hours to no more than 24 hours. While the person with overt symptoms is allowed to go home and be under home quarantine, there is no mechanism in place to ensure compliance. Besides the risk of spreading the virus to family members, if the person has not already done so, the risk of virus spread outside the family cannot be dismissed as the person who has undergone the test can freely move around in the community. The responsibility to prevent virus spread rests solely on individuals and their family members. This needs to change for any meaningful reduction in daily cases is to be achieved.
Protocol for testing contacts
The second most important aspect that Tamil Nadu and Chennai Corporation need to address is the testing protocol of family members of a person who has tested positive. The current protocol that limits testing only to family members who show overt symptoms should be done away with in favour of a broad testing strategy that includes every member immaterial of the symptom status. There is enough and more evidence to show that a significant number of people infected with the virus remain asymptomatic and such individuals can in turn infect others. Each untested asymptomatic person can potentially infect two-three people and the transmission chain can grow exponentially. No matter how quickly the number of fever clinics is increased and whether the number of daily tests is further ramped up, asymptomatic family contacts who remain untested will keep the transmission chain well and alive. The State cannot aim to bend the curve until the weakest link in the testing protocol is immediately fixed.
The third priority should be to expand the scope of contact tracing so as to include non-family contacts. The importance of this cannot be overemphasised. Suffice to say that inability to track and test each contact and delay of every single day in tracing and testing non-family contacts would mean the virus continues to spread manifold in the community every five-seven days.
Boots on the ground
The good news is that, with the daily fresh cases continuing to remain high at 1,100-1,200 despite aggressive testing, the Chennai Corporation has finally realised the importance of aggressive tracing of contacts — both family and non-family contacts. Already, 200-odd volunteers, one for each ward, have been recruited solely for tracing the contacts within and outside the family by Chennai Corporation, says Dr Kaur. These volunteers are being trained by a team from Chennai’s National Institute of Epidemiology.
Though belated, the only consolation is that State and Chennai Corporation are moving in the right trajectory. If the State can trace contacts as efficiently as they did in the beginning of the pandemic, further increase the number of daily tests and fever clinics, ensure that people awaiting test results and under home quarantine are monitored, and the turnaround time of testing is halved, the curve will bend in about a month or so. And this model can be replicated in districts where cases are beginning to rise. If done early, controlling the spike in other districts will be easy.
Tamil Nadu along with Kerala has been a guiding star for the rest of the country when it comes to public health and disease control. There is no reason why it cannot succeed again and regain the pole position in the battle against coronavirus. Now that there is political will to battle the virus head-on, nothing may stop the State from succeeding.
Science Chronicle 