Epidemiological model studying spread of Covid-19 recommends testing and isolation

Rather than a lockdown, extensive testing to identify asymptomatic carriers and quarantining those diagnosed with Covid-19 with continued social distancing would effectively contain the pandemic in India, recommends the first India-specific epidemiological model for Covid-19 spread.

Termed INDISCI-SIM, the first, detailed, state-level, epidemiological model for India has been developed by scientists from Savitribai Phule Pune University (SPPU), Chennai-based Institute of Mathematical Sciences, Indian Institute of Science at Bengaluru and Ashoka University.

Gautam Menon, professor of biology and physics at Ashoka University, said INDISCI-SIM is the most detailed and versatile among current models for the disease’s trajectory in India. The model involves nine, different, detailed compartments – susceptible, exposed, pre-symptomatic, asymptomatic, mild symptomatic, severely symptomatic, hospitalised, recovered, and dead. Each stage is compared with non-pharmaceutical interventions (such as lockdown, quarantining and expanded testing) to draw an inference on propagation of the disease.

“In case of the virus and depending on a person, the patient may take one of these nine paths. Our model demonstrates how one phase of a typical population will travel from one compartment to another,” said Bhalchandra Pujari of SPPU. For instance, the window of recovery is highest for tested asymptomatic individuals followed by mildly symptomatic, while it’s the least for severely symptomatic and critical. Pujari further said, “Extension or not of the lockdown after May 3, India must increase testing capacities faster than the propagation of the disease.”

“We stress that a comprehensive testing and quarantining regime is the only real long-term solution until a vaccine is found,” said Menon. While emphasising that these simulations do not quantify the economic costs of lockdown, Pujari said, “Opening up transport pan-India is not a good idea as per our model.”

Subsequent versions of the model will incorporate district level description, in addition to differing health care capacities across different regions and their implications for disease spread. Menon said the program will be made publicly available soon.

On Tuesday, principal scientific advisor to the government of India K VijayRaghavan said on social media that the findings of INDISCI-SIM “are being looked at carefully along with other inputs”.