What will major cities look like once the lockdown is lifted on May 3? How will COVID-19 evolve post the restrictions?
Researchers at the Indian Institute of Science (IISc.) and Tata Institute of Fundamental Research (TIFR) have carried out city-scale simulation experiments and modelled the outcomes of post-lockdown scenarios to answer these questions in a working paper that aims to provide useful insights for public health officials and policymakers.
According to the researchers, unless we continue to aggressively trace and isolate cases, and prevent the influx of new infections, there is likely to be a second wave of infections and the public health threat will continue to persist.
According to an IISc. release, the team simulated the infection spread in Bengaluru and Mumbai using an agent-based model, which builds a fine-grained replica of a city and mimics various interaction spaces such as households, schools, and workplaces. The model also takes into account population densities, age distribution, household size distribution, and commute distances, among others.
The researchers ‘seeded’ infections in the simulated cities and tested how the epidemic would spread under different scenarios when restrictions are phased out. For example, one scenario is a return to normal activity on May 4, but with ‘case isolation’ continuing. Another considers an ‘odd-even’ strategy between April 20 and May 3, where half the workforce returns to their offices, along with other restrictions in place. Yet another scenario looks at a complete lockdown for an indefinite period. In all of these, the researchers assumed that cases would continue to be isolated with 90% compliance.
The model forecasts that in a city like Bengaluru, if the lockdown is lifted on April 20, and normal activity resumes, the number of direct COVID-19 fatalities might increase to levels under a no intervention scenario, but with some delay. Similarly, the model also forecasts an increase in COVID-19 fatalities if the lockdown is lifted from April 20 to May 3 in the following phases: case isolation, home quarantine, social distancing of those 65 years and older, closure of schools and colleges, and thereafter normal activity resumes but with case isolation.
On the other hand, if the lockdown were to continue indefinitely, the number of direct COVID-19 fatalities in Bengaluru will likely be much smaller than in the no intervention scenario, the model predicts.
The researchers have added a caveat that their study only looks at the public health outcomes of interventions and their relaxations and not economic or ethical issues, or aggressive contact tracing, testing, and isolation which can change the course of the epidemic.
