Dynamics of SARS-CoV-2 Transmission Among Indian Nationals Evacuated From Iran

Objective: During the coronavirus disease (COVID-19) pandemic, Indian nationals evacuated from Iran were quarantined at Jaisalmer, Rajasthan. We wished to study the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in this closed population. Methods: A basic susceptible, exposed, infected, and removed (SEIR) compartmental model was developed using the daily stepwise approach in Microsoft Excel. An advanced model using standard differential equations in Python software version 3.6 was used to estimate R₀ based on model fit to actual data. Results: Forty-eight SARS-CoV-2 infections were found among the 474 quarantined individuals. Out of these, 44 (92%) were asymptomatic. R₀ for the overall duration was found to be 2.29 (95% CI: 1.84-2.78). Male gender and age ≥ 60 years were associated with SARS-CoV-2 infection (RR = 4.33, 95% CI: 2.07-9.05 and 5.32, 95% CI: 3.13-9.04, respectively). Isolation of infected individuals and stricter quarantine of remaining individuals reduced the R₀ from 2.41 initially to 1.17 subsequently. Conclusion: R₀ value was found comparable to the earlier studies indicating similar transmission dynamics among quarantined individuals in India. Universal testing and prompt isolation of infected individuals reduced the transmission of SARS-CoV-2. Smaller group sizes should be preferred to large groups during facility-based quarantine in evacuation situations. The role of asymptomatic individuals appears to be strong in SARS-CoV-2 transmission within closed populations.