Dynamics of SARS-CoV-2 transmission among evacuees quarantined at Jaisalmer, India

Abstract Background During COVID-19 pandemic, Indian nationals were evacuated from foreign countries to various quarantine facilities in India. Individuals arriving from Iran on 14 March 2020 were quarantined at Jaisalmer, Rajasthan. All individuals were tested for SARS-CoV-2 infection after completing 14 days of quarantine. Those testing positive were isolated at AIIMS Jodhpur, India. We attempt to describe the transmission dynamics of SARS-CoV2 in this cohort. Methods Basic SEIR compartmental model was developed using daily stepwise approach in Microsoft Excel. 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 evacuees. Out of them 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 greater than 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. Further, universal testing and prompt isolation of infected individuals was found effecting in interrupting the transmission of SARS-CoV-2. Role of asymptomatic individuals in transmission appears to be strong in the context of quarantine of evacuees.