Grappling with COVID-19 by imposing and lifting non-pharmaceutical interventions in Sri Lanka: A modeling perspective

Mahesh Jayaweera; Chamath Dannangoda; Dilum Dilshan; Janith Dissanayake; Hasini Perera; Jagath Manatunge; Buddhika Gunawardana

doi:10.1016/j.idm.2021.06.004

Grappling with COVID-19 by imposing and lifting non-pharmaceutical interventions in Sri Lanka: A modeling perspective

Infect Dis Model. 2021:6:820-831. doi: 10.1016/j.idm.2021.06.004. Epub 2021 Jul 7.

Authors

Mahesh Jayaweera¹, Chamath Dannangoda², Dilum Dilshan¹, Janith Dissanayake³, Hasini Perera⁴, Jagath Manatunge¹, Buddhika Gunawardana¹

Affiliations

¹ Department of Civil Engineering, University of Moratuwa, Sri Lanka.
² Department of Physics and Astronomy, University of Texas at Rio Grande Valley, Brownsville, TX, 78520, USA.
³ Department of Civil & Environmental Engineering, College of Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
⁴ Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka.

Abstract

The imposition and lifting of non-pharmaceutical interventions (NPIs) to avert the COVID-19 pandemic have gained popularity worldwide and will continue to be enforced until herd immunity is achieved. We developed a linear regression model to ascertain the nexus between the time-varying reproduction number averaged over a time window of six days (R_ts) and seven NPIs: contact tracing, quarantine efforts, social distancing and health checks, hand hygiene, wearing of facemasks, lockdown and isolation, and health-related supports. Our analysis suggests that the second wave that emerged in Sri Lanka in early October 2020 continued despite numerous NPIs. The model indicates that the most effective single NPI was lockdown and isolation. Conversely, the least effective individual NPIs were hand hygiene and wearing of facemasks. The model also demonstrates that to mitigate the second wave to a satisfactory level (R_ts<1), the best single NPI was the contact tracing with stringent imposition (% of improvement of R_ts was 69.43 against the base case). By contrast, the best combination of two NPIs was the lockdown & isolation with health-related supports (% of improvement was 31.92 against the base case). As such, many health authorities worldwide can use this model to successfully strategize the imposition and lifting of NPIs for averting the COVID-19 pandemic.

Keywords: Contact tracing; Isolation; Lockdown; Modeling; Reproduction number.