Model Shows Combined Efforts May Cut SARS-CoV-2 Infections

Combined intervention of quarantine, school closure, workplace distancing projected to be most effective

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THURSDAY, March 26, 2020 (HealthDay News) -- Combined interventions of quarantining infected individuals and their family members, workplace distancing, and school closure can substantially reduce the number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, according to a modeling study published online March 23 in The Lancet Infectious Diseases.

Joel R. Koo, from the Saw Swee Hock School of Public Health at the National University of Singapore, and colleagues adapted an influenza epidemic simulation model to estimate the likelihood of human-to-human transmission of SARS-CoV-2 in a simulated population. The cumulative number of SARS-CoV-2 infections was estimated at 80 days after detecting 100 cases of community transmission under three scenarios (basic reproduction number [R0] of 1.5, 2.0, or 2.5). The baseline scenario assumed no intervention was in place and was compared to intervention scenarios: isolation for infected individuals and quarantine of family members (quarantine); quarantine plus school closure; quarantine plus workplace distancing; and quarantine, school closure, and workplace distancing (combined intervention).

The researchers found that the median cumulative number of infections was 279,000 at day 80 for the baseline scenario when R0 was 1.5. With higher infectivity, the median number of infections increased: 727,000 and 1,207,000 cases when R0 was 2.0 and 2.5, respectively. The combined intervention was the most effective compared with the baseline scenario, reducing the estimated median number of infections by 99.3, 93.0, and 78.2 percent when R0 was 1.5, 2.0, and 2.5.

"These combined interventions should therefore be implemented rapidly upon confirmation of second-generation local transmission occurring within the resident population to suppress increases in the national R0," the authors write.

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