Frequency of Routine Testing for Coronavirus Disease 2019 (COVID-19) in High-risk Healthcare Environments to Reduce Outbreaks

Abstract

Routine asymptomatic testing strategies for COVID-19 have been proposed to prevent outbreaks in high-risk healthcare environments. We used simulation modeling to evaluate the optimal frequency of viral testing. We found that routine testing substantially reduces risk of outbreaks, but may need to be as frequent as twice weekly.

Keywords: SARS-CoV-2; epidemiology; infection control; pandemic.

Figure 1.

Projected impact of routine PCR testing frequency on the mean effective reproduction number under different testing scenarios. We estimated the effectiveness of increasing frequency of routine PCR testing to reduce the mean effective reproduction number, R_e, under different assumptions on the underlying basic reproduction number, R₀. The x-axis refers to the frequency of PCR testing simulated, from daily (testing frequency of 1 day) to once a month (testing frequency of 30 days). The y-axis represents the mean effective reproduction number (R_e), which is the average number of secondary infections caused by an infected person averaged over the simulation period, starting with a fully susceptible population, and accounting for the impact of interventions. The goal is to reduce R_c to below one to ensure decline in the number of cases when averaged over time. Bands represent the interquartile range accounting for parameter and stochastic uncertainty. Abbreviation: PCR, polymerase chain reaction.