Modeling layered non-pharmaceutical interventions against SARS-CoV-2 in the United States with Corvid

Dennis L Chao; Assaf P Oron; Devabhaktuni Srikrishna; Michael Famulare

closed, the shelter-in-place reduced the largest remaining component of transmission, the community ( Figure 2 ). However, for these demonstration parameters there was still substantial transmission in the home ( Figure 2 and Table 2 ) Finally, we added three different test-and-isolate strategies to the combination of workplace, school, and community NPIs described above. We simulated home isolation, self isolation, and home isolation with household quarantine of ascertained cases. First, we studied a best-case testing scenario in which symptomatic people are tested and results are ready immediately upon becoming symptomatic. To simulate home isolation, we assumed a person stops going to work or school after testing positive, though there is still some contact with the community during isolation. In this scenario, adding home isolation to the other NPIs can reduce transmission in the community (Figures 1-3 and Table 1 ). The impact was not substantial when the other NPIs were already controlling the epidemic (bottom panels of Figure 1 ), but its contribution made a qualitative difference when the combined impact of all the NPIs changed the epidemic's trajectory from a slow rise to a slow decline, leading to near-elimination (top panels of Figure 1 ). We simulated self isolation by blocking transmission to all contacts including household members. For this scenario where individuals are completely isolated from the susceptible population, self isolation was a little more effective than home isolation, indicating the role of secondary transmission in the household from the ascertained case. The household quarantine 3 . CC-BY 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.