Rapid real-time tracking of non-pharmaceutical interventions and their association with SARS-CoV-2 positivity: The COVID-19 Pandemic Pulse Study

Clipman, Steven J; Wesolowski, Amy P; Gibson, Dustin G; Agarwal, Smisha; Lambrou, Anastasia S; Kirk, Gregory D; Labrique, Alain B; Mehta, Shruti H; Solomon, Sunil S

BACKGROUND: Current mitigation strategies for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rely on population-wide adoption of non-pharmaceutical interventions (NPIs). Monitoring NPI adoption and their association with SARS-CoV-2 infection history can provide key information for public health. METHODS: We sampled 1,030 individuals in Maryland from June 17 – June 28, 2020 to capture socio-demographically and geographically resolved information about NPI adoption, access to SARS-CoV-2 testing, and examine associations with self-reported SARS-CoV-2 positivity. RESULTS: Overall, 92% reported traveling for essential services and 66% visited friends/family. Use of public transport was reported by 18%. In total, 68% reported strict social distancing indoors and 53% strict masking indoors; indoor social distancing was significantly associated with age, and race/ethnicity and income with masking. Overall, 55 participants (5.3%) self-reported ever testing positive for SARS-CoV-2 with strong dose-response relationships between several forms of movement frequency and SARS-CoV-2 positivity. In multivariable analysis, history of SARS-CoV-2 infection was negatively associated with strict social distancing (adjusted Odd Ratio for outdoor social distancing [aOR]: 0.10; 95% Confidence Interval: 0.03 – 0.33); only public transport use (aOR for ≥7 times vs. never: 4.29) and visiting a place of worship (aOR for ≥3 times vs. never: 16.0) remained significantly associated with SARS-CoV-2 infection after adjusting for strict social distancing and demographics. CONCLUSIONS: These results support public health messaging that strict social distancing during most activities can reduce SARS-CoV-2 transmission. Additional considerations are needed for indoor activities with large numbers of persons (places of worship and public transportation) where even NPIs may not be possible or sufficient.