Association of Trends in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Seroprevalence and State-Issued Nonpharmaceutical Interventions: United States, 1 August 2020 to 30 March 2021.

Abstract

ObjectivesTo assess if state-issued nonpharmaceutical interventions (NPIs) are associated with reduced rates of SARS-CoV-2 infection as measured through anti-nucleocapsid (anti-N) seroprevalence, a proxy for cumulative prior infection that distinguishes seropositivity from vaccination).MethodsMonthly anti-N seroprevalence during August 1, 2020 – March 30, 2021 was estimated using a nationwide blood donor serosurvey. Using multivariable logistic regression models, we measured the association of seropositivity and state-issued, county-specific NPIs for mask mandates, gathering bans, and bar closures.ResultsCompared with individuals living in a county with all three NPIs in place, the odds of having anti-N antibodies were 2.2 (95% CI: 2.0-2.3) times higher for people living in a county that did not have any of the three NPIs, 1.6 (95% CI: 1.5-1.7) times higher for people living in a county that only had a mask mandate and gathering ban policy, and 1.4 (95% CI: 1.3-1.5) times higher for people living in a county that had only a mask mandate.ConclusionsConsistent with studies assessing NPIs relative to COVID-19 incidence and mortality, the presence of NPIs were associated with lower SARS-CoV-2 seroprevalence indicating lower rates of cumulative infections. Multiple NPIs are likely more effective than single NPIs.