ABSTRACT
Background. Nursing home residents account for 45% SARS-CoV-2 related deaths in the U.S. but only 0.6% of the population. Our research group conducted a large pragmatic cluster randomized influenza vaccine trial in 965 nursing homes (NCT03965195). Due to the pandemic and its impact after the influenza season, we prospectively collected reports of SARS-CoV-2 outbreaks and performed a prospective study on the association between contract staffing and reported outbreaks of SARSCoV- 2. We hypothesized those using more contract nursing care would have higher risk of an outbreak. Methods. From February through April, we collected monthly facility-level, self-reported data on SARS-CoV-2 outbreaks. Facility characteristics were taken from public data from Centers for Medicaid and Medicare services. Predictors of SARSCoV- 2 outbreaks were identified using a LASSO variable selection procedure, with a generalized linear, Poisson family model. Facility characteristics evaluated include demographics (e.g. number of residents), influenza vaccination rates, quality measures (e.g. % with UTI), and functional status (e.g. % with tube feedings). Facilities with contract staffing hours in the upper 25% quantile of direct care (RN, LPN, CNA) were considered 'heavy use'. Results. Of 965 randomized NHs, 663/965 (69%) reported data on SARS-CoV-2 outbreaks. On average, 13% of facilities had at least one outbreak, with 5/842 (0.5%) outbreaks in February, 91/835 (10.8%) in March and 217/686 (30%) in April. SARSCoV- 2 (+) facilities were larger (average total beds, 151 vs. 117), but were mostly similar by functional and cognitive status. Occupancy rate, total residents, Influenza vaccination rate, % with UTI, receiving respiratory treatments, tube feedings, and Medicaid payers were adjusted for in the analysis. The 'heavy use' of contract staffing included those with >223 hours per quarter. A multivariable regression found the relative risk SARS-CoV-2 outbreak was 1.56 (95% Confidence Interval: 1.22, 1.99) with heavy use of contract staffing. Conclusion. The participating nursing homes in our vaccine trial with SARSCoV- 2 outbreaks were larger. Our study highlights that heavy use of contract staffing was associated with 56% increased risk of an outbreak.