While nursing home residents only make up 0.6% of the US population, they have accounted for 45% of the COVID-19 related deaths.

As nursing homes have seen such a substantial mortality rate, one research group decided to conduct a prospective study looking at the association of contract nursing and SARS-CoV-2 outbreaks.

This research group had conducted a large pragmatic cluster randomized influenza vaccine trial in 965 nursing homes, and with the impact of the pandemic, they hypothesized that facilities using contract staff would have a higher risk of outbreaks.

“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), the investigators wrote. “Facilities with contract staffing hours in the upper 25% quantile of direct care (RN, LPN, CNA) were considered ‘heavy use’."

The investigators collected data from February through April, and of the 965 nursing homes, 663 reported on COVID-19 outbreaks. According to the investigators, that 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.

“The ‘heavy use’ of contract staffing included those with >223 hours per quarter,” the investigators reported. “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.”

“The participating nursing homes in our vaccine trial with SARS-CoV-2 outbreaks were larger,” investigators concluded. “Our study highlights that heavy use of contract staffing was associated with 56% increased risk of an outbreak.”

The study, “Association between contract staffing and reported outbreaks of SARS-CoV-2 in a cluster-randomized trial of 965 U.S. nursing homes,” was presented virtually at ID Week 2020.