Table 10.

Short description of the effectiveness of selected interventions.

Study	Intervention Category/Setting	Findings	Conclusions
[24]	Surveillance/Hospital	OR calculation for locations with PCR or antibody positives (2400 environmental swabs) vs. locations without positives (3000 environmental swabs) reveals that locations with coronavirus-positive environmental surfaces had 10 times greater odds (p ≤ 0.05) of having positive employees compared to locations with no positive surfaces.	Environmental surface testing results can be used to inform the need for employee testing
[70]	PPE/Hospital	The risk of COVID-19 infection was more than double among HCWs self-washing their masks compared with the hospital laundry (HR 2.04 (95% CI 1.03 to 4.00); p = 0.04). There was no significant difference in infection between HCWs who wore cloth masks washed in the hospital laundry compared with medical masks (p = 0.5).	Self-washing cloth masks by hand more than doubles the risk of seasonal respiratory illnesses. Double-layered cloth masks washed in the hospital laundry were as protective as medical masks.
[52]	PPE/Meatpacking	After initiating both universal masking and physical barrier interventions, 8/11 facilities showed a statistically significant reduction in COVID-19 incidence in <10 days. Facilities that only initiated a universal mask policy showed no significant difference before and after the intervention.	Together, universal masking and physical barriers can prevent COVID-19 transmission in meatpacking plants. These interventions should be accompanied by ventilation enhancements and worker education on mask use and adherence.
[51]	Education/Nursing home	Special focus facilities (n = 123) started with higher infection rates than control facilities (n = 237) but rapidly declined to the same level as the other facilities within a week of starting on-site and virtual infection control consultations. Compliance with cohorting and PPE were associated with large reductions in the weekly infection rate (−50%; p = .004; −23%; p = .0379) and increased odds of a zero-infection rate ([OR] = 3.0; p = .0076; OR = 2.16; p = .0003).	Monitored adherence to infection control processes, especially proper wearing of PPE and cohorting, can reduce weekly infections and mortality.
[72]	Changes in work arrangements/Nursing home	Long-term care facilities (LTCF) that organized staff compartmentalization within zones were significantly more likely to avoid a COVID-19 outbreak (OR = 0.19 (0.07–0.48)) as were LTCFs whose staff perceived high-quality implementation of preventive measures (OR = 0.65 (0.43–0.98)).	Staff compartmentalization within zones and high-quality implementation of preventive measures can help prevent COVID-19 outbreaks in LTCFs.
[53]	Changes in work arrangements/Nursing home	Staff working across different care homes (14/27, 52%) had a 3.0-fold (95% CI, 1.9–4.8; p < 0.001) higher risk of SARS-CoV-2 positivity than staff working in single care homes (39/227, 17%). Whole-genome sequencing identified distinct clusters of SARS-CoV-2 infection between staff only, including those with minimal resident contact.	Staff should be encouraged and incentivized to work in single care homes and movement of staff across multiple care homes should be limited. Infection control should be extended for all contacts, including those between staff, whilst on the care home premises.