Work

Timing of outbreak-triggered unit-wide screening and COVID-19 outbreak size in long-term care and related social welfare facilities in Okinawa, Japan

Year: 2026

Type: article

Abstract: Objectives: Coronavirus disease 2019 outbreaks in long-term care facilities can spread rapidly, but evidence on whether delayed outbreak-triggered unit-wide screening is associated with outbreak size is limited. Methods: We conducted a retrospective observational study using outbreak-support records from long-term care and related social welfare facilities in Okinawa Prefecture, Japan, from April to September 2022. We included outbreaks with documented unit-wide screening. The outcome was the final outbreak size. The exposure was the delay from outbreak recognition to the first unit-wide screening (same day, 1 day, 2 days, or ≥3 days). We used multivariable negative binomial regression, adjusting for index case type, facility type, recognition period, and facility-level resident vaccination coverage. Results: We analyzed 707 outbreaks. Compared with same-day screening, the adjusted incidence rate ratios for outbreak size were 0.95 (95% confidence interval 0.72-1.26) for a 1-day delay, 1.16 (0.87-1.54) for a 2-day delay, and 1.44 (1.09-1.91) for delays of ≥3 days. The association was attenuated after adjustment for on-site infection prevention and control visit timing. Conclusion: Delays of ≥3 days from outbreak recognition to the first unit-wide screening were associated with a larger final outbreak size. Earlier outbreak-triggered screening may support outbreak control in long-term care facilities, although causal interpretation is limited by the observational design.

Source: IJID Regions

DOI: 10.1016/j.ijregi.2026.101042