Clusters of COVID‐19 in long‐term care hospitals and facilities in Japan from 16 January to 9 May 2020

• Published in: Geriatrics & gerontology international Vol. 20; no. 7; pp. 715 - 719
• Main Authors: Iritani, Osamu, Okuno, Tazuo, Hama, Daisuke, Kane, Asami, Kodera, Kumie, Morigaki, Kozue, Terai, Toshio, Maeno, Norie, Morimoto, Shigeto
• Format: Journal Article
• Language: English
• Published: Kyoto, Japan John Wiley & Sons Australia, Ltd 01.07.2020; Blackwell Publishing Ltd; Wiley-Blackwell
• Subjects: Aged; Betacoronavirus - isolation & purification; cluster; Cluster Analysis; Coronavirus Infections - mortality; Coronavirus Infections - prevention & control; COVID-19; Epidemics; Female; Hospitals, Chronic Disease - statistics & numerical data; Humans; Infection Control - organization & administration; Japan - epidemiology; Long term care insurance; Long-Term Care - methods; Long-Term Care - organization & administration; Long-Term Care - trends; long‐term care facility; Male; Morbidity; Mortality; Original : Epidemiology, Clinical Practice and Health; Pandemics - prevention & control; Pneumonia, Viral - mortality; Pneumonia, Viral - prevention & control; SARS-CoV-2; Skilled Nursing Facilities - statistics & numerical data; Japan; COVID-19; mortality; cluster; long-term care facility; morbidity
• ISSN: 1444-1586; 1447-0594; 1447-0594
• DOI: 10.1111/ggi.13973

Aim To clarify the association of cluster number and size of coronavirus disease 2019 (COVID‐19) in long‐term care (LTC) hospitals/facilities, general medical/welfare facilities and non‐medical/welfare facilities with morbidity and mortality in 47 prefectures during 16 January to 9 May 2020 in Japan. Methods Information on COVID‐19 clusters (n ≥2), and morbidity and mortality of COVID‐19 was collected. Results A total of 381 clusters with 3786 infected cases were collected, accounting for 23.9% of 15 852 cumulated cases on 9 May 2020. Although the cluster number (/107 subjects) in LTC hospitals/facilities was significantly smaller compared with those in the other two groups, the cluster size in LTC hospitals/facilities was significantly larger than that in non‐medical/welfare facilities. Cluster numbers in general medical/welfare facilities and in non‐medical/welfare facilities were significantly positively correlated with morbidity (/105), indicating relatively early identification of clusters in these facilities. Unlike in these facilities, cluster size in LTC hospitals/facilities was significantly positively correlated with morbidity, indicating that clusters in LTC hospitals/facilities were finally identified after already having grown to a large size in areas where infection was prevalent. Multivariate logistic regression analysis showed that both cluster number and cluster size only in LTC hospitals/facilities were independently associated with higher mortality (≥median 0.64/105 subjects) after adjustment. Conclusions Preventive efforts against COVID‐19 outbreaks even at the early phase of the epidemic are critically important in LTC hospitals/facilities, as both the larger number and size of clusters only in LTC hospitals/facilities were independently linked to higher mortality in prefectures in Japan. Geriatr Gerontol Int 2020; 20: 715–719.