Nosocomial outbreak of coronavirus disease in two general wards during the initial wave of the pandemic in 2020, Tokyo, Japan

Authors

  • Naoya Sakamoto Department of Infectious Diseases, Tokyo Metropolitan Bokutoh General Hospital, Tokyo, Japan
  • Masayuki Ota Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan
  • Tomoko Takeda Sumida Public Health Center, Tokyo, Japan
  • Atsushi Kosaka Department of Infectious Diseases, Tokyo Metropolitan Bokutoh General Hospital, Tokyo, Japan
  • Takuya Washino Department of Infectious Diseases, Tokyo Metropolitan Bokutoh General Hospital, Tokyo, Japan
  • Sentaro Iwabuchi Department of Infectious Diseases, Tokyo Metropolitan Bokutoh General Hospital, Tokyo, Japan
  • Minako Beppu Sumida Public Health Center, Tokyo, Japan
  • Itaru Nishiduka Sumida Public Health Center, Tokyo, Japan
  • Tamano Matsui Center for Surveillance, Immunization, and Epidemiologic Research, National Institute of Infectious Diseases, Tokyo, Japan
  • Motoi Suzuki Center for Surveillance, Immunization, and Epidemiologic Research, National Institute of Infectious Diseases, Tokyo, Japan
  • Fukumi Nakamura-Uchiyama Department of Infectious Diseases, Tokyo Metropolitan Bokutoh General Hospital, Tokyo, Japan

DOI:

https://doi.org/10.5365/wpsar.2022.13.1.906

Abstract

Objective: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in China and subsequently spread worldwide. In Japan, many clusters occurred during the first wave in 2020. We describe the investigation of an early outbreak in a Tokyo hospital.

Methods: A COVID-19 outbreak occurred in two wards of the hospital from April to early May 2020. Confirmed cases were individuals with laboratory-confirmed SARS-CoV-2 infection linked to Wards A and B, and contacts were patients or workers in Wards A or B 2 weeks before the index cases developed symptoms. All contacts were tested, and cases were interviewed to determine the likely route of infection and inform the development of countermeasures to curb transmission.

Results: There were 518 contacts, comprising 472 health-care workers (HCWs) and 46 patients, of whom 517 were tested. SARS-CoV-2 infection was confirmed in 42 individuals (30 HCWs and 12 patients). The proportions of SARS-CoV-2 infections in HCWs were highest among surgeons, nurses, nursing assistants and medical assistants. Several HCWs in these groups reported being in close proximity to one another while not wearing medical masks. Among HCWs, infection was thought to be associated with the use of a small break room and conference room.

Discussion: Nosocomial SARS-CoV-2 infections occurred in two wards of a Tokyo hospital, affecting HCWs and patients. Not wearing masks was considered a key risk factor for infection during this outbreak; masks are now a mandated countermeasure to prevent the spread of SARS-CoV-2 infection in hospital settings.

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Published

24-03-2022

How to Cite

1.
Sakamoto N, Ota M, Takeda T, Kosaka A, Washino T, Iwabuchi S, Beppu M, Nishiduka I, Matsui T, Suzuki M, Nakamura-Uchiyama F. Nosocomial outbreak of coronavirus disease in two general wards during the initial wave of the pandemic in 2020, Tokyo, Japan. Western Pac Surveill Response J [Internet]. 2022 Mar. 24 [cited 2026 Mar. 20];13(1). Available from: https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/906

Issue

Vol. 13 No. 1 (2022): January ‒ March

Section

COVID-19: Outbreak Investigation Report

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