Control of a Nosocomial Outbreak of COVID-19 in a University Hospital.

COVID-19 infection control strategy nosocomial infection nosocomial outbreak

Journal

Open forum infectious diseases
ISSN: 2328-8957
Titre abrégé: Open Forum Infect Dis
Pays: United States
ID NLM: 101637045

Informations de publication

Date de publication:
Dec 2020
Historique:
received: 03 08 2020
accepted: 16 10 2020
entrez: 17 12 2020
pubmed: 18 12 2020
medline: 18 12 2020
Statut: epublish

Résumé

Nosocomial spread of coronavirus disease 2019 (COVID-19) causes clusters of infection among high-risk individuals. Controlling this spread is critical to reducing COVID-19 morbidity and mortality. We describe an outbreak of COVID-19 in Keio University Hospital, Japan, and its control and propose effective control measures. When an outbreak was suspected, immediate isolation and thorough polymerase chain reaction (PCR) testing of patients and health care workers (HCWs) using an in-house system, together with extensive contact tracing and social distancing measures, were conducted. Nosocomial infections (NIs) were defined as having an onset or positive test after the fifth day of admission for patients and having high-risk contacts in our hospital for HCWs. We performed descriptive analyses for this outbreak. Between March 24 and April 24, 2020, 27 of 562 tested patients were confirmed positive, of whom 5 (18.5%) were suspected as NIs. For HCWs, 52 of 697 tested positive, and 40 (76.9%) were considered NIs. Among transmissions, 95.5% were suspected of having occurred during the asymptomatic period. Large-scale isolation and testing at the first sign of outbreak terminated NIs. The number of secondary cases directly generated by a single primary case found before March 31 was 1.74, compared with 0 after April 1. Only 4 of 28 primary cases generated definite secondary infection; these were all asymptomatic. Viral shedding from asymptomatic cases played a major role in NIs. PCR screening of asymptomatic individuals helped clarify the pattern of spread. Immediate large-scale isolation, contact tracing, and social distancing measures were essential to containing outbreaks.

Sections du résumé

BACKGROUND BACKGROUND
Nosocomial spread of coronavirus disease 2019 (COVID-19) causes clusters of infection among high-risk individuals. Controlling this spread is critical to reducing COVID-19 morbidity and mortality. We describe an outbreak of COVID-19 in Keio University Hospital, Japan, and its control and propose effective control measures.
METHODS METHODS
When an outbreak was suspected, immediate isolation and thorough polymerase chain reaction (PCR) testing of patients and health care workers (HCWs) using an in-house system, together with extensive contact tracing and social distancing measures, were conducted. Nosocomial infections (NIs) were defined as having an onset or positive test after the fifth day of admission for patients and having high-risk contacts in our hospital for HCWs. We performed descriptive analyses for this outbreak.
RESULTS RESULTS
Between March 24 and April 24, 2020, 27 of 562 tested patients were confirmed positive, of whom 5 (18.5%) were suspected as NIs. For HCWs, 52 of 697 tested positive, and 40 (76.9%) were considered NIs. Among transmissions, 95.5% were suspected of having occurred during the asymptomatic period. Large-scale isolation and testing at the first sign of outbreak terminated NIs. The number of secondary cases directly generated by a single primary case found before March 31 was 1.74, compared with 0 after April 1. Only 4 of 28 primary cases generated definite secondary infection; these were all asymptomatic.
CONCLUSIONS CONCLUSIONS
Viral shedding from asymptomatic cases played a major role in NIs. PCR screening of asymptomatic individuals helped clarify the pattern of spread. Immediate large-scale isolation, contact tracing, and social distancing measures were essential to containing outbreaks.

Identifiants

pubmed: 33330740
doi: 10.1093/ofid/ofaa512
pii: ofaa512
pmc: PMC7665726
doi:

Types de publication

Journal Article

Langues

eng

Pagination

ofaa512

Informations de copyright

© The Author(s) 2020. Published by Oxford University Press on behalf of Infectious Diseases Society of America.

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Auteurs

Sei Harada (S)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Shunsuke Uno (S)

Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
Division of Infectious Diseases and Infection Control, Keio University Hospital, Tokyo, Japan.

Takayuki Ando (T)

Center for General Medicine Education, Keio University School of Medicine, Tokyo, Japan.

Miho Iida (M)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Yaoko Takano (Y)

Division of Infectious Diseases and Infection Control, Keio University Hospital, Tokyo, Japan.

Yoshiki Ishibashi (Y)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Yoshifumi Uwamino (Y)

Division of Infectious Diseases and Infection Control, Keio University Hospital, Tokyo, Japan.
Department of Laboratory Medicine, Keio University School of Medicine, Tokyo, Japan.

Tomoyasu Nishimura (T)

Keio University Health Center, Tokyo, Japan.

Ayano Takeda (A)

Keio University Health Center, Tokyo, Japan.

Sho Uchida (S)

Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
Division of Infectious Diseases and Infection Control, Keio University Hospital, Tokyo, Japan.

Aya Hirata (A)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Mizuki Sata (M)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Minako Matsumoto (M)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Ayano Takeuchi (A)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Hideaki Obara (H)

Division of Infectious Diseases and Infection Control, Keio University Hospital, Tokyo, Japan.
Department of Surgery, Keio University School of Medicine, Tokyo, Japan.

Hirokazu Yokoyama (H)

Keio University Health Center, Tokyo, Japan.

Koichi Fukunaga (K)

Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.

Masayuki Amagai (M)

Department of Dermatology, Keio University School of Medicine, Tokyo, Japan.

Yuko Kitagawa (Y)

Department of Surgery, Keio University School of Medicine, Tokyo, Japan.

Toru Takebayashi (T)

Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.

Naoki Hasegawa (N)

Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan.
Division of Infectious Diseases and Infection Control, Keio University Hospital, Tokyo, Japan.

Classifications MeSH