SARS-CoV-2 transmission by asymptomatic healthcare workers positive to screening swab: an Italian study.
Eur J Public Health
; 32(5): 813-817, 2022 10 03.
Article
in English
| MEDLINE | ID: covidwho-2017911
ABSTRACT
BACKGROUND:
SARS-CoV-2 spreads primarily through respiratory droplets of symptomatic individuals. With respect to asymptomatic individuals, there are conflicting results in the literature and a lack of studies specifically examining transmission in healthcare settings.METHODS:
The aim of this retrospective study, conducted in a northeastern Italian region, was to estimate the contagiousness of asymptomatic healthcare workers (HCWs) who tested positive for SARS-CoV-2. Asymptomatic HCWs who tested positive for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction (rRT-PCR) at a regular screening nasopharyngeal or oropharyngeal swab between 1 February 2020 and 15 September 2020 were considered index cases. Contacts who were at high risk of infection and had follow-up swabs were included. Contacts were considered infected if they had a positive follow-up swab and/or symptoms associated with COVID-19 confirmed by a positive test within 14 days of exposure. Information was taken from records previously collected to identify contacts. Infectivity was estimated using the attack rate (AR) with a 95% confidence interval (95% CI).RESULTS:
Thirty-eight asymptomatic HCWs who were positive at the screening swab and 778 contacts were identified. Contacts included 63.8% of colleagues, 25.6% of patients, 7.7% of family members and 3.0% of other contacts. Seven contacts tested positive for SARS-CoV-2 (AR 0.91%, 95% CI 0.89-0.93). Five of them were family members (AR 8.3%), one was a colleague (0.2%) and one was a contact of other type (4.2%).CONCLUSIONS:
Viral spread by asymptomatic HCWs was less than in other settings. Identification of risk factors for transmission and reliable indicators of infectivity would be important to prioritize preventive measures.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
SARS-CoV-2
/
COVID-19
Type of study:
Cohort study
/
Diagnostic study
/
Observational study
/
Prognostic study
Limits:
Humans
Country/Region as subject:
Europa
Language:
English
Journal:
Eur J Public Health
Journal subject:
Epidemiology
/
Public Health
Year:
2022
Document Type:
Article
Affiliation country:
Eurpub
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