Dataset Information

Risk factors and vectors for SARS-CoV-2 household transmission: a prospective, longitudinal cohort study.

ABSTRACT:

Background

Despite circumstantial evidence for aerosol and fomite spread of SARS-CoV-2, empirical data linking either pathway with transmission are scarce. Here we aimed to assess whether the presence of SARS-CoV-2 on frequently-touched surfaces and residents' hands was a predictor of SARS-CoV-2 household transmission.

Methods

In this longitudinal cohort study, during the pre-alpha (September to December, 2020) and alpha (B.1.1.7; December, 2020, to April, 2021) SARS-CoV-2 variant waves, we prospectively recruited contacts from households exposed to newly diagnosed COVID-19 primary cases, in London, UK. To maximally capture transmission events, contacts were recruited regardless of symptom status and serially tested for SARS-CoV-2 infection by RT-PCR on upper respiratory tract (URT) samples and, in a subcohort, by serial serology. Contacts' hands, primary cases' hands, and frequently-touched surface-samples from communal areas were tested for SARS-CoV-2 RNA. SARS-CoV-2 URT isolates from 25 primary case-contact pairs underwent whole-genome sequencing (WGS).

Findings

From Aug 1, 2020, until March 31, 2021, 620 contacts of PCR-confirmed SARS-CoV-2-infected primary cases were recruited. 414 household contacts (from 279 households) with available serial URT PCR results were analysed in the full household contacts' cohort, and of those, 134 contacts with available longitudinal serology data and not vaccinated pre-enrolment were analysed in the serology subcohort. Household infection rate was 28·4% (95% CI 20·8-37·5) for pre-alpha-exposed contacts and 51·8% (42·5-61·0) for alpha-exposed contacts (p=0·0047). Primary cases' URT RNA viral load did not correlate with transmission, but was associated with detection of SARS-CoV-2 RNA on their hands (p=0·031). SARS-CoV-2 detected on primary cases' hands, in turn, predicted contacts' risk of infection (adjusted relative risk [aRR]=1·70 [95% CI 1·24-2·31]), as did SARS-CoV-2 RNA presence on household surfaces (aRR=1·66 [1·09-2·55]) and contacts' hands (aRR=2·06 [1·57-2·69]). In six contacts with an initial negative URT PCR result, hand-swab (n=3) and household surface-swab (n=3) PCR positivity preceded URT PCR positivity. WGS corroborated household transmission.

Interpretation

Presence of SARS-CoV-2 RNA on primary cases' and contacts' hands and on frequently-touched household surfaces associates with transmission, identifying these as potential vectors for spread in households.

Funding

National Institute for Health Research Health Protection Research Unit in Respiratory Infections, Medical Research Council.

SUBMITTER: Derqui N

PROVIDER: S-EPMC10132910 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature

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Publications

Risk factors and vectors for SARS-CoV-2 household transmission: a prospective, longitudinal cohort study.

Derqui Nieves N Koycheva Aleksandra A Zhou Jie J Pillay Timesh D TD Crone Michael A MA Hakki Seran S Fenn Joe J Kundu Rhia R Varro Robert R Conibear Emily E Madon Kieran J KJ Barnett Jack L JL Houston Hamish H Singanayagam Anika A Narean Janakan S JS Tolosa-Wright Mica R MR Mosscrop Lucy L Rosadas Carolina C Watber Patricia P Anderson Charlotte C Parker Eleanor E Freemont Paul S PS Ferguson Neil M NM Zambon Maria M McClure Myra O MO Tedder Richard R Barclay Wendy S WS Dunning Jake J Taylor Graham P GP Lalvani Ajit A

The Lancet. Microbe 20230406 6

<h4>Background</h4>Despite circumstantial evidence for aerosol and fomite spread of SARS-CoV-2, empirical data linking either pathway with transmission are scarce. Here we aimed to assess whether the presence of SARS-CoV-2 on frequently-touched surfaces and residents' hands was a predictor of SARS-CoV-2 household transmission.<h4>Methods</h4>In this longitudinal cohort study, during the pre-alpha (September to December, 2020) and alpha (B.1.1.7; December, 2020, to April, 2021) SARS-CoV-2 variant ...[more]

PMID: 37031689

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Dataset Information

Risk factors and vectors for SARS-CoV-2 household transmission: a prospective, longitudinal cohort study.

Background

Methods

Findings

Interpretation

Funding

Publications

Risk factors and vectors for SARS-CoV-2 household transmission: a prospective, longitudinal cohort study.

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