2023-04-06 インペリアル・カレッジ・ロンドン(ICL)
この研究は、COVID-19の家庭内伝播に関する新しい光を当て、SARS-CoV-2が人の手や家庭内の頻繁に触れる物体に存在することと、感染者の接触者における感染リスクの関連付けを初めて示している。
研究は、279世帯を対象に行われ、感染が最も発生する場所である家庭内でのCOVID-19の感染拡大について示唆し、家庭内感染時の介入方法として、手洗い、定期的な表面の消毒、身体的距離の確保、そしてマスクの使用を推奨している。
<関連情報>
- https://www.imperial.ac.uk/news/244251/covid-19-spread-households-linked-virus-hands/
- https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(23)00069-1/fulltext
SARS-CoV-2の家庭内伝播の危険因子とベクター:前向き縦断コホート研究 Risk factors and vectors for SARS-CoV-2 household transmission: a prospective, longitudinal cohort study
Nieves Derqui, Aleksandra Koycheva, Jie Zhou, Timesh D Pillay, Michael A Crone, Seran Hakki, Joe Fenn, Rhia Kundu, Robert Varro, Emily Conibear, Kieran J Madon, Jack L Barnett, Hamish Houston, Anika Singanayagam, Janakan S Narean, Mica R Tolosa-Wright, Lucy Mosscrop, Carolina Rosadas, Patricia Watber, Charlotte Anderson, Eleanor Parker, Paul S Freemont, Neil M Ferguson, Maria Zambon, Myra O McClure, Richard Tedder, Wendy S Barclay, Jake Dunning, Graham P Taylor, Ajit Lalvani, on behalf of the INSTINCT and ATACCC study group
The Lancet Microbe Published:April 06, 2023
DOI:https://doi.org/10.1016/S2666-5247(23)00069-1
Summary
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.
