Relationship of close contact settings with transmission and infection during the Sars-CoV-2 Omicron BA.2 epidemic in Shanghai

Bibliographic Data

ID21878783
AuthorsWenlong Zhu (0000-0002-6538-9905, Fudan University), Shiying Yuan (0000-0002-6415-1604, Shanghai Municipal Center For Disease Control Prevention), Shenghua Mao (Shanghai Municipal Center For Disease Control Prevention), Jian Chen (0000-0002-9033-4033, Shanghai Municipal Center For Disease Control Prevention), Yaxu Zheng (0009-0004-6977-6074, Shanghai Municipal Center For Disease Control Prevention), Xianjin JIANG (Shanghai Municipal Center For Disease Control Prevention), Xiao Yu (0000-0002-0964-756X, Shanghai Municipal Center For Disease Control Prevention), Chenyan Jiang (0000-0003-1649-5901, Shanghai Municipal Center For Disease Control Prevention), Qiwen Fang (0000-0001-5895-442X, Shanghai Municipal Center For Disease Control Prevention), Weibing Wang (0000-0002-4497-5251, Fudan University), Zheng'an Yuan (Shanghai Municipal Center for Disease Control and Prevention), Zhengan Yuan (Shanghai Municipal Center For Disease Control Prevention, corresponding author), Ye Yao (0000-0002-0878-8942, Fudan University, corresponding author)
Year2023
Volume8
Issue12
Pagese012289
Publication date2023-12-01
Open AccessYes
TypeARTICLE
VenueBMJ Global Health (JOURNAL)
Journal identifiersISSN: 2059-7908 • E-ISSN: 2059-7908
PublisherBMJ (PUBLISHER • GB)
DOI10.1136/bmjgh-2023-012289
PMID38135296
OpenAlexW4390101474
LanguageEN
Citations received1
References cited33

INTRODUCTION: We analysed case-contact clusters during the Omicron BA.2 epidemic in Shanghai to assess the risk of infection of contacts in different settings and to evaluate the effect of demographic factors on the association of infectivity and susceptibility to the Omicron variant. METHODS: Data on the settings and frequency of contact, demographic characteristics and comorbidities of index cases, contacts and secondary cases were analysed. Independent effect of multiple variables on the risk for transmission and infection was evaluated using generalised estimating equations. RESULTS: From 1 March to 1 June 2022, we identified 450 770 close contacts of 90 885 index cases. The risk for infection was greater for contacts in farmers' markets (fixed locations where farmers gather to sell products, adjusted OR (aOR): 3.62; 95% CI 2.87 to 4.55) and households (aOR: 2.68; 95% CI 2.15 to 3.35). Children (0-4 years) and elderly adults (60 years and above) had higher risk for infection and transmission. During the course of the epidemic, the risk for infection and transmission in different age groups initially increased, and then decreased on about 21 April (17th day of citywide home quarantine). Compared with medical workers (reference, aOR: 1.00), unemployed contacts (aOR: 1.77; 95% CI 1.53 to 2.04) and preschoolers (aOR: 1.61; 95% CI 1.26 to 2.05) had the highest risk for infection; delivery workers (aOR: 1.90, 95% CI 1.51 to 2.40) and public service workers (aOR: 1.85; 95% CI 1.64 to 2.10) had the highest risk for transmission. Contacts who had comorbidities (aOR: 1.10; 95% CI 1.09 to 1.12) had a higher risk for infection, particularly those with lung diseases or immune deficiency. CONCLUSION: Farmers' markets and households were the main setting for transmission of Omicron. Children, the elderly, delivery workers and public service workers had the highest risk for transmission and infection. These findings should be considered when implementing targeted interventions

Biology · Disease · Infection risk · Infectivity · Public health · Risk of infection · COVID-19 and Mental Health · COVID-19 epidemiological studies · Demography · Infection Control and Ventilation · Medicine · Emergency Medicine · Immunology · Internal Medicine

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