Association between living with children, vaccination, and outcomes from COVID-19: an OpenSAFELY cohort study of 12 million adults in England during 2021–22

<ns4:p><ns4:bold>Background:</ns4:bold> Living with children has been associated with greater risks of SARS-CoV-2 infection, COVID-19 hospitalisation, and COVID-19 death. We examined how these associations varied during 2021–22 and according to the COVID-19 vaccination status of adults.</ns4:p><ns4:p> <ns4:bold>Methods</ns4:bold>: We carried out a population-based cohort study, with the approval of NHS England. Primary care data and pseudonymously-linked hospital and death records from England, between 20<ns4:sup>th</ns4:sup> December 2020 and 21<ns4:sup>st</ns4:sup> February 2022, were used for adults (≥18 years) registered at a general practice on 20<ns4:sup>th</ns4:sup> December 2020. Adjusted hazard ratios (HRs) for SARS-CoV-2 infection, COVID-19 hospitalisation, or COVID-19 death, by presence of children in the household were calculated.</ns4:p><ns4:p> <ns4:bold>Results: </ns4:bold>The cohort included 9,417,278 adults aged ≤65 years and 2,866,602 adults aged &gt;65 years. Adults aged ≤65 years living with children of any age (<ns4:italic>versus</ns4:italic> no children) had greater risks of SARS-CoV-2 infection and COVID-19 hospitalisation (but not COVID-19 death), both when schools were open and closed (<ns4:italic>e.g.</ns4:italic> HR=1.50, 95% CI:1.49-1.51, for SARS-CoV-2 infection in the ‘Omicron dominant’ period, when schools were open, in adults living with children aged 0–11 years only). These associations also existed for adults aged &gt;65 years, and there was some evidence that adults living with children also had greater risks of COVID-19 death. Vaccinated adults living with children had greater risks of SARS-CoV-2 infection, but lower risks of COVID-19 hospitalisation and death, than unvaccinated adults not living with children.</ns4:p><ns4:p> <ns4:bold>Conclusions</ns4:bold>: In an era of widespread adult vaccination, adults living with children remained at increased risk of SARS-CoV-2 infection and COVID-19 hospitalisation.</ns4:p>