This expert summary is for the peer-reviewed article linked above. We also summarized this paper before it underwent peer-review, which only included results from the first wave of the pandemic in England. You can find our original review of the preprint by clicking here.
Study population and setting
This was a large study that examined whether the risk of SARS-CoV-2 infection and COVID-19 related outcomes differed between adults living with school-age children, and adults not living with school-age children during the first (February 1 – August 31, 2020) and second (September 1 –December 18, 2020) waves of the COVID-19 pandemic in England. OpenSAFELY, a data analytics platform created on behalf of NHS England to answer urgent COVID-19 related research questions was used to link primary care records to data on hospital admissions, SARS-CoV-2 testing data, COVID-19 related intensive care unit admissions, and mortality records. Participants had to have at least three months of follow-up before the start of the study and were followed up until they had an outcome (defined as positive SARS-CoV-2 swab test, hospital or ICU admission, or COVID-19 death). Exposure was characterized into four categories according to the number and ages of children living in the home: (a) no children under 18 years; (b) only children aged 0-11 years; (c) only children aged 12-18 years; (d) and at least one child aged 0-11 years and at least one aged 12-18 years. Data were analyzed using adjusted Cox proportional hazards models clustered by household.
Summary of Main Findings
Data were analyzed for a total of 9,334,392 adults ≤65 years and 2,684, 524 adults >65 years in the first wave, and for 9,266,919 adults ≤65 years in the second wave. Across both waves, 37% of adults ≤65 years lived with children compared to only 3% among those ≥65 years. Overall, absolute risks were low. In the first wave, there were 51,560 (0.55%) recorded SARS-CoV-2 infections; 6,374 (0.07%) COVID-19 related hospitalizations; 1,601 (0.02%) ICU admissions for ventilatory support with COVID-19; and 1219 (0.01%) COVID-19 deaths. In the second wave, there were 241,693 (2.61%) recorded SARS-CoV-2 infections; 3616 (0.04%) COVID-19 related hospitalizations; 1102 (0.01%) ICU admissions for ventilatory support with COVID-19; and 591 (0.01%) COVID-19 deaths. Among those ≤65 years, living with children was not associated with an increased risk of SARS-CoV-2 infection or COVID-19 related outcomes compared to not living with children in wave 1; however, in wave 2, living with children was associated with an increased risk of infection and hospitalization, but not ICU admission. Among those >65 years, living with children was not associated with increased risk of any outcomes in wave 1; however, in wave 2, living with children aged 0-11 and 12-18 years was associated with higher risks of ICU admission (hazard ratio: 1.86, 95% CI: 1.11-1.34) and death (hazard ratio: 1.44, 95% CI: 1.05-1.97). Across both waves, living with a child of any age was associated with a 30% lower risk of non-COVID death in those ≤65 years, but no such association was observed for those >65 years.
The large study sample, and ability to link millions of primary care records to data on SARS-CoV-2 testing, hospital admissions, COVID-19 related intensive care unit admissions, and mortality records. Additional robust analytical checks bolstered evidence that the model was able to identify infections transmitted from children to adults.
Persons missing certain demographic information, and those living in areas or attending health facilities not served by the specific electronic systems used in this study were excluded, thus there is potential for selection bias if those excluded were systematically different from those included in the analysis. As the availability of testing changed over time, identification of COVID-19 cases may have been different between the two waves (specifically, those in the first wave may have been more likely to be those in high-risk jobs), biasing testing outcomes; however other outcomes are robust to this potential bias.
This analysis examines whether risk of infection with SARS-CoV-2 and severe outcomes related to COVID-19 differ between adults living with and without children during the first two waves of the COVID-19 pandemic in England. Such analyses are useful to inform policies around school re-opening.
This review was posted on: 1 September 2021