In England, COVID-19 Transmission Risk Was Child’s Play

During the second wave of COVID-19 infections in England last year, households with children had higher risk of infection and hospitalization, but not death, versus households without children, a large population-based study found.

From September to December 2020, adults younger than 65 living with children ages 12-18 showed increased risk of SARS-CoV-2 infection (adjusted HR 1.22, 95% CI 1.20-1.24) and COVID-19 hospitalization (adjusted HR 1.26, 95% CI 1.12-1.40), with slightly smaller risks associated with children ages 0-11, reported Ben Goldacre, MBBS, of the University of Oxford, and colleagues.

However, adults with children did not have increased risk of infection, hospitalization, or death during the first wave of COVID-19 from February to August 2020, the authors wrote in their study online in The BMJ.

During that first wave, schools were largely closed, but they were open in England throughout the fall. As well, the more transmissible U.K. variant, B.1.1.7, was first detected in September, according to media reports. Early evidence indicated this variant was responsible for a larger share of cases among kids under 20 than the original virus.

Goldacre’s group analyzed data from the OpenSAFELY study, a population-based cohort study on behalf of NHS England, including primary care data and linked hospital and ICU admissions and death records during wave 1 (February-August) and wave 2 (September-December) last year.

The cohort included about 9.3 million adults ages 65 and younger and about 2.7 million adults older than 65. About 63% of the cohort did not live with children, 20% lived with only children ages 0-11, and 10% lived with only children ages 12-18. Among adults older than 65, there were 97% who did not live with children.

Interestingly, for adults older than 65 living with children, there was an increased risk of infection tied to living with children, and an increased risk of ICU admission and death for those living with children ages 0-11 and 12-18.

For adults younger than 65, living with children ages 0-11 was tied to a reduced risk of COVID-19 death during both waves, but during wave 2, the authors found “no increase in risk of death for those living with older children.”

Living with children was also not associated with increased risk of ICU admission in this population.

Limitations to the data, the researchers said, included lack of generalizability to the overall British population (or others elsewhere), and that the study could not examine the direct association between children and adults within a household testing positive for the virus, “as a substantial proportion of infections in this age group will be asymptomatic or undiagnosed.”

“Data from population-based studies show that the reopening of schools was temporally associated with progressively increasing prevalence of SARS-CoV-2 among children of all ages,” the researchers wrote, adding that there is a possibility that “widespread school attendance may have led to increased risks in households.”