The role of multi-generational household clusters in COVID-19 in England

BackgroundHousehold transmission has been demonstrated to be an important factor in the population-level growth of COVID-19. UK Health Security Agency (UKHSA) maintains data on positive tests for COVID-19 and the residential addresses of cases. We sought to use this information to characterise clusters of COVID-19 in multi-generational households in England. MethodsUsing cross-sectional design, cases of COVID-19 were assigned to clusters if they occurred in the same residential property in a 14-day rolling window. Patient demographic data were supplemented with reference to the ONS index of multiple deprivation and population density. Multi-generational households were defined as a cluster with at least three people, with one case in a person who was 0-16 years old and one case in a person who was [≥] 60 years old, with at least 16 years between two members of each age group. ResultsA total of 3,647,063 COVID-19 cases were reported between 01 April 2020 and 20 May 2021. Of these, 1,980,527 (54.3 %) occurred in residential clusters. Multi-generational households formed 1.5 % of clusters, with these more likely to occur in areas of higher population density and higher relative deprivation. Multi-generational clusters were more common among households of non-White ethnicity and formed larger clusters than non-multi-generational clusters (median cluster size 6, IQR 4-11 vs 3, IQR 3-4, respectively). ConclusionMulti-generational clusters were not highly prevalent in England during the study period, however were more common in certain populations. BOX TEXTO_ST_ABSWhat is already known on this subjectC_ST_ABSGreater risk of infection with SARS-CoV-2 in England is associated with being of non-White ethnicity, residence in an area of greater deprivation and higher population density. What is less clear is the role of household composition in the risk of COVID-19 transmission. It has been hypothesised that multi-generational housing (in which at least three different generations are resident in the same property) accounted for a substantial proportion of COVID-19 cases. We sought to test this hypothesis. What this study addsThis study provides descriptive evidence around the role of multi-generational households in the COVID-19 pandemic in England between April 2020 and March 2021. It does not support the hypothesis that this period (a period of low incidence in England), a substantial proportion of COVID-19 cases occurred in multi-generational households.