Household transmission of SARS-CoV-2 in the paediatric age group and associated factors: an ambispective community-based study.

BACKGROUND

Households represent a major setting for SARS-CoV-2 transmission due to prolonged close contact and shared living environments. Although household transmission has been widely investigated, studies focusing on households including children and incorporating long-term follow-up data remain limited.

METHODS

This ambispective community-based observational study included 119 households comprising 501 individuals in Zonguldak, Türkiye, all containing at least one child and at least one laboratory-confirmed COVID-19 case between March 2020 and March 2021. Retrospective data were used to assess intra-household transmission and calculate the household secondary attack rate (SAR). Subsequently, households were followed prospectively for approximately 2 years (until March 2023) to evaluate reinfection, post-COVID symptoms, vaccination status, and mortality. Household-level and individual-level factors associated with transmission were analysed.

RESULTS

Intra-household transmission occurred in 63.0% of households, and complete household infection was observed in 23.5% of households. The mean household secondary attack rate was 40.7%. Adult age of the index case, presence of comorbidities, symptomatic disease, and close-contact behavior's such as shared sleeping arrangements and shared meals were associated with increased transmission risk. In contrast, implementation of household isolation and mask use significantly reduced the likelihood of complete household infection. During long-term follow-up, reinfection occurred in 8.4% of participants, post-COVID symptoms were reported in 27.1% of confirmed cases, and mortality was observed only among older individuals with multiple comorbidities.

CONCLUSION

This ambispective household-based study with extended follow-up demonstrates that SARS-CoV-2 transmission in families with children is common and strongly influenced by modifiable behavioural factors. Household-level preventive measures, particularly effective isolation and mask use, may play a crucial role in reducing transmission and mitigating long-term consequences of COVID-19 in paediatric-inclusive households.