Household Severe Acute Respiratory Syndrome Coronavirus 2 Transmission and Children: A Network Prospective Study

Abstract

Background The role of children in household transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains uncertain. Here, we describe the epidemiological and clinical characteristics of children with COVID-19 in Catalonia (Spain) and investigate the dynamics of household transmission. Methods Prospective, observational, multicenter study performed during summer and school periods (1 July-31 October, 2020), in which epidemiological and clinical features, and viral transmission dynamics were analyzed in COVID-19 patients <16 years. A pediatric index case was established when a child was the first individual infected within a household. Secondary cases were defined when another household member tested positive for SARS-CoV-2 before the child. The secondary attack rate (SAR) was calculated, and logistic regression was used to assess associations between transmission risk factors and SARS-CoV-2 infections. Results The study included 1040 COVID-19 patients <16 years. Almost half (47.2%) were asymptomatic, 10.8% had comorbidities, and 2.6% required hospitalization. No deaths were reported. Viral transmission was common among household members (62.3%). More than 70% (756/1040) of pediatric cases were secondary to an adult, whereas 7.7% (80/1040) were index cases. The SAR was significantly lower in households with COVID-19 pediatric index cases during the school period relative to summer (p=0.02), and when compared to adults (p=0.006). No individual or environmental risk factors associated with the SAR were identified. Conclusions Children are unlikely to cause household COVID-19 clusters or be major drivers of the pandemic even if attending school. Interventions aimed at children are expected to have a small impact on reducing SARS-CoV-2 transmission.

Lower household transmission rates of SARS-CoV-2 from children compared to adults

“…0 • 166 in a review by Madewell et al 2 vs. 0 • 35 in our study). However, the low rate of underage index-cases and their lower SAR compared to adult index-cases is consistent with previous studies [3][4][5] . This supports existing evidence that children are not only less likely to develop severe disease courses but also are less susceptible 6 , 7 and less likely to transmit SARS-CoV-2 8 , 9 .…”

Pediatric household transmission of SARS-CoV-2 infection

“…In the Danish study the OR for children aged 0-5 was 1.11 (95% CI: 1.01-1.19) compared to the 30-35 year reference group, versus 0.82 (95% CI: 0.78-0.85) for children aged 10-15. 22 Soriano-Arandes et al 16 also found that the highest OR for transmission was among index cases 0-2 years (2.27, 95% CI: 0.62-8.35 versus 12-15 year group), but confidence intervals were wide. Grijalva et al 23 observed high household secondary attack rates (SAR) for both pediatric and adult index cases in Tennessee and Wisconsin, USA; the SAR for index cases <12 years was 53% (95% CI: 31%-74%) and for cases 12-17 years was 38% (95% CI: 23%-56%).…”

SARS-CoV-2 transmission in students of public schools of Catalonia (Spain) after a month of reopening

“…This is aligned with studies that showed that children in quarantined households are equally likely to become infected by SARS-CoV-2 as adults [ 34 ]. Also, the transmission of SARS-CoV-2 among household members can be originated from either children or adults [ 35 ], although different studies suggest the same [ 36 ] or lower [ 37 ] infectivity in children. A large contact-tracing study in India observed an increased risk of transmission among children and young adults [ 38 ] and a large cohort study in the UK showed an increased risk of reported SARS-CoV-2 infection and COVID-19 hospitalisations among adults living with children in the second wave [ 39 ].…”