Objectives: Studies of household transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) focused on households with children are limited. We investigated household secondary attack rate (SAR), transmission dynamics, and contributing factors in households with children.Materials and Methods: In this prospective case-ascertained study in Los Angeles County, California, all households members were enrolled if ≥1 member tested positive for SARS-CoV-2 by polymerase chain reaction (PCR). Nasopharyngeal PCRs, serology, and symptom data were obtained over multiple visits.Results: A total of 489 individuals in 105 households were enrolled from June to December 2020. The majority (77.3%) reported a household annual income of <$50,000, and most (92.9%) were of Hispanic/Latinx ethnicity. Children <18 years old accounted for 46.9% index cases, of whom 45.3% were asymptomatic. Household index cases were predominantly children during low community transmission and adults during the high community transmission period (χ2 = 7.647, p = 0.0036. The mean household SAR was 77.0% (95% CI: 69.4–84.6%). Child and adult index cases both efficiently transmitted SARS-CoV-2 within households [81.9%, (95% CI: 72.1–91.9%) vs. 72.4% (95% CI: 59.8–85.1%), p = 0.23]. Household income and pets were significantly associated with higher SAR in the multivariable analysis of household factors (p = 0.0013 and 0.004, respectively).Conclusions: The SAR in households with children in an urban setting with a large ethnic minority population is much higher than previously described. Children play important roles as index cases. SAR was disproportionately impacted by household income. Vaccination and public health efforts need special focus on children and vulnerable communities to help mitigate SARS-CoV-2 spread.

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Background Age and obesity status are associated with severe outcomes among hospitalized individuals with COVID‐19. It remains unclear whether age and obesity are risk factors for milder COVID‐19 illness. Methods We prospectively enrolled SARS‐CoV‐2‐exposed individuals. Participants recorded symptoms for 28 days and were tested for SARS‐CoV‐2 by reverse transcription polymerase chain reaction (RT‐PCR) and serology. Type, number, and duration of symptoms and SARS‐CoV‐2 laboratory parameters were compared by age and obesity status. Results Of 552 individuals enrolled from June 2020 to January 2021, 470 (85.1%) tested positive for SARS‐CoV‐2 including 261 (55.5%) adults ≥18 years, 61 (13.0%) adolescents 12–17 years, and 148 (31.5%) children <12 years. Children had fewer symptoms (median 2 vs. 3, p < 0.001) lasting fewer days (median 5 vs. 7, p < 0.001) compared with adolescents/adults. Body mass index of 300 (63.8%) individuals classified with overweight or obesity (OWOB). Individuals with OWOB suffered more symptoms compared with individuals without OWOB (median 3 vs. 2, p = 0.037), including more cough and shortness of breath ( p = 0.023 and 0.026, respectively). Adolescents with OWOB were more likely to be symptomatic (66.7% vs. 34.2%, p = 0.008) and have longer respiratory symptoms (median 7 vs. 4 days, p = 0.049) compared with adolescents without OWOB. Lower RT‐PCR Ct values were found in children and symptomatic individuals compared with adolescent and adults and asymptomatic individuals, respectively ( p = 0.001 and 0.022). Conclusions Adolescents and adults with OWOB experience more respiratory symptoms from COVID‐19 despite similar viral loads. These findings underscore the importance of vaccinating individuals with OWOB.