Household Transmission of Severe Acute Respiratory Syndrome Coronavirus-2 in the United States

Abstract

Background Although many viral respiratory illnesses are transmitted within households, the evidence base for SARS-CoV-2 is nascent. We sought to characterize SARS-CoV-2 transmission within US households and estimate the household secondary infection rate (SIR) to inform strategies to reduce transmission. Methods We recruited laboratory-confirmed COVID-19 patients and their household contacts in Utah and Wisconsin during March 22–April 25, 2020. We interviewed patients and all household contacts to obtain demographics and medical histories. At the initial household visit, 14 days later, and when a household contact became newly symptomatic, we collected respiratory swabs from patients and household contacts for testing by SARS-CoV-2 rRT-PCR and sera for SARS-CoV-2 antibodies testing by enzyme-linked immunosorbent assay (ELISA). We estimated SIR and odds ratios (OR) to assess risk factors for secondary infection, defined by a positive rRT-PCR or ELISA test. Results Thirty-two (55%) of 58 households had evidence of secondary infection among household contacts. The SIR was 29% (n = 55/188; 95% confidence interval [CI]: 23–36%) overall, 42% among children (<18 years) of the COVID-19 patient and 33% among spouses/partners. Household contacts to COVID-19 patients with immunocompromised conditions had increased odds of infection (OR: 15.9, 95% CI: 2.4–106.9). Household contacts who themselves had diabetes mellitus had increased odds of infection (OR: 7.1, 95% CI: 1.2–42.5). Conclusions We found substantial evidence of secondary infections among household contacts. People with COVID-19, particularly those with immunocompromising conditions or those with household contacts with diabetes, should take care to promptly self-isolate to prevent household transmission.

Symptoms and Transmission of SARS-CoV-2 Among Children — Utah and Wisconsin, March–May 2020

“…In collaboration with state and local health departments and in the setting of public health emergency response, the U.S. Centers for Disease Control and Prevention (CDC) conducted a household transmission investigation during March-May 2020 in Milwaukee, Wisconsin, and Salt Lake City, Utah, metropolitan areas. Methods from the full investigation are available at Lewis et al 11 ; here, we describe a secondary analysis of the overall household transmission investigation focusing on details related to children in the households. In brief, we approached and enrolled a convenience sample of index case-patients with laboratory-confirmed SARSby guest on October 31, 2020 www.aappublications.org/news Downloaded from…”

“…Among adult contacts, 74% were between 18-49 years, and 49 (41%) had an underlying medical condition. A full description of household characteristics and mitigation measures in the household is available at Lewis et al 11 Prepublication Release ©2020 American Academy of Pediatrics…”

COVID ‐19, children and schools: overlooked and at risk

“…Some report lower attack rates in children compared with adults, 10,11 while others show no difference. [12][13][14][15] In a study of 58 United States households (58 index cases plus 188 household contacts), children and partners of index cases were more likely to be infected than other household members including siblings, parents and extended family members. 13 This suggests that children and adults may be similarly susceptible to infection, and that behavioural and environmental factors may underlie any difference in attack rate.…”

COVID-19 in Children: Looking Forward, Not Back

“…In this issue of Pediatrics, Laws and colleagues add to this body of literature with a secondary analysis of a previously reported household contact study. 1 They describe infection rates, transmission dynamics, and symptom profiles in a cohort of US children with household SARS-CoV-2 exposure between March and May 2020 in Milwaukee and Salt Lake City. 2 The authors found that secondary infection rates in household contacts was similar in children (19/68 contacts; 28%) and adults (36/120 contacts; 30%).…”