SARS-CoV-2 Transmission Dynamics in Households With Children, Los Angeles, California

Abstract

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.

Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status

“…We identified 2097 records (1791 from PubMed, 306 from medRxiv, and 2 from reference lists of eligible articles) published between June 18, 2021, and March 8, 2022 (eFigure 1 in the Supplement ). Fifty-eight new studies 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 (eTable 2 in the Supplement ) were combined with 77 studies from ou...…”

“…Fifty-eight new studies 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 (eTable 2 in the Supplement ) were combined with 77 studies from our previous review 1 (see eTable 3 in the Supplement for references included from our previous review), with…”

Twelve-Month Longitudinal Serology in SARS-CoV-2 Naïve and Experienced Vaccine Recipients and Unvaccinated COVID-19-Infected Individuals

“…Participants were enrolled into one of two COVID-19 cohorts in Los Angeles, CA from Children’s Hospital Los Angeles (CHLA) and nearby community SARS-CoV-2 testing sites using a convenience recruitment strategy. Individuals were enrolled in the Household Exposure and Respiratory Virus Transmission and Immunity Study (HEARTS) if they were exposed to a household member who tested positive for SARS-CoV-2 by RT-PCR within 2 weeks [ 29 ]. Only those who tested positive for SARS-CoV-2 were included in the analyses described here.…”

We need more support and less normalcy to stop airborne viruses

“…And the data reflect this as well. In a study of low income, primarily Hispanic families, household transmission of SARS-CoV-2 was found to be much higher than in most other studies examining the general population; and risk of disease spread was associated with lower household incomes 5…”