A contactless method for monitoring household circulation of respiratory viruses was successfully implemented by researchers from the University of Washington and other institutions, and their results were published in Clinical Infectious Diseases.

Households (N=303) in the Seattle metropolitan area were recruited at elementary and middle schools to participate in this prospective longitudinal cohort study between November 2019 and April 2020. Households had a minimum of 3 individuals (including at least 1 child) living together at least 4 days per week.

Participants completed an online questionnaire, kept a weekly symptom log, and provided mid-turbinate nasal swabs when symptoms of an acute respiratory illness (ARI) were present. Samples were mailed at ambient temperature and tested for 24 respiratory pathogens.

The participants were living in households with a median size of 4 individuals (range, 3-7), 5% of households had an individual aged 65 years or older, 42% had a child under 5 years of age, and 67% had a child aged 5 to 12 years. Most households (87%) completed the weekly symptoms logs and submitted at least 1 nasal swab (70%). In total, 678 samples were collected from 477 individuals.

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Non-influenza virus was confirmed among 61% of households, and 87% of households had at least 1 infected sample. Families with children under 5 years of age were more likely to have had a non-influenza viral infection (52%) compared with households without confirmed infections (25%; P <.001), households with older children (aged 13-17 years; 14%; P <.001), or households with an older adult (aged 50-64 years; 12%; P <.001).

The most commonly detected viruses were human rhinovirus (n=86; 21.7 primary cases per 100 person-years [py]), human coronavirus (n=65; 19.3 primary cases per 100 py), and respiratory syncytial virus (n=19; 5.4 primary cases per 100 py). Coinfections were detected among 30 samples.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was detected among 4 samples in 3 households (1.4 primary cases per 100 py), and 1 individual had a secondary infection.

Respiratory syncytial virus symptoms were reported to last the shortest time (2.6 days) and adenovirus the longest (12.1 days).

This study may have been limited by the inconsistency around home collection of nasal swabs. Furthermore, 57% of the enrolled households reported earning more than $150,000 annually, so this study may not be generalizable to the average population.

The study authors concluded that a home-based longitudinal monitoring program of ARIs was feasible. This low-contact monitoring may be more important during the SARS-CoV-2 pandemic, especially for monitoring infections that did not require in-person medical care.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Emanuels A, Heimonen J, O’Hanlon J, et al. Remote household observation for non-influenza respiratory viral illness. Clin Infect Dis. 2020;ciaa1719. doi:10.1093/cid/ciaa1719.