Citation
Qasmieh, Saba A.; Robertson, McKaylee M.; Rane, Madhura S.; Shen, Yanhan; Zimba, Rebecca; Picchio, Camila A.; Parcesepe, Angela M.; Chang, Mindy; Kulkarni, Sarah G.; & Grov, Christian, et al. (2022). The Importance of Incorporating At-Home Testing into SARS-COV-2 Point Prevalence Estimates: Findings from a U.S. National Cohort, February 2022. JMIR Public Health and Surveillance, 8(12), e38196. PMCID: PMC9822564Abstract
BACKGROUND: Passive case-based surveillance underestimates the true extent of active infections in the population due to undiagnosed and untested cases, the exclusion of probable cases diagnosed point-of-care rapid antigen tests, and/or the exclusive use of at-home rapid tests which are not reported as part of case-based surveillance. The extent in which COVID-19 surveillance may be underestimating the burden of infection is likely due to time-varying factors such as decreased test-seeking behaviors and increased access to and availability of at-home testing.OBJECTIVE: The objective of this study was to estimate the prevalence of SARS-CoV-2 based on different definitions of a case to ascertain the extent to which cases of SARS-CoV-2 may be underestimated by case-based surveillance.
METHODS: A survey on COVID-19 exposure, infection, and testing was administered to calculate point prevalence of SARS-CoV-2 among a diverse sample of cohort adults between 8-22 February 2022. Three-point prevalence estimates were calculated among the cohort 1) proportion positives based on PCR and/or rapid antigen tests, 2) proportion positive based on testing exclusively with rapid at-home tests, and 3) proportion of probable undiagnosed cases. Test positivity and prevalence differences across booster status were also examined.
RESULTS: Among a cohort of 4328, there were a total of 644 cases. The point prevalence estimate based on PCR and/or rapid antigen tests was 5.5% (95% CI: 4.8% - 6.2%), 3.7% (95% CI: 3.1%- 4.2%) based on at-home rapid tests and 5.7% (95% CI: 5.0% - 6.4%) based on the case definition of a probable case. The total point prevalence across all definitions was 14.9% (95% CI: 13.8% - 16.0%). The percent positivity among PCR and/or rapid tests was 50.2%. No statistically significant differences were observed in prevalence between participants with a COVID-19 booster compared to fully vaccinated and non-boosted participants except among exclusive at-home rapid testers.
CONCLUSIONS: Our findings suggest a substantial proportion of cases were missed by case-based surveillance systems during the Omicron BA.1 surge, when at-home testing was common. Point prevalence surveys may be a rapid tool to be used to understand SARS-CoV-2 prevalence and would be especially important during case surges to measure the scope and spread of active infections in the population.
URL
http://dx.doi.org/10.2196/38196Reference Type
Journal ArticleYear Published
2022Journal Title
JMIR Public Health and SurveillanceAuthor(s)
Qasmieh, Saba A.Robertson, McKaylee M.
Rane, Madhura S.
Shen, Yanhan
Zimba, Rebecca
Picchio, Camila A.
Parcesepe, Angela M.
Chang, Mindy
Kulkarni, Sarah G.
Grov, Christian
Nash, Denis