COVID-19 Self-Test Data: Challenges and Opportunities — United States, October 31, 2021–June 11, 2022

During October 2021-May 2022, approximately 393 million self-tests were produced by the four manufacturers assessed in this study. Although not all self-tests produced by these manufacturers were distributed, purchased, and used, the 10.7 million results voluntarily reported by users and made available for public health surveillance likely reflect a small fraction of the number of self-tests used. This finding indicates that throughout the COVID-19 pandemic, including during the Omicron variant surge period (December 2021-February 2022) covered by this analysis (6,7), underascertainment of cases has occurred (5). Underascertainment might be attributed to multiple factors, including the lack of formal mechanisms to enable reporting of self-test results to public health authorities and persons with mild or no symptoms not seeking testing or health care.

Self-tests provide another option for persons seeking accessible testing and remain an important tool to guide individual decision-making and risk reduction. Mandating reporting of all self-test results to public health authorities is not practical and could negatively affect acceptability and use of self-tests, which would be detrimental to minimizing disease spread. Although the increase in self-testing (4) might result in underascertainment of total case counts, this analysis indicates that the NAAT data captured via CELR, combined with case data, remain robust and continue to track trends in community transmission.^††† In addition, persons with more severe disease are probably more likely to receive a NAAT when seeking care in outpatient or inpatient settings, and national surveillance primarily focuses on these cases. Furthermore, other types of surveillance data provide insights into aspects of disease burden such as demands on health care systems, highly or disproportionately affected populations, and severity indicators. Therefore, even without self-testing result data being formally included in national surveillance efforts, the integrated, whole-of-government surveillance activity for the COVID-19 pandemic^§§§ remains strong, incorporating data from various sources, including case surveillance, laboratory testing, syndromic surveillance, genomics testing, hospitalizations, health care use, supply chain capacities, school data, wastewater surveillance, vital statistics, and vaccination.

Current limitations in self-test data reduce their usefulness to guide public health decision-making. Cases based solely on positive self-test results do not meet national guidance for confirmed or probable cases because self-tests are not administered by Clinical Laboratory Improvement Amendments (CLIA)-certified providers (8). The quality of the specimen, execution of the self-test, result produced, and person tested are unverified in most instances; therefore, reported interpretation of results cannot be confirmed. Moreover, in contrast to NAATs, self-test specimens cannot be submitted for culturing and viral isolate characterization to identify or describe the prevalence of variants. Voluntary reporting is often anonymous and lacks information (e.g., telephone number) necessary for action, including deduplication, case investigation, or contact tracing. Finally, because of the similarity in trends for percentage of positive test results and demographic completeness across test types, self-test results are currently unlikely to enhance the ability to understand disease transmission trends.

Despite these limitations, public health experts need to continue evaluating self-test data to understand how they can be incorporated into future surveillance models. Additional analyses can explore several factors: how communities are using and reporting self-tests, equitable access to self-tests, what factors drive decisions to report results, and representativeness of findings; how often positive self-test results lead to isolation, pursuit of treatment, or confirmation of result with laboratory-based testing; and to what degree self-testing is replacing testing in more traditional settings.

Anticipating the potential importance of self-test data for public health and the growing demand to shift testing outside of care and to individual persons, federal agencies have been building relationships with test manufacturers to enable data transmission for public health use. For example, CDC, through partnerships with the U.S. Digital Service, the National Institutes of Health, the Administration for Strategic Preparedness and Response, and the Association of Public Health Laboratories, worked with manufacturers to advise on data to be collected and supported development of data reporting and data transportation capabilities and sharing of self-test data for broad public health use. In addition, the National Institutes of Health, through their RADx Mobile Application Reporting through Standards (MARS) program, is focusing on leveraging data standards to enhance data harmonization, capture, transmission, and reporting for self-tests for clinical and public health use.^¶¶¶ Furthermore, certain jurisdictions are leveraging anonymous exposure notification systems that use voluntarily reported test result information, including for self-tests, to notify close contacts of potential COVID-19 exposures.

The findings in this report are subject to at least two limitations. First, self-test data were available from only four manufacturers and from users who voluntarily reported results, representing only approximately 3% of the total self-tests produced by these manufacturers and 0.4% produced by all manufacturers during the period; therefore, these data might not be representative of all self-tests used. Second, data completeness was based on presence of any value and not valid values, and personally identifiable information assessment only captured data for a short period; therefore, estimates provided might not represent overall data quality.

Established surveillance based on NAAT testing is in place that can monitor trends in the spread and effects of COVID-19 within communities. However, during the COVID-19 pandemic, self-tests have become an important public health tool to guide individual decision-making. Persons who use self-tests should be encouraged to report results to their health care providers, who can ensure that they receive additional testing, counselling, and medical care, as clinically indicated. Limitations in currently available self-test data limit their value for present public health COVID-19 surveillance. Continued development of infrastructure and methods to collect and analyze self-test data could improve their value for surveillance purposes during future public health emergencies.