Frequent, inexpensive, and imperfect SARS-CoV-2 antigen home tests could contribute to pandemic control and be useful as part of a containment strategy. These findings were reported in a preprint article posted to medRxiv.
Investigators adapted a simple compartmental epidemic model to simulate SARS-CoV-2 spread, death, and associated costs in the US. The model included features, such as COVID-19 infection epidemiology, behavioral response to test availability, and test results, relying on officially published data on the disease. Financial consequences of SARS-CoV-2 and illness-associated costs were also included.
With no testing, the investigators projected that over a 60-day period, there would be 15 million infections, 125,000 deaths, $6.5 billion in inpatient charges, and $3.9 billion in lost productivity.
With weekly at home testing, over the same time period, these values would decrease to 11 million infections, 106,000 deaths, and $5.9 billion in inpatient charges. Weekly testing would, however, cause an increase in lost workdays, due to isolation from positive results, corresponding to $13.9 billion, partially offsetting lower inpatient costs.
Altogether, weekly testing would avert a cost per infection of $5400 and a cost per death of $1.1 million, indicating an exceptional cost value.
To assess whether at home testing would still be beneficial in worst-case-scenario situations, the investigators altered input parameters. In the case of poor compliance (25% participation; 25% isolation of positives; 33% rate of daily abandonment), 900,000 infections would still be prevented over 60 days. In the case of more expensive tests, $1.8 million per death would be still averted. In the scenario of poor test performance, an average member of the population would only spend 1.1 days in unnecessary isolation due to a false positive.
This model may have been limited by its input parameters, as the investigators reported their results were sensitive to assumptions.
These findings suggested that a nationwide rollout of inexpensive, home-based SARS-CoV-2 testing would help decrease disease spread and mortality. Further, the tests would result in large cost savings even for scenarios in which compliance was poor, tests were more expensive, and results were relatively inaccurate.
Paltiel A D, Zheng A, Sax P E. Clinical and economic impact of widespread rapid testing to decrease SARS-CoV-2 transmission. medRxiv. Published online February 8, 2021. doi:10.1101/2021.02.06.21251270