Discussion

In this single-center retrospective study of asymptomatic patients with positive SARS-CoV-2 admission tests, most patients who had a strand-specific RT-qPCR test lacked replicating virus and therefore were presumed to be noninfectious. Our findings support the discontinuation of admission testing of asymptomatic patients. Healthcare facilities should continue emphasizing other horizontal infection controls such as ventilation, vaccination, and early detection of symptomatic cases.

In this cohort, only 21 patients (9%) had detectable minus-strand RNA (range, 4%–25% per quarter) within 48 hours of their admission testing. The highest positivity (25%) correlated with the introduction of the SARS-CoV-2 Omicron variant. These findings agree with prior studies that identified positive SARS-CoV-2 RT-qPCR tests without the presence of culturable virus, indicating a lack of infectiousness. ^{Reference Bullard, Dust and Funk2,Reference Singanayagam, Patel and Charlett3} Additionally, as the prevalence of COVID-19 has declined due to widespread immunity from vaccination and previous infections, the positive predictive value of SARS-CoV-2 diagnostic testing among asymptomatic patients has also declined. Continued use of such testing in asymptomatic patients risks delays in care and unnecessary isolation due to clinical false-positive results. ^{Reference Srinivasan, Gohil and Abeles5} Furthermore, the severity of SARS-CoV-2 infection has dramatically decreased as a result of vaccination and past infection. ^{Reference Adjei, Hong and Molinari6} Fortunately, vaccination also appears to decrease the risk of long COVID ^{Reference Azzolini, Levi and Sarti7} and the available medications (eg, paxlovid) decrease the risk of progression toward severe disease and long COVID. ^{Reference Xie, Choi and Al-Aly8} These changes in both the epidemiology and the impact of SARS-CoV-2 infection have modified the public health paradigm from detecting and isolating every possible case to an approach aimed at preventing severe presentations. Along those lines, the Society for Healthcare Epidemiology of America (SHEA) has published a position statement recommending the suspension of asymptomatic diagnostic testing on hospital admission. ^{Reference Talbot, Hayden and Yokoe9} Although it remains uncertain whether asymptomatic testing may still be warranted on admission to hospital units caring for patients at high-risk of severe disease (eg, transplant or behavioral health units), at the current stage of the pandemic, prevention of transmission of SARS-CoV-2 in healthcare facilities should capitalize on other horizontal infection prevention measures such as vaccination, testing and isolation of symptomatic patients, and improved ventilation.

This study had several limitations. These patients were from a single center. We used electronic data abstraction, which can be subject to missing data, particularly regarding the presence or absence of symptoms, as well as if patients were pre-symptomatic (ie, in the early phase of their illness) rather than asymptomatic throughout. Also, patients who had strand-specific RT-qPCR tests may have had unmeasured characteristics, making them less likely to be infectious. Because ordering the strand-specific RT-qPCR test was at the discretion of the treating provider, some bias toward the null may remain. Furthermore, there has been debate in the literature regarding the optimal Ct value that is clinically relevant and reflects infectiousness. Finally, we used the absence of viral replication as a proxy for infectiousness, although the strand assay has not been validated against gold standard viral culture. ^{Reference Hogan, Huang and Sahoo4} The strengths of this study include the use of a novel method for evaluating SARS-CoV-2 infectiousness, a significant proportion of immunocompromised individuals (21%), and a long study period (August 2020–April 2022) that included multiple SARS-CoV-2 variant surges. Given the low rate of infectiousness among asymptomatic patients with a positive diagnostic SARS-CoV-2 test, our findings support the SHEA position statement to suspend the routine use of admission SARS-CoV-2 testing among asymptomatic patients. ^{Reference Talbot, Hayden and Yokoe9,Reference Alsuhaibani, Kobayashi and Trannel10}