We thank Calbo and colleagues for highlighting the need to better understand the role of asymptomatic shedding in transmission of SARS-CoV-2 in health care settings. Our study focused on transmission of SARS-CoV-2 from asymptomatic and presymptomatic residents in a skilled nursing facility. As we noted, health care personnel with undetected infection probably contributed to transmission in this facility, but we could not document this because we were unable to test asymptomatic health care personnel as part of this investigation owing to limited testing resources at the time. Since that investigation, the CDC has provided guidance on testing strategies in nursing homes.¹ In addition, the CDC recommends universal source control in all health care settings to help prevent transmission from health care personnel with unrecognized SARS-CoV-2 infection.²

The data provided by Calbo et al. suggest important hypotheses about the role of patients and health care personnel with asymptomatic SARS-CoV-2 infection in ongoing transmission in acute care facilities, a setting that is distinct from the residential skilled nursing facility described in our article. Further studies may help to better quantify the benefit of active surveillance (including laboratory testing) when added to active symptom screening and universal source control in various health care settings.