Chronic hemodialysis is a life-sustaining therapy, delivered mostly thrice weekly in dialysis clinics. For patients on dialysis who appear to have a heightened likelihood of severe infection or death from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), travel to these facilities and proximity to fellow patients and health care providers during hemodialysis may pose an increased risk for SARS-CoV-2 infection. To prevent contagion, dialysis providers have implemented several interventions. Our goal was to better understand the dynamics of SARS-CoV-2 spread among patients on hemodialysis compared with the general population in the United States.

We used aggregated daily counts of confirmed coronavirus disease 2019 (COVID-19) cases for the general population in the United States1 and from Fresenius Medical Care North America, a large dialysis provider in the country, from March 1 to July 29, 2020. Following screenings in dialysis units, patients showing any relevant signs and symptoms or who had exposure to an infected person underwent nasopharyngeal or oropharyngeal swabs for RT-PCR testing for SARS-CoV-2. All patients included in the study were receiving in-center hemodialysis; patient characteristics are shown in Table 1. The time-varying reproduction number Rt, which represents the expected number of secondary cases arising from each new infectious individual at a particular time, was calculated using the method of Thompson et al.2 Rt is estimated from daily cases and an uncertain serial interval with a mean of 4.7 days (SD of 2.9 days) and a 14-day moving average.