COVID-19 Outbreak in an Urban Hemodialysis Unit

Abstract

Rationale & objective: Hemodialysis patients are at increased risk for coronavirus disease 2019 (COVID-19) transmission due in part to difficulty maintaining physical distancing. Our hemodialysis unit experienced a COVID-19 outbreak despite following symptom-based screening guidelines. We describe the course of the COVID-19 outbreak and the infection control measures taken for mitigation.

Study design: Retrospective cohort study.

Setting & participants: 237 maintenance hemodialysis patients and 93 hemodialysis staff at a single hemodialysis center in Toronto, Canada.

Exposure: Universal screening of patients and staff for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Outcomes: The primary outcome was detection of SARS-CoV-2 in nasopharyngeal samples from patients and staff using reverse transcriptase-polymerase chain reaction (RT-PCR).

Analytical approach: Descriptive statistics were used for clinical characteristics and the primary outcome.

Results: 11 of 237 (4.6%) hemodialysis patients and 11 of 93 (12%) staff members had a positive RT-PCR test result for SARS-CoV-2. Among individuals testing positive, 12 of 22 (55%) were asymptomatic at time of testing and 7 of 22 (32%) were asymptomatic for the duration of follow-up. One patient was hospitalized at the time of SARS-CoV-2 infection and 4 additional patients with positive test results were subsequently hospitalized. 2 (18%) patients required admission to the intensive care unit. After 30 days' follow-up, no patients had died or required mechanical ventilation. No hemodialysis staff required hospitalization. Universal droplet and contact precautions were implemented during the outbreak. Hemodialysis staff with SARS-CoV-2 infection were placed on home quarantine regardless of symptom status. Patients with SARS-CoV-2 infection, including asymptomatic individuals, were treated with droplet and contact precautions until confirmation of negative SARS-CoV-2 RT-PCR test results. Analysis of the outbreak identified 2 index cases with subsequent nosocomial transmission within the dialysis unit and in shared shuttle buses to the hemodialysis unit.

Limitations: Single-center study.

Conclusions: Universal SARS-CoV-2 testing and universal droplet and contact precautions in the setting of an outbreak appeared to be effective in preventing further transmission.

Keywords: Coronavirus 2019 (COVID-19); asymptomatic infection; dialysis clinic; end-stage kidney disease (ESKD); hemodialysis; infection prevention; kidney failure; nasopharyngeal swabs; nosocomial transmission; outbreak; screening; severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Graphical abstract

Figure 1

Epidemic curve of the coronavirus disease 2019 (COVID-19) outbreak in the St. Michael’s Hospital hemodialysis unit. Abbreviations: NP, nasopharyngeal; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Figure 2

Infection control authorities concluded that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during an outbreak at the St. Michael’s Hospital hemodialysis unit was likely to have originated from 2 index cases. Patient 1 acquired the virus through an outbreak at a skilled nursing facility and hemodialysis staff 1 likely acquired the virus in the community. Subsequent transmission likely occurred from patient-to-patient interactions or indirectly through staff. Later transmission likely occurred through a shared shuttle bus service to and from dialysis despite implementation of universal droplet and contact precautions within the hemodialysis unit. Our hemodialysis unit is divided into a 2 separate rooms, each of which is further subdivided into 3 clusters of dialysis chairs referred to as pods. Dates on the arrows reflect the day of hypothesized transmission.