The recent study by Kevin Yau and colleagues published in AJKD describes a severe acute respiratory syndrome-corona virus 2 (SARS-CoV-2) outbreak in an urban hemodialysis unit that treats 237 patients with 93 staff and located in Toronto, Canada. The study is unique because the authors performed universal screening for SARS-CoV-2 with nasopharyngeal swab and reverse transcriptase-polymerase chain reaction (RT-PCR) testing and found positive tests in 4.6% of patients and 12% in dialysis staff.

Overall, 55% of the patients who tested positive were asymptomatic at the time of testing and 32% remained asymptomatic. This percentage of asymptomatic cases is much higher than the 20% of SARS-CoV-2 infected patients in the general population who are asymptomatic at the time of testing. After 30 days of testing, 18% of the SARS-CoV-2 infected patients required ICU admission but no deaths occurred.

In a similar report from Wuhan, China, 73 of 42 (88%) patients with positive SARS-CoV-2 tests showed no symptoms of COVID-19 or mild symptoms and 7% required ICU admission. The overall mortality rate in this group of patients receiving maintenance dialysis in Wuhan China was 5%.

Many dialysis facilities in the USA currently check temperature and perform symptom screening of patients and staff upon entry to the facility, but the study by Yau et al suggests these interventions may be ineffective at preventing the entry and spread of SARS-CoV-2 within a dialysis facility. Furthermore, contact tracing and investigation on 2 index cases showed evidence of nosocomial transmission within the dialysis unit or with shared transport to the dialysis facility.

Infection control authorities concluded that SARS-CoV-2 transmission during an outbreak at the St. Michael’s Hospital hemodialysis unit was likely to have originated from two 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-patient interactions or indirectly through staff. Later transmission likely occurred through a shared bus shuttle service to and from dialysis despite implementation of universal droplet and contact precautions within the hemodialysis unit. Our hemodialysis unit is divided into a two separate rooms, each which is further subdivided into three clusters of dialysis chairs referred to as pods. Dates on the arrows reflect the day of hypothesized transmission. Figure 2 from Yau et al, AJKD © National Kidney Foundation

Some large dialysis providers in the USA have created cohort units to facilitate separation of SARS-CoV-2 infected patients and persons under investigation. Separation of patients may not be feasible for small and independent dialysis providers. The study by Yau et al shows that patients with SARS-CoV-2 infection can be safely treated within the facility by identification of infected individuals and implementation of droplet and contact precautions and follow-up testing. The duration of precautions remains controversial.

Immunocompromised patients, including those receiving dialysis, may shed the virus for up to 20 days after a confirmed infection. Staff with SARS-CoV-2 infections in this study were required to self-quarantine at home, which is necessary but will stress staffing needs at an individual facility. This study also demonstrated the use of contact tracing to localize the source of spread of the infection and mitigate further spread of the virus.

This study provides hope that we can control the spread of SARS-CoV-2 and prevent COVID-19 among the most vulnerable patients. The use of personal protective equipment, face masks, and social distancing have clearly been demonstrated to slow the spread of this highly contagious virus. As we await a vaccine, this study by Yau et al shows that we should utilize universal testing and universal droplet and contact precautions to prevent the spread of SARS-CoV-2 within a dialysis facility.

– Post prepared by Anthony Valeri, AJKDBlog Guest Contributor. He is Professor of Medicine at Columbia University Vagelos College of Physicians and Surgeons.

To view Yau et al (FREE), please visit AJKD.org.

Title: COVID-19 Outbreak in an Urban Hemodialysis Unit
Authors: K. Yau, M.P. Muller, M. Lin, N. Siddiqui, S. Neskovic, G. Shokar, R. Fattouh, L.M. Matukas, W. Beaubien-Souligny, A. Thomas, J.J. Weinstein, J. Zaltzman, and R. Wald
DOI: 10.1053/j.ajkd.2020.07.001

In the face of the unprecedented public health crisis posed by the current pandemic, this special collection gathers COVID-19–related publications from the NKF family of journals. All articles in the collection are freely available.