Once the virus that causes COVID-19 gets into a nursing home, it can spread fast. Residents who go out for hemodialysis several times a week may face extra risk, because they mix with dialysis center staff and patients from the community. Benjamin F. Bigelow, Olive Tang and colleagues at Johns Hopkins, with CDC, investigated an April 2020 outbreak that bore this out.
The setting
"Facility A" was a 200-bed skilled nursing facility in Maryland for post-acute and long-term care, with an independently run dialysis center on site. In April 2020, about a quarter of Maryland's COVID-19 tests were positive and about half the state's nursing homes had active outbreaks.
| On April 16, 2020 | |
|---|---|
| Residents | 170, three-quarters in double rooms |
| Residents on dialysis | 32 (19%) |
| Dialysis schedule | Monday–Wednesday–Friday or Tuesday–Thursday–Saturday, three 4-hour shifts each |
| Share of the center's patients from facility A | 40%; the rest came from the community, on the same shifts |
Shifts overlapped, so residents waited in a shared waiting room. By April 1, under a governor's order, staff wore surgical masks, group activities and dining were canceled, visitors were banned, staff were screened for symptoms and fever before each shift, and residents were screened every 8 hours.
How the outbreak unfolded
- April 16: A resident on the Tuesday–Thursday–Saturday dialysis schedule developed a fever and malaise and tested positive. After a further dialysis session on April 18, the resident moved to a COVID-19 unit elsewhere.
- Week of April 20: The state tested 47 residents and 10 staff with symptoms; 11 residents and 3 staff were positive, two of the residents on the other dialysis schedule.
- April 21: The dialysis center tried to group patients into four cohorts by infection status on separate shifts, but scheduling forced some groups together. Patients often struggled to keep masks on through a whole session, and space didn't always allow machines to be 6 feet apart.
- April 30: A Johns Hopkins team, offering 24-hour results rather than the state's 3–5 days, tested 152 of 164 residents. It found 25 more infections: 12 of 29 remaining dialysis residents (41%) and 13 of 123 others (11%). 18 of those 25 (72%) had no symptoms.
- Two dialysis technicians later fell ill and tested positive in early May.
In all, 40 cases: 37 residents and 3 staff.
Dialysis residents fared worse
| Residents | On dialysis | Not on dialysis |
|---|---|---|
| Infected by April 30 | 15 of 32 (47%) | 22 of 138 (16%) |
| Hospitalized within 30 days (of those infected) | 8 of 15 (53%) | 4 of 22 (18%) |
| Died within 30 days (of those infected) | 6 of 15 (40%) | 6 of 22 (27%) |
The infection and hospitalization differences were statistically significant; the difference in deaths was not. Source: CDC, MMWR.
Infection was also more common on the second floor, where many dialysis residents lived. Residents on dialysis tend to have more of the conditions linked to severe COVID-19, such as diabetes, high blood pressure and heart disease.
Infections among facility A residents. Credit: CDC, MMWR.
Where did it start?
It could not be determined. Transmission could have happened in the nursing home, at the dialysis center — including the waiting room — or on the way between them, for instance in an elevator. The first cases were in dialysis residents, but with an incubation period of up to 14 days, delayed testing and many infections without symptoms, the source stayed unclear.
Control measures
The facility stopped new admissions from April 16 until May 8, grouped residents by test results, isolated all residents in their rooms during the outbreak, required protective equipment for caring for infected or observed residents, and scheduled infected dialysis residents separately. Limited testing meant asymptomatic staff and community dialysis patients weren't tested.
Lessons
- Communicate fast. If nursing homes promptly tell dialysis centers about infected or suspected residents, centers can cohort them — for example, dialyzing positive patients on the last shift of the day, followed by terminal cleaning. If centers tell nursing homes about infected community patients or staff, homes can test everyone and quarantine the exposed.
- Review the whole dialysis journey, from leaving the facility to returning: masks, distancing and ventilation in transport and waiting areas.
- Consider single rooms near the dialysis center for residents on dialysis, with closer monitoring.
- Watch residents who leave for outpatient care, a potentially overlooked route for the virus.
The investigation could not observe infection control in the dialysis center, assess other outside appointments, or test all asymptomatic staff.
Sources
Based on Bigelow BF, Tang O, Toci GR, et al., "Transmission of SARS-CoV-2 Involving Residents Receiving Dialysis in a Nursing Home — Maryland, April 2020," MMWR, Centers for Disease Control and Prevention; in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from www.cdc.gov
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