In May 2015, a Korean was diagnosed with Middle East respiratory syndrome (MERS) coronavirus (CoV) infection after travel to the Arabian Peninsula. Within 1 month, there was the largest outbreak outside the Middle East with 186 laboratory-confirmed MERS-CoV infections resulting in 36 fatalities.Reference Oh, Choe and Oh ¹ There were relatively few cases of MERS-CoV infection in patients requiring chronic hemodialysis. Here we report the precaution measures, hemodialysis methods, and outcomes of the contacted patients in our dialysis unit (DU).

At the time of the MERS outbreak in 2015, precaution measures were applied in our hospital. All visitors had their body temperatures monitored and were encouraged to perform hand hygiene before entering the hospital. If a person reported respiratory symptoms, such as cough, sputum, or dyspnea, a surgical mask was applied. Surgical masks were applied to all patients in the DU regardless of respiratory symptoms.

During the outbreak, 1 hemodialysis patient in our hospital was confirmed to have MERS-CoV infection. The beds in the DU are spaced approximately 1.2 meters apart without screens. During the hemodialysis sessions, 1 nurse usually cares for 6 patients, making both the patients and the healthcare providers (HCPs) vulnerable to the transmission of infectious diseases.

The patients and HCPs in the DU were isolated. Contact was classified according to the closeness and the timing of the contact. Grade 1 contact means that the person stayed within 2 meters of the index patient. Grade 2 contact means that the person stayed in the DU while the index patient was undergoing hemodialysis. Grade 3 contact means that the person stayed in the DU at different times but possibly contacted the index patient indirectly.

All hemodialysis patients were hospitalized in isolation rooms. For individual isolation hemodialysis (IIH), 25 hemodialyzers were installed in the inpatient wards. In the DU, 7–8 patients underwent cohort hemodialysis (CH) at 1 session. HCPs caring for those patients utilized contact and droplet precautions with level D personal protection equipment in accordance with World Health Organization recommendations, ² including waterproof disposable gowns, gloves, face shields or goggles, and N95 masks. After each hemodialysis sessions, DU and IIH rooms were disinfected.

Sputum or throat swab specimens were obtained for real-time reverse-transcriptase polymerase chain reaction (RT-PCR) testing. RT-PCR tests were performed for surveillance at the beginning and end of the isolation, and when the patient had symptoms possibly related to MERS. At 2 and 4 weeks after exposure, blood samples were collected for serologic testing for MERS-CoV.

A total of 104 patients and 18 HCPs were exposed to MERS-CoV in the DU. There were 92 patients undergoing regular hemodialysis and 12 peritoneal dialysis patients visiting the DU. Fifty patients underwent IIH and 42 patients underwent CH. During the CH sessions, the distances between the beds were extended to 2.5 meters. The patient characteristics are summarized in Table 1.

TABLE 1 Characteristics of 104 Patients in Study of MERS-CoV in Dialysis Unit

NOTE. Data are no. (%) of patients unless otherwise specified. CoV, coronavirus; HD, hemodialysis; MERS, Middle East respiratory syndrome; PCR, polymerase chain reaction; PD, peritoneal dialysis.

During the isolation, 23 patients (22.1%) developed symptoms possibly related to MERS. Two patients died of aspiration pneumonia during the isolation. RT-PCR test results of 23 patients with symptoms were all negative.

The results of RT-PCR surveillance were all negative. Serologic testing was performed in 84 patients who consented to the test and the results were negative in all patients.

Because hemodialysis patients must continue hemodialysis in the DU, complete isolation is more difficult and the risk of exposure to infectious diseases is increased. As a result, when one patient is diagnosed with an infection such as MERS, there is a high risk of transmission through possible continuous exposure within the DU. To our knowledge, ours is the first case of isolating hemodialysis patients with direct or indirect contact with MERS-CoV.

In our hospital, there were no additional MERS-CoV infections among 104 dialysis-dependent patients. We believe this was because the precaution measures and isolations were effective. During the MERS outbreak, we practiced intensified precaution measures for dialysis patients, given their increased susceptibility to infection.Reference Eleftheriadis, Liakopoulos, Leivaditis, Antoniadi and Stefanidis ^{3 ,} Reference Pitcher, Rao and Caskey ⁴ In a report from Saudi Arabia in 2013, there were 9 additional MERS-CoV infections in the DU from 1 confirmed patient without precaution measures.Reference Assiri, McGeer and Perl ⁵

There are some reports on the management of SARS in hemodialysis patients.Reference Wong, Mak and Lo ^{6 –} Reference Kwan, Leung and Szeto ⁸ But there are no data on the effect of precaution measures for hemodialysis patients who have contacted a SARS case. One study showed that surgical masks would be helpful for preventing transmission of SARS in patients in the DU.Reference Kao, Huang, Huang, Tsai, Hsieh and Wu ⁹ Though the World Health Organization recommended the N95 mask in the precaution measures for MERS, ² it can cause physiological stress. One Taiwanese study showed that wearing the N95 mask for 4 hours during hemodialysis significantly reduced P_aO₂ and increased adverse respiratory outcomes in hemodialysis patients.Reference Kao, Huang, Huang, Tsai, Hsieh and Wu ⁹

With a large number of patients exposed to an infection in the DU, isolation and IIH are practically impossible owing to limited space as well as device and HCP availability. We isolated and classified all patients. IIH was performed for patients with grade 1 exposure or those with symptoms possibly related to MERS. CH was performed for patients with grade 2 or 3 exposure and no symptoms possibly related to MERS. Because fewer patients stayed in the DU, we could maintain more space between the patients during CH, reducing the possibility of transmission.

IIH and CH were performed to prevent further transmission of MERS. Because there was no further infection, we could not determine whether this measure was effective or not.

During a MERS outbreak, surgical masks, appropriate hand hygiene, and body temperature monitoring would be useful as precaution measures for hemodialysis patients. In the case of confirmed MERS in the DU, IIH and CH would be the means of maximum isolation minimizing possible secondary transmission with limited facilities and manpower.