Infection Control & Hospital Epidemiology
Initial Test Result
Case No.
4 3 2
20 18 11 8
24 21 17 19 16 15 12 22 25 40 44 41 45 42 46 48 43 47
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Days from exposure to specimen collection
Fig. 3. Real-time reverse-transcription polymerase chain reaction (rRT-PCR) testing results from the date of exposure to the date of first rRT-PCR positive result for healthcare personnel (HCP) cases at hospitals A and B.
In addition, 2 secondary cases, cases 5 and 6, overlapped with
index patient A in the ED and were themselves associated with subsequent superspreading events (Table 2). Initially, case 6 was not identified as a contact of index patient A and was suspected to have had community exposure. However, later medical record review demonstrated overlap with index patient A during his initial ED visit for non-MERS illness on May 28. He subsequently visited an outpatient dialysis unit, followed by a second ED presentation with admission to hospital A on June 1. Case 6 was directly linked to 6 secondary cases: 1 patient at hospital A, 2 patients and 1 cleaner at the outpatient dialysis unit, and 2 household contacts. Molecular evidence showed that case 6 clustered with index A and other subsequent cases at hospital A. Case 5 was a known contact of index patient A in the ED,
where he stayed for 2 days before transfer to a medical ward (ward B). He remained on ward B for 3 days, where he developed respiratory distress and was intubated on June 1. On June 2, MERS was suspected, airborne precautions were implemented, and a sample was obtained for testing. MERS-CoV was confirmed on June 3, and the patient died the same day. Case 5 was linked to 10 subsequent cases on ward B, including 6 HCP (Fig. 2), 4 of whom were present during the intubation procedure on case 5. Of 17 HCP cases linked to hospital A, 10 were available for
interview and serum collection. All 10 interviewed HCP cases reported ≥1 symptom when tested for MERS-CoV, with most HCP cases reporting mild upper-respiratory symptoms and/or diarrhea; none developed severe illness, and all survived. Of these 10 available HCP, 9 reported prolonged, close contact with an unrecognized patient case before implementation of MERS-CoV IPC measures and with limited PPE use (Table 3). The remaining HCP case cared for a non-MERS patient in the same room as a MERS patient case. Of these 10 HCP cases, 4 reported having been in the same room as a patient case during intubation, and none reported wearing an N95 mask or a powered air purifying respirator (PAPR). Among the 10 interviewed HCP cases, the time from first
positive MERS-CoV result to serum collection was 55–61 days, and 1 was seropositive: a 32-year-old female who had reported
headache, muscle aches, and productive cough. Additionally, we interviewed and collected serum from 66 HCP contacts of cases; none were seropositive. Among all 15 HCP cases identified at hospital A and the
ambulance driver, 8 tested positive on their first rRT-PCR test, and among these 8, the median time from likely exposure to positive sample collection was 5.5 days (range, 3–11 days). The 8 HCP cases who did not test positive on their initial test, tested positive on a second or later test, with amedian time fromlikely exposure to first positive sample collection of 8 days (range, 5–12) (Fig. 3).
Hospital B and clinic C
Ten cases were identified at hospital B; index patient B and 9 HCP cases who reported direct contact with him. Index patient B was a 23-year-old butcher who slaughtered camels and contacted camel products. On May 28, he developed fever, cough, and rhinorrhea and presented to clinic C. He was discharged home but returned to clinic C 3 times over 4 days with worsening respiratory symptoms. On June 1, he was diagnosed with pneu- monia and cardiomegaly and was referred to hospital B, where he presented to the ED on June 2. He was not initially suspected to have MERS; however, a chest radiograph revealed bilateral infil- trates and additional history indicated camel contact. He was then placed on isolation precautions, and specimens were collected for MERS-CoV testing. He was intubated later that day after IPC measures for MERS-CoV had been implemented, including transfer to a negative pressure room. He died on June 3. At clinic C, index patient B had 15 HCP contacts, including 2
with close, prolonged contact; no rRT-PCR confirmed HCP-cases were documented at clinic C. Of 15 HCP contacts of index B, 14 (93%) were interviewed and had serum collected. Among these, 2 HCP were seropositive; both were physicians with initial inde- terminate rRT-PCR test results. Subsequent rRT-PCR testing was negative, and neither was recorded as a MERS case. Both cared for index B during multiple clinic visits and reported being within 1.5m of index patient B for <10 minutes. One reported no PPE use, and the other reported wearing gloves and a surgical mask.
Test Result Positive
Indeterminate Negative
83
HCW case
Negative Hospital B
Indeterminate Positive Negative Hospital A Positive
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