Risk Factors for Middle East Respiratory Syndrome Coronavirus Infection Among Healthcare Personnel

Basem M. Alraddadi; Hanadi S. Al-Salmi; Kara Jacobs-Slifka; Rachel B. Slayton; Concepcion F. Estivariz; Andrew I. Geller; Hanan H. Al-Turkistani; Sanaa S. Al-Rehily; Haleema A. Alserehi; Ghassan Y. Wali; Abeer N. Alshukairi; Esam I. Azhar; Lia Haynes; David L. Swerdlow; John A. Jernigan; Tariq A. Madani

Disclosures

Emerging Infectious Diseases. 2016;22(11):1915-1920. 

In This Article

Results

Of 363 HCP eligible for the MICU (178 HCP), ED (137 HCP), and neurology unit (48 HCP) cohorts, 292 (80.4%) HCP were enrolled: 131 (73.5%) from the MICU, 127 (92.7%) from the ED, and 34 (70.8%) from the neurology unit. Of the 292 enrolled persons, 9 were excluded because serum specimens were unavailable.

For study participants who worked in units that treated MERS-CoV patients, the attack rate was 8.0% (20/250) and varied by hospital unit: MICU, 11.7% (15/128); ED, 4.1% (5/122). (The attack rate in the neurology unit, where no known MERS-CoV patients were treated, was 0% [0/33].) Attack rates in the MICU and ED also varied by occupation; radiology technicians had the highest attack rate (29.4% [5/17]), followed by nurses (9.4% [13/138]), respiratory therapists (3.2% [1/31]), and physicians (2.4% [1/41]). No clerical staff (7 participants) or patient transporters (14 participants) were seropositive. Most participants (64.4% [161/250]) were female; attack rate did not differ by sex (male 7.9%, female 8.1%; p = 0.95). The mean age of seropositive HCP was 40 years (range 29–59 years) and of seronegative HCP 37 years (range 18–66 years).

The most common manifestations of illness among case-HCP were muscle pain, fever, headache, and dry cough (Table 1). These signs and symptoms, along with shortness of breath, occurred significantly more often among seropositive than among seronegative HCP. Seropositive HCP were also more likely to report gastrointestinal symptoms (p<0.001). Of the 20 case-HCP, 3 (15%) were asymptomatic, 12 (60%) had mild illness (symptomatic illness not requiring hospital admission), 2 (10%) had moderate illness (required hospital admission but not mechanical ventilation), and 3 (15%) had severe illness (required mechanical ventilation). All case-HCP survived, and all had been previously tested for MERS-CoV by rRT-PCR of nasopharyngeal swab specimens, but only 5 (25%) rRT-PCRs were positive.

Nineteen (95%) of 20 case-HCP reported having been in the same room as or within 2 meters of a patient known to be infected with MERS-CoV. The 1 seropositive HCP who had no MERS-CoV patient contact reported being in an automobile with a symptomatic person subsequently confirmed to have MERS-CoV infection. We therefore limited our analysis of risk factors, including PPE use, to any study participant who reported direct contact (i.e., within 2 meters) with MERS-CoV patients in the hospital (Table 2 http://wwwnc.cdc.gov/EID/article/22/11/16-0920-T2.htm). Total time spent in a MERS-CoV patient's room or handling the patient's bedding, equipment, or fluids did not significantly differ between seropositive and seronegative HCP (p = 0.93), nor did the number of MERS-CoV patients cared for during the study period (median 3.0 and 5.0 patients for seropositive and seronegative HCP, respectively; p = 0.75). We found no association between animal contact and infection.

We assessed HCP's self-reported use of PPE during care of MERS-CoV patients, stratified by type of equipment and type of patient interaction (Table 3). HCP who reported always covering their nose and mouth with either a medical mask or N95 respirator had lower risk for infection than did HCP reporting not always or never doing so, although this association was statistically significant only among HCP present in the room where aerosol-generating procedures were conducted. HCP who reported always using a medical mask for direct patient contact were ≈3 times more likely to have MERS-CoV infection than were HCP who reported not always or never using a medical mask (98% of whom reported always or sometimes using an N95 respirator), a trend that was not statistically significant (p = 0.10). Conversely, those who reported always using N95 respirators for direct patient contact were less likely to be seropositive, a trend that approached statistical significance (p = 0.07).

Because medical mask and N95 respirator use were strongly and inversely correlated, we built separate multivariate models, one that assessed risk for medical mask use (model 1) and another that assessed risk for N95 respirator use (model 2). In both models, having participated in infection control training that included information about MERS-CoV prevention was associated with a significant and strong protective effect, and there was a strong but statistically insignificant trend toward increased risk among smokers. In model 1, HCP who reported always using a medical mask for direct MERS-CoV patient care were significantly more likely to be seropositive than those who reported not always or never wearing a medical mask (almost all of whom sometimes or always wore an N95 respirator) (relative risk [RR] 2.73, 95% CI 0.99–7.54). This model also included past or current smoking (RR 2.54, 95% CI 0.93–6.96) and participation in MERS-CoV infection control training (RR 0.28, 95% CI 0.10–0.80). In model 2, N95 respirator use was associated with a strong protective trend; HCP who always used an N95 respirator for direct MERS-CoV patient care were 56% less likely to be seropositive than were those who reported not always or never using an N95 respirator (almost all of whom sometimes or always wore a medical mask) (RR 0.44, 95% CI 0.15–1.24). This model also included past or current smoking (RR 2.51, 95% CI 0.92–6.87) and participation in MERS-CoV infection control training (RR 0.33, 95% CI 0.12–0.90).

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