December 03, 2014
2 min read

MERS spread linked to failures in infection control

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Gaps in infection control were largely responsible in numerous published incidents of health care-associated transmission of Middle East respiratory syndrome, or MERS, coronavirus, according to the results of a recent review.

Researchers from the Hellenic Center for Disease Control and Prevention in Athens, Greece, reviewed 252 published papers on the disease, choosing to focus on 11 events of possible or confirmed health care-associated transmission with high mortality and morbidity. They determined that “gaps in infection control were the common denominator in the events of health care-associated transmission,” adding that health care workers, particularly nurses, are at increased risk for MERS infection.

Since the virus was first isolated from a patient in Saudi Arabia in September 2012, MERS cases have been identified in 10 countries in the Middle East, Europe, Asia, Africa and the Americas, including the United States. In the spring, an upsurge of MERS cases in the Arabian Peninsula was attributed to nosocomial outbreaks. However, there are no data available to suggest a change in the virus’ transmissibility that would allow for sustained human-to-human transmission in hospitals, according to the researchers.

The largest recorded outbreak of MERS occurred in four health care facilities in Al-Hasa, Saudi Arabia, in 2013. The outbreak lasted 2 months and involved 34 cases, including two health care workers. The researchers said the Al-Hasa outbreak provided an opportunity to study several epidemiologic characteristics of the disease, including its incubation period (5.2 days; 95% CI, 1.92-14.7), serial interval (7.6 days; 95% CI, 2.5-23.1) and heterogeneity in transmission (eg, many infected patients did not transmit the infection while one infected patient transmitted the disease to seven others).

The outbreak also underscored the possibility of transmission through direct or even indirect contact. Recent data suggest the MERS virus remained stable for up to 2 days in environmental conditions similar to those in a hospital, and that its stability is unchanged by aerosolization. The researchers noted that the disease can be spread through vomiting and diarrhea, which are common in MERS patients; the virus has been detected using PCR for up to 16 days in stool and up to 13 days in urine. There is limited evidence regarding viral shedding and viral load kinetics, however, that would provide any useful guidance for infection control and prevention of MERS in the health care setting.

In the absence of vaccines or antiviral prophylaxis, the prevention and control of health care-associated MERS infections “relies solely on early detection, isolation and strict implementation of infection control measures,” the researchers said.

“Patients with confirmed or suspected [MERS] infection should be cared for under contact and droplet precautions until testing results,” they wrote.

WHO guidelines recommend wearing high protection masks, such as the N95 respirator, as well as eye goggles, gowns and gloves during aerosol-generating procedures. The CDC also recommends the use of these respirator masks when treating suspected or confirmed MERS patients, since airborne transmission cannot be ruled out.

“Overall, there is a need to increase infection control capacity in affected areas and areas at increased risk of being affected to prevent transmission in health care settings,” the researchers concluded.

Disclosure: The researchers report no relevant financial disclosures.