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January 27, 2014

Experts recommend an urgent collaborative study of treatment options for the Middle East respiratory syndrome

coronavirus (MERS-CoV), which has the potential to become a worldwide public health threat, according to a case

series published onlineJanuary 27 in theAnnals of Internal Medicine.

"In September 2012, a new coronavirus was isolated for the first time from a patient in Saudi Arabia, who presented

with acute pneumonia and renal failure," write Yaseen M. Arabi, MD, from the Intensive Care Department, College of

Medicine, King Saud bin Abdulaziz University for Health Sciences, Kingdom of Saudi Arabia, and colleagues. "Since

then, 170 laboratory-confirmed cases of infection with MERS-CoV have been reported to the World Health

Organization, including 72 deaths. The disease has a high fatality rate and has several clinical features that resemble

the infection caused by the severe acute respiratory syndrome coronavirus (SARS-CoV)."

Despite concern that MERS-CoV has the potential to cause a pandemic, data on critically ill patients with MERS-

CoV infection are limited. The goal of this case series was to describe the critical illness associated with MERS-CoV

At 3 intensive care units (ICUs) at 2 tertiary care hospitals in Saudi Arabia, the investigators tested 114 patientsbetween December 2012 and August 2013 and identified 12 with confirmed or probable MERS-CoV infection. They

collected data on patients' initial symptoms, comorbidities, pulmonary and extrapulmonary findings, illness severity,

organ failure, ICU course, and outcome. The investigators also reported surveillance results of healthcare workers

(HCWs) and patients with potential exposure.

MERS-CoV Infection Has High Mortality

Eleven patients (10%) met criteria for confirmed or probable cases, and 3 of these patients were part of a healthcare-

associated cluster that included 3 HCWs. The 12th patient in this case series was one of the HCWs who became

critically ill.

All 12 patients presented with acute severe hypoxemic respiratory failure and had underlying comorbid conditions.

The median Acute Physiology and Chronic Health Evaluation II score was 28 (range, 16 to 36). Most (92%) of the

case-patients experienced shock, acute kidney injury, thrombocytopenia, or other extrapulmonary manifestations. At

day 90, only 5 patients (42%) survived.

The investigators suggest that patients with chronic comorbid conditions are susceptible hosts for MERS-CoV.

Although only 4 (1%) of the 520 exposed HCWs tested positive for MERS-CoV, this did suggest human-to-human

transmission.

"MERS-CoV causes severe acute hypoxemic respiratory failure and considerable extrapulmonary organ dysfunctionand is associated with high mortality," the authors write. "Community-acquired and healthcare-associated MERS-

CoV infection occurs in patients with chronic comorbid conditions. The healthcare-associated cluster suggests that

human-to-human transmission does occur with unprotected exposure."

Limitations of this study include the case series design and small sample size.

Lessons Learned From SARS-CoV

In an accompanying editorial, Trish M. Perl, MD, from Johns Hopkins University School of Medicine and Bloomberg

School of Public Health in Baltimore, Maryland, and colleagues point out that lessons learned from SARS-CoV may

MERS-CoV May Become a Pandemic Threat, Experts WarnLaurie Barclay, MD

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8/13/2019 MERS-CoV May Become a Pandemic Threat

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apply to MERS-CoV, given many similarities in clinical presentation.

However, they note, preexisting chronic illness is more common in patients with severe MERS-CoVassociated

pneumonia than in those with SARS. Rates of diabetes, renal disease, and heart disease are 68%, 49%, and 28%,

respectively, in patients with MERS compared with 24%, 2.6%, and 10%, respectively, among those with SARS.

Case-control studies could help clinicians identify pertinent exposures and develop preventive strategies.

Given the high mortality, researchers will need to develop a range of effective treatments, such as antivirals,

convalescent serum therapy, and therapeutic drug options.

"Analysis to date suggests that MERS-CoV does not yet have pandemic potential," the editorialists write. "However,

we must keep in mind both the rapid evolution that occurred with SARS and the fact that it emerged in a much more

densely populated region. Given the right environment and a crowded part of the world, MERS-CoV might propagate

more readily."

It is still unknown whether MERS-CoV infection results from repeated introductions from an animal reservoir with

subsequent limited transmission in humans or from sustained human-to-human transmission, with most cases being

subclinical disease.

The editorialists note both the need for infection control practices and the paucity of data regarding virus

transmission. In fact, the Centers for Disease Control and Prevention and the World Health Organization disagree on

the need for airborne isolation, the editorialists write.

"Health careassociated MERS-CoV transmission to patients, workers, and visitors remains significant but is

underplayed," the editorialists conclude. "Focus on the health care setting may prevent continued human-to-human

transmission among at-risk patients. We applaud these brave authors for providing independent data and enhancing

the scientific collaborations that MERS-CoV has created. Globalization and emerging viruses combine to demand

new levels of scientific transparency and collaboration to effectively protect populations, a change we must all strive

to achieve."

This study received no primary funding. Full conflict-of-interest information is available on the journal's Web site for

both the articleand the editorial.

Ann Intern Med. Published online January 27, 2014.AbstractEditorial

Medscape Medical News 2014 WebMD, LLC

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Cite this article: MERS-CoV May Become a Pandemic Threat, Experts Warn. Medscape. Jan 27, 2014.

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