Rapid person-to-person transmission seen in SARS-like virus

Rapid person-to-person transmission seen in SARS-like virus
Rapid person-to-person transmission seen in SARS-like virus

HealthDay News -- Person-to-person transmission of the novel Middle East respiratory syndrome coronavirus (MERS-CoV) has been described in a cluster of health care-associated infections in Saudi Arabia, according to research published in the New England Journal of Medicine.

"Person-to-person transmission of MERS-CoV can occur in health care settings and may be associated with considerable morbidity," writes Abdullah Assiri, MD, from the Al-Faisal University in Riyadh, Saudi Arabia, and colleagues, adding that "surveillance and infection-control measures are critical to a global public health response."

In September 2012, the World Health Organization (WHO) reported two cases of severe community-acquired pneumonia caused by a novel human β-coronavirus, later named MERS-CoV.  The Saudi Arabian Ministry of Health subsequently requested that all patients with pneumonia requiring admission to the ICU be tested for MERS-CoV.

Since then, MERS-CoV has been identified as the cause of pneumonia in patients in Saudi Arabia, Qatar, Jordan, the United Kingdom, Germany, France, Tunisia, and Italy.  The natural host and reservoir of MERS-CoV remain unknown.

Between April 1 and May 23, 2013, researchers reviewed medical records and interviewed case patients in a cluster of 23 cases of health care-acquired MERS-CoV infection reported at a general hospital serving a semi-urban region in eastern Saudi Arabia. Most of the case patients were men, and the median age was 56.

They then proceeded to follow up with 217 household contacts of these patients.

The study defined a confirmed MERS-CoV infection in a patient if there was laboratory evidence of MERS-CoV and if the person had either fever and at least one respiratory symptom or two respiratory symptoms without another identifiable cause. Proximity to a household, family, or health care contact of a person with a confirmed case was also considered, as was the development of pneumonia.

Between April 14 and April 30, MERS-CoV infection was confirmed in nine persons who were undergoing hemodialysis at the hospital in a unit that placed patients in adjacent beds to one another, despite infection-control interventions, including monitoring of hand hygiene, enhancement of environmental cleaning, and use of protective masks, that were implemented on April 21.

Moreover, MERS-CoV infection developed in five adult family members who were hospital visitors, and in one health care worker on May 5 who was in contact with the patients.  Three days later, the infection developed in a nurse who had had face-to-face contact with the same health care worker.

Common symptoms included fever (in 87% of the patients) and cough (in 89%), whereas 35% presented with vomiting or diarrhea

Among patients in whom the illness progressed, the median time from the onset of symptoms to ICU admission was five days, the median time to the need for mechanical ventilation was seven days and the median time to death was 11 days .

As of June 12, 15 of the patients had died, six have recovered, and two are still hospitalized.

The identification of the symptoms and the fast rate of transmission and infection concerned the researchers, who labeled MERS-CoV as “similar to SARS” and urged healthcare providers to increase their measures.

“The current WHO recommendations for surveillance and control should be regarded as the minimum standards,” they opined, and recommended that "hospitals should use contact and droplet precautions and should consider the follow-up of persons who were in the same ward as a patient with MERS-CoV infection.”

The study noted that the episodes of transmission in this outbreak could be explained by assuming that patients were infectious only when they were symptomatic, although such a distinction would “not rule out transmission during the incubation phase or during asymptomatic infection.”


References

  1. Assiri A et al. NEJM. 2013; DOI: 10.1056/NEJMoa1306742.
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