The Middle East Respiratory Syndrome—How Worried Should We Be?

Perlman, Stanley

M iddle East respiratory syndrome-coronavirus (MERS-CoV) was initially isolated in September 2012 from a patient in Saudi Arabia who had developed a lethal infection characterized by pneumonia and renal failure (1) . A nearly identical virus was then isolated from a second Saudi Arabian patient with respiratory disease who had been flown to London for therapy. In retrospect, the first cases of MERS occurred in an extended family in Zarqa, Jordan, in April 2012. Virus was detected in two patients in that outbreak, but several other family members and health care workers developed respiratory disease. Virus was not isolated from these individuals. Renal failure was noted in some of the early reports, but it is not yet clear whether it was virus induced or occurred as a consequence of respiratory failure. Since those early days, several other clusters of infection have been identified, indicating that human-to-human transmission occurred, although spread may not be efficient (2) . The incubation time for patients with confirmed disease was 5.2 days (confidence interval, 1.9 to 14.7 days), according to one study (3) .