Pneumonia is the leading cause of hospital admission during the annual Islamic pilgrimage (Hajj). The etiology of severe pneumonia is complex and includes the newly emerged Middle East respiratory syndrome coronavirus (MERS-CoV). Since 2012, the Saudi Ministry of Health (MoH) has required screening for MERS-CoV for all cases of severe pneumonia requiring hospitalization. We aimed to screen Hajj pilgrims admitted to healthcare facilities in 2013 with severe community-acquired pneumonia (CAP) for MERS-CoV and to determine other etiologies.

Sputum samples were collected from all pilgrims admitted to 15 healthcare facilities in the cities of Makkah and Medina, Saudi Arabia, who were diagnosed with severe CAP on admission, presenting with bilateral pneumonia. The medical records were reviewed to collect information on age, gender, nationality, and patient outcome. Samples were screened for MERS-CoV by PCR, and a respiratory multiplex array was used to detect up to 22 other viral and bacterial respiratory pathogens.

Thirty-eight patients met the inclusion criteria; they were predominantly elderly (mean age 58.6 years, range 25–83 years) and male (68.4%), and all were from developing countries. Fourteen of the 38 patients died (36.8%). MERS-CoV was not detected in any of the samples. Other respiratory pathogens were detected in 26 (68.4%) samples. Of these, bacterial pathogens were detected in 84.6% (22/26) and viruses in 80.7% (21/26). Twenty-one (80.7%) samples were positive for more than one respiratory pathogen and 17 (65.3%) were positive for both bacteria and viruses. The most common respiratory virus was human rhinovirus, detected in 57.7% of the positive samples, followed by influenza A virus (23.1%) and human coronaviruses (19.2%). Haemophilus influenzae and Streptococcus pneumoniae were the predominant bacteria, detected in 57.7% and 53.8%, respectively, of the positive samples, followed by Moraxella catarrhalis (36.4%).

MERS-CoV was not the cause of severe CAP in any of the hospitalized pilgrims investigated. However we identified a variety of other respiratory pathogens in the sputum of this small number of patients. This indicates that the etiology of severe CAP in Hajj is complex with implications regarding its management.