Increase in Middle East Respiratory Syndrome-Coronavirus Cases in Saudi Arabia Linked to Hospital Outbreak With Continued Circulation of Recombinant Virus, July 1–August 31, 2015

Assiri, Abdullah M.; Biggs, Holly M.; Abedi, Glen R.; Lu, Xiaoyan; Bin Saeed, Abdulaziz; Abdalla, Osman; Mohammed, Mutaz; Al-Abdely, Hail M.; Algarni, Homoud S.; Alhakeem, Raafat F.; Almasri, Malak M.; Alsharef, Ali A.; Nooh, Randa; Erdman, Dean D.; Gerber, Susan I.; Watson, John T.

There are limitations to this study. We were unable to determine transmission chains and locations of transmission among all cases linked to Hospital A, and we were unable to delineate transmission beyond the secondary level (eg, tertiary, etc). Additional cases linked to Hospital A outside of our defined study period were not included in the analysis; therefore, this is not a complete description of the Hospital A outbreak. We considered any contact with a healthcare setting during the exposure period a criterion for classification as a secondary case, regardless of whether MERS-CoV cases had been reported from the facility. In cases where proxies were used for telephone interviews, knowledge of the case-patient's activities during the exposure period may have been incomplete. Although we were able to obtain sequences from a small number of available specimens, additional sequences could have allowed a better understanding of links between cases. Our study was not designed to detect differences in virus transmissibility or virulence compared with previous outbreaks.