Middle East respiratory syndrome coronavirus - Kingdom of Saudi Arabia

MERS is a zoonotic viral respiratory disease caused by MERS-CoV, for which dromedary camels serve as the primary animal reservoir. Human infection can range from asymptomatic or mild illness to severe disease and death. Human infections continue to occur through direct or indirect exposure to infected dromedaries or their products, while limited human-to-human transmission has been documented, primarily among close contacts and in healthcare settings. Sustained community transmission has not been observed. No licensed vaccine for MERS-CoV exists to date.

As of 5 October 2026, WHO had been notified of 2643 laboratory-confirmed MERS cases globally, including 965 deaths, since the virus was first identified in 2012. The majority of cases (84%; 2232 cases and 870 deaths) have been reported from Saudi Arabia. These figures likely underestimate the true number of infections since mild and asymptomatic cases may remain undetected/unreported, while the reported case fatality of ratio of 37% may overestimate mortality among infections.

Although the number of reported MERS cases has declined substantially since 2020, MERS-CoV continues to circulate in dromedary camel populations in the Middle East and African regions and continues to cause sporadic human infections. The observed decline in reported MERS cases, in particular during the COVID-19 pandemic emergency phase, is thought to be a result of pandemic-related IPC measures that also limited human-to-human transmission of MERS-CoV, as well as behavioral changes during the pandemic. Any role of potential cross-reactive immunity from SARS-CoV-2 infection and/ or vaccination remains in need of further investigation. Other hypotheses—such as reduced surveillance, viral attenuation, or decreased circulation in camel populations—are not supported by current evidence.

WHO expects additional sporadic MERS cases to occur in countries where the virus circulates in camels and anticipates that travel-associated exportation of cases will continue. Delays in detection remain possible due to the clinical presentation of MERS being similar with other respiratory infections, including influenza and COVID-19. Numerous outbreaks in KSA and the Republic of Korea have demonstrated that primary cases can result in substantial secondary transmission, particularly in healthcare settings and through importation of travel related cases.

The notification of the recent cases in Saudi Arabia does not change WHO's overall risk assessment - the risk remains moderate at both the regional and global levels, reflecting the continued occurrence of sporadic zoonotic infections, the potential for healthcare-associated outbreaks and international exportation of cases, in the absence of sustained human-to-human transmission.

WHO continues to monitor the epidemiological situation through routine surveillance and reporting under the International Health Regulations (IHR 2005) and conducts ongoing risk assessments using available epidemiological and virological information.