MERS Clusters Under Investigation
- The first cluster of two cases, both fatal, occurred near Amman, Jordan, in April 2012. Stored samples from these two cases tested positive retrospectively for MERS-CoV. This cluster was temporally associated with cases of illness among workers in a hospital (2).
- A second cluster occurred in October 2012, in Saudi Arabia. Of the four individuals in the household, three were laboratory-confirmed cases, two of them died.
- In February 2013, a third cluster of three family members was identified in the United Kingdom. All three people tested positive for MERS-CoV. Among them, two died, and one recovered after experiencing a mild respiratory illness. This cluster provides evidence of person-to-person transmission of novel coronavirus. It also provides the first example of mild illness being associated with MERS-CoV infection.
- A fourth cluster among two family contacts occurred in Saudi Arabia in February 2013. One of the individuals died, and one recovered after experiencing a mild respiratory illness.
- In May 2013, a fifth geographic cluster was reported in Saudi Arabia and was initially linked to one healthcare facility. At least one of the cases was a family member contact. At least two of the cases were reported as not linked to the healthcare facility. Two healthcare providers in this cluster were infected after caring for patients who had MERS-CoV infection. A total of 24 cases have been reported in the cluster, of which 13 have died.
- A sixth cluster of two cases was reported in France in May 2013. One person became infected after sharing a hospital room with the country’s first infected person. The initial case died. He had a history of recent travel from the United Arab Emirates prior to becoming ill.
- A seventh family cluster among two laboratory-confirmed cases and one probable case was reported in Tunisia in May 2013. These were the first laboratory-confirmed cases in Africa.
- An eighth cluster of three cases was reported in Italy in May 2013. The index case had recently traveled from Jordan after a 40-day visit. Two more people were infected after having close contact with the index case.
The reservoir and route of transmission of MERS-CoV are still being investigated. Genetic sequencing to date has determined the virus is most closely related to coronaviruses detected in bats. CDC is continuing to collaborate with WHO and affected countries to better characterize the epidemiology of MERS-CoV infection in humans.