The first case of MERS was reported in a 60-year-old man in Jeddah, Saudi Arabia in 2012.[14]Zaki AM, van Boheemen S, Bestebroer TM, et al. Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. N Engl J Med. 2012;367:1814-1820.
http://www.nejm.org/doi/full/10.1056/NEJMoa1211721#t=article
http://www.ncbi.nlm.nih.gov/pubmed/23075143?tool=bestpractice.com
The patient died from severe pneumonia and multi-organ failure. Since then, many cases and clusters have been reported with the majority of infections acquired in the Arabian Peninsula and its surrounding countries, most commonly Saudi Arabia, the United Arab Emirates (UAE), Oman, Qatar, and Jordan.
Cases associated with travel from these countries have been limited to small clusters of a few individuals,[15]Puzelli S, Azzi A, Santini MG, et al. Investigation of an imported case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in Florence, Italy, May to June 2013. Euro Surveill. 2013;18:20564.
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20564
http://www.ncbi.nlm.nih.gov/pubmed/23987829?tool=bestpractice.com
[16]Kraaij-Dirkzwager M, Timen A, Dirksen K, et al. Middle East respiratory syndrome coronavirus (MERS-CoV) infections in two returning travellers in the Netherlands, May 2014. Euro Surveill. 2014;19:20817.
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20817
http://www.ncbi.nlm.nih.gov/pubmed/24906375?tool=bestpractice.com
[17]Guery B, Poissy J, el Mansouf L, et al. Clinical features and viral diagnosis of two cases of infection with Middle East Respiratory Syndrome coronavirus: a report of nosocomial transmission. Lancet. 2013;381:2265-2272.
http://www.ncbi.nlm.nih.gov/pubmed/23727167?tool=bestpractice.com
[18]Abroug F, Slim A, Ouanes-Besbes L, et al. Family cluster of Middle East respiratory syndrome coronavirus infections, Tunisia, 2013. Emerg Infect Dis. 2014;20:1527-1530.
http://www.ncbi.nlm.nih.gov/pubmed/25148113?tool=bestpractice.com
except for one large outbreak of 186 reported cases in the Republic of Korea (South Korea) in 2015,[19]Lee SI. Costly lessons from the 2015 Middle East respiratory syndrome coronavirus outbreak in Korea. J Prev Med Public Health. 2015;48:274-276.
https://www.jpmph.org/journal/view.php?doi=10.3961/jpmph.15.064
http://www.ncbi.nlm.nih.gov/pubmed/26639740?tool=bestpractice.com
[20]Hui DS, Perlman S, Zumla A. Spread of MERS to South Korea and China. Lancet Respir Med. 2015;3:509-510.
http://www.ncbi.nlm.nih.gov/pubmed/26050550?tool=bestpractice.com
[21]Ha KM. A lesson learned from the MERS outbreak in South Korea in 2015. J Hosp Infect. 2016;92:232-234.
http://www.ncbi.nlm.nih.gov/pubmed/26601605?tool=bestpractice.com
and one superspreader event in Riyadh (Saudi Arabia) in 2017 where 44 cases were linked to one patient who presented with acute renal failure.[11]Amer H, Alqahtani AS, Alzoman H, et al. Unusual presentation of Middle East respiratory syndrome coronavirus leading to a large outbreak in Riyadh during 2017. Am J Infect Control. 2018 Apr 13. pii: S0196-6553(18)30146-9.
http://www.ncbi.nlm.nih.gov/pubmed/29661625?tool=bestpractice.com
Two cases were reported in the US in 2014, both in travellers from Saudi Arabia.[22]Centers for Disease Control and Prevention. MERS in the US. September 2017 [internet publication].
http://www.cdc.gov/coronavirus/mers/us.html
There have been no cases reported in the US since. Five laboratory-confirmed cases have been reported in the UK since 2012, with the latest reported in August 2018.[23]Public Health England. MERS-CoV case in England. August 2018 [internet publication].
https://www.gov.uk/government/news/mers-cov-case-in-england
Other countries with travel-associated cases include France, Italy, Greece, Turkey, Lebanon, Germany, Austria, Netherlands, China, Malaysia, Thailand, Philippines, and Egypt. A case was reported in the Republic of Korea in September 2018 in a Korean national who visited Kuwait and returned to Korea via Dubai. Twenty-one contacts are currently under active surveillance.[24]World Health Organization. Disease outbreak news. Middle East respiratory syndrome coronavirus (MERS-CoV) infection – Republic of Korea. September 2018 [internet publication].
http://www.who.int/csr/don/12-september-2018-mers-republic-of-korea/en/
As of the end of August 2018, 2248 laboratory-confirmed cases, including 798 deaths (35.5% case fatality rate), were reported globally since 2012 across 27 countries. The majority of these cases were reported from Saudi Arabia (1871 cases). The 50-59 years age group is at highest risk for acquiring primary infection.[25]World Health Organization. MERS situation update. August 2018 [internet publication].
http://www.emro.who.int/pandemic-epidemic-diseases/mers-cov/mers-situation-update-august-2018.html
World Health Organization (WHO): disease outbreak news
external link opens in a new window
Ninety-eight percent of cases have been reported in adults (defined as age >14 years).[8]Assiri A, Al-Tawfiq JA, Al-Rabeeah AA, et al. Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. Lancet Infect Dis. 2013;13:752-761.
http://www.ncbi.nlm.nih.gov/pubmed/23891402?tool=bestpractice.com
Although infection has been reported in different age groups within the adult population, the median age of patients ranges from 50 to 67 years of age.[4]WHO MERS-CoV Research Group. State of knowledge and data gaps of Middle East respiratory syndrome coronavirus (MERS-CoV) in humans. PLoS Curr. 2013;5.
http://currents.plos.org/outbreaks/article/state-of-knowledge-and-data-gaps-of-middle-east-respiratory-syndrome-coronavirus-mers-cov-in-humans-2/
http://www.ncbi.nlm.nih.gov/pubmed/24270606?tool=bestpractice.com
[9]Al-Tawfiq JA, Hinedi K, Ghandour J, et al. Middle East respiratory syndrome coronavirus: a case-control study of hospitalized patients. Clin Infect Dis. 2014;59:160-165.
https://academic.oup.com/cid/article/59/2/160/2895452/Middle-East-Respiratory-Syndrome-Coronavirus-A
http://www.ncbi.nlm.nih.gov/pubmed/24723278?tool=bestpractice.com
[26]Omrani AS, Saad MM, Baig K, et al. Ribavirin and interferon alfa-2a for severe Middle East respiratory syndrome coronavirus infection: a retrospective cohort study. Lancet Infect Dis. 2014;14:1090-1095.
http://www.ncbi.nlm.nih.gov/pubmed/25278221?tool=bestpractice.com
Age ≥50 years is associated with a higher risk of mortality.[5]Shalhoub S, Farahat F, Al-Jiffri A, et al. IFN-alpha-2a or IFN-beta-1a in combination with ribavirin to treat Middle East respiratory syndrome coronavirus pneumonia: a retrospective study. J Antimicrob Chemother. 2015;70:2129-2132.
http://www.ncbi.nlm.nih.gov/pubmed/25900158?tool=bestpractice.com
[27]Saad M, Omrani AS, Baig K, et al. Clinical aspects and outcomes of 70 patients with Middle East respiratory syndrome coronavirus infection: a single-center experience in Saudi Arabia. Int J Infect Dis. 2014;29:301-306.
http://www.ijidonline.com/article/S1201-9712(14)01622-1/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/25303830?tool=bestpractice.com
In one cohort study, mortality increased with increasing age to reach 75% in patients >60 years of age.[8]Assiri A, Al-Tawfiq JA, Al-Rabeeah AA, et al. Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. Lancet Infect Dis. 2013;13:752-761.
http://www.ncbi.nlm.nih.gov/pubmed/23891402?tool=bestpractice.com
The majority of cases occur in males.[25]World Health Organization. MERS situation update. August 2018 [internet publication].
http://www.emro.who.int/pandemic-epidemic-diseases/mers-cov/mers-situation-update-august-2018.html
Infection in children is rare, although the reason for this is unknown.[12]Memish ZA, Al-Tawfiq JA, Assiri A, et al. Middle East respiratory syndrome coronavirus disease in children. Pediatr Infect Dis J. 2014;33:904-906.
http://www.ncbi.nlm.nih.gov/pubmed/24763193?tool=bestpractice.com
[13]Khuri-Bulos N, Payne DC, Lu X, et al. Middle East respiratory syndrome coronavirus not detected in children hospitalized with acute respiratory illness in Amman, Jordan, March 2010 to September 2012. Clin Microbiol Infect. 2014;20:678-682.
http://www.clinicalmicrobiologyandinfection.com/article/S1198-743X(14)61157-5/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/24313317?tool=bestpractice.com
The majority of cases are a result of human-to-human transmission rather than camel-to-human transmission, with peaks of confirmed cases occurring during nosocomial outbreaks.[6]Oboho IK, Tomczyk SM, Al-Asmari AM, et al. 2014 MERS-CoV outbreak in Jeddah - a link to health care facilities. N Engl J Med. 2015;372:846-854.
http://www.nejm.org/doi/full/10.1056/NEJMoa1408636#t=article
http://www.ncbi.nlm.nih.gov/pubmed/25714162?tool=bestpractice.com
[7]Assiri A, McGeer A, Perl TM, et al. Hospital outbreak of Middle East respiratory syndrome coronavirus. N Engl J Med. 2013;369:407-416.
http://www.nejm.org/doi/full/10.1056/NEJMoa1306742#t=article
http://www.ncbi.nlm.nih.gov/pubmed/23782161?tool=bestpractice.com
[28]Alenazi TH, Al Arbash H, El-Saed A, et al. Identified transmission dynamics of Middle East respiratory syndrome coronavirus infection during an outbreak: implications of an overcrowded emergency department. Clin Infect Dis. 2017;65:675-679.
http://www.ncbi.nlm.nih.gov/pubmed/28575307?tool=bestpractice.com
Transmission has been well documented in family clusters.[18]Abroug F, Slim A, Ouanes-Besbes L, et al. Family cluster of Middle East respiratory syndrome coronavirus infections, Tunisia, 2013. Emerg Infect Dis. 2014;20:1527-1530.
http://www.ncbi.nlm.nih.gov/pubmed/25148113?tool=bestpractice.com
[29]Rubin LG, Levin MJ, Ljungman P, et al. 2013 IDSA clinical practice guideline for vaccination of the immunocompromised host. Clin Infect Dis. 2014;58:309-318.
https://academic.oup.com/cid/article/58/3/309/340555/Executive-Summary-2013-IDSA-Clinical-Practice
http://www.ncbi.nlm.nih.gov/pubmed/24421306?tool=bestpractice.com
[30]Memish ZA, Zumla AI, Al-Hakeem RF, et al. Family cluster of Middle East respiratory syndrome coronavirus infections. N Engl J Med. 2013;368:2487-2494.
http://www.nejm.org/doi/full/10.1056/NEJMoa1303729#t=article
http://www.ncbi.nlm.nih.gov/pubmed/23718156?tool=bestpractice.com
However, it has been reported more commonly in nosocomial outbreaks (e.g., haemodialysis units, intensive care units, medical wards).[6]Oboho IK, Tomczyk SM, Al-Asmari AM, et al. 2014 MERS-CoV outbreak in Jeddah - a link to health care facilities. N Engl J Med. 2015;372:846-854.
http://www.nejm.org/doi/full/10.1056/NEJMoa1408636#t=article
http://www.ncbi.nlm.nih.gov/pubmed/25714162?tool=bestpractice.com
[7]Assiri A, McGeer A, Perl TM, et al. Hospital outbreak of Middle East respiratory syndrome coronavirus. N Engl J Med. 2013;369:407-416.
http://www.nejm.org/doi/full/10.1056/NEJMoa1306742#t=article
http://www.ncbi.nlm.nih.gov/pubmed/23782161?tool=bestpractice.com
[30]Memish ZA, Zumla AI, Al-Hakeem RF, et al. Family cluster of Middle East respiratory syndrome coronavirus infections. N Engl J Med. 2013;368:2487-2494.
http://www.nejm.org/doi/full/10.1056/NEJMoa1303729#t=article
http://www.ncbi.nlm.nih.gov/pubmed/23718156?tool=bestpractice.com
[31]Omrani AS, Matin MA, Haddad Q, et al. A family cluster of Middle East Respiratory Syndrome Coronavirus infections related to a likely unrecognized asymptomatic or mild case. Int J Infect Dis. 2013;17:e668-e672.
http://www.ijidonline.com/article/S1201-9712(13)00225-7/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/23916548?tool=bestpractice.com
[32]Memish ZA, Cotten M, Watson SJ, et al. Community case clusters of Middle East respiratory syndrome coronavirus in Hafr Al-Batin, Kingdom of Saudi Arabia: a descriptive genomic study. Int J Infect Dis. 2014;23:63-68.
http://www.ijidonline.com/article/S1201-9712(14)01451-9/fulltext
http://www.ncbi.nlm.nih.gov/pubmed/24699184?tool=bestpractice.com
[33]Al-Abdallat MM, Payne DC, Alqasrawi S, et al. Hospital-associated outbreak of Middle East respiratory syndrome coronavirus: a serologic, epidemiologic, and clinical description. Clin Infect Dis. 2014;59:1225-1233.
https://academic.oup.com/cid/article/59/9/1225/419021/Hospital-Associated-Outbreak-of-Middle-East
http://www.ncbi.nlm.nih.gov/pubmed/24829216?tool=bestpractice.com
[34]Shehata MM, Gomaa MR, Ali MA, et al. Middle East respiratory syndrome coronavirus: a comprehensive review. Front Med. 2016;10:120-136.
http://www.ncbi.nlm.nih.gov/pubmed/26791756?tool=bestpractice.com