Differences in MERS Epidemiology in the Middle East and South Korea
Received: 15-Feb-2018 / Accepted Date: 22-Feb-2018 / Published Date: 26-Feb-2018 DOI: 10.4172/2161-0711.1000592
Abstract
The majority of Middle East Respiratory Syndrome (MERS) cases have occurred in the Middle East and South Korea. MERS transmission and severity has shown different patterns in those areas. Viral, host, and environmental factors may be the cause of such differences. The MERS virus in South Korea has exhibited higher genetic variability and mutation rates compared with in the Middle East. Host factors including race, population structure, and health behavior may also relate to the differences in outbreaks. Finally, characteristics of the transmission environment, including factors such as hospital systems and population density, could contribute. This article reviews the factors associated with the different attributes of MERS outbreaks in the two regions.
Keywords: Middle east respiratory syndrome; Epidemiology transmission; Environmental factors
Short Communication
Middle East Respiratory Syndrome (MERS) was first reported in Saudi Arabia [1], and most cases have occurred in the Middle East [2]. In 2015, a MERS outbreak took place in South Korea [3], which has been the only outbreak to date outside of the Middle East [2].
MERS transmission patterns and severity differed between the Middle East and South Korea outbreaks. Although Middle East studies reported 0.42-4% attack rates, attack rates in South Korea were 4-6% for patients or hospital visitors [4] and 14-16% overall [5]. However, mortality from MERS was higher in Middle East (25-40%) [6-8] than in South Korea (20.4%) [9].
Viral, host, and environmental factors may be responsible for MERS outbreak-related differences between the two regions. Therefore, in this review, the author analyzed differences in viral, host, and environmental factors related to MERS outbreak between the Middle East (focusing on Saudi Arabia, which has the highest number of MERS cases) and South Korea.
Concerning viral factors, South Korean MERS coronavirus (MERSCoV) strains showed higher genetic variability and mutation rates [10]. Another study reported Korean MERS-CoV strains had a mutation in the receptor-binding domain, which could cause reduced affinity to the human cognate receptor [11]. Severe acute respiratory syndrome (SARS), another CoV, also showed a moderate mutation rate [12] and genetic mutations were related to temporal or geographic characteristics of disease epidemic [13]. Similarly, mutation of MERSCoV could be responsible for differences in outbreak patterns in South Korea and the Middle East.
Host factors also varied between the Middle East and South Korea, including race, population structure, and behavior. Differences in host antiviral response according to ethnicity have been reported in several infectious diseases including hepatitis C [14] and pandemic H1N1 influenza [15]. Likewise, it is possible that differences in MERS epidemiology in the Middle East and South Korea are attributable to ethnicity, although the effect of ethnicity on MERS infection has not yet been analyzed, excluding one study that showed a significant difference in risk of MERS infection by nationality [16].
In addition, the proportion of the aged population in the two areas may explain differences in MERS epidemics. Previous studies reported that older age was related to MERS infection [16] and mortality [17,18]. Chen et al. showed that the mean age of MERS patients in South Korea was significantly older than that of MERS patients in Saudi Arabia [19]. In Saudi Arabia, the average life expectancy is 74.6 years and adults >65 years comprise only 2.8% of the total population [20]. Conversely, in South Korea, the average life expectancy is 82.4 years, and approximately 17.7% of the population is older than 65 years [21]. This difference in the proportion of aged individuals might be related to the high attack rate in South Korea compared with Saudi Arabia.
Additionally, individual behavior could affect MERS epidemiology. Choi et al. showed that preventive behaviors were associated with perceived risk, knowledge, age, and sex [22]. Individuals aware of MERS were more likely to practice preventive behavior [23], and awareness of MERS was also influenced by factors such as sex, education [24], and nationality [25]. Although no report has compared the level of awareness or preventive behaviors between Saudi Arabia and South Korea, differences in demographic characteristics and perceived risk might affect patients’ preventive behavior.
Finally, the transmission environment could also contribute to differences in MERS epidemiology. Compared with MERS in Saudi Arabia, which demonstrated only 13.3% of cases were related to hospital-linked history [19], the outbreak in South Korea involved intra-hospital and hospital-to-hospital transmission [3,26]. In a previous study describing structural factors of the MERS outbreak in South Korea, overcrowding of emergency rooms and inadequate infection control in hospitals were considered the main reasons [27].
The higher population density in Korea (509 persons/km2 overall, >16,000 persons/km2 in Seoul) [21] compared with Saudi Arabia (15 persons/km2) [20] also seemed to contribute to spreading of the MERS outbreak, since population density is related to infectious disease outbreak [28,29]. However, the proportion of cases linked to community transmission was significantly lower in South Korea compared with Saudi Arabia [19]. Whether this was caused by the small effect of population density or other factors, such as quarantine and school closure, remains unclear.
Oh noted super-spreaders as a key factor of the MERS outbreak in South Korea [30]. Approximately 83.2% of MERS cases in South Korea were associated with five super-spreading events [9]. Recent studies have shown the involvement of super-spreaders in other infectious diseases such as Ebola and SARS [31]. Although a previous study demonstrated that a MERS outbreak related to a healthcare facility occurred in Jeddah, Saudi Arabia in 2014 [32], the existence of superspreaders was not reported outside of South Korea. Several studies reported high body temperature, multiple pulmonary infiltrates, longer non-isolated in-hospital stay [33], and hospitalization or emergency room visit before isolation [34] as risk factors of a super-spreader. Factors associated with super-spreading events must be analyzed in further studies.
Acknowledgments
This work was supported by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIP) (No. CRC-16-01-KRICT) and Korea Institute of Oriental Medicine (G17273).
References
- Zaki AM, van Boheemen S, Bestebroer TM, Osterhaus AD, Fouchier RA (2012) Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. N Engl J Med 367: 1814-1820.
- Ki M (2015) 2015 MERS outbreak in Korea: Hospital-to-hospital transmission. Epidemiol Health 37: e2015033.
- Cho SY, Kang JM, Ha YE, Park GE, Lee JY, et al. (2016) MERS-CoV outbreak following a single patient exposure in an emergency room in South Korea: An epidemiological outbreak study. Lancet 388: 994-1001.
- Park SH, Kim YS, Jung Y, Choi SY, Cho NH, et al. (2016) Outbreaks of middle east respiratory syndrome in two hospitals initiated by a single patient in Daejeon, South Korea. Infect Chemother. 48: 99-107.
- Ahmed AE (2017) Diagnostic delays in 537 symptomatic cases of middle east respiratory syndrome coronavirus infection in Saudi Arabia. Int J Infect Dis 62: 47-51.
- Sha J, Li Y, Chen X, Hu Y, Ren Y, et al. (2017) Fatality risks for nosocomial outbreaks of middle east respiratory syndrome coronavirus in the Middle East and South Korea. Arch Virol 162: 33-44.
- Alenazi TH, Al Arbash H, El-Saed A, Alshamrani MM, Baffoe-Bonnie H, et al. (2017) Identified transmission dynamics of middle east respiratory syndrome coronavirus infection during an outbreak: Implications of an overcrowded emergency department. Clin Infect Dis 65: 675-679.
- Ministry of Health and Welfare, Republic of Korea (2015). MERS white book.
- Kim DW, Kim YJ, Park SH, Yun MR, Yang JS, et al. (2016) Variations in spike glycoprotein gene of MERS-CoV, South Korea, 2015. Emerg Infect Dis 22: 100-104.
- Kim Y, Cheon S, Min CK, Sohn KM, Kang YJ, et al. (2016) Spread of mutant middle east respiratory syndrome coronavirus with reduced affinity to human CD26 during the South Korean Outbreak. mBio 7: e00019.
- Zhao Z, Li H, Wu X, Zhong Y, Zhang K, et al. (2004) Moderate mutation rate in the SARS coronavirus genome and its implications. BMC Evol Biol 4: 21.
- Zhu Y, Liu M, Zhao W, Zhang Y, Wang K, et al. (2005) Isolation of virus from a SARS patient and genome-wide analysis of genetic mutations related to pathogenesis and epidemiology from 47 SARS-CoV isolates. Virus genes 30: 93-102.
- Golden-Mason L, Stone AE, Bambha KM, Cheng L, Rosen HR (2012) Race and gender-related variation in natural killer p46 expression associated with differential anti-hepatitis C virus immunity. Hepatol 56: 1214-1222.
- Placzek H, Madoff L (2014) Effect of race/ethnicity and socioeconomic status on pandemic H1N1-related outcomes in Massachusetts. Am J Public Health 104: e31-8.
- Hastings DL, Tokars JI, Abdel Aziz IZ, Alkhaldi KZ, Bensadek AT, et al. (2016) Outbreak of middle east respiratory syndrome at tertiary care hospital, Jeddah, Saudi Arabia, 2014. Emerg Infect Dis 22: 794-801.
- Adegboye OA, Gayawan E, Hanna F (2017) Spatial modelling of contribution of individual level risk factors for mortality from middle east respiratory syndrome coronavirus in the Arabian Peninsula. PloS one 12: e0181215.
- Korea Centers for Disease C, Prevention (2015) middle east respiratory syndrome coronavirus outbreak in the Republic of Korea, 2015. Osong Public Health Res Perspect 6: 269-278.
- Chen X, Chughtai AA, Dyda A, MacIntyre CR (2017) Comparative epidemiology of middle east respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia and South Korea. Emerg Microbes 6: e51.
- Choi JS, Kim JS (2016) Factors influencing preventive behavior against middle east respiratory syndrome-coronavirus among nursing students in South Korea. Nurse Educ Today 40: 168-172.
- Alqahtani AS, Wiley KE, Mushta SM, Yamazaki K, BinDhim NF, et al. (2016) Association between Australian Hajj Pilgrims' awareness of MERS-CoV, and their compliance with preventive measures and exposure to camels. J Travel Med 23.
- Kim JS, Choi JS (2016) Middle East respiratory syndrome-related knowledge, preventive behaviours and risk perception among nursing students during outbreak. J Clin Nurs 25: 2542-2549.
- Alqahtani AS, Rashid H, Basyouni MH, Alhawassi TM, BinDhim NF (2017) Public response to MERS-CoV in the middle east: IPhone survey in six countries. J Infect Public Health 10: 534-540.
- Lee SS, Wong NS (2015) Probable transmission chains of Middle East respiratory syndrome coronavirus and the multiple generations of secondary infection in South Korea. Int J Infect Dis 38: 65-67.
- Kim DH (2015) Structural Factors of the middle east respiratory syndrome coronavirus outbreak as a publichealth crisis in Korea and future response strategies. J Prev Med Public Health 48: 265-270.
- Tarwater PM, Martin CF (2001) Effects of population density on the spread of disease. Complexity 6: 29-36.
- Lidsky PV, Andino R, Rouzine IM (2017) Variability in viral pathogenesis: Modeling the dynamic of acute and persistent infections. Curr Opin Virol 23: 120-124.
- Oh MD (2016) The Korean middle east tespiratory syndrome coronavirus outbreak and our responsibility to the global scientific community. Infect Chemother 48: 145-146.
- Wong G, Liu W, Liu Y, Zhou B, Bi Y, Gao GF (2015) MERS, SARS, and Ebola: The role of super-spreaders in infectious disease. Cell Host Microbe 18: 398-401.
- Oboho IK, Tomczyk SM, Al-Asmari AM, Banjar AA, Mugti HA, et al. (2015) 2014 MERS-CoV outbreak in Jeddah--a link to health care facilities. N Engl J Med 372: 846-854.
- Kang CK, Song KH, Choe PG, Park WB, Bang JH, et al. (2017) Clinical and epidemiologic characteristics of spreaders of middle east respiratory syndrome coronavirus during the 2015 outbreak in Korea. N Engl J Med 32: 744-749.
- Kim SW, Park JW, Jung HD, Yang JS, Park YS, et al. (2017) Risk factors for transmission of middle east respiratory syndrome coronavirus infection during the 2015 outbreak in South Korea. Clin Infect Dis 64: 551-557.
Citation: Park JE (2018) Differences in MERS Epidemiology in the Middle East and South Korea. J Community Med Health Educ 8: 592. DOI: 10.4172/2161-0711.1000592
Copyright: © 2018 Park JE. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Share This Article
Recommended Journals
Open Access Journals
Article Tools
Article Usage
- Total views: 3595
- [From(publication date): 0-2018 - Aug 16, 2024]
- Breakdown by view type
- HTML page views: 2983
- PDF downloads: 612