ObjectivesThe outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the Republic of Korea started from the index case who developed fever after returning from the Middle East. He infected 26 cases in Hospital C, and consecutive nosocomial transmission proceeded throughout the nation. We provide an epidemiologic description of the outbreak, as of July 2015.MethodsEpidemiological research was performed by direct interview of the confirmed patients and reviewing medical records. We also analyzed the incubation period, serial interval, the characteristics of superspreaders, and factors associated with mortality. Full genome sequence was obtained from sputum specimens of the index patient.ResultsA total of 186 confirmed patients with MERS-CoV infection across 16 hospitals were identified in the Republic of Korea. Some 44.1% of the cases were patients exposed in hospitals, 32.8% were caregivers, and 13.4% were healthcare personnel. The most common presenting symptom was fever and chills. The estimated incubation period was 6.83 days and the serial interval was 12.5 days. A total of 83.2% of the transmission events were epidemiologically linked to five superspreaders, all of whom had pneumonia at presentation and contacted hundreds of people. Older age [odds ratio (OR) = 4.86, 95% confidence interval (CI) 1.90–12.45] and underlying respiratory disease (OR = 4.90, 95% CI 1.64–14.65) were significantly associated with mortality. Phylogenetic analysis showed that the MERS-CoV of the index case clustered closest with a recent virus from Riyadh, Saudi Arabia.ConclusionA single imported MERS-CoV infection case imposed a huge threat to public health and safety. This highlights the importance of robust preparedness and optimal infection prevention control. The lessons learned from the current outbreak will contribute to more up-to-date guidelines and global health security.

A cross-sectional study was performed to assess current public awareness of herpes zoster (HZ) and its vaccine, determine the factors that influence people's intention regarding HZ vaccination, and investigate the barriers for vaccination by changing decisions with sequential questions regarding knowledge, cost, and physician's recommendation in the Department of Infectious Diseases, Korea University Guro Hospital, in South Korea, between August 23 and September 15 of 2013. Among 603 subjects who completed the survey, 85.7% and 43.6% subjects were aware of HZ and HZ vaccination, respectively. Women, younger age group, those with higher income or higher education levels were more likely to be aware of HZ. Overall, 85.8% of subjects aware of HZ were willing to be vaccinated or vaccinate their parents. The main obstacles for the increased acceptance toward vaccination were the high cost and low perceived risk, which decreased acceptance to 60.2%. However, physician's recommendation reversed 69.5% of the refusal to accept HZ vaccine. These results indicate that expanding public education and physician's recommendations are important factors aimed at increasing HZ vaccine coverage rate.

Since the beginning of 2014, the Republic of Korea has experienced a resurgence of measles cases. Among the 220 cases confirmed as measles during epidemiological weeks 1-20 (December 29, 2013 to May 17, 2014), 10 imported cases were identified. The predominant genotype was B3, which reflects the circulating measles virus in adjacent countries. Even with the verification of measles elimination in March 2014 by the World Health Organization, recent importation has been related to international travel. Targeted control measures have been implemented in addition to proper isolation and patient care. A vigilant surveillance system and high levels of vaccine coverage should be maintained to sustain the measles elimination status.

ObjectivesThis study aims to identify clinical case definitions of influenza with higher accuracy in patients stratified by age group and influenza activity using hospital-based surveillance system.MethodsIn seven tertiary hospitals across South Korea during 2011–2012 influenza season, respiratory specimens were obtained from patients presenting an influenza-like illness (ILI), defined as having fever plus at least one of following symptoms: cough, sore throat or rhinorrhea. Influenza was confirmed by reverse transcriptase-polymerase chain reaction. We performed multivariate logistic regression analyses to identify clinical variables with better relation with laboratory-confirmed influenza, and compared the accuracy of combinations.ResultsOver the study period, we enrolled 1417 patients, of which 647 had laboratory-confirmed influenza. Patients with cough, rhinorrhea, sore throat or headache were more likely to have influenza (p<0.05). The most accurate criterion across the study population was the combination of cough, rhinorrhea, sore throat and headache (sensitivity 71.3%, specificity 60.1% and AUROC 0.66). The combination of rhinorrhea, sore throat and sputum during the peak influenza activity period in the young age group showed higher accuracy than that using the whole population (sensitivity 89.3%, specificity 72.1%, and AUROC 0.81).ConclusionsThe accuracy of clinical case definitions of influenza differed across age groups and influenza activity periods. Categorizing the entire population into subgroups would improve the detection of influenza patients in the hospital-based surveillance system.