Evaluation of an expanded case definition for vaccine-modified measles in a school outbreak in South Korea in 2010.

In this study, we have described the clinical characteristics of vaccine-modified measles to assess the performance of an expanded case definition in a school outbreak that occurred in 2010. The sensitivity, specificity, and the positive and negative predictive values were evaluated. Among 74 cases of vaccine-modified measles, 47 (64%) met the original case definition. Fever and rash were observed in 73% (54/74); fever was the most common (96%, 71/74) presenting symptom, and rash was noted in 77% (57/74) of the cases. The original case definition showed an overall sensitivity of 63.5% and a specificity of 100.0%. The expanded case definition combining fever and rash showed a higher sensitivity (72.9%) but a lower specificity (88.2%) than the original. The presence of fever and one or more of cough, coryza, or conjunctivitis scored the highest sensitivity among the combinations of signs and symptoms (77.0%), but scored the lowest specificity (52.9%). The expanded case definition was sensitive in identifying suspected cases of vaccine-modified measles. We suggest using this expanded definition for outbreak investigation in a closed community, and consider further discussions on expanding the case definition of measles for routine surveillance in South Korea.

Epidemiology of Japanese encephalitis in South Korea, 2007-2010.

BACKGROUND: Japanese encephalitis (JE) was the leading cause of viral encephalitis among children in South Korea in the 20(th) century. This study summarizes recent changes in the epidemiology of JE following the implementation of a vigorous immunization program in the country. METHODS: Epidemiological investigations were performed for all reported laboratory-confirmed JE cases, and the cumulative incidence was calculated for the surveillance years 2007-2010. RESULTS: During the surveillance period, 45 cases of JE were confirmed in the country, resulting in a cumulative incidence of 0.013-0.055 cases per 100 000 population. The median age of cases was 49.4 years, and by age group, 44.4% were aged 40-49 years. Just under a quarter (22.2%) of the cases were found to live close to a pigsty, while 42.2% of the cases were found to reside in the metropolitan areas of Seoul, Incheon, and Gyeonggi-do. None of the cases had a history of vaccination. CONCLUSIONS: Although JE has traditionally been regarded as a children's disease, the majority of cases now occur in adults in countries where strong immunization programs exist, such as in South Korea. Consideration should be given to an adult vaccination policy in the near future.

2009-2010 novel influenza A (H1N1) vaccination coverage in the Republic of Korea.

This study aimed to assess vaccination coverage for novel influenza A (H1N1) in Korea using a immunization registry system as the data source. Vaccination coverage was found to be 26.1% for the total population and 54.4% for priority groups targeted by a national vaccination campaign between October 27, 2009, to March 31, 2010. The factors associated with increased coverage were rapid vaccination and free vaccination; these factors may need to be considered in future pandemics.

Active surveillance of adverse events following immunization against pandemic influenza A (H1N1) in Korea.

Surveillance of vaccine safety is one of the public health interventions used to investigate the causal relationship between vaccines and adverse events. Using active surveillance data, we aimed to compile a detailed summary describing the safety of the pandemic influenza A (H1N1) vaccine. Computer-assisted telephone interview was used to investigate adverse events for 9,000 subjects who had received non-adjuvanted vaccines between November 2009 and January 2010, and for 19,000 adults who received adjuvanted vaccines from January through March 2010. The participants were interviewed to obtain information about local and systemic adverse events. Among subjects who received the non-adjuvanted vaccine, 5.5% (n=492) reported adverse events after vaccination, while 6.7% of those who received the adjuvanted vaccine reported adverse events. In the group receiving the adjuvanted vaccine, the highest reported rate of adverse events was among persons aged 19-49 years (9.1%, 577/6,329), followed by persons aged 50-64 years (7.2%, 485/6,718), and elderly persons aged 65 years and over (3.4%, 204/5,953). The implementation of this active surveillance study demonstrated the safety of both the adjuvanted and non-adjuvanted H1N1 vaccines.

National action plan for response to poliovirus importation.

The Division of Vaccine-Preventable Disease Control and National Immunization Program of the Korea Centers for Disease Control and Prevention has prepared a plan of action as a guide for key actions that will be taken if a poliovirus outbreak occurs in the Republic of Korea. The history of poliomyelitis and vaccination against poliovirus in the nation was reviewed and the routine surveillance procedures that are currently in place were described. The principles and specific actions for an effective response to a poliovirus outbreak were prepared. The guidelines clearly outline the actions to be taken in case of a polio outbreak. When a suspected case of poliovirus infection is reported, an immediate epidemiological investigation is to be conducted. The response to a poliovirus outbreak includes case isolation, management of potential contacts and immunization. All stakeholders are to be made aware of what key actions should be taken at each stage of the response to a poliovirus outbreak in the nation.

Surveillance and control of rubella in the republic of Korea from 2001 to 2009: the necessity for enhanced surveillance to monitor congenital rubella syndrome.

OBJECTIVES: The aim of this study was to review the epidemiologic data of rubella and congenital rubella syndrome (CRS) supplied by surveillance systems from 2001 to 2009 and to propose measures to improve the quality of the surveillance system in the Republic of Korea. METHODS: The epidemiological data for rubella and CRS cases reported to the Korea Centers for Disease Control and Prevention from 2001 to 2009 were retrospectively reviewed, and insurance reimbursement data from the Korea National Health Insurance Review Agency were collected for comparison. RESULTS: The number of yearly reported rubella cases to the Korea Centers for Disease Control and Prevention from 2001 to 2009 was 128, 24, 8, 24, 15, 12, 35, 30, and 36, respectively. The occurrence of rubella shifted to a slightly higher age group during the 9-year period, i.e. from 0-9 years to 10-19 years. Among the 309 reported rubella cases, three were confirmed cases of CRS. In addition, according to data sourced from Health Insurance Review Agency, 24, 19, 19, 9, and 5 CRS cases were reported for medical insurance reimbursement from 2005 to 2009, respectively. CONCLUSION: According to available surveillance data, the reported cases of rubella and CRS were not high, but a more detailed surveillance with emphasis on susceptible women of childbearing age is necessary for better monitoring and control of rubella and CRS in the Republic of Korea.