Geun-Ryang Bae

Relationship between intention of novel influenza A (H1N1) vaccination and vaccination coverage rate

We carried out this study to describe the difference between intention to receive vaccine against influenza A (H1N1) before the vaccination campaign and actual vaccine coverage rate after vaccination campaign; and to find out the factors affecting the acceptability. We analyzed data on intention to receive vaccine against influenza A (H1N1) and actual vaccination coverage rate from IR (immunization registry). In a survey of pre-vaccination, the sample size was 1042 and the survey results were weighted with gender and age distribution for sample distribution to be similar to population distribution. Although the intention to receive vaccine against influenza A (H1N1) was high, the actual vaccination coverage was lower than their intention. The factors affecting their intention were the degree of fear for novel influenza A (H1N1), the possibility to be infected with the virus, priority for production of novel influenza vaccine between timing and safety, and belief for effectiveness of novel influenza vaccine. Besides 2009 influenza A (H1N1) vaccination experience developing to resolve the effecting factors on intentions to receive vaccine, which would be the effective way to prepare for anther pandemic in the future.

Outbreak of measles in the Republic of Korea, 2007: importance of nosocomial transmission.

BACKGROUND From 2002 through 2006, Republic of Korea conducted extensive measles elimination activities and declared elimination in 2006. An outbreak of measles involving 180 confirmed cases occurred during 2007. METHODS An outbreak investigation was performed and enhanced surveillance was implemented. Detailed case investigations and laboratory testing included serologic and molecular diagnostic methods. Cases were classified according to World Health Organization and national guidelines. RESULTS During 2007, 451 suspected cases were reported and 180 (40%) cases were confirmed as measles during epidemiologic weeks 14-42. Incidence during the outbreak was 3.7 cases per million persons, excluding imported cases. Most confirmed cases were reported from Seoul; 137 (76%) cases were among children <24 months old, 124 (69%) case patients had no history of measles vaccination, and 81 (45%) case patients resulted from nosocomial transmission in 6 hospitals. Community members, patients, and health care workers all contributed to measles virus transmission. Limited outbreak control measures were implemented; high population immunity likely accounted for the self-limited transmission during this outbreak. CONCLUSIONS Limited outbreaks of measles, in which nosocomial transmission can play an important role, may occur after countries have declared elimination. Timely and opportunistic vaccination may help prevent such outbreaks; high-quality surveillance is critical for their detection.

No association between influenza A(H1N1)pdm09 vaccination and narcolepsy in South Korea: An ecological study

BACKGROUND There is concern about a possible association between influenza A(H1N1)pdm09 vaccination and narcolepsy. In this study, we assessed the incidence and incidence rate of narcolepsy in the South Korean population before and after the implementation of an A(H1N1)pdm09 vaccination campaign to see if vaccination led to a change in the occurrence of narcolepsy. METHODS We conducted an ecological study, comparing incident cases and incidence rates for newly diagnosed narcolepsy case-patients in South Korea, between July 2006 and June 2011. We used data from the Health Insurance Review Agency and Korea Centers for Disease Control and Prevention, which have limited information on case ascertainment. During vaccination campaign period, South Korea used non-adjuvanted and MF59-adjuvanted A(H1N1)pdm09 vaccines. RESULTS Generally, incidence rate was highest in prepandemic period. No trend toward increase in the incidence of narcolepsy after pandemic period was found. Observation of incidence by season did not suggest any time pattern for occurrence of narcolepsy. CONCLUSION No increase in cases or incidence rate for narcolepsy during the A(H1N1)pdm09 vaccination campaign was found in South Korea. Our data do not support the use of MF59-adjuvanted or non-adjuvanted A(H1N1)pdm09 vaccine as a trigger for narcolepsy on a population level.

Guillain―Barré syndrome following receipt of influenza A (H1N1) 2009 monovalent vaccine in Korea with an emphasis on Brighton Collaboration case definition

BACKGROUND In 2009-2010 season, with ongoing of influenza A (H1N1), employment of mass vaccination has generated concerns in issue of adverse events following immunization (AEFI). This study investigates the clinical and laboratory data of reported cases of Guillain-Barré syndrome (GBS) and Fisher syndrome (FS) following receipt of influenza A (H1N1) 2009 monovalent vaccine to the National Vaccine Injury Compensation Program (NVICP) in Korea, with all cases reviewed under case definition developed by Brighton Collaboration GBS Working Group. METHOD Retrospective review of medical records for all suspected cases of GBS ad FS following receipt of influenza A (H1N1) monovalent vaccine reported to NVICP from December 1, 2009, through April 28, 2010 was conducted. Additional analyses were performed for identification of levels of diagnostic certainty according to Brighton Collaboration case definition. RESULT Of 29 reported cases, 22 were confirmed to meet Brighton criteria level 1, 2, or 3 for GBS (21) or FS (1). Of those, 2 (9.1%) met level 1, 9 (40.9%) met level 2, and 11 (50.0%) met level 3. The male to female ratio was 2:0 in cases with level 1, 8:1 in cases with level 2, and 3:8 in cases with level 3. The mean age was older in cases with level 1 (54.0 ± 26.9) than that of cases with level 2 (25.6 ± 22.8), and level 3 (13.6 ± 2.4, P=0.005). The median onset interval was longer in cases with level 1 (16 days) than that of cases that met level 2 (12.44 days), and 3 (1.09 days, P=0.019). CONCLUSION The Brighton case definition was used to improve the quality of AEFI data in Korea, and was applicable in retrospective review of medical records in cases with GBS and FS after influenza A (H1N1) vaccination. These findings suggest that standardized case definition was feasible in clarifying the AEFI data, and to further increase the understanding of possible relationship of influenza vaccine and GBS.

National pertussis surveillance in South Korea 1955-2011: epidemiological and clinical trends

BACKGROUND Although there has been substantial progress in controlling pertussis in South Korea, the reported number of pertussis case-patients has gradually been increasing during the last decade. To address this, we summarized the surveillance data on pertussis collected during the period 1955-2011. Detailed epidemiologic and clinical data were determined, primarily using data from recent years. METHODS We analyzed data from the national surveillance system to describe the occurrence of pertussis. The annual numbers of reported pertussis case-patients were identified for the period 1955-2000. For 2001-2009, information including limited demographic characteristics and the date of onset of symptoms were identified. For 2010-2011, detailed epidemiologic and clinical information of reported pertussis case-patients were collected. RESULTS During 1955-2011, the secular trend was characterized by a gradual decrease in the reported number of cases from 1955 to the late 1990s, then a recent increase starting in the early 2000s. In 2009, a large number of reported cases occurred in infants <1 year of age. In 2011, an increase in reported cases among adolescents and adults aged ≥15 years was observed. During 2010-2011, 29.8% of reported cases were not immunized and 11.3% had not been immunized in a timely manner. Of adolescents and adults aged ≥15 years, 91.7% did not have a record of immunization. CONCLUSIONS During 2010-2011, a shift in age group was observed in pertussis case-patients: 33.8% were young infants <3 months of age and 29.0% were adolescents and adults ≥15 years of age. Considering that infants without timely vaccination may be vulnerable to an increased risk of pertussis infection, steps to provide timely vaccination to infants, to provide Tdap vaccination to adolescents and adults, and to enhance surveillance to capture adult pertussis cases should be taken in South Korea.

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.

Trends in the incidence rate of device-associated infections in intensive care units after the establishment of the Korean Nosocomial Infections Surveillance System

BACKGROUND The effectiveness of continuous nationwide surveillance on healthcare-associated infections should be investigated in each country. AIM To assess the rate of device-associated infections (DAIs) in intensive care units (ICUs) since the establishment of the Korean Nosocomial Infections Surveillance System (KONIS). METHODS Nationwide data were obtained on the incidence rate of DAI in ICUs reported to KONIS by all participating hospitals. The three major DAIs were studied: ventilator-associated pneumonia (VAP), central line-associated bloodstream infection (CABSI), and catheter-associated urinary tract infection (CAUTI). The pooled and year-wise incidence rates (cases per 1000 device-days) of these DAIs were determined for the period 2006 and 2012. In addition, data from institutions that had participated in KONIS for at least three consecutive years were analysed separately. FINDINGS The number of ICUs participating in KONIS gradually increased from 76 in 2006 to 162 in 2012. Between 2006 and 2012, the incidence rate per 1000 device-days for VAP decreased significantly from 3.48 to 1.64 (F = 11, P < 0.01), for CAUTI the rate decreased non-significantly from 1.85 to 1.26 (F = 2.02, P = 0.07), and for CABSI the rate also decreased non-significantly from 3.4 to 2.57 (F = 1.73, P = 0.12). In the 132 ICUs that had participated in KONIS for at least three consecutive years, the VAP rate significantly decreased from the first year to third year (F = 20.57, P < 0.01), but the rates of CAUTI (F = 1.06, P = 0.35) and CABSI (F = 1.39, P = 0.25) did not change significantly. CONCLUSION The decreased incidence rate of VAP in ICUs in Korea might be associated with the continuous prospective surveillance provided by KONIS.

Serious adverse events following receipt of trivalent inactivated influenza vaccine in Korea, 2003-2010.

BACKGROUND Vaccination is very important for the control and prevention of influenza, yet no vaccine is perfectly safe. Little is known, however, about influenza vaccination-associated serious adverse events following immunization (AEFI). This study aimed to identify background information on influenza vaccination-related serious AEFI in Korea. METHODS Retrospective review of data from Korea National Vaccine Injury Compensation Program from 2003 to 2010. RESULTS Distribution of approximately 75 million doses of influenza vaccine by end of 2010 gave rise to 42 potentially serious AEFI. In all, nine Guillain-Barré syndrome, eighteen other neurologic events, eight local events, and seven miscellaneous events were included. 62% of these events were identified to have unlike causal association with the vaccine. The reporting rate of serious AEFI ranged from 0.006 to 0.07 cases per 100,000 distributed doses of the vaccine. CONCLUSION GBS was the most common influenza vaccination-related serious AEFI. Enhancing post-vaccination GBS surveillance may increase public confidence in future routine and pandemic influenza vaccination.

Economic analysis of measles elimination program in the Republic of Korea, 2001: A cost benefit analysis study

BACKGROUND In this study, we modeled the cost benefit analysis for three different measles vaccination strategies based upon three different measles-containing vaccines in Korea, 2001. We employed an economic analysis model using vaccination coverage data and population-based measles surveillance data, along with available estimates of the costs for the different strategies. In addition, we have included analysis on benefit of reduction of complication by mumps and rubella. METHODS We evaluated four different strategies: strategy 1, keep-up program with a second dose measles-mumps-rubella (MMR) vaccine at 4-6 years without catch-up campaign; strategy 2, additional catch-up campaign with measles (M) vaccine; strategy 3, catch-up campaign with measles-rubella (MR) vaccine; and strategy 4, catch-up campaign with MMR vaccine. The cost of vaccination included cost for vaccines, vaccination practices and other administrative expenses. The direct benefit of estimated using data from National Health Insurance Company, a government-operated system that reimburses all medical costs spent on designated illness in Korea. RESULTS With the routine one-dose MMR vaccination program, we estimated a baseline of 178,560 measles cases over the 20 years; when the catch-up campaign with M, MR or MMR vaccines was conducted, we estimated the measles cases would decrease to 5936 cases. Among all strategies, the two-dose MMR keep-up program with MR catch-up campaign showed the highest benefit-cost ratio of 1.27 with a net benefit of 51.6 billion KRW. CONCLUSION Across different vaccination strategies, our finding suggest that MR catch-up campaign in conjunction with two-dose MMR keep-up program was the most appropriate option in terms of economic costs and public health effects associated with measles elimination strategy in Korea.

Outbreak of Ciprofloxacin-Resistant Shigella sonnei Associated with Travel to Vietnam, Republic of Korea

We investigated an October 2014 outbreak of illness caused by Shigella sonnei in a daycare center in the Republic of Korea (South Korea). The outbreak strain was resistant to extended-spectrum cephalosporins and fluoroquinolones and was traced to a child who had traveled to Vietnam. Improved hygiene and infection control practices are needed for prevention of shigellosis.