Cost-Utility of a Two-Dose Human Papillomavirus Vaccination Programme Added to Cervical Cancer Screening Compared with Cervical Cancer Screening Alone in Korea

Background: Cervical cancer is caused by the human papillomavirus and is a leading cause of cancer death among young Korean women. Current screening programmes could benefit from the addition of HPV vaccination into their schedule to help reduce disease burden. Two-dose vaccination schedules targeting HPV types 16 and 18, which are responsible for most cervical cancer cases, have recently been approved. Of the two available vaccines, AS04-adjuvanted HPV16/18 vaccine (AS04-HPV16/18v) provides greater protection against non-vaccine oncogenic HPV, while HPV-6/11/16/18 vaccine (4vHPVv) provides protection against genital warts. Methods: The health and economic consequences of introducing a two-dose HPV vaccination programme in 12-year-old girls together with screening were assessed in the Korean healthcare setting using a previously-published Markov model. Results: Compared with screening alone, AS04-HPV16/18v was cost-effective (incremental cost-effectiveness ratio below and within the Korean Won [KRW] 20-30 million treshold). When comparing the two vaccines, at 3% discount rate, AS04-HPV16/18v dominated 4vHPVv (i.e., provided 174 more quality-adjusted life-years (QALYs), 304 more life-years (LYs) and cost-savings of KRW 980 million). At a 5% discount rate, AS04-HPV16/18v provided comparable QALYs (albeit 5 fewer), 105 more LYs and cost-savings of KRW 292 million compared with 4vHPVv. Results were particularly sensitive to the discount rate used, as the health benefits of preventing cervical cancer are observed much later than those of preventing genital warts. Conclusion: For the Korean setting, HPV vaccination with a two-dose schedule is a cost-effective option, and AS04-HPV16/18v is likely to offer better health outcomes at a cost-saving compared with 4vHPVv.

Factors affecting influenza vaccination in adults aged 50-64 years with high-risk chronic diseases in South Korea.

Influenza is a communicable disease with most of the mortality burden falling on high-risk populations and those with pre-existing comorbidities and chronic diseases. In South Korea, adults aged 50-64 years are recommended for influenza vaccination, but no government financial support is offered to encourage vaccination uptake, which has led to suboptimal vaccination rates and significant public health concerns. The purpose of this study was to identify the factors affecting influenza vaccine uptake in adults aged 50-64 years and to compare high-risk and non-high-risk groups. We conducted randomized telephone questionnaires in South Korea on influenza vaccination-related behavioural factors in adults aged 50-64 years based on their vaccination history during the 2015-2016 flu season. The vaccination rate was 29.9% in non-high-risk adults aged 50-64 years and 41.3% in high-risk adults aged 50-64 years, which is considerably lower than the 81.7% rate in adults aged ≥65 years. Individuals who reported awareness of the potential severity of influenza, the importance and safety of vaccination, and who had experienced influenza after immunization or received a healthcare recommendation reported higher influenza vaccination rates. Therefore, highlighting awareness of influenza disease and vaccination through public campaigns and by information from healthcare professionals could represent opportunities to improve vaccination uptake in this population.

Cost Effectiveness of Quadrivalent Influenza Vaccines Compared with Trivalent Influenza Vaccines in Young Children and Older Adults in Korea.

INTRODUCTION: Trivalent influenza vaccines (TIVs) are currently reimbursed for subjects aged ≥ 65 years and children between 6 and 59 months of age under a national immunization program in South Korea. Quadrivalent influenza vaccines (QIVs) are expected to address the potential problem of influenza B-lineage mismatch for TIVs. OBJECTIVE: The objective of this analysis was to compare the cost effectiveness of QIV versus TIV in children aged 6-59 months and older adults ≥ 65 years of age in South Korea. METHODS: A 1-year static population model was employed to compare the costs and outcomes of a QIV vaccination program compared with TIV in children aged 6-59 months and older adults ≥ 65 years of age in South Korea. Influenza-related parameters (probabilities, health resource use, and costs) were derived from an analysis of the National Health Insurance System claims database between 2010 and 2013 under a broad and narrow set of International Classification of Diseases, Tenth Revision (ICD-10) codes used to identify influenza. Other inputs were extracted from published literature. Incremental cost-effectiveness ratios (2016 South Korean Won [KRW] per quality-adjusted life-year [QALY] gained) were estimated using a 'limited' societal perspective as per the Korean pharmacoeconomic guidelines. QALYs lost due to premature mortality were discounted at 5% annually. RESULTS: For both age groups combined, under the narrow definition of influenza, QIV is expected to prevent nearly 16,000 (2923 in children and 13,011 in older adults) medically attended influenza cases, nearly 8000 (672 in children, 7048 in older adults) cases of complications, and over 230 (0 in children, 238 in older adults) deaths annually compared with TIV. The impact of using QIV versus TIV in this setting translates into savings of KRW 24 billion (KRW 0.6 billion in children, KRW 23.4 billion in older adults) in annual medical costs, and over 2100 (18 in children, 2084 in older adults) QALYs. Under the broad definition, the corresponding results are over 190,000 (50,697 in children, 140,644 in older adults) influenza cases, over 37,000 (12,623 in children, 24,526 in older adults) complications, 270 deaths (0 in children, 270 in older adults), KRW 94.22 billion (KRW 16 billion in children, KRW 78.2 billion in older adults), and over 3500 QALYs saved (316 in children, 3260 in older adults). CONCLUSION: The use of QIV over TIV was estimated to not be cost effective in children 6-59 months of age, but cost saving in older adults, using the narrow definition of influenza; however, QIV use was cost saving in both age groups using the broad definition. QIV is expected to yield more benefits in older adults ≥ 65 years of age than in children aged 6-59 months due to higher influenza-related mortality and costs among the older adults. Further analyses considering the indirect effects of influenza vaccination in children are required.

Statistical estimations for Plasmodium vivax malaria in South Korea.

OBJECTIVE: To calculate the numbers of weekly infections and prevalence of malaria, and to predict future trend of malaria incidences in South Korea. METHODS: Weekly incidences of malaria for 13 years from the period 2001-2013 in South Korea were analyzed. The back-calculation equations were used with incubation period distributions. The maximum likelihood estimation for Poisson model was also used. The confidence intervals of the estimates were obtained by a bootstrap method. A regression model for time series of malaria incidences over 13 years was fitted by the non-linear least squares method, and used to predict futuretrend. RESULTS: The estimated infection curve is narrower and more concentrated in the summer than in the incidence distribution. Infection started around the 19th week and was over around the 41st week. The maximum weekly infection 110 was obtained at the 29th week. The prevalence at the first week was around 496 persons, the minimum number was 366 at 22nd week, and the maximum prevalence was 648 at 34th week. Prevalence drops in late spring with people that falling ill and had had long incubation periods and rose in the summer with new infections. Our future forecast based on the regression model was that an increase at year 2014 compared to 2013 may reach a peak (at maximum about 70 weekly cases) at year 2015, with a decreasing trend after then. CONCLUSIONS: This work shows that back-calculation methods could work well in estimating the infection rates and the prevalence of malaria. The obtained results can be useful in establishing an efficient preventive program for malaria infection. The method presented here can be used in other countries where incidence data and incubation period are available.

Alcohol consumption and the risk of type 2 diabetes mellitus: effect modification by hypercholesterolemia: the Third Korea National Health and Nutrition Examination Survey (2005).

OBJECTIVE: While the protective nature of moderate alcohol consumption against diabetes mellitus is well known, inconsistent findings continue to be reported. The possibility of different mixes of effect modifiers has been raised as a reason for those inconsistent findings. Our study aim was to examine potential effect modifiers that can change the effect of alcohol consumption on type 2 diabetes. METHODS: From data in the third Korea National Health and Nutrition Examination Survey, 3,982 individuals over the age of 30 years who had not been diagnosed with diabetes were selected for inclusion in the study population. Breslow and Day's test and the Wald test between hypercholesterolemia and alcohol consumption in a multiple logistic regression model were used to assess effect modification. RESULTS: Odds ratios for diabetes stratified by alcohol consumption strata and assessed using Breslow and Day's tests for homogeneity indicated that hypercholesterolemia was not a significant confounding factor (p=0.01). However, the Wald test for interaction terms, which is a conservative method of effect modification, was significant (p=0.03). CONCLUSIONS: The results indicate that moderate alcohol consumption is not necessarily protective for type 2 diabetes mellitus, if a person has hypercholesterolemia. People who have hypercholesterolemia should be aware of the risk associated with alcohol consumption, a risk that contrasts with the reported protective effect of moderate alcohol consumption on diabetes.

Differences in obesity rates between people with and without disabilities and the association of disability and obesity: a nationwide population study in South Korea.

OBJECTIVES: The objective of this study was to identify the differences in obesity rates among people with and without disabilities, and evaluate the relationship between obesity rates and the existence of disabilities or characteristics of disabilities. METHODS: Mass screening data from 2008 from the National Disability Registry and National Health Insurance (NHI) are used. For analysis, we classified physical disability into three subtypes: upper limb disability, lower limb disability, and spinal cord injury. For a control group, we extracted people without disabilities by each subtype. To adjust for the participation rate in the NHI mass screening, we calculated and adopted the weight stratified by sex, age, and grade of disability. Differences in obesity rates between people with and without disabilities were examined by a chi-squared test. In addition, the effect of the existence of disabilities and grade of disabilities on obesity was examined by multiple logistic regression analysis. RESULTS: People with disabilities were found to have a higher obesity rate than those without disabilities. The obesity rates were 35.2% and 35.0% (people with disabilities vs. without disabilities) in the upper limb disability, 44.5% and 34.8% in the lower limb disability, 43.4% and 34.6% in the spinal cord injury. The odds for existence of physical disability and grade of disability are higher than the non-disabilities. CONCLUSIONS: These results show that people with physical disability have a higher vulnerability to obesity.

Factors affecting public prejudice and social distance on mental illness: analysis of contextual effect by multi-level analysis.

OBJECTIVES: While there have been many quantitative studies on the public's attitude towards mental illnesses, it is hard to find quantitative study which focused on the contextual effect on the public's attitude. The purpose of this study was to identify factors that affect the public's beliefs and attitudes including contextual effects. METHODS: We analyzed survey on the public's beliefs and attitudes towards mental illness in Korea with multi-level analysis. We analyzed the public's beliefs and attitudes in terms of prejudice as an intermediate outcome and social distance as a final outcome. Then, we focused on the associations of factors, which were individual and regional socio-economic factors, familiarity, and knowledge based on the comparison of the intermediate and final outcomes. RESULTS: Prejudice was not explained by regional variables but was only correlated with individual factors. Prejudice increased with age and decreased by high education level. However, social distance controlling for prejudice increased in females, in people with a high education level, and in regions with a high education level and a high proportion of the old. Therefore, social distance without controlling for prejudice increased in females, in the elderly, in highly educated people, and in regions with a high education and aged community. CONCLUSIONS: The result of the multi-level analysis for the regional variables suggests that social distance for mental illness are not only determined by individual factors but also influenced by the surroundings so that it could be tackled sufficiently with appropriate considering of the relevant regional context with individual characteristics.