Emerged HA and NA Mutants of the Pandemic Influenza H1N1 Viruses with Increasing Epidemiological Significance in Taipei and Kaohsiung, Taiwan, 2009–10

The 2009 influenza pandemic provided an opportunity to observe dynamic changes of the hemagglutinin (HA) and neuraminidase (NA) of pH1N1 strains that spread in two metropolitan areas -Taipei and Kaohsiung. We observed cumulative increases of amino acid substitutions of both HA and NA that were higher in the post–peak than in the pre-peak period of the epidemic. About 14.94% and 3.44% of 174 isolates had one and two amino acids changes, respective, in the four antigenic sites. One unique adaptive mutation of HA2 (E374K) was first detected three weeks before the epidemic peak. This mutation evolved through the epidemic, and finally emerged as the major circulated strain, with significantly higher frequency in the post-peak period than in the pre-peak (64.65% vs 9.28%, p<0.0001). E374K persisted until ten months post-nationwide vaccination without further antigenic changes (e.g. prior to the highest selective pressure). In public health measures, the epidemic peaked at seven weeks after oseltamivir treatment was initiated. The emerging E374K mutants spread before the first peak of school class suspension, extended their survival in high-density population areas before vaccination, dominated in the second wave of class suspension, and were fixed as herd immunity developed. The tempo-spatial spreading of E374K mutants was more concentrated during the post–peak (p = 0.000004) in seven districts with higher spatial clusters (p<0.001). This is the first study examining viral changes during the naïve phase of a pandemic of influenza through integrated virological/serological/clinical surveillance, tempo-spatial analysis, and intervention policies. The vaccination increased the percentage of E374K mutants (22.86% vs 72.34%, p<0.001) and significantly elevated the frequency of mutations in Sa antigenic site (2.36% vs 23.40%, p<0.001). Future pre-vaccination public health efforts should monitor amino acids of HA and NA of pandemic influenza viruses isolated at exponential and peak phases in areas with high cluster cases

Financial incentives and physicians' prescription decisions on the choice between brand-name and generic drugs: Evidence from Taiwan

This paper tests the hypothesis of whether or not financial incentives affect a physician's prescription decision on the choice of generic versus brand-name drugs within a system in which physicians prescribe and dispense drugs. By using data obtained from Taiwan and focusing on diabetic patients, our empirical results provide several consistent findings in support of the hypothesis that profit incentives do affect the physician's prescribing decision, suggesting that physicians act as imperfect agents. An important implication of our findings is that rent seeking for profit margin between the reimbursement and the acquisition price instead of reducing costs is the major driving force behind generic substitution. As a result, the providers instead of the payers or consumers reap the financial benefits of generic substitution.Incentives Prescription decision Price regulation Generic drugs Brand-name drugs

The determinants of the adoption of pharmaceutical innovation: Evidence from Taiwan

In recent years, a substantial amount of technological progress in medicine has taken the form of pharmaceutical innovation. This paper uses the launch of a series of new drugs designed for treating type 2 diabetic patients as an example to investigate the determinants that affect the diffusion of new medical technology. Based on prescription-level data that are obtained from the national health insurance program in Taiwan, we find that the probability of prescribing new drugs declines as more competing products enter the pharmaceutical market. Meanwhile, physicians are less likely to prescribe new drugs to treat their patients as the provider market becomes less concentrated. These results suggest that the providers' incentives for cost reduction dominate incentives for quality improvement as markets become more competitive and hence an increase in market competition is associated with a decrease in the diffusion of new drugs. As a result, access to new drugs is not uniform among patients in a country with universal coverage for prescription drugs. An important implication of our study is that profit-seeking behavior among providers can become an access barrier to new medical technology.Competition Technology adoption Pharmaceutical innovation Access to new drugs National health insurance Taiwan Diabetes

A retrospective study on the usage of cough and cold medications in viral respiratory tract infections in Taiwanese children

Objective: We sought to describe the epidemiology of viral respiratory-tract infections and patterns in prescriptions of cough and cold medications among young children who were suffering from viral respiratory tract infections (vRTIs). Methods: We conducted a cross-sectional study to examine vRTI-episode occurrence and cold-medication utilization in outpatients in 2007 using the National Health Insurance Research Database (NHIRD) in Taiwan. One-third of the children under 12years of age who had at least one outpatient visit for a vRTI as randomly selected from NHIRD were included in the analysis. Results: A total of 895942 children had a diagnosis of vRTI (6144336 visits) during 2007, 58% of whom were aged 6 to 12years, and 52% of whom were male. The mean cumulative incidence of vRTIs by ages were 5.6 in infancy, 7.1 in preschool, and 4.0 in school children. The average number of cough and cold medications without other drugs prescribed per visit was two to three. Among cough and cold medications, antihistamines for systemic use were prescribed most frequently (20%), followed by mucolytics (12%), selective beta-2 agonists (11%), decongestants for systemic use (10%), and analgesic-antipyretics including acetaminophen (7%) or non-steroid anti-inflammatory drugs (6%). There was considerable variation of prescriptions, which increased with increasing age, where the top 20 prescription accounted for only 36%, 30%, and 25% of all prescriptions in infants, preschool, and school age children, respectively. Conclusions: A more rational use of medicines for treatment of vRTIs in children in Taiwan needs to be developed. © 2013 John Wiley & Sons, Ltd