Changing sero-epidemiology of hepatitis A in Asia Pacific countries: A systematic review.

OBJECTIVES: Hepatitis A is a viral liver disease whose prevalence is associated with low socio-economic and hygiene levels due to its faecal-oral transmission. Severity increases with age, and immunity is life-long. Decreased endemicity could result in increased age and severity of cases. A literature review was conducted to describe changes in age-stratified hepatitis A seroprevalence in Asia Pacific countries from 1980 to 2016, and to identify gaps in the literature. The PRISMA guidelines were followed. METHODS: The PubMed database was searched for studies on age-specific hepatitis A seroprevalence in 17 Asia Pacific countries. All studies published in the English language, reporting human hepatitis A seroprevalence levels in any age group, were included. RESULTS: Seventy-three publications from 11 countries were identified. A trend of increasing age at first exposure over time was observed, particularly in developed countries such as Japan, Taiwan, Thailand, and Korea, suggesting a transition in terms of endemicity. CONCLUSIONS: Extensive gaps in the literature were identified between countries and year of publication, indicating the need for further research. Decreasing hepatitis A exposure and thus immunity conferred during childhood, may render older populations susceptible to infection. The public health and economic value of vaccination against hepatitis A should be assessed within this changing epidemiological context.

Improving seasonal and pandemic influenza vaccines.

Challenges facing seasonal and pandemic influenza vaccination include: increasing the immunogenicity of seasonal vaccines for the most vulnerable, increasing vaccination coverage against seasonal influenza, and developing vaccines against pandemic strains that are immunogenic with very low quantities of antigen to maximize the number of people who can be vaccinated with a finite production capacity. We review Sanofi Pasteur's epidemic and pandemic influenza research and development programmes with emphasis on two key projects: intradermal influenza vaccine for seasonal vaccination of both elderly and younger adults, and pandemic influenza vaccine.

Economic evidence of influenza vaccination in children.

OBJECTIVE: We review published economic evaluations of influenza vaccination for children, including direct individual benefits and indirect societal benefits, to determine whether more studies are needed to fully understand the expected benefits of such strategies. METHODS: We searched MEDLINE and EMBASE databases to May 2006 and in-press articles to October 2006 for studies including economic analyses of influenza vaccination in children. Abstracts of all potentially relevant articles were screened. RESULTS: Fifteen relevant articles from 1983 were retained. Most were based on modelling, using previously published data and considered the societal perspective. Three were a part of prospective clinical trials. Various paediatric vaccination scenarios and parameters were considered. Vaccinating children against influenza was cost saving or cost effective in 10/15 studies, cost saving or effective only under certain conditions in three studies, and not cost saving or effective in two studies whatever the outcome or perspective considered. CONCLUSIONS: Most published evidence points to an economic interest for society of vaccinating children against influenza. However, differences in study design hinder the comparison of the various vaccination strategies considered. Comparable and complete data on the burden and cost of disease, and the cost of vaccination are needed, especially outside of North America.

Long-term clinical trial safety experience with the inactivated split influenza vaccine, Vaxigrip.

Safety data on the inactivated split influenza vaccine, Vaxigrip, were compiled and analysed from 28 clinical trials (total: 4599 subjects aged 6 months to 99 years) to provide a robust estimate of the reactogenicity profile. The most frequent solicited reactions were non-severe injection site pain and erythema in children, adults, and elderly. Mild or moderate fever was the most frequent reaction in 6-36 months olds; few systemic reactions were reported in older groups. Reactogenicity was comparable in healthy and high-risk children. The long-term experience with the world's most widely used influenza vaccine, Vaxigrip, confirms its excellent tolerability, and supports its continued use in clinical practice worldwide.