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Vaccine Oct 2012We conducted a systematic review of the published literature to examine the impact of new vaccine introduction on countries' immunization and broader health systems. Six... (Review)
Review
We conducted a systematic review of the published literature to examine the impact of new vaccine introduction on countries' immunization and broader health systems. Six publication databases were searched using 104 vaccine and health system-related search terms. The search yielded 15,795 unique articles dating from December 31, 1911 to September 29, 2010. Based on review of the title and abstract, 654 (4%) of these articles were found to be potentially relevant and were referred for full review. After full review, 130 articles were found to be relevant and included in the analysis. These articles represented vaccines introduced to protect against 10 different diseases (hepatitis A, hepatitis B, Haemophilus influenzae type b disease, human papilloma virus infection, influenza, Japanese encephalitis, meningococcal meningitis, Streptococcus pneumoniae disease, rotavirus diarrhea and typhoid), in various formulations and combinations. Most reviewed articles (97 [75%]) reported experiences in high-income countries. New vaccine introduction was most efficient when the vaccine was introduced into an existing delivery platform and when introduced in combination with a vaccine already in the routine childhood immunization schedule (i.e., as a combination vaccine). New vaccine introduction did not impact coverage of vaccines already included in the routine childhood immunization schedule. The need for increased cold chain capacity was frequently reported. New vaccines facilitated the introduction and widespread use of auto-disable syringes into the immunization and the broader health systems. The importance of training and education for health care workers and social mobilization was frequently noted. There was evidence in high-income countries that new vaccine introduction was associated with reduced health-care costs. Future evaluations of new vaccine introductions should include the systematic and objective assessment of the impacts on a country's immunization system and broader health system, especially in lower-income countries.
Topics: Developed Countries; Health Care Costs; Humans; Immunization Programs; Vaccination; Vaccines
PubMed: 22940378
DOI: 10.1016/j.vaccine.2012.08.029 -
Bulletin of the World Health... Oct 2011To update the estimated global incidence of Japanese encephalitis (JE) using recent data for the purpose of guiding prevention and control efforts. (Review)
Review
OBJECTIVE
To update the estimated global incidence of Japanese encephalitis (JE) using recent data for the purpose of guiding prevention and control efforts.
METHODS
Thirty-two areas endemic for JE in 24 Asian and Western Pacific countries were sorted into 10 incidence groups on the basis of published data and expert opinion. Population-based surveillance studies using laboratory-confirmed cases were sought for each incidence group by a computerized search of the scientific literature. When no eligible studies existed for a particular incidence group, incidence data were extrapolated from related groups.
FINDINGS
A total of 12 eligible studies representing 7 of 10 incidence groups in 24 JE-endemic countries were identified. Approximately 67,900 JE cases typically occur annually (overall incidence: 1.8 per 100,000), of which only about 10% are reported to the World Health Organization. Approximately 33,900 (50%) of these cases occur in China (excluding Taiwan) and approximately 51,000 (75%) occur in children aged 0-14 years (incidence: 5.4 per 100,000). Approximately 55,000 (81%) cases occur in areas with well established or developing JE vaccination programmes, while approximately 12,900 (19%) occur in areas with minimal or no JE vaccination programmes.
CONCLUSION
Recent data allowed us to refine the estimate of the global incidence of JE, which remains substantial despite improvements in vaccination coverage. More and better incidence studies in selected countries, particularly China and India, are needed to further refine these estimates.
Topics: Adolescent; Age Factors; Child; Child Welfare; Child, Preschool; Disease Outbreaks; Encephalitis, Japanese; Female; Global Health; Humans; Incidence; Infant; Infant, Newborn; Japanese Encephalitis Vaccines; Male; Pediatrics; Population Surveillance; Risk Assessment; World Health Organization
PubMed: 22084515
DOI: 10.2471/BLT.10.085233 -
The Cochrane Database of Systematic... Jul 2007Vaccination is recognized as the only practical measure for preventing Japanese encephalitis. Production shortage, costs, and issues of licensure impair vaccination... (Review)
Review
BACKGROUND
Vaccination is recognized as the only practical measure for preventing Japanese encephalitis. Production shortage, costs, and issues of licensure impair vaccination programmes in many affected countries. Concerns over vaccine effectiveness and safety also have a negative impact on acceptance and uptake.
OBJECTIVES
To evaluate vaccines for preventing Japanese encephalitis in terms of effectiveness, adverse events, and immunogenicity.
SEARCH STRATEGY
In March 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 1), MEDLINE, EMBASE, LILACS, BIOSIS, and reference lists. We also attempted to contact corresponding authors and vaccine companies.
SELECTION CRITERIA
Randomized controlled trials (RCTs), including cluster-RCTs, comparing Japanese encephalitis vaccines with placebo (inert agent or unrelated vaccine), no intervention, or alternative Japanese encephalitis vaccine.
DATA COLLECTION AND ANALYSIS
Authors independently extracted data and assessed methodological quality. Dichotomous data were compared with relative risks and a 95% confidence interval (CI), and converted into percentage vaccine efficacy.
MAIN RESULTS
Eight RCTs involving 358,750 participants were included. These trials investigated two available and three pre-licensure vaccines. Two RCTs assessing efficacy of the commercially available inactivated Nakayama vaccine were identified. A two-dose schedule of the licensed vaccine provided significant protection of 95% (95% CI 10% to 100%) for one year only, while two doses of an unpurified precursor vaccine protected children by 81% (95% CI 45% to 94%) in year one and by 59% (95% CI 2% to 83%) in year two. Serious adverse events were not observed. Mild and moderate episodes of injection site soreness, fever, headache, and nausea were reported in less than 6% of children receiving inactivated vaccine compared to 0.6% of unvaccinated controls. One cluster-RCT compared the live-attenuated SA14-14-2 vaccine (widely used in China) with no intervention measuring adverse events. Fever was reported in 2.7% of vaccinees compared to 3.1% of controls, while 0.1% of both groups suffered diarrhoea or seizures. Four small pre-licensure RCTs assessing a genetically engineered vaccine and two cell culture-derived inactivated vaccines revealed high immunogenicity and relative safety.
AUTHORS' CONCLUSIONS
Only one of the three currently used vaccines has been assessed for efficacy in a RCT. Other RCTs have assessed their safety, however, and they appear to cause only occasional mild or moderate adverse events. Further trials of effectiveness and safety are needed for the currently used vaccines, especially concerning dose levels and schedules. Trials investigating several new vaccines are planned or in progress.
Topics: Encephalitis, Japanese; Humans; Japanese Encephalitis Vaccines; Randomized Controlled Trials as Topic; Vaccines, Attenuated; Vaccines, Inactivated
PubMed: 17636750
DOI: 10.1002/14651858.CD004263.pub2