Vaccine Efficacy Rates Research Articles

HPV vaccination and allocative efficiency: regional analysis of the costs and benefits with the bivalent AS04-adjuvanted vaccine, from the perspective of public health, for the prevention of cervical cancer and its pre-cancerous lesions

Introduction: by means of the decisions on whether to introduce the HPV vaccination, Public Health has already established the importance of associating the vaccination strategy to the policy of secondary prevention. The screening + vaccination strategy is more effective than the two methods taken individually. In support of this combined strategy and in order to make available per each region concrete elements for their regional planning, an assessment has been made, which also takes into account the effect of cross-protection regarding high-risk strains not contained in both vaccines, bivalent and quadrivalent, and more frequently responsible for pre-cancerous lesions and cervical cancer (CCU). This analysis evaluates the costs and benefits of screening + vaccination strategy in a 12-year-old female cohort. Furthermore, the paper provides results that may be useful to assess the opportunity to extend the vaccination to a second cohort of 24-25-year-old women. The analysis is preceded by a brief summary of CCU epidemiology available data, public health policies that give precise guidelines for vaccination strategies and analytical tools suitable to support public policy makers to efficiently allocate resources. Methods: two different models were used for two regional analyses.The vaccines may have different sustained- and cross-protection levels against non-vaccine oncogenic HPV-types. In the first analysis, a prevalence-based model estimated the potential net difference in HPV-related lesions (abnormal pap smear, cervical intraepithelial neoplasia (CIN), cervical cancer (CC) and genital warts (GW)) and associated costs generated by the two vaccines. Vaccine efficacy rates were based on published data for each vaccine. Lifetime vaccine efficacy was assumed. Results are reported over one year after reaching a steady state. Incidence and treatment costs were obtained from Italian and European sources. We also performed a cost-effectiveness analysis with a Markov model for each Italian region, previously described and successfully adapted to the national scenario. The analysis compares the HPV vaccination of a single cohort (12-year-old females) with a multiple cohort (12- + 25-year-old girls). Resource use was based on a standard therapeutic path applied to all regions. However we quantified the impact of the so-called “decentralization progress” by collecting regional data on: pap test coverage, tariffs for treatments, and cost of the vaccination course. Results: the results are set out in 21 regional reports. Conclusions: in the Italian scenario, characterized by decentralization and local autonomy, a further level of detail is essential in order to describe the specific local settings and implications of a new health intervention. The results show that the vaccination on a multiple cohort is more effective than a single cohort. Indeed, a major number of pre-cancerous lesions, cases of cancer, and related deaths are avoided. In a period of sharp decline in the health budget, investment in prevention seems to be the most reasonable choice in view of avoiding in the medium term pre-cancerous and cancerous lesions generating a significant expense. Our analysis places the extent of HPV vaccination among the measures that the regional decision-makers should put in place to maximize the efficiency of scarce resource.

A numerical study on an influenza epidemic model with vaccination and diffusion

A vaccinated diffusive compartmental epidemic model is developed to explore the impact of vaccination as well as diffusion on the transmission dynamics of influenza. The basic reproduction numbers with and without vaccination are obtained. Sensitivity analysis of the reproduction number based on parameters involved in the system has been investigated. Stability analysis of the points of equilibrium has also been investigated. Using the combined effect of the vaccine efficacy and vaccination rate, the model is analysed to determine criteria for control of influenza epidemic. The roles of vaccine efficacy and vaccination rate are compared. It is shown that higher levels of vaccine efficacy and vaccination rate lead to a decrease in the epidemic size. It is also shown that an accurate estimation of the efficiency of vaccine is necessary to control the spread of influenza and thus vaccination strategy needs to be implemented carefully.

Mosquirix (RTS,S): A Novel Vaccine for the Prevention of Plasmodium falciparum Malaria

To summarize and evaluate the literature for Mosquirix (RTS,S) and provide insight into the therapeutic and economic controversies of this novel malaria vaccine candidate. A systematic literature search was performed using the terms Mosquirix; RTS,S; malaria; vaccine; and Plasmodium in MEDLINE (1948-November 2011), EMBASE (1980-November 2011), International Pharmaceutical Abstracts (1970-November 2011), Google, and Google Scholar. Clinical trials describing vaccine development, pharmacology, pharmacokinetics, efficacy, and safety were reviewed. For efficacy, clinical trials were reviewed that reported acquisition of malarial disease. Information regarding study design, population, study period, baseline characteristics, clinical outcomes, results, and assessors of quality was extracted. Five randomized controlled trials and 4 follow-up extension studies were identified. In Phase 2 trials, vaccine efficacy rates were 33-65% in infants and 30-53% in children for preventing the first episode of clinical disease. In Phase 3 trials, vaccine efficacy was 56% in children aged 5-17 months. RTS,S reduced the number of clinical malaria episodes and prevented severe malaria in several studies. The follow-up period for vaccine efficacy ranged from 6 to 45 months. RTS,S 25 μg is administered intramuscularly as 3 injections given 1 month apart for infants and children. RTS,S appears to be generally well tolerated. A few cases of meningitis and seizures (within 7 days of vaccination) have been reported. RTS,S has demonstrated efficacy and safety in Phase 1, 2, and 3 trials, and has the potential to decrease morbidity and mortality from malaria worldwide. Major challenges include determination of the duration of immunity, assessment of its cost-effectiveness, its use in special populations, and its dissemination in endemic regions. Pending further studies, RTS,S has the potential to become the benchmark as the first effective vaccine against malaria.

Would vaccination against nicotine be a cost‐effective way to prevent smoking uptake in adolescents?

We used epidemiological modelling to assess whether nicotine vaccines would be a cost-effective way of preventing smoking uptake in adolescents. We built an epidemiological model using Australian data on age-specific smoking prevalence; smoking cessation and relapse rates; life-time sex-specific disability-adjusted life years lived for cohorts of 100,000 smokers and non-smokers; government data on the costs of delivering a vaccination programme by general practitioners; and a range of plausible and optimistic estimates of vaccine cost, efficacy and immune response rates based on clinical trial results. We first estimated the smoking uptake rates for Australians aged 12-19 years. We then used these estimates to predict the expected smoking prevalence in a birth cohort aged 12 in 2003 by age 20 under (i) current policy and (ii) different vaccination scenarios that varied in cost, initial vaccination uptake, yearly re-vaccination rates, efficacy and a favourable vaccine immune response rate. Under the most optimistic assumptions, the cost to avert a smoker at age 20 was $44,431 [95% confidence interval (CI) $40,023-49,250]. This increased to $296,019 (95% CI $252,307-$355,930) under more plausible scenarios. The vaccine programme was not cost-effective under any scenario. A preventive nicotine vaccination programme is unlikely to be cost-effective. The total cost of a universal vaccination programme would be high and its impact on population smoking prevalence negligible. For these reasons, such a programme is unlikely to be publicly funded in Australia or any other developed country.

Health and economic impact of PHiD-CV in Canada and the UK: a Markov modelling exercise

Objective:The spectrum of diseases caused by Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) represents a large burden on healthcare systems around the world. Meningitis, bacteraemia, community-acquired pneumonia (CAP), and acute otitis media (AOM) are vaccine-preventable infectious diseases that can have severe consequences. The health economic model presented here is intended to estimate the clinical and economic impact of vaccinating birth cohorts in Canada and the UK with the 10-valent, pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) compared with the newly licensed 13-valent pneumococcal conjugate vaccine (PCV-13).Methods:The model described herein is a Markov cohort model built to simulate the epidemiological burden of pneumococcal- and NTHi-related diseases within birth cohorts in the UK and Canada. Base-case assumptions include estimates of vaccine efficacy and NTHi infection rates that are based on published literature.Results:The model predicts that the two vaccines will provide a broadly similar impact on all-cause invasive disease and CAP under base-case assumptions. However, PHiD-CV is expected to provide a substantially greater reduction in AOM compared with PCV-13, offering additional savings of Canadian $9.0 million and £4.9 million in discounted direct medical costs in Canada and the UK, respectively.Limitations:The main limitations of the study are the difficulties in modelling indirect vaccine effects (herd effect and serotype replacement), the absence of PHiD-CV- and PCV-13-specific efficacy data and a lack of comprehensive NTHi surveillance data. Additional limitations relate to the fact that the transmission dynamics of pneumococcal serotypes have not been modelled, nor has antibiotic resistance been accounted for in this paper.Conclusion:This cost-effectiveness analysis suggests that, in Canada and the UK, PHiD-CV’s potential to protect against NTHi infections could provide a greater impact on overall disease burden than the additional serotypes contained in PCV-13.

Global stability for a tuberculosis model

A deterministic model is developed to describe the effects of vaccination and treatment on the spread of tuberculosis. It is shown that the basic reproduction number characterizes the disease transmission dynamics: if R 0 ≤ 1 , there exists only the disease-free equilibrium which is globally asymptotically stable, and if R 0 > 1 then there is a disease endemic equilibrium and the disease persists. Global stability of the endemic equilibrium is also discussed. Analysis of the dependence of R 0 on the vaccination rate, vaccine efficacy and treatment rate shows that the spread of tuberculosis can be controlled if the vaccine rate or the efficacy or the treatment rate reaches a certain threshold.

Cost–consequences evaluation between bivalent and quadrivalent HPV vaccines in Italy: The potential impact of different cross-protection profiles

Objectives Two human papillomavirus (HPV) vaccines are currently available: a bivalent HPV-16/18 and a quadrivalent HPV-6/11/16/18 vaccine. The vaccines may have different sustained- and cross-protection levels against non-vaccine oncogenic HPV-types. This study investigated the potential difference in clinical and economic impacts provided by two HPV vaccines in Italy. Methods A prevalence-based model estimated the potential net difference in HPV-related lesions (abnormal pap smear, cervical intraepithelial neoplasia (CIN), cervical cancer (CC) and genital warts (GW)) and associated costs generated by the two vaccines. Incidence and treatment costs were obtained from Italian and European sources. Vaccine efficacy rates were based on published data for each vaccine. Lifetime vaccine efficacy was assumed. Results are reported over one year after reaching a steady state. Sensitivity analyses were performed on the lesion incidence, vaccine effectiveness, treatment costs and sustained protection. Results The bivalent vaccine would prevent an additional reduction of 7976 abnormal pap smears; 601 CIN1; 1826 CIN2/3 and 295 CC cases compared to the quadrivalent vaccine while 25,848 genital wart cases would be prevented by the quadrivalent vaccine. The additional cost averted with the bivalent vaccine was estimated at €2,385,354 per year compared to the quadrivalent vaccine. The most influential parameters were CC- and GW-related costs and the difference in sustained protection. Conclusions Our model suggests that, in the Italian setting, the bivalent vaccine would prevent more precancerous and CC lesions than the quadrivalent vaccine. This translates into a greater cost averted for the bivalent vaccine, which could completely offset savings in GW-related costs associated with the quadrivalent vaccine.

Economic Evaluation of Universal Infant Vaccination with 7vPCV in Hong Kong

The purpose of this study was to evaluate the clinical and economic benefits of routine infant vaccination with seven-valent pneumococcal conjugate vaccine (7vPCV) in Hong Kong. A decision-analytic model was populated with local age-specific incidence data to simulate the expected health outcomes resulting from 7vPCV vaccination of a birth cohort of 57,100 children compared with an unvaccinated cohort over a 10-year horizon. Primary analyses were conducted from a payer perspective, using local inpatient and outpatient costs associated with the treatment of pneumococcal disease. Vaccine efficacy rates were consistent with results from pivotal clinical trials. The reduction in adult invasive pneumococcal disease (IPD) and associated cost avoidance due to the indirect effect of vaccination were estimated in line with published overseas rates. Universal 7vPCV vaccination was estimated to prevent 524 cases of IPD and more than 2580 cases of otitis media in the birth cohort over a 10-year period, leading to a reduction of HK$28.7 million (US$3.7 million) in direct medical costs. Additional cost savings from the indirect prevention of 919 adult cases of IPD during this time period also resulted. Overall, 7vPCV vaccination was estimated to have an incremental cost per life-year gained of HK$50,456 (US$6460) from a payer perspective or HK$46,308 (US$5929) when both direct and indirect costs were included. With reference to the World Health Organization's threshold for cost-effectiveness, results from this study indicate that routine infant vaccination with 7vPCV is a cost-effective intervention because of the added cost savings resulting from the indirect effect of vaccination on adult disease.

Cost‐Effectiveness of Rotavirus Vaccination in Peru

There are plans to introduce the oral rotavirus vaccine Rotarix (GlaxoSmithKline), 1 of 2 recently developed vaccines against rotavirus, in Peru. We modeled the cost-effectiveness of adding a rotavirus vaccine to the Peruvian immunization program under 3 scenarios for the timing of vaccination: (1) strictly according to schedule, at 2 and 4 months of age (on time); (2) distributed around the target ages in the same way as the actual timings in the program (flexible); and (3) flexible but assuming vaccination is not initiated for infants >12 weeks of age (restricted). We assumed an introductory price of US $7.50 per dose, and varied the annual rate of price decrease in sensitivity analyses. The discounted cost per disability-adjusted life-year averted for restricted, flexible, and on-time schedules was $621, $615, and $581, respectively. For each of the 3 scenarios, the percentage reduction in deaths due to rotavirus infection was 53%, 66%, and 69%, respectively. The cost per disability-adjusted life-year averted for alternative "what-if" scenarios ranged from $229 (assuming a 1-dose schedule, administered on time) to $1491 (assuming a 2-dose schedule, with half the baseline vaccine efficacy rates and a restricted timing policy). On the basis of current World Health Organization guidelines, rotavirus vaccination represents a highly cost-effective intervention in Peru. Withholding the vaccine from children who present for their first dose after 12 weeks of age would reduce the number of deaths averted by approximately 20%. A single dose may be more cost-effective than 2 doses, but more evidence on the protection conferred by a single dose is required.

Knowledge synthesis of benefits and adverse effects of measles vaccination: the Lasbela balance sheet

BackgroundIn preparation for a cluster-randomized controlled trial of a community intervention to increase the demand for measles vaccination in Lasbela district of Pakistan, a balance sheet summarized published evidence on benefits and possible adverse effects of measles vaccination.MethodsThe balance sheet listed: 1) major health conditions associated with measles; 2) the risk among the unvaccinated who contract measles; 3) the risk among the vaccinated; 4) the risk difference between vaccinated and unvaccinated; and 5) the likely net gain from vaccination for each condition.ResultsTwo models revealed very different projections of net gain from measles vaccine. A Lasbela-specific combination of low period prevalence of measles among the unvaccinated, medium vaccination coverage and low vaccine efficacy rate, as revealed by the baseline survey, resulted in less-than-expected gains attributable to vaccination. Modelled on estimates where the vaccine had greater efficacy, the gains from vaccination would be more substantial.ConclusionSpecific local conditions probably explain the low rates among the unvaccinated while the high vaccine failure rate is likely due to weaknesses in the vaccination delivery system. Community perception of these realities may have had some role in household decisions about whether to vaccinate, although the major discouraging factor was inadequate access. The balance sheet may be useful as a communication tool in other circumstances, applied to up-to-date local evidence.

Effectiveness of childhood vaccination against rotavirus in sub-Saharan Africa: The case of Nigeria

Rotavirus diarrhoea is associated with high childhood mortality in developing countries. A new vaccine was recently licensed in Mexico. The objective of this study was to assess the effectiveness of routine childhood vaccination by this new vaccine in a developing country. We constructed a decision tree to compare two alternatives: “no vaccination programme” and “vaccination programme”. The estimates used for disease incidence, vaccine efficacy and coverage rates were derived from published data. We followed a hypothetical Nigerian cohort from birth to age five. The vaccine programme would prevent 284,000 cases of rotavirus diarrhoea annually and 6129 deaths due to the disease. In this study in a sub-Saharan country, we showed that rotavirus vaccination with a new vaccine substantially reduces the number of deaths from rotavirus diarrhoea and may be of great use in developing countries.

The efficacy and safety of influenza vaccination in pregnancy

205 THE EFFICACY AND SAFETY OF INFLUENZA VACCINATION IN PREGNANCY JEANNE SHEFFIELD, VANESSA LAIBL, SCOTT ROBERTS, MARY LORIMER, BRIAN CASEY, DON MCINTIRE, GEORGE D. WENDEL JR, University of Texas Southwestern Medical Center at Dallas, Obstetrics and Gynecology, Dallas, Texas OBJECTIVE: Limited data are available about the efficacy of influenza vaccination in pregnant women. We sought to measure the efficacy and safety of the inactivated influenza vaccine in pregnant women during the 2003-2004 influenza season. STUDY DESIGN: Pregnant women R20 weeks gestation from our prenatal clinics were offered the inactived influenza vaccine during the 2003-2004 influenza season. Data prospectively were collected on vaccinated women and a matched control group receiving prenatal care during the influenza season at the same gestational age who did not get vaccinated. Student t-test and chisquare analysis were performed to compare the two groups. RESULTS: During the 2003-2004 influenza season, 2889 pregnant women received the inactive influenza vaccine. To date, 2352 (81%) of these women have delivered, and the analysis is limited to this subset. The comparison group includes 1988 women. There were no significant differences in demographic characteristics between the 2 groups.The mean EGA at vaccination was 30.0 G 5.9 weeks. The vaccinated group was less likely to deliver an infant !36 weeks (3% versus 5%, P = .02) and less likely to have a newborn NICU admission (P = .04). All other obstetric and neonatal complications were similar in the 2 groups, including neonatal infection and malformation rates. Overall, 6 women (2.6 per 1000) in the vaccinated group developed laboratory confirmed influenza and 13 women (6.5 per 1000) developed infection in the non-vaccinated group (P = .047). When restricting the analysis to those women developing influenza >2 weeks after vaccination, the time required to develop immunity, there was 1 case (0.4 per 1000) of influenza (P ! .001: RR = 15.5 (2.02,118.4)). CONCLUSION: The influenza vaccine efficacy rate during the 2003-2004 season in our pregnant population was >99%. Significantly fewer women developed influenza after the vaccine, and it reduced the rate of influenza 15 fold when given over 2 weeks before exposure. The inactivated influenza vaccine is very effective and safe for women in the second half of prenancy. S66 SMFM Abstracts

Contagiousness of Varicella in Vaccinated Cases

Infectious Diseases| November 01 2004 Contagiousness of Varicella in Vaccinated Cases AAP Grand Rounds (2004) 12 (5): 61. https://doi.org/10.1542/gr.12-5-61 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Contagiousness of Varicella in Vaccinated Cases. AAP Grand Rounds November 2004; 12 (5): 61. https://doi.org/10.1542/gr.12-5-61 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search nav search search input Search input auto suggest search filter All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: chickenpox, human herpesvirus 3, vaccination Source: Seward JF, Zhang JX, Maupin TJ, et al. Contagiousness of varicella in vaccinated cases: a household contact study. JAMA. 2004;292:704–708. Household transmission studies performed prior to licensure of varicella vaccine and its introduction into clinical practice in 1995 revealed secondary attack rates among susceptible children of 61%–100%.1–,3 This study by investigators from the Centers for Disease Control and Prevention and the Los Angeles County Department of Health Services, Calif, provides the first post-licensure, quantitative data on the secondary attack rates within households as well as an estimate of the effectiveness of varicella vaccine based on secondary attack rates in unvaccinated and vaccinated children and adolescents. For the study, active surveillance of varicella cases in a community of 320,000 within Los Angeles County was conducted; a total of 6,316 varicella cases were reported between 1997 and 2001. A varicella case was defined as “an illness characterized by acute onset of a diffuse papulovesicular rash without other known cause recognizing its variability in vaccinated persons.” Vaccination status of both cases and household contacts were based on immunization records and/or parental recall. Data from children and adolescents aged 1–14 years revealed secondary attack rates that varied according to age and by disease and vaccination status of the primary case and exposed household contacts. Among contacts aged 1–14 years exposed to unvaccinated cases, the secondary attack rate was 71.5% for unvaccinated household contacts and 15.1% among those who had been vaccinated. Overall, vaccinated cases were half as contagious as unvaccinated cases; however, vaccinated cases with 50 or more lesions were as contagious as unvaccinated cases. If fewer than 50 lesions were present in a vaccinated case, the secondary attack rate dropped to 23.4%. Calculated vaccine effectiveness for prevention of all disease was 78.9%, moderate disease 92%, and severe disease 100%. Disease (by history) was 90% protective in preventing a second episode of varicella. The reported variability of protection provided by the current varicella vaccine4 and the timing of its administration clearly require further study to provide the basis for decisions regarding the necessity of routine second varicella vaccination. 5 Meanwhile, pediatricians should reassure parents that although the varicella vaccine may not prevent the disease in every child, adverse reactions are uncommon, breakthrough disease is usually mild, and the prevention of severe disease almost certain. (See related articles in AAP Grand Rounds, May 2004;11:49–51.6–,8) Although varicella cases were based on clinical rather than laboratory criteria, the size of this study and consistency of the results suggest that the estimates of varicella vaccine efficacy and secondary attack rates are both valid and precise. You do not currently have access to this content.

Cost-effectiveness of a potential vaccine for human papillomavirus.

Human papillomavirus (HPV) infection, usually a sexually transmitted disease, is a risk factor for cervical cancer. Given the substantial disease and death associated with HPV and cervical cancer, development of a prophylactic HPV vaccine is a public health priority. We evaluated the cost-effectiveness of vaccinating adolescent girls for high-risk HPV infections relative to current practice. A vaccine with a 75% probability of immunity against high-risk HPV infection resulted in a life-expectancy gain of 2.8 days or 4.0 quality-adjusted life days at a cost of $246 relative to current practice (incremental cost effectiveness of $22,755/quality-adjusted life year [QALY]). If all 12-year-old girls currently living in the United States were vaccinated, >1,300 deaths from cervical cancer would be averted during their lifetimes. Vaccination of girls against high-risk HPV is relatively cost effective even when vaccine efficacy is low. If the vaccine efficacy rate is 35%, the cost effectiveness increases to $52,398/QALY. Although gains in life expectancy may be modest at the individual level, population benefits are substantial.

The cost-effectiveness of routine childhood varicella vaccination in Germany

This study explores the economic value of a routine varicella vaccination program for Germany. An age-structured decision analytic model was used to assess the benefits, costs and cost-effectiveness of an immunization program for a period of 30 years. Three interventions were compared with no vaccination: universal vaccination of around 15 months old healthy children, vaccination of susceptible adolescents (11–12 years of age), and the combined strategy. The analysis was conducted from both the societal perspective and the payers’, i.e. sickness funds, perspective. Input data were mainly derived from a retrospective survey (analyzed were1334 patient records) and from a seroprevalence study ( n=4602 sera). Using a coverage rate of 85% and a vaccine efficacy rate of 86% routine children vaccination could prevent around 611,000 varicella cases and over 4700 major complications per year. Average yearly cost savings for the society are 51.3 million Euro. The benefit-cost ratio (BCR) is 4.12. From the third-party payer’s perspective, the BCR is 1.75 which is a consequence of significant reimbursement of parent’s lost earnings by German sickness funds. The adolescent vaccination strategy has a favorable BCR ratio of 8.44 from the societal perspective, but clearly inferior medical effects. The combined vaccination strategy showed similar results as the children strategy. Routine childhood varicella vaccination appears to be a highly efficient strategy to reduce the burden of varicella and results in significant savings for both the society and the payers.

Cost-benefit analysis of a Haemophilus influenzae type b meningitis prevention programme in The Philippines.

Haemophilus influenzae type b (Hib) meningitis is associated with high mortality and serious sequelae in children under 5 years of age. Vaccines which can prevent this infection are available. To evaluate the costs and benefits of a 3-dose immunisation schedule in Manila, Philippines. Government and societal perspectives. A cost-benefit analysis based on a birth cohort of 100,000 children. The state of health of the cohort with and without a Hib immunisation programme was modelled over a 5-year period. A survey of medical records of patients with Hib in Manila provided data on the extent and cost of sequelae following infection. A 3-dose Hib vaccination programme given at ages 2, 3 and 4 months. The model predicted that vaccinating children against Hib meningitis would prevent 553 cases per year in a birth cohort of 100,000, at a cost of 56,200 Philippine pesos (PHP) [$US1,605; 1998 exchange rate] per case (base case assumptions of 90% vaccine efficacy rate, 95 per 100,000 Hib incidence rate, 85% vaccination coverage). Results from the cost-benefit analyses indicated that the saving to the government would be around PHP39 million ($US1.11 million), and the saving to society would be PHP255 million ($US7.28 million). There would be a positive economic benefit for the Philippine government and for the Filipino society if a Hib vaccination programme was introduced in Manila.

Rotavirus vaccines and vaccination in Latin America.

Worldwide, rotaviruses account for more than 125 million cases of infantile gastroenteritis and nearly 1 million deaths per year, mainly in developing countries. Rather than other control measures, vaccination is most likely to have a major impact on rotavirus disease incidence. The peak incidence of rotavirus diarrhea occurs between 6 and 24 months of age. In developing countries, however, cases are not uncommon among children younger than 6 months. G serotypes 1 to 4 are responsible for most disease, but there are indications that in Brazil that G type 5 is of emerging epidemiological importance. Both homotypic and heterotypic responses are elicited during natural rotavirus infection, and the immunological response at the intestinal mucosal surface is probably the more consistent predictor of clinical immunity. With the primary objective of protecting children against life-threatening dehydrating diarrhea, many approaches to rotavirus vaccine development have been attempted. One vaccine, the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV), was given licensing approval in the United States of America, introduced to the market, and later withdrawn. A number of studies have found better efficacy of RRV-TV in developed countries than in developing ones. Field trials with a 4 x 10(4) plaque-forming units (PFU) preparation of RRV-TV have been carried out in two countries in Latin America, Brazil and Peru. Those trials yielded protective efficacy rates against all rotavirus diarrhea ranging from 18% to 35%. Data from a large catchment trial in Venezuela with a higher RRV-TV dose, of 4 x 10(5) PFU/dose, indicated an efficacy rate of 48% against all rotavirus diarrhea and 88% against severe rotavirus diarrhea. It appears that breast-feeding does not compromise the efficacy of RRV-TV if three doses of the vaccine are administered. Similarly, possible interference of oral poliovirus vaccine with the "take" of the rotavirus vaccine can be overcome by giving three doses of the rotavirus vaccine or by using a higher-titer formulation of it. Wild enteroviruses, however, may cause primary rotavirus vaccine failure in developing countries. Studies in Peru with RRV-TV have shown a trend towards higher vaccine efficacy rates against "pure" (rotavirus-only) diarrheal episodes. Economic analyses made in the United States indicate that a vaccine that costs less than US$ 9 per dose would lead to a net savings in medical costs. To date, however, cost-benefit studies have not been done in developing countries. In the future, it is possible that some Latin American countries might adapt their polio production facilities to the preparation of rotavirus vaccines for human use. A year after RRV-TV was licensed for vaccination of infants in the United States, the occurrence of intussusception as an adverse event led to the vaccine's withdrawal from the market. The implications of that action, particularly for Latin America, will be addressed in this article, including the need to explore alternative rotavirus candidate vaccines, particularly through the conduct of parallel clinical trials in both developed and developing countries.

Introducing a Novel Model to Estimate National and global measles disease burden

Objectives: In discussions of expanded measles control, elimination, and possible eradication, better estimates of disease burden are increasingly important to target vaccination control measures. Because global surveillance for measles is inadequate, a model to quantify country-specific estimates of measles disease burden was formulated to help policy-makers consider control options. Methods: Country-specific demographics, developmental status, historic vaccine coverage rates, and age-specific vaccine efficacy and attack rates were used to determine the number of measles cases and deaths for 5-year periods. Results: The model estimates an annual global incidence of 32 million measles-susceptible persons (∼25% of the global birth cohort), resulting in 28 million cases and 691 thousand deaths. Eighty-four percent (578,000) of the global deaths occur in the World Health Organization African and Southeast Asian regions. Twenty countries account for 82% of deaths attributable to measles. In nine countries, over 2% of the birth-cohort are estimated to die from measles. Conclusions: This methodology quantifies country- and age-specific measles disease burden and establishes regional and global disease patterns, allowing aggregations by income groups and regions, which aids policy formulation. The data may be continuously updated, based on dynamic changes in vaccine coverage rates and the incorporation of national vaccination campaigns.

Pneumococcal Immunization Program: Cost‐Utility Analysis for Quebec

A cost-utility analysis of a pneumococcal immunization program was conducted for Quebec. The goal of this study was to estimate the cost, effectiveness and benefit of an immunization program against pneumococcal infection in Quebec. Two strategies were evaluated using the cu rrent situation of infrequent use of 23-valent polysaccharide vaccine as a reference point. The first strategy the 'private ' program was a vaccine promotion program, with no change in the current distribution system. The second strategy the 'public' program consisted of a promotional program combined with free vaccine distribution through the public health care system. The pneumococcal immunization program targeted practically the same clientele as the influenza program , so that in the two scenarios promotional activities and vaccination were linked . A cost-utility analysis was conducted for four target groups: persons living in residential and extended care centres , persons with certain predisposing chronic conditions (primarily diabetes and heart or lung disease) , persons with human immunodeficiency virus (HIV), and person aged 65 years and over who do not fall into any of the other categories. An additional analysis was conducted for all persons aged 65 years and over, with or without a predisposing chronic condition. Assuming that the same number of individuals would be immunized against influenza and pneumococcus , there would be about 100,000 persons to vaccinate each yea r when the program was in its maintenance phase, and about 375,000 persons targeted for catch-up. In the basic scenario, the vaccine was considered of maximum efficacy in preventing invasive infections with bacteremia but less than half as effective in preventing infections without bacteremia, which are twice as common. Sensitivity analyses were conducted on the assumption that the vaccine was totally ineffective in preventing infections without bacteremia or that it was just as effective for both types of infections. The vaccine efficacy rates were taken from the case control study with the most subjects, and reflected reduced efficacy over the course of time and the fact that 10% of strains are not covered by 23-valent vaccine. For persons with HIV, we used efficacy estimates from a group of American experts. In the basic scenario, the total cost of a private program is about $1 million, two-thirds of which is borne by individuals through vaccine purchases and one-third by the public sector (vaccination). The unit cost is $22.80 per dose. If it was decided to revaccinate individuals at risk after six years, the cost would increase by about $1.7 million to a total of$2.7 million per year for the program. In a public program, all costs, a little less than $800,000, are borne by the public sector. The unit cost is $22.1 O per dose. The difference of approximately one-quarter of a million dol -

A Bioeconomic Analysis of Bovine Respiratory Disease Complex

Bovine Respiratory Disease Complex (BRDC) is an important disease affecting both beef and dairy cattle produced in confinement operations. A bioeconomic model of BRDC is developed for a typical Midwestern feedlot. Using vaccine efficacy rates found in the veterinary science literature, significant returns to vaccination are estimated.