Partial vaccination programs and the eradication of infectious diseases

We incorporate the possibility of eradicating infectious diseases through partial vaccinations into a static model where each individual incurs a cost, which differs among the individuals, when he/she is administered a vaccine. We show that if an infectious disease is eradicated by vaccinating up to the individual whose vaccination cost is lower than a threshold, then the partial compulsory vaccination program is strictly preferable to the free choice vaccination program in terms of social welfare otherwise, the free choice vaccination program is strictly preferable to the partial compulsory vaccination program. Our result is a generalization of Brito, Sheshinski, and Intriligator (1991).infectious disease, partial compulsory vaccination, eradication

Role of word-of-mouth for programs of voluntary vaccination: A game-theoretic approach

We propose a model describing the synergetic feedback between word-of-mouth (WoM) and epidemic dynamics controlled by voluntary vaccination. We combine a game-theoretic model for the spread of WoM and a compartmental model describing $SIR$ disease dynamics in the presence of a program of voluntary vaccination. We evaluate and compare two scenarios, depending on what WoM disseminates: (1) vaccine advertising, which may occur whether or not an epidemic is ongoing and (2) epidemic status, notably disease prevalence. Understanding the synergy between the two strategies could be particularly important for organizing voluntary vaccination campaigns. We find that, in the initial phase of an epidemic, vaccination uptake is determined more by vaccine advertising than the epidemic status. As the epidemic progresses, epidemic status become increasingly important for vaccination uptake, considerably accelerating vaccination uptake toward a stable vaccination coverage.Comment: 10 pages, 2 figure

Using Intervention Mapping to Develop an Efficacious Multicomponent Systems-Based Intervention to Increase Human Papillomavirus (HPV) Vaccination in a Large Urban Pediatric Clinic Network

Background: The CDC recommends HPV vaccine for all adolescents to prevent cervical, anal, oropharyngeal, vaginal, vulvar, and penile cancers, and genital warts. HPV vaccine rates currently fall short of national vaccination goals. Despite evidence-based strategies with demonstrated efficacy to increase HPV vaccination rates, adoption and implementation of these strategies within clinics is lacking. The Adolescent Vaccination Program (AVP) is a multicomponent systems-based intervention designed to implement five evidence-based strategies within primary care pediatric practices. The AVP has demonstrated efficacy in increasing HPV vaccine initiation and completion among adolescents 10-17 years of age. The purpose of this paper is to describe the application of Intervention Mapping (IM) toward the development, implementation, and formative evaluation of the clinic-based AVP prototype. Methods: Intervention Mapping (IM) guided the development of the Adolescent Vaccination Program (AVP). Deliverables comprised: a logic model of the problem (IM Step 1); matrices of behavior change objectives (IM Step 2); a program planning document comprising scope, sequence, theory-based methods, and practical strategies (IM Step 3); functional AVP component prototypes (IM Step 4); and plans for implementation (IM Step 5) and evaluation (IM Step 6). Results: The AVP consists of six evidence-based strategies implemented in a successful sequenced roll-out that (1) established immunization champions in each clinic, (2) disseminated provider assessment and feedback reports with data-informed vaccination goals, (3) provided continued medical and nursing education (with ethics credit) on HPV, HPV vaccination, message bundling, and responding to parent hesitancy, (4) electronic health record cues to providers on patient eligibility, and (5) patient reminders for HPV vaccine initiation and completion. Conclusions: IM provided a logical and systematic approach to developing and evaluating a multicomponent systems-based intervention to increase HPV vaccination rates among adolescents in pediatric clinics

Implementation of an HPV vaccination program in Eldoret, Kenya: results from a qualitative assessment by key stakeholders

Background: Cervical cancer strikes hard in low-resource regions yet primary prevention is still rare. Pilot projects have however showed that Human Papillomavirus (HPV) vaccination programs can attain high uptake. Nevertheless, a study accompanying a vaccination demonstration project in Eldoret, Kenya, revealed less encouraging outcomes: uptake during an initial phase targeting ten schools (i.e., 4000 eligible girls), was low and more schools had to be included to reach the proposed number of 3000 vaccinated girls. The previously conducted study also revealed that many mothers had not received promotional information which had to reach them through schools: teachers were sensitized by health staff and asked to invite students and parents for HPV vaccination in the referral hospital. In this qualitative study, we investigate factors that hampered promotion and vaccine uptake. Methods: Focus group discussions (FGD) with teachers (4) and fathers (3) were organized to assess awareness and attitudes towards the vaccination program, cervical cancer and the HPV vaccine, as well as a FGD with the vaccinators (1) to discuss the course of the program and potential improvements. Discussions were recorded, transcribed, translated, and analyzed using thematic analysis In addition, a meeting with the program coordinator was set up to reflect upon the program and the results of the FGD, and to formulate recommendations for future programs. Results: Cervical cancer was poorly understood by fathers and teachers and mainly linked with nonconforming sexual behavior and modern lifestyle. Few had heard about the vaccination opportunity: feeling uncomfortable to discuss cervical cancer and not considering it as important had hampered information flow. Teachers requested more support from health staff to address unexpected questions from parents. Non-uptake was also the result of distrust towards new vaccines. Schools entering the program in the second phase reacted faster: they were better organized, e.g., in terms of transport, while the community was already more familiarized with the vaccine. Conclusions: Close collaboration between teachers and health staff is crucial to obtain high HPV vaccine uptake among schoolgirls. Promotional messages should, besides providing correct information, tackle misbeliefs, address stigma and stress the priority to vaccinate all, regardless of lifestyle. Monitoring activities and continuous communication could allow for detection of rumors and unequal uptake in the community

Game-Theoretical Model of Retroactive Hepatitis B Vaccination in China

Game-Theoretical Model of Retroactive Hepatitis B Vaccination in China Vooha Putalapattu, Depts. of Psychology, Chemistry, & Biology, with Dr. Jan Rychtar, Dept. of Mathematics Hepatitis B (HepB) is one of the most common infectious diseases affecting over two billion people worldwide. About one third of all HepB cases are in China. In recent years, China made significant efforts to implement a nationwide HepB vaccination program and reduced the number of unvaccinated infants from 30% to 10%. However, many individuals still remain unprotected, particularly those born before 2003. Consequently, a catch-up retroactive vaccination is an important and especially cost-effective way to reduce HepB prevalence. In this paper, we analyze a game theoretical model of HepB dynamics that incorporates government-provided vaccination at birth coupled with voluntary retroactive vaccinations. We show that this retroactive vaccination should be a necessary component of any HepB eradication effort. Due to the vaccine waning, the optimal vaccination rates are almost independent of the vaccination coverage at birth. Moreover, it is in an individual\u27s self-interest to vaccinate (and re-vaccinate) at a rate just slightly below the vaccine waning rate.https://scholarscompass.vcu.edu/uresposters/1329/thumbnail.jp

Cost-benefit analysis of foot and mouth disease control in Ethiopia

Foot and mouth disease (FMD) occurs endemically in Ethiopia. Quantitative insights on its national economic impact and on the costs and benefits of control options are, however, lacking to support decision making in its control. The objectives of this study were, therefore, to estimate the annual costs of FMD in cattle production systems of Ethiopia, and to conduct an ex ante cost-benefit analysis of potential control alternatives.<br/><br/>The annual costs of FMD were assessed based on production losses, export losses and control costs. The total annual costs of FMD under the current status quo of no official control program were estimated at 1354 (90% CR: 864–2042) million birr. The major cost (94%) was due to production losses. The costs and benefits of three potential control strategies: 1) ring vaccination (reactive vaccination around outbreak area supported by animal movement restrictions, 2) targeted vaccination (annual preventive vaccination in high risk areas plus ring vaccination in the rest of the country), and 3) preventive mass vaccination (annual preventive vaccination of the whole national cattle population) were compared with the baseline scenario of no official control program. Experts were elicited to estimate the influence of each of the control strategies on outbreak incidence and number of cases per outbreak. Based on these estimates, the incidence of the disease was simulated stochastically for 10 years. Preventive mass vaccination was epidemiologically the most efficient control strategy by reducing the national outbreak incidence below 5% with a median time interval of 3 years, followed by targeted vaccination strategy with a corresponding median time interval of 5 years. On average, all evaluated control strategies resulted in positive net present values. The ranges in the net present values were, however, very wide, including negative values. The targeted vaccination strategy was the most economic strategy with a median benefit cost ratio of 4.29 (90%CR: 0.29–9.63). It was also the least risky strategy with 11% chance of a benefit cost ratio of less than one.<br/><br/>The study indicates that FMD has a high economic impact in Ethiopia. Its control is predicted to be economically profitable even without a full consideration of gains from export. The targeted vaccination strategy is shown to provide the largest economic return with a relatively low risk of loss. More studies to generate data, especially on production impact of the disease and effectiveness of control measures are needed to improve the rigor of future analysis.<br/

Uptake of the human papillomavirus vaccine in Kenya : testing the health belief model through pathway modeling on cohort data

Background: Many studies investigate HPV vaccine acceptability, applying health behavior theories to identify determinants; few include real uptake, the final variable of interest. This study investigated the utility of the Health Belief Model (HBM) in predicting HPV vaccine uptake in Kenya, focusing on the importance of promotion, probing willingness to vaccinate as precursor of uptake and exploring the added value of personal characteristics. Methods: Longitudinal data were collected before and after a pilot HPV vaccination program in Eldoret among mothers of eligible girls (N = 255). Through pathway modeling, associations between vaccine uptake and the HBM constructs, willingness to vaccinate and adequate promotion were examined. Adequate promotion was defined as a personal evaluation of promotional information received. Finally, baseline cervical cancer awareness and socio-demographic variables were added to the model verifying their direct, mediating or moderating effects on the predictive value of the HBM. Results: Perceiving yourself as adequately informed at follow-up was the strongest determinant of vaccine uptake. HBM constructs (susceptibility, self-efficacy and foreseeing father's refusal as barrier) only influenced willingness to vaccinate, which was not correlated with vaccination. Baseline awareness of cervical cancer predicted uptake. Conclusions: The association between adequate promotion and vaccination reveals the importance of triggers beyond personal control. Adoption of new health behaviors might be more determined by organizational variables, such as promotion, than by prior personal beliefs. Assessing users' and non-users' perspectives during and after implementing a vaccination program can help identifying stronger determinants of vaccination behavior

Costs of delivering human papillomavirus vaccination to schoolgirls in Mwanza Region, Tanzania.

BACKGROUND: Cervical cancer is the leading cause of female cancer-related deaths in Tanzania. Vaccination against human papillomavirus (HPV) offers a new opportunity to control this disease. This study aimed to estimate the costs of a school-based HPV vaccination project in three districts in Mwanza Region (NCT ID: NCT01173900), Tanzania and to model incremental scaled-up costs of a regional vaccination program. METHODS: We first conducted a top-down cost analysis of the vaccination project, comparing observed costs of age-based (girls born in 1998) and class-based (class 6) vaccine delivery in a total of 134 primary schools. Based on the observed project costs, we then modeled incremental costs of a scaled-up vaccination program for Mwanza Region from the perspective of the Tanzanian government, assuming that HPV vaccines would be delivered through the Expanded Programme on Immunization (EPI). RESULTS: Total economic project costs for delivering 3 doses of HPV vaccine to 4,211 girls were estimated at about US$349,400 (including a vaccine price of US$5 per dose). Costs per fully-immunized girl were lower for class-based delivery than for age-based delivery. Incremental economic scaled-up costs for class-based vaccination of 50,290 girls in Mwanza Region were estimated at US$1.3 million. Economic scaled-up costs per fully-immunized girl were US$26.41, including HPV vaccine at US$5 per dose. Excluding vaccine costs, vaccine could be delivered at an incremental economic cost of US$3.09 per dose and US$9.76 per fully-immunized girl. Financial scaled-up costs, excluding costs of the vaccine and salaries of existing staff were estimated at US$1.73 per dose. CONCLUSIONS: Project costs of class-based vaccination were found to be below those of age-based vaccination because of more eligible girls being identified and higher vaccine uptake. We estimate that vaccine can be delivered at costs that would make HPV vaccination a very cost-effective intervention. Potentially, integrating HPV vaccine delivery with cost-effective school-based health interventions and a reduction of vaccine price below US$5 per dose would further reduce the costs per fully HPV-immunized girl

Vaccines: Propaganda and Practice

Vaccines are a cost effective, time tested means of reducing morbidity and mortality. As more and more new vaccines are introduced and more diseases come under the purview of ‘vaccination net’, the routine immunization program is sidelined.\ud This is compounded by vaccination practices in private health care system and anti vaccine propaganda and confusing pro vaccine propaganda. The primary purpose of the vaccine is shifting from prevention of diseases to monetary gains for the health care providers and manufacturers. There is a need to regulate the vaccination practices in the private health care system especially in the developing countries. The regulatory process should educate not only the community but also the health care providers and take adequate measures to control the ‘vaccine market forces

Economic evaluation of HBV vaccination: a systematic review of recent publications (2000-2013).

Aim: To conduct a systematic review of the economic evaluations (EE) of HBV vaccination, taking also into account the studies published in the new millennium. Methods: An extensive scientific literature review was conducted using two electronic medical journal databases: Scopus and PubMed engines for published studies on EE of HBV vaccination. Results: 22 articles were reviewed, 9, 5 and 8 cost-effectiveness, cost-benefit and cost-utility analysis, respectively. Studies were mainly concerning EE of universal vaccination (UV), mostly with regards to low or low-medium income countries. For high income countries, EE were focused on the possible implementation of HBV vaccination in particular settings, such as diabetic, renal and other chronic conditions care, as well as infectious diseasesUV has usually a very good cost-effectiveness ratio (80%), ranging from cost-saving (China) or few Euro per LY/QALY gained (in Thailand, and Vietnam) to 630.00$/ QALY in USA (Asian and Pacific Islands) Moreover, EE of HBV vaccination are favorable in the infectious diseases field as well as for chronic conditions. In relation to diabetes the studies gave controversial results. Conclusion: This systematic review highlighted the importance of introducing HBV vaccination not only for infant UV program but also for other settings in which patients are people affected by communicable and non-communicable diseases