Guaranteed Cash Incentives Boosted COVID-19 Vaccinations Of Young Adults: Evidence From West Virginia.

Guaranteed small cash incentives were widely employed by policy makers during the COVID-19 vaccination campaign, but the impact of these programs has been largely understudied. We were the first to exploit a statewide natural experiment of one such program implemented in West Virginia in 2021 that provided a $100 incentive to fully vaccinated adults ages 16-35. Using individual-level data from the Census Bureau's Household Pulse Survey, we isolated the policy effect through a difference-in-discontinuities design that exploited the discontinuity in incentive eligibility at age thirty-five. We found that the $100 incentive was associated with a robust increase in the proportion of people ever vaccinated against COVID-19 and the proportion who completed or intended to complete the primary series of COVID-19 vaccines. The policy effects were also likely to be more pronounced among people with low incomes, those who were unemployed, and those with no prior COVID-19 infection. The guaranteed cash incentive program may have created more equitable access to vaccines for disadvantaged populations. Additional outreach may also be needed, especially to unvaccinated people with prior COVID-19 infections.

Public health and economic benefits of seasonal influenza vaccination in risk groups in France, Italy, Spain and the UK: state of play and perspectives.

BACKGROUND: Seasonal influenza epidemics have a substantial public health and economic burden, which can be alleviated through vaccination. The World Health Organization (WHO) recommends a 75% vaccination coverage rate (VCR) in: older adults (aged ≥ 65 years), individuals with chronic conditions, pregnant women, children aged 6-24 months and healthcare workers. However, no European country achieves this target in all risk groups. In this study, potential public health and economic benefits achieved by reaching 75% influenza VCR was estimated in risk groups across four European countries: France, Italy, Spain, and the UK. METHODS: A static epidemiological model was used to estimate the averted public health and economic burden of increasing the 2021/2022 season VCR to 75%, using the efficacy data of standard-dose quadrivalent influenza vaccine. For each country and risk group, the most recent data on population size, VCR, pre-pandemic influenza epidemiology, direct medical costs and absenteeism were identified through a systematic literature review, supplemented by manual searching. Outcomes were: averted influenza cases, general practitioner (GP) visits, hospitalisations, case fatalities, number of days of work lost, direct medical costs and absenteeism-related costs. RESULTS: As of the 2021/2022 season, the UK achieved the highest weighted VCR across risk groups (65%), followed by Spain (47%), France (44%) and Italy (44%). Based on modelling, the 2021/2022 VCR prevented an estimated 1.9 million influenza cases, avoiding 375,200 GP visits, 73,200 hospitalisations and 38,400 deaths. To achieve the WHO 75% VCR target, an additional 24 million at-risk individuals would need to be vaccinated, most of which being older adults and patients with chronic conditions. It was estimated that this could avoid a further 918,200 influenza cases, 332,000 GP visits, 16,300 hospitalisations and 6,300 deaths across the four countries, with older adults accounting for 52% of hospitalisations and 80% of deaths. An additional €84 million in direct medical costs and €79 million in absenteeism costs would be saved in total, with most economic benefits delivered in France. CONCLUSIONS: Older adults represent most vaccine-preventable influenza cases and deaths, followed by individuals with chronic conditions. Health authorities should prioritise vaccinating these populations for maximum public health and economic benefits.

Evaluating the health and economic outcomes of a PCV15 vaccination program for adults aged 65 years-and-above in Switzerland.

OBJECTIVE: To assess the health and economic outcomes of a PCV13 or PCV15 age-based (65 years-and-above) vaccination program in Switzerland. INTERVENTIONS: The three vaccination strategies examined were:Target population: All adults aged 65 years-and-above. Perspective(s): Switzerland health care payer. TIME HORIZON: 35 years. Discount rate: 3.0%. Costing year: 2023 Swiss Francs (CHF). STUDY DESIGN: A static Markov state-transition model. DATA SOURCES: Published literature and publicly available databases or reports. OUTCOME MEASURES: Pneumococcal diseases (PD) i.e., invasive pneumococcal diseases (IPD) and non-bacteremic pneumococcal pneumonia (NBPP); total quality-adjusted life-years (QALYs), total costs and incremental cost-effectiveness ratios (CHF/QALY gained). RESULTS: Using an assumed coverage of 60%, the PCV15 strategy prevented a substantially higher number of cases/deaths than the PCV13 strategy when compared to the No vaccination strategy (1,078 IPD; 21,155 NBPP; 493 deaths). The overall total QALYs were 10,364,620 (PCV15), 10,364,070 (PCV13), and 10,362,490 (no vaccination). The associated overall total costs were CHF 741,949,814 (PCV15), CHF 756,051,954 (PCV13) and CHF 698,329,579 (no vaccination). Thus, the PCV13 strategy was strongly dominated by the PCV15 strategy. The ICER of the PCV15 strategy (vs. no vaccination) was CHF 20,479/QALY gained. In two scenario analyses where the vaccine effectiveness for serotype 3 were reduced (75% to 39.3% for IPD; 45% to 23.6% for NBPP) and NBPP incidence was increased (from 1,346 to 1,636/100,000), the resulting ICERs were CHF 29,432 and CHF 13,700/QALY gained, respectively. The deterministic and probabilistic sensitivity analyses demonstrated the robustness of the qualitative results-the estimated ICERs for the PCV15 strategy (vs. No vaccination) were all below CHF 30,000/QALYs gained. CONCLUSIONS: These results demonstrate that using PCV15 among adults aged 65 years-and-above can prevent a substantial number of PD cases and deaths while remaining cost-effective over a range of inputs and scenarios.

Economic burden of pertussis in children: A single-center analysis in Hangzhou, China.

The "reemergence of pertussis" has elicited international concerns, occurring paradoxically amidst the expansion of immunization programs. This study was aimed to evaluate quantitatively the economic burden and identify the determinants that influence the cost associated with treating pertussis in Chinese children. We evaluated the economic burden by Chinese children diagnosed with pertussis at the Children's Hospital, Zhejiang University School of Medicine in 2022. Direct medical expenses and the utilization of medical resources attributed to pertussis were calculated. A generalized linear regression model was applied to analyze the determinants that were associated with the direct medical expenses among patients. Among the 1110 pertussis patients included in the study, 1060 were outpatients and 50 were inpatients. The average direct medical cost was ¥1878.70(i.e. $279.33). Living in urban areas (OR:1.27, p = .04), complications (OR:1.40, p < .001), hospitalization (OR:10.04, p < .001), and ≥ 3 medical visits (OR:3.71, p < .001) were associated with increased direct medical expenses. Having received four doses of the pertussis vaccine was associated with reduced direct medical expenses (OR:0.81, p = .04). This study underscores a substantial economic burden of pertussis in Hangzhou, with pronounced implications for patients residing in urban areas, experiencing complications, requiring hospitalization, having multiple medical consultations, or lacking comprehensive pertussis vaccination.

An economic evaluation and incremental analysis of the cost effectiveness of three universal childhood varicella vaccination strategies for Ireland.

BACKGROUND: The cost effectiveness of childhood varicella vaccination is uncertain, as evidenced by variation in national health policies. Within the European Economic Area (EEA), only 10 of 30 countries offer universally funded childhood varicella vaccination. This study estimates the cost effectiveness of universal childhood varicella vaccination for one EEA country (Ireland), highlighting the difference in cost effectiveness between alternative vaccination strategies. METHODS: An age-structured dynamic transmission model, simulating varicella zoster virus transmission, was developed to analyse the impact of three vaccination strategies; one-dose at 12 months old, two-dose at 12 and 15 months old (short-interval), and two-dose at 12 months and five years old (long-interval). The analysis adopted an 80-year time horizon and considered payer and societal perspectives. Clinical effectiveness was based on cases of varicella and subsequently herpes zoster and post-herpetic neuralgia avoided, and outcomes were expressed in quality-adjusted life-years (QALYs). Costs were presented in 2022 Irish Euro and cost effectiveness was interpreted with reference to a willingness-to-pay threshold of €20,000 per QALY gained. RESULTS: From the payer perspective, the incremental cost-effectiveness ratio (ICER) for a one-dose strategy, compared with no vaccination, was estimated at €8,712 per QALY gained. The ICER for the next least expensive strategy, two-dose long-interval, compared with one-dose, was estimated at €45,090 per QALY gained. From a societal perspective, all three strategies were cost-saving compared with no vaccination; the two-dose short-interval strategy dominated, yielding the largest cost savings and health benefits. Results were stable across a range of sensitivity and scenario analyses. CONCLUSION: A one-dose strategy was highly cost effective from the payer perspective, driven by a reduction in hospitalisations. Two-dose strategies were cost saving from the societal perspective. These results should be considered alongside other factors such as acceptability of a new vaccine within the overall childhood immunisation schedule, programme objectives and budget impact.

Cost-effectiveness analysis of 20-valent pneumococcal conjugate vaccine for routine pediatric vaccination programs in Japan.

BACKGROUND: The Japanese National Immunization Program currently includes the pediatric 13 valent pneumococcal conjugate vaccine (PCV13) to prevent pneumococcal infections. We aimed to evaluate the cost-effectiveness of 20-valent PCV (PCV20) as a pediatric vaccine versus PCV13. METHODS: A decision-analytic Markov model was used to estimate expected costs, quality-adjusted life-years (QALYs), and prevented cases and deaths caused by invasive pneumococcal disease, pneumonia, and acute otitis media over a ten-year time horizon from the societal and healthcare payer perspectives. RESULTS: PCV20 was dominant, i.e. less costly and more effective, over PCV13 (gained 294,599 QALYs and reduced Japanese yen [JPY] 352.6 billion [2.6 billion United States dollars, USD] from the societal perspective and JPY 178.9 billion [USD 1.4 billion] from the payer perspective). Sensitivity and scenario analyses validated the robustness of the base scenario results. When comparing PCV20 with PCV13, the threshold analysis revealed an incremental cost-effectiveness ratio that was within the threshold value (JPY 5 million/QALY) at a maximum acquisition cost of JPY 74,033 [USD 563] (societal perspective) and JPY 67,758 [USD 515] (payer perspective). CONCLUSIONS: As a pediatric vaccine, PCV20 was dominant over PCV13 regardless of the study perspective.

Vaccination May Be Economically and Epidemiologically Advantageous Over Frequent Screening for Gonorrhea Prevention.

BACKGROUND: Gonorrhea's rapid development of antimicrobial resistance underscores the importance of new prevention modalities. Recent evidence suggests that a serogroup B meningococcal vaccine may be partially effective against gonococcal infection. However, the viability of vaccination and the role it should play in gonorrhea prevention are an open question. METHODS: We modeled the transmission of gonorrhea over a 10-year period in a heterosexual population to find optimal patterns of year-over-year investment of a fixed budget in vaccination and screening programs. Each year, resources could be allocated to vaccinating people or enrolling them in a quarterly screening program. Stratifying by mode (vaccination vs. screening), sex (male vs. female), and enrollment venue (background screening vs. symptomatic visit), we consider 8 different ways of controlling gonorrhea. We then found the year-over-year pattern of investment among those 8 controls that most reduced the incidence of gonorrhea under different assumptions. A compartmental transmission model was parameterized from existing literature in the US context. RESULTS: Vaccinating men with recent symptomatic infection, which selected for higher sexual activity, was optimal for population-level gonorrhea control. Given a prevention budget of $3 per capita, 9.5% of infections could be averted ($299 per infection averted), decreasing gonorrhea sequelae and associated antimicrobial use by similar percentages. These results were consistent across sensitivity analyses that increased the budget, prioritized incidence or prevalence reductions in women, or lowered screening costs. Under a scenario where only screening was implemented, just 5.5% of infections were averted. CONCLUSIONS: A currently available vaccine, although only modestly effective, may be superior to frequent testing for population-level gonorrhea control.

Cost-effectiveness of seasonal influenza vaccination of children in China: a modeling analysis.

BACKGROUND: China has a high burden of influenza-associated illness among children. We aimed to evaluate the cost-effectiveness of introducing government-funded influenza vaccination to children in China (fully-funded policy) compared with the status quo (self-paid policy). METHODS: A decision tree model was developed to calculate the economic and health outcomes, from a societal perspective, using national- and provincial-level data. The incremental cost-effectiveness ratio (ICER) [incremental costs per quality-adjusted life year (QALY) gained] was used to compare the fully-funded policy with the self-paid policy under the willingness-to-pay threshold equivalent to national and provincial GDP per capita. Sensitivity analyses were performed and various scenarios were explored based on real-world conditions, including incorporating indirect effect into the analysis. RESULTS: Compared to the self-paid policy, implementation of a fully-funded policy could prevent 1,444,768 [95% uncertainty range (UR): 1,203,446-1,719,761] symptomatic cases, 92,110 (95% UR: 66,953-122,226) influenza-related hospitalizations, and 6494 (95% UR: 4590-8962) influenza-related death per season. The fully-funded policy was cost-effective nationally (7964 USD per QALY gained) and provincially for 13 of 31 provincial-level administrative divisions (PLADs). The probability of a funded vaccination policy being cost-effective was 56.5% nationally, and the probability in 9 of 31 PLADs was above 75%. The result was most sensitive to the symptomatic influenza rate among children under 5 years [ICER ranging from - 25,612 (cost-saving) to 14,532 USD per QALY gained]. The ICER of the fully-funded policy was substantially lower (becoming cost-saving) if the indirect effects of vaccination were considered. CONCLUSIONS: Introducing a government-funded influenza policy for children is cost-effective in China nationally and in many PLADs. PLADs with high symptomatic influenza rate and influenza-associated mortality would benefit the most from a government-funded influenza vaccination program.

Correspondence to: Estimating the full health and economic benefits of current and future influenza vaccines.

We recently published an article in BMC Medicine looking at the potential health and economic impact of paediatric vaccination using next-generation influenza vaccines in Kenya: a modelling study. In their commentary on our article, Lafond et al. highlight the potential importance of the wider benefits of vaccination on cost-effectiveness. Whilst we agree with many points raised in the commentary, we think it raises further interesting discussion points, specifically around model complexity, model assumptions and data availability. These points are both relevant to this manuscript but have wider implications for vaccine cost-effectiveness studies.

Estimating the delivery costs of COVID-19 vaccination using the COVID-19 Vaccine Introduction and deployment Costing (CVIC) tool: the Lao People's Democratic Republic experience.

BACKGROUND: The COVID-19 Vaccine Introduction and deployment Costing (CVIC) tool was developed to assist countries to estimate incremental financial costs to roll out COVID-19 vaccines. This article describes the purposes, assumptions and methods used in the CVIC tool and presents the estimated financial costs of delivering COVID-19 vaccines in the Lao People's Democratic Republic (Lao PDR). METHODS: From March to September 2021, a multidisciplinary team in Lao PDR was involved in the costing exercise of the National Deployment and Vaccination Plan for COVID-19 vaccines to develop potential scenarios and gather inputs using the CVIC tool. Financial costs of introducing COVID-19 vaccines for 3 years from 2021 to 2023 were projected from the government perspective. All costs were collected in 2021 Lao Kip and presented in United States dollar. RESULTS: From 2021 to 2023, the financial cost required to vaccinate all adults in Lao PDR with primary series of COVID-19 vaccines (1 dose for Ad26.COV2.S (recombinant) vaccine and 2 doses for the other vaccine products) is estimated to be US$6.44 million (excluding vaccine costs) and additionally US$1.44 million and US$1.62 million to include teenagers and children, respectively. These translate to financial costs of US$0.79-0.81 per dose, which decrease to US$0.6 when two boosters are introduced to the population. Capital and operational cold-chain costs contributed 15-34% and 15-24% of the total costs in all scenarios, respectively. 17-26% went to data management, monitoring and evaluation, and oversight, and 13-22% to vaccine delivery. CONCLUSIONS: With the CVIC tool, costs of five scenarios were estimated with different target population and booster dose use. These facilitated Lao PDR to refine their strategic planning for COVID-19 vaccine rollout and to decide on the level of external resources needed to mobilize and support outreach services. The results may further inform inputs in cost-effectiveness or cost-benefit analyses and potentially be applied and adjusted in similar low- and middle-income settings.

Lessons Learned from Health Disparities in Coronavirus Disease-2019 in the United States.

In the United States, the coronavirus disease-2019 (COVID-19) pandemic has disproportionally affected Black, Latinx, and Indigenous populations, immigrants, and economically disadvantaged individuals. Such historically marginalized groups are more often employed in low-wage jobs without health insurance and have higher rates of infection, hospitalization, and death from COVID-19 than non-Latinx White individuals. Mistrust in the health care system, language barriers, and limited health literacy have hindered vaccination rates in minorities, further exacerbating health disparities rooted in structural, institutional, and socioeconomic inequities. In this article, we discuss the lessons learned over the last 2 years and how to mitigate health disparities moving forward.

Use of Utility and Disability Weights in Economic Evaluation of Pediatric Vaccines.

OBJECTIVE: To describe how utility weights and disability weights have been used in the context of quality-adjusted life-years (QALYs) and disability-adjusted life-years (DALYs)-based cost-effectiveness analysis (CEA) of pediatric vaccines for infectious diseases and assess the comparability between weights. METHODS: A systematic review was conducted of CEAs of pediatric vaccines for 16 infectious diseases, published between January 2013 and December 2020 and using QALYs or DALYs as outcome measure. Data on values and sources of weights for the estimation of QALYs and DALYs were extracted from studies and compared across similar health states. Reporting was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. RESULTS: Out of 2154 articles identified, 216 CEAs met our inclusion criteria. Of the included studies, 157 used utility weights and 59 used disability weights in their valuation of health states. In QALY studies, the source, background, who's preferences (adults'/children's) were applied and adjustments made to utility weights were poorly reported. In DALY studies, the Global Burden of Disease study was most often referenced. Valuation weights for similar health states varied within QALY studies and between DALY and QALY studies, but no systematic differences were identified. CONCLUSIONS: This review identified considerable gaps in the way valuation weights are used and reported on in CEA. The nonstandardized use of weights may lead to different conclusions about cost-effectiveness of vaccines and policy decisions.

Financial incentives for vaccination do not have negative unintended consequences.

Financial incentives to encourage healthy and prosocial behaviours often trigger initial behavioural change1-11, but a large academic literature warns against using them12-16. Critics warn that financial incentives can crowd out prosocial motivations and reduce perceived safety and trust, thereby reducing healthy behaviours when no payments are offered and eroding morals more generally17-24. Here we report findings from a large-scale, pre-registered study in Sweden that causally measures the unintended consequences of offering financial incentives for taking the first dose of a COVID-19 vaccine. We use a unique combination of random exposure to financial incentives, population-wide administrative vaccination records and rich survey data. We find no negative consequences of financial incentives; we can reject even small negative impacts of offering financial incentives on future vaccination uptake, morals, trust and perceived safety. In a complementary study, we find that informing US residents about the existence of state incentive programmes also has no negative consequences. Our findings inform not only the academic debate on financial incentives for behaviour change but also policy-makers who consider using financial incentives to change behaviour.

Correspondencia vacunación-inmunización como necesidad social y reto para la ciencia y la educación médica / Vaccination-immunization correspondence as a social need and challenge for science and medical education

Introducción: La vacunación constituye el arma preventiva más efectiva para las enfermedades trasmisibles que conoce la humanidad. Hacer que las vacunas aplicadas sean realmente inmunizantes resulta la responsabilidad de los profesionales de la atención primaria. Del mismo modo, es importante que se acepte, sin recelo, la vacunación, sobre todo en la situación epidemiológica actual. Objetivo: Describir las implicaciones sociales, económicas y éticas relacionadas con la existencia de vacunas teóricamente no inmunizantes. Métodos: Se emplearon los resultados de un programa de intervención educativa en edades pediátricas en el Policlínico 13 de marzo. Se utilizó la prueba de rangos con signo de Wilcoxon, con índice de confianza del 95 por ciento. Resultados: Inicialmente, predominó el nivel inadecuado de conocimiento, que luego mejoró significativamente. Se recuperaron 48 niños no vacunados y 29 vacunaciones no inmunizados. Conclusiones: No existe correspondencia entre las coberturas vacunales y la inmunización. Están instauradas, como correctas, falsas contraindicaciones para la vacunación. La intervención educativa fue efectiva, y se hizo patente la pertinencia de programas de pregrado y posgrado que perfeccionen la formación de los profesionales y la calidad en el desempeño profesional(AU)

Introduction: Vaccination is the most effective preventive weapon for communicable diseases known to humanity. It is the responsibility of primary health care professionals to ensure that the administered vaccines are truly immunizing. Likewise, it is important that vaccination be accepted without hesitations, especially in the current epidemiological situation. Objective: To describe the social, economic and ethical implications related to the existence of theoretically nonimmunizing vaccines. Methods: The results of an educational intervention program in pediatric ages at 13 de Marzo Policlinic were used. The Wilcoxon signed-rank test was used, with a confidence index of 95 percent. Results: Initially, an inadequate level of knowledge predominated, which later improved significantly. Forty-eight unvaccinated children and 29 unimmunized children recovered. Conclusions: There is no correspondence between vaccination coverage and immunization. False contraindications for vaccination are established as correct. The educational intervention was effective, while the relevance became evident for undergraduate and postgraduate programs to improve the training of professionals and the quality of professional performance(AU)

COVID-19 Vaccination Preferences of University Students and Staff in Hong Kong.

Importance: COVID-19 has required universities to rapidly develop vaccination policies for students and staff, yet little is known about the preferences of these individuals toward vaccination. Objective: To quantify student and staff preferences for COVID-19 vaccination at a university in Hong Kong. Design, Setting, and Participants: A cross-sectional online survey study was conducted from July 20 to September 21, 2021, before the announcement of a campus-wide vaccine mandate. A survey of 42 451 eligible university students and staff used discrete-choice experiment methods to quantify 7 attributes of COVID-19 vaccination: risk of a mild or moderate adverse event after vaccination, risk of a severe adverse event after vaccination, efficacy against COVID-19 infection, efficacy against severe manifestation of COVID-19 infection, duration of protection after vaccination, incentive for completing vaccination, and out-of-pocket costs. Main Outcomes and Measures: A mixed logit regression model was used to estimate the preferences of attributes for COVID-19 vaccines and marginal willingness to pay (mWTP) adjusted for background characteristics, role, vaccination, and COVID-19 infection status of family or friends, adverse event status after vaccination among family and friends of participants, and scenario block. Results: Among 42 451 eligible university students and staff invited, 3423 individuals completed the survey (mean [SD] age, 27.1 [9.9] years; 2053 [60.0%] women). Participants included 2506 students (73.2%) and 917 staff (26.8%), with a response rate of 8.1%. Quarantine-free travel was preferred (ß = 0.86; 95% CI, 0.72-0.99; mWTP: $235.9; 95% CI, $190.3-$294.2), followed by efficacy against any COVID-19 infection (ß = 0.30; 95% CI, 0.29-0.32; mWTP: $84.1; 95% CI, $71.8-$100.8), against severe manifestation of COVID-19 infection (ß = 0.25; 95% CI, 0.24-0.27; mWTP: $69.7; 95% CI, $465-$653), and risk of severe adverse events following vaccination (ß = -0.24; 95% CI, -0.27 to -0.21; mWTP: -$66.8; 95% CI, -$81.5 to -$55.3). Participants were less concerned about protection duration (ß = 0.17; 95% CI, 0.15-0.18; mWTP: $46.0; 95% CI, $38.6-$56.2) and risk of mild to moderate adverse events (ß = -0.12; 95% CI, -0.13 to -0.10; mWTP: -$32.7; 95% CI, -$41.2 to -$26.4). Conclusions and Relevance: Preference of all attributes were significant and were considered important by the participants for vaccine decision-making. Insights drawn could assist policy makers in future vaccination decisions, such as campus vaccine mandate and requirement of a third dose.

The Value(s) of Vaccination: Building the Scientific Evidence According to a Value-Based Healthcare Approach.

Objectives: To provide a new value-based immunization approach collating the available scientific evidence on the topic. Methods: Four value pillars (personal, allocative, technical, and societal) applied to vaccination field were investigated. A systematic literature review was performed querying three database from December 24th, 2010 to May 27th, 2020. It included studies on vaccine-preventable diseases (VPDs) that mentioned the term value in any part and which were conducted in advanced economies. An in-depth analysis was performed on studies addressing value as key element. Results: Overall, 107 studies were considered. Approximately half of the studies addressed value as a key element but in most of cases (83.3%) only a single pillar was assessed. Furthermore, the majority of papers addressed the technical value by looking only at classical methods for economic assessment of vaccinations whereas very few dealt with societal and allocative pillars. Conclusions: Estimating the vaccinations value is very complex, even though their usefulness is certain. The assessment of the whole value of vaccines and vaccinations is still limited to some domains and should encompass the wider impact on economic growth and societies.

Acceptance and Willingness to Pay for Vaccine Against Human Papilloma Virus (HPV) Among Parents of Boys in Central Vietnam.

Human papilloma virus (HPV) vaccine for adolescents was recommended as an effective prevention strategy of HPV-related cancers. In Vietnam, HPV vaccination has not been introduced to male adolescent. This study was conducted to examine the acceptance of having boys vaccinated against HPV and its underlying reasoning, and to identify their parent's willingness to pay (WTP) for HPV vaccination in central Vietnam. 785 parents of boys were directly interviewed based on a structured questionnaire. Parent's acceptability of HPV vaccine for their sons was identified by one question with response on 3-point scale (agree, don't know, and disagree). Multivariate logistic regression model was used to determine contributing factors to participant's acceptance. Bidding game method was applied to elicit WTP values for HPV vaccination with initial bid of 161.2 USD. The results showed that 49.2% of parents agreed to have their sons vaccinated against HPV. Factors that influenced parent's acceptance including son's age older than 12 years (OR = 1.5; 95% CI: 1.08-1.98); being eldest son (OR = 1.6; 95% CI: 1.13-2.19), being mother (OR = 1.4; 95% CI: 1.01-1.91), parents with high educational level (OR = 1.7; 95% CI: 1.11-2.47) and their knowledge of HPV and HPV vaccine (OR = 1.8; 95% CI: 1.23-2.65). Average WTP value for full doses of HPV vaccine was 137.5 USD, ranging between 9 USD and 188.3 USD. Parents' knowledge of HPV and HPV vaccine was the only factor affecting WTP value (Rho: 0.11; p-value: 0.030). The findings suggest a strategy be introduced for HPV vaccination to male adolescents in Vietnam.