Pertussis in adolescents and adults: should we vaccinate?

Cost-effectiveness of pertussis booster vaccination for preschool children in Japan

INTRODUCTION

Japan currently recommends four doses of the diphtheria-tetanus-acellular pertussis (DTaP) vaccine in its routine vaccination program, but the introduction of a fifth dose is currently under consideration. An objective of the booster vaccination is to prevent severe cases of pertussis in infants through herd immunity. Thus, the aim of this analysis was to demonstrate the cost-effectiveness of a fifth-dose of the DTaP vaccine for 6-year-old children, taking herd immunity for unvaccinated infants into account.

METHOD

An economic model analysis was conducted comparing the cost and effectiveness of the two strategies based on quality-adjusted life years (QALYs). We evaluated the incremental cost-effectiveness ratio (ICER) of the booster strategy to the no booster strategy. This model contained two sub-models: one for children aged 6 years or older and one for infants under 3 months old. Herd immunity for infants is modeled as when siblings in the same family are infected.

RESULTS

The ICER was JPY 71,605,491 (USD 656,931) per QALY gained from the societal perspective, and 7.10% of incremental QALYs (0.0000934) were from a reduction in infant infection. In the sensitivity analysis, no variables moved the ICER under the threshold (JPY 5,000,000 per QALY gained), and the duration of pertussis disease and the incidence rate of pertussis had a significant impact on the ICER. When the disease burden of pertussis decreased, the booster strategy resulted in fewer QALYs gained and greater costs compared with the no booster strategy.

CONCLUSION

The introduction of a DTaP booster vaccination to the routine immunization schedule can be expected to reduce the number of pertussis cases in the target population. However, our study showed that adding a booster vaccination for 6-year-old children to the schedule in Japan would not be cost-effective in terms of achieving herd immunity among unvaccinated infants.

Benefit-Risk Assessment of Vaccines. Part I: A Systematic Review to Identify and Describe Studies About Quantitative Benefit-Risk Models Applied to Vaccines

Introduction

Understanding the balance between the benefits and risks of vaccination is essential to ensure informed and adequate public health decision making. Quantitative benefit–risk models (qBRm) represent useful tools to help decision makers with supporting benefit–risk assessment throughout the lifecycle of a medical product. However, few initiatives have been launched to harmonise qBRm approaches, specifically for vaccines.

Objectives

The aim of this paper was to identify publications about qBRm applied to vaccines through a systematic literature review, and to describe their characteristics.

Methods

Medline, Scopus and Institute for Scientific Information Web of Knowledge databases were searched to identify articles in English, published from database inceptions up to December 2019. The search strategy included the combination of three key concepts: ‘benefit–risk’, ‘modelling’ and ‘vaccines’. Data extracted included the modelling context and the methodological approaches used.

Results

Of 3172 publications screened, 48 original publications were included. Most of the selected studies were published over the past decade and focused on rotavirus (15), dengue (10) and influenza (6) vaccines. The majority (30) of studies reported analyses related to high-income countries. The methodology of the studies differed, particularly in modelling techniques, benefit–risk measures, and sensitivity analyses. The present work also pointed out a high level of variability in the quality of reporting across studies, with particular regard to input parameters and methodological approaches.

Conclusions

This review provides an extensive list of qBRm applied to vaccines. Discrepancies across studies were identified during our review. While the number of published qBRm studies is increasing, no reporting guidance for qBRm applied to vaccines is currently available. This may affect decision makers’ confidence in the results and their benefit–risk assessment(s); therefore, the development of such reporting guidance is highly needed.

Electronic supplementary material

The online version of this article (10.1007/s40264-020-00984-7) contains supplementary material, which is available to authorized users.

Benefit-Risk Assessment of Vaccines. Part II: Proposal Towards Consolidated Standards of Reporting Quantitative Benefit-Risk Models Applied to Vaccines (BRIVAC)

INTRODUCTION

Quantitative benefit-risk models (qBRm) applied to vaccines are increasingly used by public health authorities and pharmaceutical companies as an important tool to help decision makers with supporting benefit-risk assessment (BRA). However, many publications on vaccine qBRm provide insufficient details on the methodological approaches used. Incomplete and/or inadequate qBRm reporting may affect result interpretation and confidence in BRA, highlighting a need for the development of standard reporting guidance.

OBJECTIVES

Our objective was to provide an operational checklist for improved reporting of vaccine qBRm.

METHODS

The consolidated standards of reporting quantitative Benefit-RIsk models applied to VACcines (BRIVAC) were designed as a checklist of key information to report in qBRm scientific publications regarding the assessed vaccines, the methodological considerations and the results and their interpretation.

RESULTS

In total, 22 items and accompanying definitions, recommendations, explanations and examples were provided and divided into six main sections corresponding to the classic subdivisions of a scientific publication: title and abstract (items 1-2), introduction (items 3-4), methods (items 5-15), results (items 16-17), discussion (items 18-20) and other (items 21-22).

CONCLUSIONS

The BRIVAC checklist is the first initiative providing an operational checklist for improved reporting of qBRm applied to vaccines in scientific articles. It is intended to assist authors, peer-reviewers, editors and readers in their critical appraisal. Future initiatives are needed to provide methodological guidance to perform qBRm while taking into account the vaccine specificities.

Tetanus, diphtheria and acellular pertussis (Tdap) vaccine for prevention of pertussis among adults aged 19 years and older in the United States: A cost-effectiveness analysis

Currently, the Advisory Committee on Immunization Practices recommends one-time tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination for all adults 19 years and older. This study is designed to evaluate the cost-effectiveness of Tdap vaccination for Tdap-eligible adults aged 19 through 85 in the United States. A cost-effectiveness model was developed to compute costs and health outcomes associated with pertussis among 100,000 Tdap-eligible persons of each age cohort. From the societal perspective, the cost per quality-adjusted life-year (QALY) saved was evaluated under the vaccination scenarios. Sensitivity analyses were also conducted to evaluate the impacts of changes in key variables. All costs were adjusted to 2018 US$ with an annual discount rate of 3% applied to costs and outcomes. The incremental cost-effectiveness ratios (ICERs) for vaccinating US adults aged 19 to 85 with Tdap ranged from $248,000/QALY to $900,000/QALY. The lowest cost per QALY was found to be $248,000 for the age 65 cohort, followed by $332,000 for the cohort of age 19, and followed by $477,000 for the age 50 cohort. Sensitivity analysis showed the most dramatic changes in ICER occurred when changing the underreporting factor, vaccine effectiveness and vaccination costs. While Tdap vaccination may not be as cost effective as predicted earlier, it remains the best available preventive measure against pertussis. Further investigation of the true burden of pertussis disease among adults and the effectiveness of Tdap vaccination in this population is needed to better estimate the impact of Tdap vaccination.

Improving vaccination uptake among adolescents

BACKGROUND

Adolescent vaccination has received increased attention since the Global Vaccine Action Plan's call to extend the benefits of immunisation more equitably beyond childhood. In recent years, many programmes have been launched to increase the uptake of different vaccines in adolescent populations; however, vaccination coverage among adolescents remains suboptimal. Therefore, understanding and evaluating the various interventions that can be used to improve adolescent vaccination is crucial.

OBJECTIVES

To evaluate the effects of interventions to improve vaccine uptake among adolescents.

SEARCH METHODS

In October 2018, we searched the following databases: CENTRAL, MEDLINE Ovid, Embase Ovid, and eight other databases. In addition, we searched two clinical trials platforms, electronic databases of grey literature, and reference lists of relevant articles. For related systematic reviews, we searched four databases. Furthermore, in May 2019, we performed a citation search of five other websites.

SELECTION CRITERIA

Randomised trials, non-randomised trials, controlled before-after studies, and interrupted time series studies of adolescents (girls or boys aged 10 to 19 years) eligible for World Health Organization-recommended vaccines and their parents or healthcare providers.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened records, reviewed full-text articles to identify potentially eligible studies, extracted data, and assessed risk of bias, resolving discrepancies by consensus. For each included study, we calculated risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI) where appropriate. We pooled study results using random-effects meta-analyses and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 16 studies (eight individually randomised trials, four cluster randomised trials, three non-randomised trials, and one controlled before-after study). Twelve studies were conducted in the USA, while there was one study each from: Australia, Sweden, Tanzania, and the UK. Ten studies had unclear or high risk of bias. We categorised interventions as recipient-oriented, provider-oriented, or health systems-oriented. The interventions targeted adolescent boys or girls or both (seven studies), parents (four studies), and providers (two studies). Five studies had mixed participants that included adolescents and parents, adolescents and healthcare providers, and parents and healthcare providers. The outcomes included uptake of human papillomavirus (HPV) (11 studies); hepatitis B (three studies); and tetanus-diphtheria-acellular-pertussis (Tdap), meningococcal, HPV, and influenza (three studies) vaccines among adolescents. Health education improves HPV vaccine uptake compared to usual practice (RR 1.43, 95% CI 1.16 to 1.76; I² = 0%; 3 studies, 1054 participants; high-certainty evidence). In addition, one large study provided evidence that a complex multi-component health education intervention probably results in little to no difference in hepatitis B vaccine uptake compared to simplified information leaflets on the vaccine (RR 0.98, 95% CI 0.97 to 0.99; 17,411 participants; moderate-certainty evidence). Financial incentives may improve HPV vaccine uptake compared to usual practice (RR 1.45, 95% CI 1.05 to 1.99; 1 study, 500 participants; low-certainty evidence). However, we are uncertain whether combining health education and financial incentives has an effect on hepatitis B vaccine uptake, compared to usual practice (RR 1.38, 95% CI 0.96 to 2.00; 1 study, 104 participants; very low certainty evidence). Mandatory vaccination probably leads to a large increase in hepatitis B vaccine uptake compared to usual practice (RR 3.92, 95% CI 3.65 to 4.20; 1 study, 6462 participants; moderate-certainty evidence). Provider prompts probably make little or no difference compared to usual practice, on completion of Tdap (OR 1.28, 95% CI 0.59 to 2.80; 2 studies, 3296 participants), meningococcal (OR 1.09, 95% CI 0.67 to 1.79; 2 studies, 3219 participants), HPV (OR 0.99, 95% CI 0.55 to 1.81; 2 studies, 859 participants), and influenza (OR 0.91, 95% CI 0.61 to 1.34; 2 studies, 1439 participants) vaccination schedules (moderate-certainty evidence). Provider education with performance feedback may increase the proportion of adolescents who are offered and accept HPV vaccination by clinicians, compared to usual practice. Compared to adolescents visiting non-participating clinicians (in the usual practice group), the adolescents visiting clinicians in the intervention group were more likely to receive the first dose of HPV during preventive visits (5.7 percentage points increase) and during acute visits (0.7 percentage points for the first and 5.6 percentage points for the second doses of HPV) (227 clinicians and more than 200,000 children; low-certainty evidence). A class-based school vaccination strategy probably leads to slightly higher HPV vaccine uptake than an age-based school vaccination strategy (RR 1.09, 95% CI 1.06 to 1.13; 1 study, 5537 participants; moderate-certainty evidence). A multi-component provider intervention (including an education session, repeated contacts, individualised feedback, and incentives) probably improves uptake of HPV vaccine compared to usual practice (moderate-certainty evidence). A multi-component intervention targeting providers and parents involving social marketing and health education may improve HPV vaccine uptake compared to usual practice (RR 1.41, 95% CI 1.25 to 1.59; 1 study, 25,869 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

Various strategies have been evaluated to improve adolescent vaccination including health education, financial incentives, mandatory vaccination, and class-based school vaccine delivery. However, most of the evidence is of low to moderate certainty. This implies that while this research provides some indication of the likely effect of these interventions, the likelihood that the effects will be substantially different is high. Therefore, additional research is needed to further enhance adolescent immunisation strategies, especially in low- and middle-income countries where there are limited adolescent vaccination programmes. In addition, it is critical to understand the factors that influence hesitancy, acceptance, and demand for adolescent vaccination in different settings. This is the topic of an ongoing Cochrane qualitative evidence synthesis, which may help to explain why and how some interventions were more effective than others in increasing adolescent HPV vaccination coverage.

Assessing adolescent immunization options for pertussis in Canada: A cost-utility analysis

BACKGROUND

Adolescent tetanus, diphtheria and pertussis (Tdap) immunization helps prevent pertussis infection. Timing of Tdap receipt represents an important facet of successful adolescent pertussis immunization. Potential strategies for timing of vaccine administration are each associated with different benefits - including disease prevention - and costs. The objective of this study was to assess the cost-utility of adolescent pertussis immunization strategies in Canada.

METHODS

A cost-utility analysis was conducted using a pertussis disease history-simulating Markov model, with adolescents (beginning at age 10 years) as the cohort of interest. The model assessed three Tdap vaccination strategies: (1) immunization of 10 year olds, (2) removal of adolescent vaccination, and (3) immunization of 14 year olds (status quo). The analysis was conducted from a healthcare payer perspective and used a lifetime time horizon. Primary outcomes included life years, quality-adjusted life years (QALYs), health system costs, and an incremental cost-effectiveness ratio (ICER). Costs and outcomes were discounted at 1.5 percent annually. Deterministic and probabilistic sensitivity analyses were performed to assess parameter uncertainty.

RESULTS

The current recommended adolescent immunization strategy (at age 14) resulted in an average of 40.4432 expected QALYs and $26.28 per individual. This strategy was dominated by immunization at 10 years and no immunization. Compared to no immunization, immunizing adolescents at age 10 had an ICER of $74,899 per QALY. Results were most sensitive to the incidence of pertussis and the utility of moderate or severe pertussis. At a cost-effectiveness threshold of $50,000/QALY, removal of adolescent vaccination represented the most cost-effective strategy in 78% of simulations.

CONCLUSION

Analysis assumes a policy context where immunization of pregnant women is recommended. Findings suggest that alternate adolescent Tdap vaccine strategies - either immunization of 10 year olds, or removal of the adolescent vaccine - are more cost-effective than the current practice of immunizing 14 year olds.

Cost-effectiveness analysis of universal adult immunization with tetanus-diphtheria-acellular pertussis vaccine (Tdap) versus current practice in Brazil

BACKGROUND

A pertussis outbreak occurred in Brazil from 2011 to 2014, despite high coverage of whole-cell pertussis containing vaccines in early childhood. Infants were the most affected. This study aimed to evaluate the cost-effectiveness of introducing universal adult vaccination with Tdap into the National Immunization Program in Brazil.

METHODS

Economic evaluation using a dynamic model to compare two strategies: (1) universal vaccination with single dose of Tdap at 20 years of age and (2) current practice (only pregnant women pertussis vaccination). The health system perspective was adopted. Temporal horizon was 10 years. Discount rate of 5% was applied to costs and benefits. Vaccine effectiveness (VE) was obtained from a population-based observational study. Epidemiological, resource utilization and cost estimates were obtained from the Brazilian Health Information Systems. The primary outcome was cost per life year saved (LYS), based on life expectancy at birth in Brazil in 2015. Univariate and multivariate sensitivity analysis were performed.

RESULTS

Adult vaccination with VE of 82.6% and coverage of 40%, at price of US$7.01 per dose, and assuming herd protection would avoid 167 infant deaths by pertussis, saving 12,325 years of life and costing a total of US$105495891.61, from the health system perspective. The universal immunization would result in ICER of US$8459.13. The results were highly sensitive to disease incidence.

CONCLUSIONS

The results suggest that universal adult vaccination with Tdap would not be a cost-effective intervention for preventing pertussis cases and deaths in infants in Brazil.

Cost-effectiveness of adult vaccinations: A systematic review

BACKGROUND

Coverage levels for many recommended adult vaccinations are low. The cost-effectiveness research literature on adult vaccinations has not been synthesized in recent years, which may contribute to low awareness of the value of adult vaccinations and to their under-utilization. We assessed research literature since 1980 to summarize economic evidence for adult vaccinations included on the adult immunization schedule.

METHODS

We searched PubMed, EMBASE, EconLit, and Cochrane Library from 1980 to 2016 and identified economic evaluation or cost-effectiveness analysis for vaccinations targeting persons aged ≥18 years in the U.S. or Canada. After excluding records based on title and abstract reviews, the remaining publications had a full-text review from two independent reviewers, who extracted economic values that compared vaccination to "no vaccination" scenarios.

RESULTS

The systematic searches yielded 1688 publications. After removing duplicates, off-topic publications, and publications without a "no vaccination" comparison, 78 publications were included in the final analysis (influenza = 25, pneumococcal = 18, human papillomavirus = 9, herpes zoster = 7, tetanus-diphtheria-pertussis = 9, hepatitis B = 9, and multiple vaccines = 1). Among outcomes assessing age-based vaccinations, the percent indicating cost-savings was 56% for influenza, 31% for pneumococcal, and 23% for tetanus-diphtheria-pertussis vaccinations. Among age-based vaccination outcomes reporting $/QALY, the percent of outcomes indicating a cost per QALY of ≤$100,000 was 100% for influenza, 100% for pneumococcal, 69% for human papillomavirus, 71% for herpes zoster, and 50% for tetanus-diphtheria-pertussis vaccinations.

CONCLUSIONS

The majority of published studies report favorable cost-effectiveness profiles for adult vaccinations, which supports efforts to improve the implementation of adult vaccination recommendations.

Economic evaluation of adolescents and adults' pertussis vaccination: A systematic review of current strategies

The reemergence of pertussis in the last two decades led to the introduction of adolescents and adults immunization strategies of tetanus–diphtheria–acellular pertussis vaccines (Tdap) in several countries. The health authorities must consider economic aspects when deciding to recommend and fund new programs. Here we present a systematic review of worldwide full economic evaluations of pertussis vaccination targeting adolescents or adults published from 2000. Studies were identified by searching MEDLINE, Excerpta Medica, CRD, and Lilacs databases. Twenty-seven economic evaluations of different strategies with Tdap were identified. Booster vaccination for adolescents and adults were the most frequent, followed by cocooning and pregnant women vaccination. Strategies performance varied considerably among different studies. Assumptions regarding underreporting correction, herd protection and vaccine coverage were crucial to cost-effectiveness results. Understanding the model and the parameters used is essential to understand the results, and identify the major issues important to public health decisions.

Cost effectiveness of a practice-based intervention to improve vaccination rates in adults less than 65-years-old

The cost-effectiveness of the 4 Pillars™ Practice Transformation Program to improve vaccination rates in adults <65-years-old is unknown. Two vaccines, influenza and Tdap (tetanus, diphtheria, acellular pertussis), were targeted for this age group. Cost-effectiveness of the intervention compared with control, with a primary outcome of cost per quality adjusted life year (QALY) gained, was estimated from societal and third party payer perspectives over a 10-year time horizon using a decision analysis model. Vaccination rates and intervention costs were derived from an intervention trial, and vaccine effectiveness, illness rates, and costs with/without vaccination were obtained from US databases and literature data. Future costs and effectiveness were discounted at 3%/year. The intervention cost was $1.78 per eligible patient/year. From the societal perspective, per patient total vaccination and illness costs with the intervention were $27.43 higher than control while gaining 0.00087 QALYs, costing $31,700/QALY gained. The intervention, extrapolated to the US population, could prevent 4.2 million cases, 87,489 hospitalizations, and 5,680 deaths due to influenza over 10 y in adults <65-years-old. In a probabilistic sensitivity analysis, the intervention was favored in 68.2% of model runs at a $50,000/QALY level and in 94.3% at $100,000/QALY. In a separate scenario analysis, the intervention became cost saving if influenza economic burden was >$2,099 per case (societal base case $846). Thus, the 4 Pillars Practice Transformation Program is an economically reasonable intervention to improve vaccination rates in adults <65-years-old, and could have a substantial public health impact.

Cost-effectiveness of increasing vaccination in high-risk adults aged 18-64 Years: a model-based decision analysis

BACKGROUND

Adults aged 18-64 years with comorbid conditions are at high risk for complications of certain vaccine-preventable diseases, including influenza and pneumococcal disease. The 4 Pillars™ Practice Transformation Program (4 Pillars Program) increases uptake of pneumococcal polysaccharide vaccine, influenza vaccine and tetanus-diphtheria-acellular pertussis vaccine by 5-10% among adults with high-risk medical conditions, but its cost-effectiveness is unknown.

METHODS

A decision tree model estimated the cost-effectiveness of implementing the 4 Pillars Program in primary care practices compared to no program for a population of adults 18-64 years of age at high risk of illness complications over a 10 year time horizon. Vaccination rates and intervention costs were derived from a randomized controlled cluster trial in diverse practices in 2 U.S. cities. One-way and probabilistic sensitivity analyses were conducted.

RESULTS

From a third-party payer perspective, which considers direct medical costs, the 4 Pillars Program cost $28,301 per quality-adjusted life year gained; from a societal perspective, which adds direct nonmedical and indirect costs, the program was cost saving and more effective than no intervention. Cost effectiveness results favoring the program were robust in sensitivity analyses. From a public health standpoint, the model predicted that the intervention reduced influenza cases by 1.4%, with smaller decreases in pertussis and pneumococcal disease cases.

CONCLUSION

The 4 Pillars Practice Transformation Program is an economically reasonable, and perhaps cost saving, strategy for protecting the health of adults aged < 65 years with high-risk medical conditions.

Inclusion of the value of herd immunity in economic evaluations of vaccines. A systematic review of methods used

OBJECTIVE

The objectives of this review were to identify vaccine economic evaluations that include herd immunity and describe the methodological approaches used.

METHODS

We used Kim and Goldie's search strategy from a systematic review (1976-2007) of modelling approaches used in vaccine economic evaluations and additionally searched PubMed/MEDLINE and Embase for 2007-2015. Studies were classified according to modelling approach used. Methods for estimating herd immunity effects were described, in particular for the static models.

RESULTS

We identified 625 economic evaluations of vaccines against human-transmissible diseases from 1976 to 2015. Of these, 172 (28%) included herd immunity. While 4% of studies included herd immunity in 2001, 53% of those published in 2015 did this. Pneumococcal, human papilloma and rotavirus vaccines represented the majority of studies (63%) considering herd immunity. Ninety-five of the 172 studies utilised a static model, 59 applied a dynamic model, eight a hybrid model and ten did not clearly state which method was used. Relatively crude methods and assumptions were used in the majority of the static model studies.

CONCLUSION

The proportion of economic evaluations using a dynamic model has increased in recent years. However, 55% of the included studies used a static model for estimating herd immunity. Values from a static model can only be considered reliable if high quality surveillance data are incorporated into the analysis. Without this, the results are questionable and they should only be included in sensitivity analysis.

Prevalence, diagnosis, and disease course of pertussis in adults with acute cough: a prospective, observational study in primary care

Background

Most cases of adult pertussis probably remain undiagnosed.

Aim

To explore the prevalence, diagnosis, and disease course of acute pertussis infection in adult patients presenting with acute cough.

Design and setting

Prospective observational study between 2007 and 2010 in primary care in 12 European countries.

Method

Adults presenting with acute cough (duration of ≤28 days) were included. Bordetella pertussis infection was determined by polymerase chain reaction (from nasopharyngeal flocked swabs and sputa) and by measurement of immunoglobulin G antibodies to pertussis toxin (PT) in venous blood at day 28. An antibody titre to PT of ≥125 IU/ml or PCR positive result in a respiratory sample defined recent infection. Patients completed a symptom diary for 28 days.

Results

Serum and/or respiratory samples were obtained in 3074 patients. Three per cent (93/3074) had recent B. pertussis infection. Prior cough duration >2 weeks discriminated to some extent between those with and without pertussis (adjusted odds ratio 1.89, 95% confidence interval = 1.17 to 3.07; P = 0.010). Median cough duration after presentation was 17 and 12 days in patients with and without pertussis, respectively (P = 0.008). Patients with pertussis had longer duration of phlegm production (P = 0.010), shortness of breath (P = 0.037), disturbed sleep (P = 0.013) and interference with normal activities or work (P = 0.033) after presentation.

Conclusion

Pertussis infection plays a limited role among adults presenting with acute cough in primary care, but GPs should acknowledge the possibility of pertussis in uncomplicated lower respiratory tract infection. As in children, pertussis also causes prolonged symptoms in adults. However, pertussis is difficult to discern from other acute cough syndromes in adults at first presentation.

Knowledge, attitudes and practices on adolescent vaccination among adolescents, parents and teachers in Africa: A systematic review

INTRODUCTION

Vaccines are the most successful and cost-effective public health interventions available to avert vaccine-preventable diseases and deaths. Despite global progress in adolescent health, many adolescents in Africa still get sick and die from vaccine-preventable diseases due to lack of vaccination. Adolescents, parents and teachers are key players in the development and implementation of adolescent vaccination policies. Optimal knowledge, attitudes and practices towards adolescent vaccination among these key players may improve vaccine uptake among adolescents. We conducted a qualitative and quantitative systematic review on knowledge, attitudes and practices of adolescent vaccination among adolescents, parents and teachers in Africa.

METHODS

We searched PubMed, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, WHOLIS, Africa Wide and CINAHL for eligible quantitative and qualitative primary studies with no time limits. We also checked reference lists of included studies for eligible studies and searched grey literature. Two authors independently screened the search outputs, selected studies and extracted data; resolving discrepancies by consensus and discussion. Qualitative data were analysed using thematic analyses where applicable, while analyses from quantitative studies used different methods based on the type of outcomes.

RESULTS

We included 18 cross-sectional studies in this review. The included studies were conducted in 10 out of the 54 countries in Africa. The 18 studies focused on a wide range of adolescent vaccines. Thirteen studies evaluated vaccines against Human Papilloma Virus, while each of the remaining 5 studies, evaluated vaccines against rabies, HIV, tetanus toxoid, tuberculosis and adolescent vaccines in general. Among the key players, we found low to moderate levels of knowledge about adolescent vaccination. Positive attitudes and practices towards adolescent vaccination, especially against Human Papilloma Virus were reported. Despite the low knowledge, our results showed high levels of acceptability to adolescent vaccination among adolescents, parents and teachers.

CONCLUSIONS

It was evident in our review that all key demographics (parents, adolescents and teachers) were receptive towards adolescent vaccines. We propose relevant policy makers in Africa to consider continuous education programs such as those aimed to inform the parents, adolescents and teachers on adolescent vaccination.

Pertussis post-exposure prophylaxis among household contacts: a cost-utility analysis

Background

Recent pertussis outbreaks have prompted re-examination of post-exposure prophylaxis (PEP) strategies, when immunization is not immediately protective. Chemoprophylaxis is recommended to household contacts; however there are concerns of clinical failure and significant adverse events, especially with erythromycin among infants who have the highest disease burden. Newer macrolides offer fewer side effects at higher drug costs. We sought to determine the cost-effectiveness of PEP strategies from the health care payer perspective.

Methods

A Markov model was constructed to examine 4 mutually exclusive strategies: erythromycin, azithromycin, clarithromycin, or no intervention, stratified by age group of contacts (“infant”, “child”, and “adult”). Transition probabilities, costs and quality-adjusted life years (QALYs) were derived from the literature. Chronic neurologic sequelae were modeled over a lifetime, with costs and QALYs discounted at 5%. Associated health outcomes and costs were compared, and incremental cost-effectiveness ratios (ICER) were calculated in 2012 Canadian dollars. Deterministic and probabilistic sensitivity analyses were performed to evaluate the degree of uncertainty in the results.

Findings

Azithromycin offered the highest QALYs in all scenarios. While this was the dominant strategy among infants, it produced an ICER of $16,963 per QALY among children and $2,415 per QALY among adults. Total QALYs with azithromycin were 19.7 for a 5-kg infant, 19.4 for a 10-year-old child, and 18.8 for a 30-year-old adult. The costs of azithromycin PEP among infants, children and adults were $1,976, $132 and $90, respectively. While results were sensitive to changes in PEP effectiveness (11% to 87%), disease transmission (variable among age groups) and hospitalization costs ($379 to $59,644), the choice of strategy remained unchanged.

Interpretation

Pertussis PEP is a cost-effective strategy compared with no intervention and plays an important role in contact management, potentially in outbreak situations. From a healthcare payer perspective, azithromycin is the optimal strategy among all contact groups.

Epidemiology of pertussis in adolescents and adults in Turkey

Two hundred and fourteen patients who had a cough illness lasting at least 2 weeks were studied to investigate Bordetella pertussis as a cause of prolonged cough in adolescents and adults. Medical history and nasopharyngeal swab specimens for culture and polymerase chain reaction (PCR) were obtained at presentation. Three (1·4%) patients were B. pertussis culture-positive; 15 (7%) were B. pertussis PCR-positive (including the culture-positive patients) and 11 (5·1%) were Bordetella spp. PCR-positive. Symptom combinations were significantly high both in patients with pertussis and patients with indeterminate results (P < 0·05). We conclude that B. pertussis should be considered among differential diagnoses of prolonged cough in adolescents and adults and PCR and culture should be used to detect these cases and facilitate public health response.

Knowledge, attitudes and practices on adolescent vaccination among parents, teachers and adolescents in Africa: a systematic review protocol

BACKGROUND

Vaccines are the most successful and cost-effective public health interventions available to avert vaccine-preventable diseases and deaths. Despite progress in the field of adolescent health, many young people in Africa still get sick and die from vaccine-preventable diseases due to lack of vaccination. Parents, adolescents and teachers are key players with regard to implementation of adolescent vaccination policies. Therefore, understanding their knowledge, attitudes and practices towards adolescent vaccination may provide clues on what can be done to improve vaccine uptake among adolescents. The aim of this study is to conduct a qualitative and quantitative systematic review on knowledge, attitudes and practices on adolescent vaccination among parents, teachers and adolescents in Africa.

METHODS

We will include both quantitative and qualitative primary studies. Eligible quantitative studies include both intervention and observational studies. Qualitative studies to be included are focus group discussions, direct observations, in-depth interviews and case ethnographic studies. We will search PubMed, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, WHOLIS, Africa Wide and CINAHL for eligible studies with no time and language limits. We will also check reference lists of included studies for other eligible reports. Two authors will independently screen the search output, select studies and extract data, resolving discrepancies by consensus and discussion. We will analyse qualitative data using thematic analysis where applicable, and quantitative studies findings will be presented in a narrative synthesis form based on the outcomes.

DISCUSSION

The findings from this systematic review will guide the identification of gaps on knowledge, attitudes and practices among the key role players on adolescent vaccination. We anticipate that our findings will guide the development of adolescent-focused vaccination policy in Africa, which is virtually non-existent at present.

SYSTEMATIC REVIEW REGISTRATION

This review is registered with PROSPERO, registration number CRD42014010395.

Whooping cough in school age children presenting with persistent cough in UK primary care after introduction of the preschool pertussis booster vaccination: prospective cohort study

OBJECTIVE

To estimate the prevalence and clinical severity of whooping cough (pertussis) in school age children presenting with persistent cough in primary care since the introduction and implementation of the preschool pertussis booster vaccination.

DESIGN

Prospective cohort study (November 2010 to December 2012).

SETTING

General practices in Thames Valley, UK.

PARTICIPANTS

279 children aged 5 to 15 years who presented in primary care with a persistent cough of two to eight weeks' duration. Exclusion criteria were cough likely to be caused by a serious underlying medical condition, known immunodeficiency or immunocompromise, participation in another clinical research study, and preschool pertussis booster vaccination received less than one year previously.

MAIN OUTCOME MEASURES

Evidence of recent pertussis infection based on an oral fluid anti-pertussis toxin IgG titre of at least 70 arbitrary units. Cough frequency was measured in six children with laboratory confirmed pertussis.

RESULTS

56 (20%, 95% confidence interval 16% to 25%) children had evidence of recent pertussis infection, including 39 (18%, 13% to 24%) of 215 children who had been fully vaccinated. The risk of pertussis was more than three times higher (21/53; 40%, 26% to 54%) in children who had received the preschool pertussis booster vaccination seven years or more previously than in those who had received it less than seven years previously (20/171; 12%, 7% to 17%). The risk of pertussis was similar between children who received five and three component preschool pertussis booster vaccines (risk ratio for five component vaccine 1.14, 0.64 to 2.03). Four of six children in whom cough frequency was measured coughed more than 400 times in 24 hours.

CONCLUSIONS

Pertussis can still be found in a fifth of school age children who present in primary care with persistent cough and can cause clinically significant cough in fully vaccinated children. These findings will help to inform consideration of the need for an adolescent pertussis booster vaccination in the United Kingdom.

STUDY REGISTRATION

UK Clinical Research Network portfolio ID 8361.

A computer simulation model of the cost-effectiveness of routine Staphylococcus aureus screening and decolonization among lung and heart-lung transplant recipients

Our objective was to model the cost-effectiveness and economic value of routine peri-operative Staphylococcus aureus screening and decolonization of lung and heart-lung transplant recipients from hospital and third-party payer perspectives. We used clinical data from 596 lung and heart-lung transplant recipients to develop a model in TreeAge Pro 2009 (Williamsport, MA, USA). Sensitivity analyses varied S. aureus colonization rate (5-15 %), probability of infection if colonized (10-30 %), and decolonization efficacy (25-90 %). Data were collected from the Cardiothoracic Transplant Program at the University of Pittsburgh Medical Center. Consecutive lung and heart-lung transplant recipients from January 2006 to December 2010 were enrolled retrospectively. Baseline rates of S. aureus colonization, infection and decolonization efficacy were 9.6 %, 36.7 %, and 31.9 %, respectively. Screening and decolonization was economically dominant for all scenarios tested, providing more cost savings and health benefits than no screening. Savings per case averted (2012 $US) ranged from $73,567 to $133,157 (hospital perspective) and $10,748 to $16,723 (third party payer perspective), varying with the probability of colonization, infection, and decolonization efficacy. Using our clinical data, screening and decolonization led to cost savings per case averted of $240,602 (hospital perspective) and averted 6.7 S. aureus infections (4.3 MRSA and 2.4 MSSA); 89 patients needed to be screened to prevent one S. aureus infection. Our data support routine S. aureus screening and decolonization of lung and heart-lung transplant patients. The economic value of screening and decolonization was greater than in previous models of other surgical populations.

Health care worker exposures to pertussis: missed opportunities for prevention

OBJECTIVE

Pediatric health care workers (HCWs) are at particular risk for pertussis exposure, infection, and subsequent disease transmission to susceptible patients. This cross-sectional study describes the epidemiology of occupational exposures to pertussis and identifies factors that may inform interventions to promote effective implementation of infection prevention and control (IPC) guidelines.

METHODS

We abstracted data from occupational health (OH) and IPC records for pertussis cases that resulted in an exposure investigation in a large quaternary pediatric care network, January 1, 2002 to July 18, 2011. We calculated the frequency of occupational exposures and measured associated characteristics. To assess the frequency of potential missed exposures, we reviewed electronic health record (EHR) data identifying laboratory-confirmed pertussis cases not documented in OH or IPC records.

RESULTS

A total of 1193 confirmed HCW pertussis exposures were associated with 219 index cases during the study period. Of these, 38.8% were infants <6 months old and 7 were HCWs. Most (77.5%) of exposures occurred in the emergency department or an ambulatory site; 27.0% of exposures occurred after documented initiation of IPC precautions. We identified 450 laboratory-confirmed pertussis cases through EHR review, of which 49.8% (N = 224) had no OH or IPC investigation. The majority of uninvestigated cases (77.2%) were from ambulatory sites.

CONCLUSIONS

Occupational exposures to pertussis occur frequently in pediatric health care settings despite appropriate IPC guidelines. Interventions are needed to ensure consistent implementation of IPC practices and timely identification and reporting of pertussis index cases to prevent HCW exposures and potential transmission to patients.

Effectiveness and cost-effectiveness of different immunization strategies against whooping cough to reduce child morbidity and mortality

INTRODUCTION

In the last years there has been a significant increase in reported cases of pertussis in developed countries, in spite of high rates of childhood immunization. Health institutions have recommended different vaccination strategies to reduce child morbidity and mortality: vaccination of adolescents and adults, pregnant women, people in contact with the newborn (cocoon strategy) and health care workers. The aim of this paper is to review the scientific evidence supporting these recommendations.

METHODS

Systematic review on the effectiveness and cost-effectiveness of the above strategies for the reduction of morbidity and mortality from pertussis in infants under 12 months. The electronic databases Medline, PreMedline, Embase, CRD, Cochrane Central, and Trip Database were consulted from 1990 to October 2012. The evidence was assessed using the GRADE system.

RESULTS

There were eight studies on the efficacy or safety of the strategies analyzed, and 18 economic evaluations. Direct evidence on the efficacy of these strategies is scarce. Economic evaluations suggest that vaccination of adolescents and adults would be cost-effective, although there is major uncertainty over the parameters used.

CONCLUSIONS

From the perspective of health technology assessment, there is insufficient evidence to recommend the vaccination strategies evaluated.

Pharmacist-led Tdap vaccination of close contacts of neonates in a women's hospital

BACKGROUND

Pertussis can cause severe illness and death in infants. Immunization of family members with the tetanus toxoid, reduced diphtheria toxoids, and acellular pertussis (Tdap) vaccine can decrease risk of pertussis infection among infants. A community pharmacy on a women's hospital campus implemented a Tdap vaccination pilot program.

OBJECTIVE

To investigate the rate of Tdap vaccination among close contacts of neonates in a women's hospital pharmacy and to assess the impact of a coordinated pharmacy and hospital Tdap vaccination program.

METHODS

The intervention entailed education from hospital staff who explained the risks of pertussis, advocated the benefits of vaccination, and encouraged family members to be vaccinated. In the on-site clinic or in the pharmacy, pharmacists administered vaccine to eligible patients. Rates of Tdap vaccinations in the intervention pharmacy with in-hospital vaccination were compared to comparison pharmacies without Tdap interventions.

RESULTS

In the pre-study period (December 2008-November 2010), there were 31 Tdap vaccinations administered at the intervention pharmacy (mean=1.3/month); during the study period (December 2010-November 2012), 2045 Tdap vaccinations were administered (mean=85.2/month). In four comparison hospital-campus pharmacies, there were 77 vaccinations (mean=0.8/month) during the pre-study period and 817 vaccinations (mean=8.5/month) during the study period. There were 155 vaccinations administered in 44 area-community pharmacies (mean=0.1/month) during the pre-study period and 2930 (mean=2.8/month) during the study period. The intervention pharmacy had the highest average monthly rate of change in Tdap volume from pre-study to study period (83.9), compared to comparison hospital-campus pharmacies (7.7, p<.001) and area-community pharmacies (2.7, p<.001). During the study period, the estimated Tdap vaccination coverage per live births was 8.1% in the intervention pharmacy versus 5.5% in the comparison hospital-campus pharmacies (p<.001).

CONCLUSIONS

Tdap vaccination rates increased after implementation of the intervention program. This project illustrates how health systems and community pharmacists can collaborate to improve patient care.

Cost-effectiveness analysis of a pertussis vaccination programme for Japan considering intergenerational infection

OBJECTIVE

The incidence of pertussis in adolescence and adulthood has been increasing, and pertussis outbreaks have occurred sporadically in Japan. The risk of intergenerational infection of pertussis is of concern. The aim of this study is to assess the cost-effectiveness of alternative vaccination programmes for replacing the conventional diphtheria-tetanus (DT) vaccine programme administered in adolescence, considering the risk of intergenerational infection.

METHODS

We examined the cost-effectiveness of 4 pertussis vaccination programmes: (1) one-time adolescent DT vaccination (DT); (2) one-time adolescent DT-acellular pertussis (DTaP) vaccination; (3) one-time adolescent DTaP with decennial booster (DTaP+booster); and (4) one-time adolescent DTaP with additional vaccination targeted at parents with infants (additional DTaP for parents). We adapted a state-transition Markov model to estimate the costs and effectiveness of vaccination in the adolescent and adult cohorts and then considered intergenerational infection from adolescents/adults to infants. We assumed a societal perspective to estimate results and expressed these in terms of cost, life expectancy, quality-adjusted life expectancy, benefit-cost ratio (BCR), and incremental cost-effectiveness ratio (ICER).

RESULTS

At an incidence of 25 per 100,000, the ICERs of the DTaP and additional DTaP for parents strategies were 3,576,072 JPY and 240,055,273 JPY, respectively, when intergenerational transmission of infection was considered. The ICER for the DTaP+booster strategy was dominated.

MAJOR CONCLUSION

Alternative vaccination programmes are not currently cost-effective. If intergenerational infection considered, one-time adolescent DTaP vaccination is cost-effective. More accurate reports of pertussis incidence are required as the results of cost-effectiveness analyses of vaccination vary greatly depending on incidence.

Infectious diseases and vaccination strategies: how to protect the "unprotectable"?

Introduction. The circulation of infectious diseases puts small infants too young to be vaccinated at risk of morbidity and mortality, often requiring prolonged hospitalization. Material and Methods. We have reviewed the medical records of children not eligible for vaccination because of age, admitted to hospital for pertussis, measles, or varicella from February 1, 2010, till February 1, 2012. Results. Of the case records scrutinized, 21 were hospitalized for pertussis, 18 for measles, and 32 for varicella. Out of them, 42%, 66%, and 78% diagnosed with, respectively, pertussis, measles, and varicella had a complicated course of the disease. Discussion. To avoid infectious disease circulation, childhood immunization strategies should be adopted, such as vaccination of healthcare givers, adult household contacts, and parents planning to have, or who have had, a newborn baby.

Vaccination based control of infections in SIRS models with reinfection: special reference to pertussis

The aim of this paper is to study the impact of introducing a partially protective vaccine on the dynamics of infection in SIRS models where primary and secondary infections are distinguished. We investigate whether a public health strategy based solely on vaccinating a proportion of newborns can lead to an effective control of the disease. In addition to carrying out the qualitative analysis, the findings are further explained by numerical simulations. The model exhibits backward bifurcation for certain values of the parameters. In these cases the standard basic reproduction number (obtained by inspection of the uninfected state) is not significant. The key threshold is the reinfection level which depends on the relative transmissibility (susceptibility) of secondary, with respect to primary, infected (susceptible) individuals and the relative loss of immunity of vaccinated, with respect to recovered, individuals. If one or all of these ratios decrease, then the threshold increases which increases the possibility to contain the infection by vaccination. The analysis shows further that symptomatic infections can be eliminated by vaccination solely.

The potential economic value of a Staphylococcus aureus vaccine among hemodialysis patients

Staphylococcus aureus infections are a substantial problem for hemodialysis patients. Several vaccine candidates are currently under development, with hemodialysis patients being one possible target population. To determine the potential economic value of an S. aureus vaccine among hemodialysis patients, we developed a Markov decision analytic computer simulation model. When S. aureus colonization prevalence was 1%, the incremental cost-effectiveness ratio (ICER) of vaccination was ≤$25,217/quality-adjusted life year (QALY). Vaccination became more cost-effective as colonization prevalence, vaccine efficacy, or vaccine protection duration increased or vaccine cost decreased. Even at 10% colonization prevalence, a 25% efficacious vaccine costing $100 prevented 29 infections, 21 infection-related hospitalizations, and 9 inpatient deaths per 1000 vaccinated HD patients. Our results suggest that an S. aureus vaccine would be cost-effective (i.e., ICERs ≤ $50,000/QALY) among hemodialysis patients over a wide range of S. aureus prevalence, vaccine costs and efficacies, and vaccine protection durations and delineate potential target parameters for such a vaccine.

Pertussis booster vaccine for adolescents and young adults in São Paulo, Brazil

OBJECTIVE

To develop a model to assess different strategies of pertussis booster vaccination in the city of São Paulo.

METHODS

A dynamic stationary age-dependent compartmental model with waning immunity was developed. The "Who Acquires Infection from Whom" matrix was used to modeling age-dependent transmission rates. There were tested different strategies including vaccine boosters to the current vaccination schedule and three of them were reported: (i) 35% coverage at age 12, or (ii) 70% coverage at age 12, and (iii) 35% coverage at age 12 and 70% coverage at age 20 at the same time.

RESULTS

The strategy (i) achieved a 59% reduction of pertussis occurrence and a 53% reduction in infants while strategy (ii) produced 76% and 63% reduction and strategy (iii) 62% and 54%, respectively.

CONCLUSION

Pertussis booster vaccination at age 12 proved to be the best strategy among those tested in this study as it achieves the highest overall reduction and the greatest impact among infants who are more susceptible to pertussis complications.

[Pertussis vaccination for parents: proposal and evaluation of two professional practices in a maternity hospital]

BACKGROUND

Despite good rates of immunization among children, an apparent increase in the incidence of pertussis disease in infants in France has been observed, mainly because of low vaccination coverage among adults. Guidelines drawn up in 2004 recommend a vaccination strategy called cocooning for parents, but those guidelines are rarely followed by the medical community. Raising the vaccination rate among parents to 65% and the extension of pertussis vaccine booster for people between 26 and 28 years old could help control the disease.

OBJECTIVE AND METHODS

In a primary healthcare setting in 2009, we studied 2 groups of 188 and 190 parents of newborns in a maternity unit. We proposed 2 strategies: information and vaccine prescription for both parents (if eligible) at the time of discharge from the maternity unit (group 1) or vaccination proposed to both parents during hospitalization in the maternity unit (group 2). After 6 weeks, the vaccination rates of both groups were compared.

RESULTS

Analysis shows that parents had insufficient knowledge of the disease. Parents were often unaware of their vaccination status. Hence, objective data concerning the vaccination status was quickly available for only 42% of the population, making determination of eligibility unreliable. Only 8% of the parents were up to date for pertussis vaccination in the last 10 years, whereas 90% of the parents had the opportunity for vaccination and 37% of them had been eligible before the pregnancy. At the end of the study, 53% of the parents in group 1 were vaccinated, showing the positive impact of the medical encounter and vaccine prescription. During the study, 40% of the parents in group 2 who were proposed immediate vaccination in the maternity unit accepted it. This increased to 43% of group 2 parents being immunized by the time they had left the maternity unit. Proposing the vaccination at the maternity hospital was the more effective of the 2 strategies (P=0.03): at the end of the study, the objective was nearly reached with 64% of the parents being vaccinated.

CONCLUSIONS

The promotion of parental vaccination by the pediatrician in the maternity ward is simple and effective. Medical encounters resulting from prescriptions made during hospitalization could raise awareness in general practitioners and enable them to identify eligible adults for pertussis vaccination and vaccinate themselves. There is a need to discuss the complementarity and interactions between perinatal teams and general practitioners within the community healthcare network.

Cost-effectiveness of adolescent pertussis vaccination for the Netherlands: using an individual-based dynamic model

BACKGROUND

Despite widespread immunization programs, a clear increase in pertussis incidence is apparent in many developed countries during the last decades. Consequently, additional immunization strategies are considered to reduce the burden of disease. The aim of this study is to design an individual-based stochastic dynamic framework to model pertussis transmission in the population in order to predict the epidemiologic and economic consequences of the implementation of universal booster vaccination programs. Using this framework, we estimate the cost-effectiveness of universal adolescent pertussis booster vaccination at the age of 12 years in the Netherlands.

METHODS/PRINCIPAL FINDINGS

We designed a discrete event simulation (DES) model to predict the epidemiological and economic consequences of implementing universal adolescent booster vaccination. We used national age-specific notification data over the period 1996-2000--corrected for underreporting--to calibrate the model assuming a steady state situation. Subsequently, booster vaccination was introduced. Input parameters of the model were derived from literature, national data sources (e.g. costing data, incidence and hospitalization data) and expert opinions. As there is no consensus on the duration of immunity acquired by natural infection, we considered two scenarios for this duration of protection (i.e. 8 and 15 years). In both scenarios, total pertussis incidence decreased as a result of adolescent vaccination. From a societal perspective, the cost-effectiveness was estimated at €4418/QALY (range: 3205-6364 € per QALY) and €6371/QALY (range: 4139-9549 € per QALY) for the 8- and 15-year protection scenarios, respectively. Sensitivity analyses revealed that the outcomes are most sensitive to the quality of life weights used for pertussis disease.

CONCLUSIONS/SIGNIFICANCE

To our knowledge we designed the first individual-based dynamic framework to model pertussis transmission in the population. This study indicates that adolescent pertussis vaccination is likely to be a cost-effective intervention for The Netherlands. The model is suited to investigate further pertussis booster vaccination strategies.

Safe and effective booster immunization using DTaP in teenagers

The incidence of reported cases with pertussis has increased in young adults in Japan and the lack of additional booster immunizations containing pertussis components is suspected to be one of the causal reasons. Instead of DT immunization at 11-12 years of age, safety and immunogenicity were investigated using 0.2 ml and 0.5 ml of DTaP. 176 subjects in DTaP 0.5ml, 178 in DTaP 0.2 ml, and 197 in DT 0.1 ml groups were enrolled in clinical trial. The relative risk of local reactions in the DTaP 0.2 ml group compared to the DT 0.1 ml group was 1.13 (95% CI: 0.97-1.30), and that of the DTaP 0.5 ml to the DT 0.1 ml group was 1.34 (95% CI: 1.18-1.53). The relative risks of local pain and heat were 1.62 (95% CI: 1.33-1.98) and 1.59 (95% CI: 1.19-2.13), respectively, in the DTaP 0.5 ml group compared to the DT 0.1 ml group. Sero-positive rates against PT and FHA were 54% and 82% before immunization and increased to >95% for both after vaccination with no significant difference in GMT. Instead of the scheduled DT program, 0.2 ml of DTaP was acceptable and demonstrated efficient immunogenicity.

Projected costs, risks, and benefits of expanded newborn screening for MCADD

OBJECTIVE

To evaluate the cost-effectiveness of newborn screening for medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD) incorporating quality-of-life effects for false-positive newborn screens and recommended dietary treatment.

METHODS

A computer simulation model was developed to predict costs and health outcomes for expanded newborn screening for MCADD compared with clinical identification. The modeled target population was a hypothetical cohort of 100 000 newborns in the United States. Probabilities, costs, and quality-of-life weights were derived from a long-term follow-up study of newborn screening compared with clinical identification, primary data collection, published data, and expert opinion. We used a lifetime time horizon and the societal perspective. The main outcome measure was the incremental cost-effectiveness ratio in dollars per quality-adjusted life-year (QALY) gained. Secondary outcomes included averted deaths and hospitalizations.

RESULTS

Using base-case assumptions, the cost-effectiveness of newborn screening for MCADD was $21 273 per QALY gained. The cost-effectiveness ratio increased to $21 278/QALY when the loss in quality of life associated with false-positive test results was incorporated and to $27 423/QALY when the quality of life associated with lifelong dietary recommendations for treating MCADD was incorporated. Results were sensitive to the false-positive rate for the newborn screening test and the cost of the initial screen.

CONCLUSIONS

Expanded newborn screening for MCADD is cost-effective compared with well-accepted pediatric health interventions. Losses in quality of life associated with dietary treatment for MCADD, however, may offset some of the gains in QALYs from newborn screening. Consideration of new disorders for expanded newborn screening panels should include the potential reduction in quality of life associated with treatments.

Boostrix: a reduced-dose acellular pertussis vaccine for use in adolescents and adults

Pertussis remains a serious problem in many countries. Even in countries with high vaccine coverage and a long vaccination history, pertussis outbreaks occur periodically. Rather than being a disease of young children, pertussis has shifted to affect adolescents and adults. Increased pertussis burden in adolescents and adults is the major source of severe infection for young infants. An effective vaccine is needed to control the spread of pertussis beyond preschool children. Boostrix is a reduced-dose acellular pertussis vaccine with diphtheria and tetanus toxoids, and is designed for use in adolescents and adults. Current evidence suggests that Boostrix is immunogenic and well tolerated. The pertussis component of Boostrix has been shown to be efficacious in a large-scale Phase III trial. More than 50 countries have given permit to the use of Boostrix, and many of them formally recommend the use of Boostrix in adolescents and adults. Designed as a vaccine for adolescence and adults, Boostrix has a long way to go to achieve large-scale use in those target groups. Nevertheless, we expect that the advent of Boostrix will lead to a much better control of pertussis in the general population.

Conclusions on (cost-)effectiveness of pertussis booster vaccination strategies highly dependent on selections made in evidence review

This letter reacts on a paper recently published in this journal, reviewing the effectiveness and (cost-)effectiveness of pertussis booster vaccination strategies. We argue that a different selection of (cost-)effectiveness data could validly be made than the one presented in the review as being considered most robust. In particular, we explicitly present an alternative set of (cost-)effectiveness data.

Vaccine adherence in adolescents

Although a number of routine and catch-up vaccinations are currently recommended for adolescents, coverage rates of these vaccines are currently suboptimal. Routine recommended immunizations for this cohort include vaccines for influenza, human papillomavirus, and meningococcal disease, as well as a booster for tetanus, diphtheria, and acellular pertussis. Adolescence is also a critical period for administration of catch-up vaccines for those not fully immunized during childhood. Adolescents who do not seek appropriate preventive healthcare are at risk for significant morbidity and possible mortality. Increasing adolescent adherence to recommended vaccine schedules presents a challenge and opportunity for pediatricians and public health advocates. This article outlines barriers to vaccine compliance among adolescents and discusses strategies to increase vaccine uptake.

Social welfare and adolescent vaccination programs in the United States: the economic opportunities for a systematic expansion

In this article, the authors review current literature to analyze the cost-effectiveness of seven vaccines now available for adolescents and one that is in development. An analysis is also performed regarding the cutoff price that deems a vaccine "cost-effective." Often, $50,000 is the limit below which a drug is viewed as cost-effective. Our article contends that $160,000 could be a new limit below which the cost-effectiveness of a vaccine is better reflected. Based on standard economic valuations of life years in the United States and the preponderance of evidence from the cost-effectiveness literature, there is a compelling case for expanding adolescent vaccine programs, guidelines, and educational initiatives in the United States; there exist considerable economic benefits in excess of costs from policies that may achieve this objective.

Adult vaccination strategies for the control of pertussis in the United States: an economic evaluation including the dynamic population effects

Background

Prior economic evaluations of adult and adolescent vaccination strategies against pertussis have reached disparate conclusions. Using static approaches only, previous studies failed to analytically include the indirect benefits derived from herd immunity as well as the impact of vaccination on the evolution of disease incidence over time.

Methods

We assessed the impact of different pertussis vaccination strategies using a dynamic compartmental model able to consider pertussis transmission. We then combined the results with economic data to estimate the relative cost-effectiveness of pertussis immunization strategies for adolescents and adults in the US. The analysis compares combinations of programs targeting adolescents, parents of newborns (i.e. cocoon strategy), or adults of various ages.

Results

In the absence of adolescent or adult vaccination, pertussis incidence among adults is predicted to more than double in 20 years. Implementing an adult program in addition to childhood and adolescent vaccination either based on 1) a cocoon strategy and a single booster dose or 2) a decennial routine vaccination would maintain a low level of pertussis incidence in the long run for all age groups (respectively 30 and 20 cases per 100,000 person years). These strategies would also result in significant reductions of pertussis costs (between −77% and −80% including additional vaccination costs). The cocoon strategy complemented by a single booster dose is the most cost-effective one, whereas the decennial adult vaccination is slightly more effective in the long run.

Conclusions

By providing a high level of disease control, the implementation of an adult vaccination program against pertussis appears to be highly cost-effective and often cost-saving.