Cost-effectiveness of childhood influenza vaccination in England and Wales: Results from a dynamic transmission model

Oxford Outcomes, Oxford, UK. Electronic address: .
Vaccine (Impact Factor: 3.62). 12/2012; 31(6). DOI: 10.1016/j.vaccine.2012.12.010
Source: PubMed


This study uses a dynamic influenza transmission model to directly compare the cost-effectiveness of various policies of annual paediatric influenza vaccination in England and Wales, varying the target age range and level of coverage. The model accounts for both the protection of those immunised and the indirect protection of the rest of the population via herd immunity. The impact of augmenting current practice with a policy to vaccinate pre-school age children, on their own or with school age children, was assessed in terms of quality adjusted life years and health service costs. Vaccinating 2-18-year olds was estimated to be the most cost-effective policy in an incremental cost-effectiveness analysis, at an assumed annual vaccine uptake rate of 50%. The mean incremental cost-effectiveness ratios for this policy was estimated at £251/QALY relative to current practice. Paediatric vaccination would appear to be a highly cost-effective intervention that directly protects those targeted for vaccination, with indirect protection extending to both the very young and the elderly.

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Available from: Richard Pitman, Jan 17, 2014
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    • "A variety of deterministic and stochastic models have been proposed to address various aspects of seasonal [13-16] or pandemic influenza [17-21] or to predict the size and timing of seasonal waves [22-24]. We have decided to use an individual-based stochastic model which allows for maximum flexibility in modeling immunity and vaccination strategies [25] and, thus, circumvents common oversimplifications of deterministic models [26]. "
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    ABSTRACT: Background Influenza vaccines contain Influenza A and B antigens and are adjusted annually to match the characteristics of circulating viruses. In Germany, Influenza B viruses belonged to the B/Yamagata lineage, but since 2001, the antigenically distinct B/Victoria lineage has been co-circulating. Trivalent influenza vaccines (TIV) contain antigens of the two A subtypes A(H3N2) and A(H1N1), yet of only one B lineage, resulting in frequent vaccine mismatches. Since 2012, the WHO has been recommending vaccine strains from both B lineages, paving the way for quadrivalent influenza vaccines (QIV). Methods Using an individual-based simulation tool, we simulate the concomitant transmission of four influenza strains, and compare the effects of TIV and QIV on the infection incidence. Individuals are connected in a dynamically evolving age-dependent contact network based on the POLYMOD matrix; their age-distribution reproduces German demographic data and predictions. The model considers maternal protection, boosting of existing immunity, loss of immunity, and cross-immunizing events between the B lineages. Calibration to the observed annual infection incidence of 10.6% among young adults yielded a basic reproduction number of 1.575. Vaccinations are performed annually in October and November, whereby coverage depends on the vaccinees’ age, their risk status and previous vaccination status. New drift variants are introduced at random time points, leading to a sudden loss of protective immunity for part of the population and occasionally to reduced vaccine efficacy. Simulations run for 50 years, the first 30 of which are used for initialization. During the final 20 years, individuals receive TIV or QIV, using a mirrored simulation approach. Results Using QIV, the mean annual infection incidence can be reduced from 8,943,000 to 8,548,000, i.e. by 395,000 infections, preventing 11.2% of all Influenza B infections which still occur with TIV (95% CI: 10.7-11.8%). Using a lower B lineage cross protection than the baseline 60%, the number of Influenza B infections increases and the number additionally prevented by QIV can be 5.5 times as high. Conclusions Vaccination with TIV substantially reduces the Influenza incidence compared to no vaccination. Depending on the assumed degree of B lineage cross protection, QIV further reduces Influenza B incidence by 11-33%.
    BMC Infectious Diseases 07/2014; 14(1):365. DOI:10.1186/1471-2334-14-365 · 2.61 Impact Factor
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    • "In addition, indirect measures of controlling infections in children (e.g., school closures) have a pronounced effect of decreasing disease rates in the general population, including the elderly (Earn et al., 2012). Although vaccinating children for influenza or pneumonia is predicted to be a cost-effective measure (Salo et al., 2006), when the indirect effects of vaccination are taken into account the cost-effectiveness of vaccination (as measured by the cost per life-year saved) increases as much as 15-fold (Ray et al., 2006; Pitman et al., 2013). "
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    ABSTRACT: Vaccination remains the most effective prophylactic intervention for infectious disease in the healthcare professional's toolkit. However, the efficacy and effectiveness of vaccines decrease with age. This becomes most apparent after an individual reaches 65-70 years old, and results from complex changes in the immune system that occur during aging. As such, new vaccine formulations and strategies that can accommodate age-related changes in immunity are required to protect this expanding population. Here, we summarize the consequences of immunosenescence on vaccination and how novel vaccination strategies can be designed to accommodate the aging immune system. We conclude that current vaccination protocols are not sufficient to protect our aging population and, in some cases, are an inefficient use of healthcare resources. However, researchers and clinicians are developing novel vaccination strategies that include modifying who and when we vaccinate and capitalize on existing vaccines, in addition to formulating new vaccines specifically tailored to the elderly in order to remedy this deficiency.
    Frontiers in Immunology 06/2013; 4:171. DOI:10.3389/fimmu.2013.00171
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    ABSTRACT: Influenza is an important cause of morbidity and mortality, especially in combination with secondary bacterial infections.1-3 Annual influenza vaccination is recommended for everyone at risk by the WHO.4 In recent years, a number of countries have recommended influenza vaccination for all children older than 6 months although the uptake has been variable. The effectiveness of inactivated influenza vaccines in children has been questioned.5 Numerous studies have been published on the subject but outcome measures used vary with some studies using influenza-like-illness while others use culture or PCR-proven influenza, making comparison and meta-analyses difficult. In several randomised clinical trials, live attenuated influenza vaccine (LAIV) has been found safe, effective compared to placebo and consistently more effective than trivalent inactivated vaccine (TIV) in children. In 2012, UK authorities announced plans to offer annual LAIV to all children aged 2-17 years and in July 2013 that a single dose of the vaccine will be offered to all 2-year-olds and 3-year-olds from September 2013. Although the evidence base supporting this decision is robust, some important questions remain unanswered. Such a campaign, if carried out successfully, could significantly reduce the burden of disease in children and, since children are thought to be important in the propagation of infection within the population and thus development of influenza epidemics, this initiative may well impact on disease in other age groups through indirect protection. However, few studies quantifying such effects have been done to date. In this paper, aspects of the implementation of universal childhood influenza vaccination are discussed.
    Archives of Disease in Childhood 08/2013; 98(11). DOI:10.1136/archdischild-2013-304681 · 2.90 Impact Factor
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