Cost-effectiveness of seasonal influenza vaccination in pregnant women, health care workers and persons with underlying illnesses in Belgium

Cost-effectiveness analysis of seasonal influenza vaccination during pregnancy: A systematic review

BACKGROUND

Seasonal influenza vaccination is clinically important and reduces hospitalization costs for pregnant women. However, is it also a cost-effective intervention?

METHOD

We conducted a systematic search of Medline (via PUBMED), EMBASE, SCOPUS, and Web of Science databases. We included any economic evaluation studies that reported Incremental Cost-Effectiveness Ratios for vaccinating pregnant women against influenza.

RESULT

Out of 927 potentially eligible articles, only 14 full texts met our inclusion criteria. In almost all studies, vaccinating pregnant women was a cost-effective and cost-saving strategy. In one study, it was not cost-effective when the researchers used costs and probabilities related to other groups (healthy adults) due to the lack of data for pregnant women. The main factors influencing the cost-effectiveness of the studies were vaccine efficacy and vaccination cost.

CONCLUSION

Influenza vaccination of pregnant women is a cost-effective intervention. More studies on the cost-effectiveness of this intervention in underdeveloped countries are needed.

The burden of influenza and the role of influenza vaccination in adults aged 50-64 years: A summary of available evidence

Influenza is a vaccine-preventable disease and a global public health problem. Although most national influenza vaccination recommendations focus on subjects aged ≥65 years, an extensive burden of influenza has also been reported in those aged ≥50 years and is exacerbated by immune system aging. The main purpose of this review is to provide an overview of the burden of influenza and its potential prevention within the 50-64 age-group. These subjects account for a large proportion of the workforce, and play a central economic and social role. Individuals aged 50-64 years had a 3-times higher rate of hospitalization and a 9-fold higher mortality rate attributable to influenza than those aged 18-49-years, generating higher influenza-related hospitalization costs. Available data suggest that including healthy subjects aged 50-64 years in influenza vaccination recommendations would allow a broader population to be reached, reducing the economic and social burden of influenza.

Economic evaluation of seasonal influenza vaccination in elderly and health workers: A systematic review and meta-analysis

BACKGROUND

A number of cost-effectiveness analysis of influenza vaccination have been conducted to estimate value of influenza vaccines in elderly and health workers (HWs). This study aims to summarize cost-effectiveness evidence by pooling the incremental net monetary benefit (INMB) of influenza vaccination.

METHODS

A systematic review was performed in electronic databases from their inceptions to February 2022. Cost-effectiveness studies reporting quality-adjusted life year (QALY), or life year (LY) of influenza vaccination were included. Stratified meta-analyses by population, perspective, country income-level, and herd-effect were performed to pool INMB across studies. The protocol was registered at PROSPERO (CRD42021246746).

FINDINGS

A total of 21 studies were included. Eighteen studies were conducted in elderly, two studies were conducted in HWs, and one study was conducted in both elderly and HWs. According to pre-specified analyses, studies for elderly in high-income economies (countries) (HIEs) and upper-middle income economies (UMIEs) without herd effect could be pooled. For HIEs under a societal perspective, the perspective which identify all relevant costs occurred in the society including direct medical cost, direct non-medical cost and indirect cost, pooled INMB was $217·38 (206·23, 228·53, I² =28.2%), while that for healthcare provider/payer perspective was $0·20 (-11,908·67, 11,909·07, I² = 0.0%). For societal perspective in UMIEs, pooled INMB was $28·39 (-190·65, 133·87, I² = 92.8%). The findings were robust across a series of sensitivity analyses for HIEs. Studies in HWs indicated that influenza vaccination was cost-effective compared to no vaccination or current practice.

INTERPRETATION

Influenza vaccination might be cost-effective for HWs and elderly in HIEs under a societal perspective with relatively small variations among included studies, while there remains limited evidence for healthcare provider/payer perspective or other level of incomes. Further evidence is warranted.

FUNDING

This study was funded by a grant of Immunization, Vaccine and Biologicals department of the World Health Organization. The authors would like to acknowledge the contributions of the US CDC which provided financial support to the development and publication of this report. Grant number US CDC, WHO IVR (U50CK000431).

Cost-Effectiveness of Influenza Vaccination Strategies in Adults: Older Adults Aged ≥65 Years, Adults Aged 50–64 Years, and At-Risk Adults Aged 19–64 Years

The high disease burden of influenza in elderly and chronically ill adults may be due to the suboptimal effectiveness and mismatch of the conventional trivalent influenza vaccine (TIV). This study evaluated the cost-effectiveness of quadrivalent (QIV), adjuvanted trivalent (ATIV), and high-dose quadrivalent (HD-QIV) vaccines versus TIV used under the current Korean National Immunization Program (NIP) in older adults aged ≥65 years. We also evaluated the cost-effectiveness of programs for at-risk adults aged 19–64 and adults aged 50–64. A one-year static population model was used to compare the costs and outcomes of alternative vaccination programs in each targeted group. Influenza-related parameters were derived from the National Health Insurance System claims database; other inputs were extracted from the published literature. Incremental cost-effectiveness ratios (ICERs) were assessed from a societal perspective. In the base case analysis (older adults aged ≥65 years), HD-QIV was superior, with the lowest cost and highest utility. Compared with TIV, ATIV was cost-effective (ICER $34,314/quality-adjusted life-year [QALY]), and QIV was not cost-effective (ICER $46,486/QALY). The cost-effectiveness of HD-QIV was robust for all parameters except for vaccine cost. The introduction of the influenza NIP was cost-effective or even cost-saving for the remaining targeted gr3oups, regardless of TIV or QIV.

Influenza Vaccination for the Prevention of Cardiovascular Disease in the Americas: Consensus document of the Inter-American Society of Cardiology and the Word Heart Federation

Background

Cardiovascular mortality is decreasing but remains the leading cause of death world-wide. Respiratory infections such as influenza significantly contribute to morbidity and mortality in patients with cardiovascular disease. Despite of proven benefits, influenza vaccination is not fully implemented, especially in Latin America.

Objective

The aim was to develop a regional consensus with recommendations regarding influenza vaccination and cardiovascular disease.

Methods

A multidisciplinary team composed by experts in the management and prevention of cardiovascular disease from the Americas, convened by the Inter-American Society of Cardiology (IASC) and the World Heart Federation (WHF), participated in the process and the formulation of statements. The modified RAND/UCLA methodology was used. This document was supported by a grant from the WHF.

Results

An extensive literature search was divided into seven questions, and a total of 23 conclusions and 29 recommendations were achieved. There was no disagreement among experts in the conclusions or recommendations.

Conclusions

There is a strong correlation between influenza and cardiovascular events. Influenza vaccination is not only safe and a proven strategy to reduce cardiovascular events, but it is also cost saving. We found several barriers for its global implementation and potential strategies to overcome them.

Workplace influenza vaccination to reduce employee absenteeism: An economic analysis from the employers' perspective

BACKGROUND

Each year, up to 10% of unvaccinated adults contracts seasonal influenza, with half of this proportion developing symptoms. As a result, employers experience significant economic losses in terms of employee absenteeism. Influenza vaccines can be instrumental in reducing this burden. Workplace vaccination is expected to reduce employee absenteeism more than linearly as a result of positive externalities. It remains unclear whether workplace influenza vaccination yields a positive return on investment.

METHODS

We simulated the spread of influenza in the seasons 2011-12 up to 2017-18 in Belgium by means of a compartmental transmission model. We accounted for age-specific social contact patterns and included reduced contact behavior when symptomatically infected. We simulated the impact of employer-funded influenza vaccination at the workplace and performed a cost-benefit analysis to assess the employers' return on workplace vaccination. Furthermore, we look into the cost-benefit of rewarding vaccinated employees by offering an additional day off.

RESULTS

Workplace vaccination reduced the burden of influenza both on the workplace and in the population at large. Compared to the current vaccine coverage - 21% in the population at large - an employee vaccine coverage of 90% could avert an additional 355 000 cases, of which about 150 000 in the employed population and 205 000 in the unemployed population. While seasonal influenza vaccination has been cost-saving on average at about €10 per vaccinated employee, the cost-benefit analysis was prone to between-season variability.

CONCLUSIONS

Vaccinated employees can serve as a barrier to limit the spread of influenza in the population, reducing the attack rate by 78% at an employee coverage of 90%. While workplace vaccination is relatively inexpensive (due to economies of scale) and convenient, the return on investment is volatile. Government subsidies can be pivotal to encourage employers to provide vaccination at the workplace with positive externalities to society as a whole.

Economic Evaluation of Vaccines: Belgian Reflections on the Need for a Broader Perspective

OBJECTIVES

The standard framework of economic evaluation of health programs, which is increasingly used for policy funding decisions, is insufficiently equipped to reflect the full range of health and economic benefits conferred by vaccines and thus undervalues vaccination.

METHODS

In 2019, a group of Belgian health economic and clinical experts, supported by 2 senior international vaccination experts (1 American, 1 Belgian), convened 4 roundtable meetings to highlight which particular value elements of vaccination remain neglected in economic evaluations.

RESULTS

They concluded that the standard economic evaluation framework fails to reflect the full value of vaccination with respect to prevention of complications linked to some vaccine-preventable diseases, health gains for caregivers, herd effects, changes in exposure to and distribution of serotypes, the effect on antimicrobial resistance, productivity gains for caregivers and patients, and the distributive implications of vaccination programs.

CONCLUSIONS

Here, suggestions are made regarding how these shortcomings can be addressed in future economic evaluations of vaccines and how a more level playing field between vaccines and other health programs can be created.

Cost-effectiveness analysis of influenza vaccination during pregnancy in Japan

BACKGROUND

Pregnant women and infants are known as high risk groups for influenza. WHO recommend pregnant women be vaccinated with inactivated influenza vaccine. In Japan, some municipalities started to give subsidy to encourage pregnant women to receive a shot on their own accord, which has made the introduction of seasonal antepartum maternal vaccination program (AMVP) into the routine vaccination list a current topic in health policy and has raised the need to evaluate the value for money of such possibility.

METHODS

We conducted a cost-effectiveness analysis to evaluate the efficiency of conducting AMVP in Japan. A decision tree model was adopted taking into consideration the duration of single-year vaccine effectiveness for infants and for mothers. The program targeted pregnant women aged 20-49 years old at or over 12 weeks gestation during October 1 through March 30. Estimated probabilities of treatments received due to influenza for pregnant/postpartum women or their infants varied by calendar time, vaccination status, and/or gestational age. Incremental cost-effectiveness ratio (ICER) compared with current no-AMVP from societal perspective was calculated. Transition probabilities, utility weights to estimate quality-adjusted life year (QALY), and disease treatment costs were either calculated or extracted from literature. Costs per vaccination was assumed at ¥3,529/US$32.1.

RESULTS

AMVP reduces disease treatment costs, while the reduction cannot offset the vaccination cost. Incremental QALYs were at 0.00009, among them 84.2% were from infants. ICER was ¥7,779,356/US$70,721 per QALY gained. One-way sensitivity analyses revealed that vaccine effectiveness for infant and costs per shot were the two main key variables affecting the ICER.

CONCLUSION

We found that vaccinating pregnant women with influenza vaccine to prevent unvaccinated infants and pregnant/postpartum women from influenza-associated disease in Japan can be cost-effective from societal perspective, under the WHO-suggested "cost-effective" criteria (1-3 times of GDP).

A cost-effectiveness analysis of antenatal influenza vaccination among HIV-infected and HIV-uninfected pregnant women in South Africa

BACKGROUND

Pregnant women and infants are at increased risk of severe disease from influenza. Antenatal influenza vaccination is safe and can reduce the risk of illness for women and their infants. We evaluated for South Africa the health effects of antenatal influenza vaccination among pregnant women and their infants aged <6 months old and assessed its cost-effectiveness.

METHODS

We constructed a decision tree model to simulate the population of pregnant women and infants aged <6 months in South Africa using TreeAge Pro Suite 2015. The model evaluated the change in societal costs and outcomes associated with a vaccination campaign that prioritized HIV-infected over HIV-uninfected pregnant women compared with no vaccination. We also examined the impacts of a campaign without prioritization. Upper and lower 90% uncertainty intervals (90% UI) were generated using probabilistic sensitivity analysis on 10000 Monte Carlo simulations. The cost-effectiveness threshold was set to the 2015 per capita gross domestic product of South Africa, US$5724.

RESULTS

Antenatal vaccination with prioritization averted 9070 (90% UI: 7407-11217) total cases of influenza among pregnant women and infants, including 411 (90% UI: 305-546) hospitalizations and 30 (90% UI: 22-40) deaths. This corresponds to an averted fraction of 13.5% (90% UI: 9.0-20.5%). Vaccinating without prioritization averted 7801 (90% UI: 6465-9527) cases of influenza, including 335 (90% UI: 254-440) hospitalizations and 24 (90% UI: 18-31) deaths. This corresponds to an averted fraction of 11.6% (90% UI: 7.8-17.4%). Vaccinating the cohort of pregnant women with prioritization had societal cost of $4689 (90% UI: $3128-$7294) per Quality Adjusted Life Year (QALY) gained while vaccinating without prioritization had a cost of $5924 (90% UI: $3992-$9056) per QALY.

CONCLUSIONS

Antenatal influenza vaccination campaigns in South Africa would reduce the impact of influenza and could be cost-effective.

Variation in loss of immunity shapes influenza epidemics and the impact of vaccination

BACKGROUND

Protective antibody immunity against the influenza A virus wanes in 2-7 years due to antigenic drift of the virus' surface proteins. The duration of immune protection is highly variable because antigenic evolution of the virus is irregular. Currently, the variable nature of the duration of immunity has had little attention in analyses of the impact of vaccination, including cost-effectiveness studies.

METHODS

We developed a range of mathematical transmission models to investigate the effect of variable duration of immunity on the size of seasonal epidemics. The models range from simple conceptual to more realistic, by distinguishing between infection- versus vaccination-induced immunity, by inclusion of primary vaccine failure, by assuming a leaky vaccine, and by the inclusion of age-dependent contact patterns.

RESULTS

We show that annual variation in the duration of immunity causes large variation in the size of epidemics, and affects the effectiveness of vaccination. Accumulation of susceptible individuals in one or more mild seasons results in a disproportionately large outbreak in a subsequent season. Importantly, variation in the duration of immunity increases the average infection attack rate when the vaccination coverage is around the outbreak threshold. Specifically, in a tailored age-stratified model with a realistic reproduction number (R ₀ = 1.4) and vaccination coverage of 25%, we find that the attack rate in unvaccinated children (<10 years old) is negligible if the duration of immunity is constant, while on average 2.8% (2.5-97.5% percentiles: 1.8-4.1%) of the children are infected if the duration of immunity is variable. These findings stem from the buildup of susceptibility over multiple seasons by waning of immunity, and the nonlinear relation between susceptibility and infection attack rates.

CONCLUSIONS

The models illustrate that variation in the duration of immunity impacts the long-term effectiveness of vaccination, and that vaccine effectiveness cannot be judged for each year in isolation. Our findings have implications for vaccination strategies that aim to maximize the vaccination coverage while extending the age range of persons eligible for vaccination.

Systematic review of the cost-effectiveness of influenza immunization programs

BACKGROUND

Seasonal influenza immunization programs vary widely across jurisdictions. In Canada, some provinces offer universal programs while others target specific population groups. However, whether targeted or universal programs provide more benefit and value-for-money is unclear. The cost-effectiveness of influenza immunization programs was systematically reviewed to inform policy.

METHODS

Citation databases and the grey literature were searched for economic evaluations of influenza immunization programs. Eligible studies were appraised using the Scottish Intercollegiate Guidelines Network (SIGN) checklist with supplemental WHO vaccine-related questions. Data from high quality studies was extracted and the studies reviewed.

RESULTS

A total of 41influenza immunization studies were identified. Of these, 31 were high quality. For pregnant and postpartum women, vaccinating all versus only high risk women study results ranged from dominance (less costly and more effective) to $9773 per QALY gained (societal) and from dominance to $58,000 per QALY gained (healthcare system). Studies of vaccinating all versus only high risk children found vaccination to be dominant to $47,000 per QALY gained (societal), and dominant to $18,000 per QALY gained (healthcare system). Vaccinating high risk adults was highly cost-effective and vaccinating health care workers resulted in $35,000 per QALY gained. Results for healthy working adults were mixed and sensitive to vaccine uptake, efficacy, and productivity loss.

CONCLUSIONS

From the societal perspective, vaccination was cost-effective for children, pregnant and postpartum women, high risk groups, and in some cases, healthy working age adults. Immunization programs using group administration are more cost-effective than programs using individual administration. The perspective, programmatic design, setting, and inclusion of herd immunity affects cost-effectiveness. In regions with targeted programs, re-evaluating "high risk" criteria and consideration of a universal program is warranted.

Unremarked or Unperformed? Systematic Review on Reporting of Validation Efforts of Health Economic Decision Models in Seasonal Influenza and Early Breast Cancer

BACKGROUND

Transparent reporting of validation efforts of health economic models give stakeholders better insight into the credibility of model outcomes. In this study we reviewed recently published studies on seasonal influenza and early breast cancer in order to gain insight into the reporting of model validation efforts in the overall health economic literature.

METHODS

A literature search was performed in Pubmed and Embase to retrieve health economic modelling studies published between 2008 and 2014. Reporting on model validation was evaluated by checking for the word validation, and by using AdViSHE (Assessment of the Validation Status of Health Economic decision models), a tool containing a structured list of relevant items for validation. Additionally, we contacted corresponding authors to ask whether more validation efforts were performed other than those reported in the manuscripts.

RESULTS

A total of 53 studies on seasonal influenza and 41 studies on early breast cancer were included in our review. The word validation was used in 16 studies (30 %) on seasonal influenza and 23 studies (56 %) on early breast cancer; however, in a minority of studies, this referred to a model validation technique. Fifty-seven percent of seasonal influenza studies and 71 % of early breast cancer studies reported one or more validation techniques. Cross-validation of study outcomes was found most often. A limited number of studies reported on model validation efforts, although good examples were identified. Author comments indicated that more validation techniques were performed than those reported in the manuscripts.

CONCLUSIONS

Although validation is deemed important by many researchers, this is not reflected in the reporting habits of health economic modelling studies. Systematic reporting of validation efforts would be desirable to further enhance decision makers' confidence in health economic models and their outcomes.

A preliminary cost-effectiveness analysis of hepatitis E vaccination among pregnant women in epidemic regions

Objective To estimate the cost-effectiveness of hepatitis E vaccination among pregnant women in epidemic regions. Methods A decision tree model was constructed to evaluate the cost-effectiveness of 3 hepatitis E virus vaccination strategies from societal perspectives. The model parameters were estimated on the basis of published studies and experts' experience. Sensitivity analysis was used to evaluate the uncertainties of the model. Results Vaccination was more economically effective on the basis of the incremental cost-effectiveness ratio (ICER< 3 times China's per capital gross domestic product/quality-adjusted life years); moreover, screening and vaccination had higher QALYs and lower costs compared with universal vaccination. No parameters significantly impacted ICER in one-way sensitivity analysis, and probabilistic sensitivity analysis also showed screening and vaccination to be the dominant strategy. Conclusion Screening and vaccination is the most economical strategy for pregnant women in epidemic regions; however, further studies are necessary to confirm the efficacy and safety of the hepatitis E vaccines.

Cost-effectiveness of an influenza vaccination program offering intramuscular and intradermal vaccines versus intramuscular vaccine alone for elderly

BACKGROUND

Intradermal (ID) injection is an alternative route for influenza vaccine administration in elderly with potential improvement of vaccine coverage. This study aimed to investigate the cost-effectiveness of an influenza vaccination program offering ID vaccine to elderly who had declined intramuscular (IM) vaccine from the perspective of Hong Kong public healthcare provider.

METHODS

A decision analytic model was used to simulate outcomes of two programs: IM vaccine alone (IM program), and IM or ID vaccine (IM/ID program) in a hypothetic cohort of elderly aged 65 years. Outcome measures included influenza-related direct medical cost, infection rate, mortality rate, quality-adjusted life years (QALYs) loss, and incremental cost per QALY saved (ICER). Model inputs were derived from literature. Sensitivity analyses evaluated the impact of uncertainty of model variables.

RESULTS

In base-case analysis, the IM/ID program was more costly (USD52.82 versus USD47.59 per individual to whom vaccine was offered) with lower influenza infection rate (8.71% versus 9.65%), mortality rate (0.021% versus 0.024%) and QALYs loss (0.00336 versus 0.00372) than the IM program. ICER of IM/ID program was USD14,528 per QALY saved. One-way sensitivity analysis found ICER of IM/ID program to exceed willingness-to-pay threshold (USD39,933) when probability of influenza infection in unvaccinated elderly decreased from 10.6% to 5.4%. In 10,000 Monte Carlo simulations of elderly populations of Hong Kong, the IM/ID program was the preferred option in 94.7% of time.

CONCLUSIONS

An influenza vaccination program offering ID vaccine to elderly who had declined IM vaccine appears to be a highly cost-effective option.

The cost-effectiveness of pneumococcal vaccination in healthy adults over 50: An exploration of influential factors for Belgium

BACKGROUND

A recent trial demonstrated the 13 valent conjugate pneumococcal vaccine (PCV13) to be effective against invasive and non-invasive pneumococcal disease in healthy adults. PCV13 might therefore be considered as an alternative to the 23 valent polysaccharide vaccine (PPV23).

AIM

To explore the cost-effectiveness of vaccinating healthy adults over 50, with either PCV13 or PPV23 alone, or with a combined strategy using both PCV13 and PPV23.

METHODS

A static multi-cohort model was developed simulating the consequences of pneumococcal vaccination in adults over 50 from a health care payer's perspective, for different scenarios of duration of vaccine protection and serotype evolution.

RESULTS

At currently expected prices, PCV13 vaccination of healthy adults over 50 is unlikely to be cost-effective either compared with no vaccination or in combination with PPV23 versus PPV23 only.

CONCLUSION

Further research is needed on vaccine efficacy of the combination strategy and of risk groups, as well as the duration of vaccine protection. Serotype evolutions under the influence of the childhood PCV program should be closely monitored.