The cost effectiveness of adult vaccination

A systematic review of the relevant literature in English on the cost-effectiveness of immunisation for adults aged 50 years or over in all EU Member States was performed for the SAATI report (see below). Cost-effectiveness studies were found for 13 EU Member States (the UK, Germany, the Netherlands, Sweden, Belgium, France, Italy, Spain, Poland, Denmark, Finland, Slovakia and Czech Republic) and for 4 of the seven key vaccine preventable diseases examined in this report: herpes zoster, seasonal influenza, IPD and pneumococcal pneumonia. These studies showed that immunisation is likely to provide a cost-effective strategy for adults aged 50 years or over. This provides strong economic support for arguments supporting comprehensive adult immunisation strategies in European countries.

During the research process, no study in English language was found in EU Member States on the cost-effectiveness of pertussis, tetanus and diphtheria for the population aged 50 years and above. This may be due to the fact that for instance for tetanus and diphtheria booster immunisation was broadly used and recognised as an effective preventative tool before the development of such economic models.

Whilst the studies were based in different country settings and applied different economic models, the findings were similar and comparable, and there is evidence that the results have face validity. Immunisation strategies can be recommended for specific age groups in a number of the seven disease areas, particularly for the high-income countries:

Herpes zoster: the general consensus across studies that compared a vaccination strategy versus no vaccination strategy was that vaccination is a cost-saving or a cost-effective intervention. Existing evidence indicated that if immunisation was not cost-effective in the short-term, it did not imply cost-ineffectiveness in the long run. [Van Hoek 2012]. There is evidence that adult vaccination is a valuable preventive option when targeting populations aged 50-54 years [Ultsch 2012] and that vaccinating older cohorts (70+) is less cost-effective than vaccinating younger cohorts [Van Hoek 2009, Bresse 2012].

IPD: A study [Evers 2007] conducted a multi-country analysis across 10 EU countries to analyse the cost-effectiveness of pneumococcal vaccination for IPD across those aged >65 years. The study observed substantial variation in the Incremental Cost-Effectiveness Ratios (ICERs) across the countries, with older populations generally having higher ICERs. A UK based study [Melegaro 2004] recommended routine vaccination of all populations aged ≥ 65 years. It was estimated to be the best strategy, with lower cost per life year gained compared to vaccinating high-risk groups only.

Pneumococcal pneumonia: Two studies conducted in the Netherlands concluded vaccination with pneumococcal conjugate vaccine to be cost-effective when compared with no vaccination [Baltussen 1997, Rozenbaum 2010] for both the generalpopulation and high risk populations aged ≥65 years. A Finnish study [Martikainen 2012] presented similar findings.

Seasonal influenza: The results of the multi-country analysis [Aballea 2007, Scuffham 2002] found vaccination for influenza to be cost-effective across all the countries of interest. An Italian study [Garattini 2011] concluded that the economic advantage of extending influenza vaccination to healthy adult workers aged 50-64 years mainly relate to indirect costs such as costs associated with productivity loss.

The systematic review highlighted the lack of health economic research in low- and middle- income EU Member States. This lack of evidence makes it difficult to draw any conclusions as to whether such strategies represent good value for the scarce health­care resources available in these countries. However, this research is helpful in understanding the various models developed in this area, their advantages and disadvantages, and will benefit these countries in developing their own cost-effectiveness analyses using the new models or adapting existing models [Postma 2011]. Potential users of these models in low- and middle-income countries need to consider the specific building blocks of cost-effectiveness analysis including the nature, scope, design, assump­tions, and how these assumptions influence the model outcomes. In addition, they need to consider results from the existing studies based in high-income economies and structured reviews such as this one [Postma 2011]. All this information, combined with local data on burden of disease, may already provide an indication of the expected benefits of adult vaccination.

The review has also shed light on some of the potential limitations of such studies:

  • Potential interdependencies across diseases: A key feature of vaccine preventable diseases is the potential interdependencies across such diseases. However, none of the economic models identified in this review considered this aspect.
  • Herd immunity: only 3 studies mentioned assump­tions surrounding herd immunity.
  • Co-morbidity: a key feature of vaccine preventable diseases is the presence of co-morbidities. However, the economic evaluations conducted across herpes zoster, influenza, invasive pneumococcal disease and pneumonia did not consider this important aspect in the analyses.

Although cost-effectiveness provides a robust demonstration of the extent to which vaccines reduce medical costs, such traditional health economic frameworks do not take into account the wider range of benefits associated with immunisation. In fact, previous research has shown that they tend to underplay the benefits of vaccination by focusing on the averted costs of medical treatment and healthcare. In particular, they tend to not take into account the following:

  • The cost of averted infections that may occur over the long-term
  • Recent academic work on the effects of health on incomes and economic growth
  • The fact that immunisation also protects indivi­duals against the long-term effects that an illness can have on an individual’s physical, emotional and cognitive development.Current health economic studies usually do not take all relevant government perspectives into account. One example is the fiscal consequences of preventing disease and death. A broader view of the long-term benefits of vaccination shows immunisation pro­grammes to be much more worthwhile in terms of their economic consequences. As such, recent research calls for a more thorough investigation of the impacts of vaccination, looking not only at direct medical cost savings and averted illness, but also at the effects on e.g. productivity, income, savings and investment [Bloom 2005].

For more information and references see: Adult Vaccination, A key component of healthy ageing