Effectiveness and cost-effectiveness of general immunisation of infants and young children with the heptavalent conjugated pneumococcal vaccine

BACKGROUND: The European Agency for the Evaluation of Medicinal Products (EMEA) granted market authorisation to the heptavalent pneumococcal vaccine Prevenar (Wyeth) in the year 2001. The indication of Prevenar is the active immunisation of infants and young children under the age of two against invasive disease caused by Streptococcus pneumonia serotypes 4, 6B, 9V, 14, 18C, 19F and 23F. At the time of this study the German vaccination scheme advises the immunisation with Prevenar only for children at high risk. OBJECTIVES: The objective of the study is first to determine the efficacy and effectiveness of the immunisation of all children with the heptavalent conjugated pneumococcal vaccine in Germany and second, whether a general recommendation for vaccination of all children would be cost-effective. METHODS: A systematic literature search was performed in 29 relevant databases for the period of January 1999 to June 2004. Thus 1,884 articles were identified which were then assessed according to predefined selection criteria. RESULTS: There is evidence for the medical effectiveness of Prevenar against invasive pneumococcal disease caused by the covered serotypes from a major double-blinded RCT undertaken in California. The vaccine shows lower values of effectiveness against otitis media and pneumonia. The values for effectiveness of the vaccine in Germany are below the data for California because of the different incidence of Serotypes. The cost-effectiveness rates for an immunisation of all children with Prevenar vary across different countries. One reason - besides different Health Systems - can be seen in the uncertainty about the duration of protection, another in the assumption on regional serotype coverage of the vaccine. From the healthcare payers' perspective a general vaccination of all children in Germany is not cost-effective, from a societal perspective the benefits from vaccination could prevail the cost. The actual price of the vaccine (if financed by the Healthcare Payer, 2004) has dropped and is lower than the assumed price in the German cost-effectiveness study. This fact could raise the cost-effectiveness-ratio of a general immunisation. DISCUSSION: The low evidence of information on the herd immunity effect of pneumococcal immunisation, the occurrence on serotype-replacement phenomenon and the effects on the prevalence of antibiotic-resistant strains shall be considered when deciding whether the pneumococcal vaccination for all infants and young children should be added to the German vaccination scheme. There is also little information on the duration of vaccine effectiveness and regional effectiveness because of different serotype incidence. The economic models thus incorporate some uncertainties. CONCLUSION: At present, relatively few pneumococcal strains in Germany show antibiotic resistance. This situation shall further be observed while improving the data evidence for future decisions (epidemiologic data of incidence of pneumococcal diseases and serotyping of pneumococcal bacteria). From the economic perspective no distinct recommendation to add the conjugated vaccination for all children to the German vaccination scheme can be given. This situation may change if the price for the vaccine further decreases. Furthermore a future cost-effectiveness analysis for Germany should incorporate the effects of the replacement phenomenon, the herd immunisation effects and the effects of the vaccination on the antibiotic-resistant pneumococcal strains.