[Vaccination--value for money?]. / Vaksinering--er det verdt pengene?

Modern vaccines may be very costly, and society needs to consider vaccination against other preventive and curative interventions. An economic assessment of health care programmes implies to quantify costs and assess health consequences in order to set better priorities. The main challenge lies in obtaining valid estimates of health effects and side effects and the consequences of herd immunity and serotype shift. This article discusses the methods and challenges of economic evaluation of vaccination programs, with vaccination against whooping cough and pneumococcal disease as examples.

Effectiveness of a 2+1 dose schedule pneumococcal conjugate vaccination programme on invasive pneumococcal disease among children in Norway.

The 7-valent pneumococcal conjugate vaccine (PCV-7) was licensed in Norway in 2001. In July 2006, PCV-7 was introduced in the Norwegian Childhood Vaccination Programme in a 2+1 dose schedule, with immunizations administered at 3, 5 and 12 months of age. PCV-7 was offered through the vaccination programme to all children born from January 2006, i.e. a catch-up for children aged 3-6 months. Prior to 2006 the use of PCV-7 was negligible. The effectiveness of the PCV-7 vaccination programme was assessed using data on invasive pneumococcal disease (IPD) incidence obtained from the Norwegian Surveillance System for Communicable Diseases, serotype distribution from the National Reference Laboratory for Pneumococci, and vaccine coverage and vaccination status from the Norwegian National Vaccination Register. Vaccine coverage quickly reached high levels; 95% of children >3 months born from January 2006 had received at least one immunization with PCV-7. The incidence rate of IPD among children <2 years rapidly declined; the rate of vaccine serotype IPD in this age group fell from an average of 47.1 cases/100,000 population in the 2 years prior to PCV-7 introduction to 13.7 cases/100,000 population in 2007. The incidence rate of nonvaccine serotype IPD remained stable. The vaccine programme effectiveness was estimated to be 74% (95% CI 57-85%). No vaccine failure was seen after complete primary immunization with two vaccine doses. Our findings indicate that PCV-7 provides highly effective protection against vaccine serotype IPD when administered in a 2+1 dose schedule.

International Circumpolar Surveillance System for invasive pneumococcal disease, 1999-2005.

The International Circumpolar Surveillance System is a population-based surveillance network for invasive bacterial disease in the Arctic. The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced for routine infant vaccination in Alaska (2001), northern Canada (2002-2006), and Norway (2006). Data for invasive pneumococcal disease (IPD) were analyzed to identify clinical findings, disease rates, serotype distribution, and antimicrobial drug susceptibility; 11,244 IPD cases were reported. Pneumonia and bacteremia were common clinical findings. Rates of IPD among indigenous persons in Alaska and northern Canada were 43 and 38 cases per 100,000 population, respectively. Rates in children <2 years of age ranged from 21 to 153 cases per 100,000 population. In Alaska and northern Canada, IPD rates in children <2 years of age caused by PCV7 serotypes decreased by >80% after routine vaccination. IPD rates are high among indigenous persons and children in Arctic countries. After vaccine introduction, IPD caused by non-PCV7 serotypes increased in Alaska.

Cost effectiveness of adding 7-valent pneumococcal conjugate (PCV-7) vaccine to the Norwegian childhood vaccination program.

BACKGROUND: Streptococcus pneumoniae is a frequent bacterial cause of serious infections that may cause permanent sequelae and death. A 7-valent conjugate vaccine may reduce the incidence of pneumococcal disease, but some previous studies have questioned the cost-effectiveness of the vaccine. The aim of this study was to estimate costs and health consequences of adding this pneumococcal vaccine to the Norwegian childhood vaccination programme, taking the possibility of herd immunity into account. METHODS: We developed a simulation model (Markov-model) using data on the risk of pneumococcal disease in Norway, the efficacy of the vaccine as observed in clinical trials from other countries and adjusted for serotype differences, the cost of the vaccine and quality of life for patients with sequelae from pneumococcal disease. The results were expressed as incremental (additional) costs (in euros; euro1.00 approximately NOK8.37), incremental life years and incremental quality adjusted life years. Four different sets of main results are presented: costs and (quality adjusted) life years, with and without indirect costs (the value of lost production due to work absenteeism) and with and without potential herd immunity (i.e. childhood vaccination protects adults against pneumococcal disease). RESULTS: When indirect costs were disregarded, and four vaccine doses used, the incremental cost per life year gained was euro153,000 when herd immunity was included, and euro311,000 when it was not. When accounting for indirect costs as well, the cost per life year gained was euro58,000 and euro124,000, respectively. Assuming that three vaccine doses provide the same protection as four, the cost per life year gained with this regimen was euro90,000 with herd immunity and euro184,000 without (when indirect costs are disregarded). If indirect costs are also included, vaccination both saves costs and gains life years. INTERPRETATION/CONCLUSION: In Norway, governmental guidelines indicate that only interventions with cost per life year of less than euro54,000 should be implemented. This implies that four dose vaccination is not cost-effective even if decision makers includes both herd immunity and indirect costs in their decisions. If three doses offer the same protection as four doses, however, vaccination would be cost-saving when indirect costs are included, but not with only herd immunity. COMMENT: In the autumn of 2005, the Norwegian Government decided to include PCV-7 in the vaccination program. This analysis was used by the Ministry of Health and Ministry of Finance during the decision process.