Cost-benefit analysis for the use of Haemophilus influenzae type b conjugate vaccine in Santiago, Chile.

ABSTRACT

PIP: Health practitioners reviewed the clinical records of all 6-60 month old children who were treated for meningitis caused by Haemophilus influenzae type b (HIB) in 1989-1990 at Roberto del Rio Children's Hospital in Santiago, Chile, to estimate costs for all phases of meningitis treatment (ambulatory visits, hospitalization, and follow-up). They also estimated annual HIB incidence. They determined the cost of adding HIB conjugate vaccine to the DTP vaccine. They assumed a cost of US$1 for a full 3-dose regimen of vaccine. They then conducted a cost benefit analysis of the use of HIB conjugate vaccine to prevent invasive HIB disease in Santiago. The National Health Service had to pay an average of US$1301/case of HIB meningitis and US$887/case of HIB invasive disease other than meningitis, including pre- and post-hospitalization costs and adjustment for frequency of sequelae. Several factors indicated that the estimates were actually underestimates. For example, the researchers did not take into account herd immunity and the fact that sequelae often do not appear until the children are older. The addition of the HIB conjugate vaccine to the immunization program would prevent at least 1229-3111 cases of HIB invasive disease, disabling sequelae, and deaths during a 10-year period. Further, it would save the National Health Service more than US$403,225. The benefit/cost ratio was 1.66. The researchers changed each of the variables in the cost benefit analysis. These sensitivity analyses revealed that if the true incidence of HIB disease were 2 times greater than the based on reported data, the 3 doses of HIB conjugate vaccine would still have a cost benefit of US$3. These results indicated that adding HIB conjugate vaccine would exert a considerable public health and cost benefit. Cost benefit analyses of vaccines would also prove useful to decision-makers in other developing countries.