Cost-Effectiveness Analysis of Tdap in the Prevention of Pertussis in the Elderly

Abstract

ObjectivesHealth benefits and costs of combined reduced-antigen-content tetanus, diphtheria, and pertussis (Tdap) immunization among adults ≥65 years have not been evaluated. In February 2012, the Advisory Committee on Immunization Practices (ACIP) recommended expanding Tdap vaccination (one single dose) to include adults ≥65 years not previously vaccinated with Tdap. Our study estimated the health and economic outcomes of one-time replacement of the decennial tetanus and diphtheria (Td) booster with Tdap in the 10% of individuals aged 65 years assumed eligible each year compared with a baseline scenario of continued Td vaccination.MethodsWe constructed a model evaluating the cost-effectiveness of vaccinating a cohort of adults aged 65 with Tdap, by calculating pertussis cases averted due to direct vaccine effects only. Results are presented from societal and payer perspectives for a range of pertussis incidences (25–200 cases per 100,000), due to the uncertainty in estimating true annual incidence. Cases averted were accrued throughout the patient 's lifetime, and a probability tree used to estimate the clinical outcomes and costs (US$ 2010) for each case. Quality-adjusted life-years (QALYs) lost to acute disease were calculated by multiplying cases of mild/moderate/severe pertussis by the associated health-state disutility; QALY losses due to death and long-term sequelae were also considered. Incremental costs and QALYs were summed over the cohort to derive incremental cost-effectiveness ratios. Scenario analyses evaluated the effect of alternative plausible parameter estimates on results.ResultsAt incidence levels of 25, 100, 200 cases/100,000, vaccinating adults aged 65 years costs an additional $336,000, $63,000 and $17,000/QALY gained, respectively. Vaccination has a cost-effectiveness ratio less than $50,000/QALY if pertussis incidence is >116 cases/100,000 from societal and payer perspectives. Results were robust to scenario analyses.ConclusionsTdap immunization of adults aged 65 years according to current ACIP recommendations is a cost-effective health-care intervention at plausible incidence assumptions.

Pertussis vaccine for adults: Knowledge, attitudes, and vaccine receipt among adults with children in the household

“…It is also noteworthy that providers were more likely to recommend Tdap vaccines to younger participants than older participants, when the study population was divided into younger and older than 25 years, 33 years, and 50 years. With the incidence of pertussis infection in the older population increasing [20], and the cost-effectiveness of Tdap in pertussis prevention in this age group [21], providers need to be educated regarding the importance of recommending and administering Tdap in this older adult population.…”

Economic evaluation of adolescents and adults’ pertussis vaccination: A systematic review of current strategies

“…Few studies considered asymptomatic cases and recognized their importance in the transmission of the disease. 24,26,28,34,35 Eleven studies that evaluated adolescents or adults vaccination considered herd protection. 14,17,19,20,22,24,26,28,29,35,38 Eight of them used dynamic models and three studies used static models and included herd protection as a correction factor.…”

Is adding maternal vaccination to prevent whooping cough cost-effective in Australia?

“…There is uncertainty regarding pertussis incidence and several studies suggest high under-reporting rates, which has led to unreported cases being included in economic models. 30-32 Unreported symptomatic pertussis cases were also included in this analysis, assuming they were less severe than reported cases by assigning much lower utility decrements to these cases. Moreover, no costs were assigned to unreported symptomatic cases, unlike a previous economic analysis which did consider associated medical costs.…”

“…Moreover, no costs were assigned to unreported symptomatic cases, unlike a previous economic analysis which did consider associated medical costs. 32 The inclusion of unreported symptomatic cases had a favourable impact on cost-effectiveness due to more avoided cases in protected individuals. Uncertainty associated with under-reporting and with the costs and disutilities of unreported symptomatic cases inevitably leads to uncertainty associated with the cost-effectiveness results.…”