Vaccine 20 (2002) 1316–1330 The potential cost-effectiveness of acellular pertussis booster vaccination in England and Wales W. John Edmunds a,b,∗ , Marc Brisson a,b , Alessia Melegaro a,c , Nigel J. Gay a a Immunisation Division, PHLS Communicable Disease Surveillance Centre, 61 Collindale Avenue, London NW9 5EQ, UK b Department of Economics, City University, London EC1V 0HB, UK c Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK Received 26 July 2001; received in revised form 31 October 2001; accepted 6 November 2001 Abstract A cost-effectiveness analysis of the introduction of acellular pertussis booster doses at either 4 or 15 years of age was performed. A transmission dynamic model was used to predict the level of indirect protection in those too young to be vaccinated. Multivariate sensitivity analyses were performed. In England and Wales there are an estimated 35,000 general practitioner (GP) consultations, 5500 inpatient days, and nine deaths annually attributable to pertussis, despite high levels of coverage for the primary course (∼95%). Around 80% of the bed-days and 90% of the deaths occur in those too young to be immunised (<3 months of age). The introduction of acellular booster doses at 4 years is expected to reduce morbidity and mortality in the younger age groups by 40–100%, and at 15 years by 0–100%. From the perspective of the health care provider, roughly 50% of the simulations result in a cost per life-year gained of less than £10,000 for vaccination at 4 years, the corresponding proportion for vaccination at 15 years being only 35%. Apart from the degree of indirect protection the model was most sensitive to the discount rate, the price of the vaccine, and the mortality rate. Significant uncertainty remains regarding the epidemiology of pertussis and the impact of booster doses. Nevertheless, the introduction of acellular boosters, particularly at 4 years, has the potential to be cost-effective in the UK. © 2002 Elsevier Science Ltd. All rights reserved. Keywords: Economic evaluation; Pertussis; Acellular vaccine 1. Introduction Pertussis, or whooping cough, is an acute disease primar- ily resulting from infection with Bordetella pertussis or oc- casionally B. parapertussis. Typical symptoms of pertussis include paroxysmal cough lasting between 2 and 4 weeks, perhaps accompanied by an inspiratory whoop, and/or post- tussive vomiting, cyanosis and apnoea. Complications of pertussis infection are most likely to occur in infants and include pneumonia, seizures and encephalopathy. The introduction of widespread whole-cell pertussis vaccination in the UK in the 1950s resulted in a dramatic de- cline in the reported incidence of pertussis associated mor- bidity and mortality [1]. Although, the reported incidence of pertussis has been lower during the past decade than in any time previously (Fig. 1 and [1]), pertussis continues to be the cause of significant morbidity and mortality in children too young to be fully protected, despite the introduction, in 1990, of an accelerated diphtheria–tetanus–pertussis (DTP) ∗ Corresponding author. Tel.: +44-20-8200-6868x4410; fax: +44-20-8200-7868. E-mail address: jedmunds@phls.org.uk (W.J. Edmunds). vaccination schedule (2,3,4 months as opposed to the pre- vious 3, 5 and 10 months schedule). In addition, there is increasing awareness that pertussis infection in adults and older children may also have a significant detrimental ef- fect on public health and result in considerable costs to the health service and wider economy [2–9]. The advent of acellular pertussis vaccines, which are less reactogenic than whole-cell vaccines when given to older children [10], of- fers the possibility of reducing pertussis associated disease in older children and adults and, more importantly, reducing infection in the youngest age groups via herd immunity [9]. Although, there have been a number of economic analy- ses of primary immunisation with pertussis vaccine [11–15] there are no published studies on the additional costs and benefits arising from adding acellular booster doses onto an existing highly effective infant immunisation programme (a recent Canadian study assessed replacing whole cell with acellular vaccine [16]). This study aims to estimate the cur- rent health and economic burden of pertussis-associated dis- ease and to determine the potential cost-effectiveness of introducing acellular pertussis vaccine booster doses into the immunisation schedule of a typical developed country (namely, England and Wales). 0264-410X/02/$ – see front matter © 2002 Elsevier Science Ltd. All rights reserved. PII:S0264-410X(01)00473-X