Economic burden of pertussis in children: A single-center analysis in Hangzhou, China

The "reemergence of pertussis" has elicited international concerns, occurring paradoxically amidst the expansion of immunization programs. This study was aimed to evaluate quantitatively the economic burden and identify the determinants that influence the cost associated with treating pertussis in Chinese children. We evaluated the economic burden by Chinese children diagnosed with pertussis at the Children's Hospital, Zhejiang University School of Medicine in 2022. Direct medical expenses and the utilization of medical resources attributed to pertussis were calculated. A generalized linear regression model was applied to analyze the determinants that were associated with the direct medical expenses among patients. Among the 1110 pertussis patients included in the study, 1060 were outpatients and 50 were inpatients. The average direct medical cost was ¥1878.70(i.e. $279.33). Living in urban areas (OR:1.27, p = .04), complications (OR:1.40, p < .001), hospitalization (OR:10.04, p < .001), and ≥ 3 medical visits (OR:3.71, p < .001) were associated with increased direct medical expenses. Having received four doses of the pertussis vaccine was associated with reduced direct medical expenses (OR:0.81, p = .04). This study underscores a substantial economic burden of pertussis in Hangzhou, with pronounced implications for patients residing in urban areas, experiencing complications, requiring hospitalization, having multiple medical consultations, or lacking comprehensive pertussis vaccination.

Epidemiology and disease burden of pertussis in the United States among individuals aged 0-64 over a 10-year period (2006-2015)

Background: Pertussis incidence has increased in recent decades despite childhood vaccination programs and high vaccination rates. To quantify the burden of pertussis, incidence, healthcare resource utilization, and costs among pertussis patients were estimated in a US managed care setting.Methods: Patients aged 0-64 years with evidence of pertussis (ICD-9-CM codes 033.0, 033.9, 484.3, ICD-10-CM codes A37.0, A37.9) and commercial insurance from 1 January 2006-12 December 2015 were identified. Incidence rates were calculated and standardized to the 2010 US Census on age, sex, and geographic region. Healthcare costs and resource utilization were compared between patients and matched comparators (health plan members without pertussis).Results: From 2006 to 2015, 11,378 pertussis cases were identified. Adjusted pertussis incidence was 15.55 cases per 100,000 person-years. Incidence was highest among infants and children; however, 59.0% of total cases were among adolescents or adults. Average adjusted healthcare costs per episode were 3.17 times higher among pertussis patients versus comparators ($5195 versus $1637, p < .001). Stratifying by age group, adjusted incremental healthcare costs per episode were $5581, $827, $700, $1429, $2530, and $4849 for patients aged <1 year, 1-6 years, 7-10 years, 11-19 years, 20-49 years, and 50-64 years, respectively.Conclusions: Managing pertussis is associated with substantial economic burden. Incidence rate estimates from this study were higher than CDC-reported rates; however, similar overall trends were observed. Although pertussis incidence has been declining since CDC-recommended vaccination for all adults in 2012, this study highlights the importance of continued management and prevention strategies, especially among adolescents and adults as they represent an important source of transmission to infants.

Impact of State Public Health Spending on Disease Incidence in the United States from 1980 to 2009

OBJECTIVE

To understand the relationship between state-level spending by public health departments and the incidence of three vaccine preventable diseases (VPDs): mumps, pertussis, and rubella in the United States from 1980 to 2009.

DATA SOURCES

This study uses state-level public health spending data from The Census Bureau and annual mumps, pertussis, and rubella incidence counts from the University of Pittsburgh's project Tycho.

STUDY DESIGN

Ordinary least squares (OLS), fixed effects, and random effects regression models were tested, with results indicating that a fixed effects model would be most appropriate model for this analysis.

PRINCIPAL FINDINGS

Model output suggests a statistically significant, negative relationship between public health spending and mumps and rubella incidence. Lagging outcome variables indicate that public health spending actually has the greatest impact on VPD incidence in subsequent years, rather than the year in which the spending occurred. Results were robust to models with lagged spending variables, national time trends, and state time trends, as well as models with and without Medicaid and hospital spending.

CONCLUSION

Our analysis indicates that there is evidence of a significant, negative relationship between a state's public health spending and the incidence of two VPDs, mumps and rubella, in the United States.

Hospital costs of Bordetella pertussis in New Zealand children

AIM

To estimate hospitalisation costs for children with pertussis in New Zealand.

METHOD

All children less than 16 years of age and hospitalised with pertussis between 01/01/2003 and 31/12/2013 were identified from the National Minimum Data Set and the National Paediatric Intensive Care Unit database. The cost of hospital care was estimated by multiplying the diagnosis-related group cost-weight by the national price and inflating to 2013/2014 values.

RESULTS

There were 1,456 children with pertussis admitted to hospital including 65 admissions to the paediatric intensive care unit. Infants (<1 year) accounted for 78% of hospital admissions, 98% of paediatric intensive care admissions and 87% of hospitalisation costs. The total inflation-adjusted cost of the 11-year cohort was estimated at $8.3 million and the mean cost of hospital ward and paediatric intensive care was $4,242 and $42,016 respectively, per child. The 2011-2013 epidemic accounted for 39% of all hospital admissions and the cost estimated at $4.2 million. Peak annual hospitalisation costs during epidemic years increased from under $800,000 in 2004 and 2009 to over $2 million in 2012.

CONCLUSION

Infants with pertussis are more likely than older children to be admitted to hospital and to the paediatric intensive care unit and generate the majority of hospitalisation costs. A revised focus on protecting vulnerable newborns and infants has the potential to both improve health outcomes for infants with pertussis and reduce medical costs.

Epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany: a systematic review

OBJECTIVES

Despite the availability of vaccines and the existence of public vaccination recommendations, outbreaks of vaccine-preventable childhood diseases still cause public health debate. The objective of this systematic review was to provide an overview of the current epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany.

METHODS

We systematically reviewed studies published since 2000. The literature search was conducted using PubMed and EMBASE. Also, we used German notification data to give an up-to-date overview of the epidemiology of the four diseases under consideration.

RESULTS

Thirty-six studies were included in our review. Results suggest that there is still considerable morbidity due to childhood diseases in Germany. Studies providing cost estimates are scarce. Comparative analyses of different data sources (notification data vs. claims data) revealed a potential underestimation of incidence estimates when using notification data. Furthermore, several studies showed regional differences in incidence of some of the diseases under consideration.

CONCLUSIONS

Our findings underline the need for improved vaccination and communication strategies targeting all susceptible age and risk groups on a national and local level.

Pertussis immunisation in pregnancy: a summary of funded Australian state and territory programs

The Australian Immunisation Handbook, 10th edition now recommends pertussis vaccination during pregnancy as the preferred option for protecting vulnerable young infants. Jurisdictionally funded pertussis immunisation programs for pregnant women have been progressively introduced in all Australian states and territories between August 2014 and June 2015. A meeting convened by the National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases was held on 31 May 2015 to share information regarding jurisdictional policies and program implementation. This report of that meeting provides the first published comparison of these jurisdictional programs, which are of a broadly similar nature but with important differences. Monitoring and evaluation of the uptake, safety and impact of the current programs in Australia will be important to inform future policy decisions.

Estimated Human and Economic Burden of Four Major Adult Vaccine-Preventable Diseases in the United States, 2013

Low uptake of routinely recommended adult immunizations is a public health concern. Using data from the peer-reviewed literature, government disease-surveillance programs, and the US Census, we developed a customizable model to estimate human and economic burden caused by four major adult vaccine-preventable diseases (VPD) in 2013 in the United States, and for each US state individually. To estimate the number of cases for each adult VPD for a given population, we multiplied age-specific incidence rates obtained from the literature by age-specific 2013 Census population data. We then multiplied the estimated number of cases for a given population by age-specific, estimated medical and indirect (non-medical) costs per case. Adult VPDs examined were: (1) influenza, (2) pneumococcal disease (both invasive disease and pneumonia), (3) herpes zoster (shingles), and (4) pertussis (whooping cough). Sensitivity analyses simulated the impact of various epidemiological scenarios on the total estimated economic burden. Estimated US annual cost for the four adult VPDs was $26.5 billion (B) among adults aged 50 years and older, $15.3B (58 %) of which was attributable to those 65 and older. Among adults 50 and older, influenza, pneumococcal disease, herpes zoster, and pertussis made up $16.0B (60 %), $5.1B (19 %), $5.0B (19 %), and $0.4B (2 %) of the cost, respectively. Among those 65 and older, they made up $8.3B (54 %), $3.8B (25 %), $3.0B (20 %), and 0.2B (1 %) of the cost, respectively. Most (80-85 %) pneumococcal costs stemmed from nonbacteremic pneumococcal pneumonia (NPP). Cost attributable to adult VPD in the United States is substantial. Broadening adult immunization efforts beyond influenza only may help reduce the economic burden of adult VPD, and a pneumococcal vaccination effort, primarily focused on reducing NPP, may constitute a logical starting place. Sensitivity analyses revealed that a pandemic influenza season or change in size of the US elderly population could increase these costs dramatically.

Pertussis post-exposure prophylaxis among household contacts: a cost-utility analysis

Background

Recent pertussis outbreaks have prompted re-examination of post-exposure prophylaxis (PEP) strategies, when immunization is not immediately protective. Chemoprophylaxis is recommended to household contacts; however there are concerns of clinical failure and significant adverse events, especially with erythromycin among infants who have the highest disease burden. Newer macrolides offer fewer side effects at higher drug costs. We sought to determine the cost-effectiveness of PEP strategies from the health care payer perspective.

Methods

A Markov model was constructed to examine 4 mutually exclusive strategies: erythromycin, azithromycin, clarithromycin, or no intervention, stratified by age group of contacts (“infant”, “child”, and “adult”). Transition probabilities, costs and quality-adjusted life years (QALYs) were derived from the literature. Chronic neurologic sequelae were modeled over a lifetime, with costs and QALYs discounted at 5%. Associated health outcomes and costs were compared, and incremental cost-effectiveness ratios (ICER) were calculated in 2012 Canadian dollars. Deterministic and probabilistic sensitivity analyses were performed to evaluate the degree of uncertainty in the results.

Findings

Azithromycin offered the highest QALYs in all scenarios. While this was the dominant strategy among infants, it produced an ICER of $16,963 per QALY among children and $2,415 per QALY among adults. Total QALYs with azithromycin were 19.7 for a 5-kg infant, 19.4 for a 10-year-old child, and 18.8 for a 30-year-old adult. The costs of azithromycin PEP among infants, children and adults were $1,976, $132 and $90, respectively. While results were sensitive to changes in PEP effectiveness (11% to 87%), disease transmission (variable among age groups) and hospitalization costs ($379 to $59,644), the choice of strategy remained unchanged.

Interpretation

Pertussis PEP is a cost-effective strategy compared with no intervention and plays an important role in contact management, potentially in outbreak situations. From a healthcare payer perspective, azithromycin is the optimal strategy among all contact groups.

Pertussis in young infants: clinical presentation, course and prevention

Pertussis is a highly contagious disease caused by the Gram negative aerobic coccobacillus, Bordetella pertussis. It may present with severe symptoms and complications in infants and can pose a diagnostic challenge. This is a vaccine preventable illness covered by the Irish Childhood Immunisation Schedule. In 2011, a retrospective review was conducted of the records of infants, under six months, with a confirmed diagnosis of pertussis, presenting to Temple Street Children's University Hospital (TSCUH). A summery of notifications of pertussis nationally, from 2001 to 2012, was also examined as part of the study. This found that the rate of reported cases of pertussis has been increasing in Ireland. This national increase corresponds with a rising number of cases identified at TSCUH. Patients commonly presented severely ill with cyanosis and apnoea, on a background of prolonged cough. We found that pertussis was diagnosed rapidly in most cases however in all cases there was a delay to commencement of appropriate macrolide therapy.

Cost-effectiveness of Tdap vaccination of adults aged ≥65 years in the prevention of pertussis in the US: a dynamic model of disease transmission

OBJECTIVES

In February 2012, the Advisory Committee on Immunization Practices (ACIP) advised that all adults aged ≥65 years receive a single dose of reduced-antigen-content tetanus, diphtheria, and acellular pertussis (Tdap), expanding on a 2010 recommendation for adults >65 that was limited to those with close contact with infants. We evaluated clinical and economic outcomes of adding Tdap booster of adults aged ≥65 to "baseline" practice [full-strength DTaP administered from 2 months to 4-6 years, and one dose of Tdap at 11-64 years replacing decennial Td booster], using a dynamic model.

METHODS

We constructed a population-level disease transmission model to evaluate the cost-effectiveness of supplementing baseline practice by vaccinating 10% of eligible adults aged ≥65 with Tdap replacing the decennial Td booster. US population effects, including indirect benefits accrued by unvaccinated persons, were estimated during a 1-year period after disease incidence reached a new steady state, with consequences of deaths and long-term pertussis sequelae projected over remaining lifetimes. Model outputs include: cases by severity, encephalopathy, deaths, costs (of vaccination and pertussis care) and quality-adjusted life-years (QALYs) associated with each strategy. Results in terms of incremental cost/QALY gained are presented from payer and societal perspectives. Sensitivity analyses vary key parameters within plausible ranges.

RESULTS

For the US population, the intervention is expected to prevent >97,000 cases (>4,000 severe and >5,000 among infants) of pertussis annually at steady state. Additional vaccination costs are $4.7 million. Net cost savings, including vaccination costs, are $47.7 million (societal perspective) and $44.8 million (payer perspective). From both perspectives, the intervention strategy is dominant (less costly, and more effective by >3,000 QALYs) versus baseline. Results are robust to sensitivity analyses and alternative scenarios.

CONCLUSIONS

Immunization of eligible adults aged ≥65, consistent with the current ACIP recommendation, is cost saving from both payer and societal perspectives.

Cost-effectiveness of targeted vaccination to protect new-borns against pertussis: comparing neonatal, maternal, and cocooning vaccination strategies

Pertussis (whooping cough) is a severe infectious disease in infants less than 6 months old. Mass vaccination programmes have been unable to halt transmission effectively. Strategies to protect new-borns against infection include vaccination of the neonate or the mother directly after birth (cocooning), or the mother during pregnancy (maternal). Here we investigate the cost-effectiveness of these three strategies in the Netherlands. Costs for health care utilization and productivity losses, as well as impact on quality of life were calculated for a 10-year vaccination programme, assuming that vaccine-induced immunity lasts 5 years. Cocooning was the most attractive option from a cost-effectiveness viewpoint (€89,000/QALY). However, both cocooning and maternal vaccination would reduce the disease burden in infants and mothers vaccinated (about 17-20 QALY/year). Specifically, with a persistent epidemic as seen in 2012, there is need for reconsidering the vaccination schedules against pertussis in order to increase protection of the vulnerable new-borns.

Centers for Disease Control and Prevention (CDC). Local health department costs associated with response to a school-based pertussis outbreak --- Omaha, Nebraska, September-November 2008

Pertussis is a highly infectious, vaccine-preventable respiratory illness. With the advent of a vaccine, case numbers fell in the United States from a high of 265,269 in 1934 to a low of 1,010 cases in 1976, but then resurged to 25,827 in 2004. During 2004-2008, the average was 18,161 cases per year. Close contacts of persons with pertussis are at increased risk for developing infection and are recommended to receive preventive antibiotics for two reasons: 1) the illness can be debilitating, with cough lasting several weeks and sometimes being severe enough to cause urinary incontinence, rib fracture, or other complications; and 2) the illness can be fatal in infants; it caused an average of 17 deaths each year during 2002-2006. During pertussis outbreaks, the resources needed to identify and treat contacts can strain local public health resources. The Douglas County Health Department (DCHD) in Omaha, Nebraska, responded to a school-based pertussis outbreak with 26 cases occurring in late 2008. To assess the costs incurred by a local health department responding to such an outbreak, DCHD and CDC evaluated the total resources used by DCHD. This report describes the results of that analysis, which indicated that 1) staff members reported 1,032 person-hours spent responding to the outbreak, and 2) the total cost of outbreak response, including overhead, labor, travel, and other costs, was $52,131 (measured in 2008 U.S. dollars). The majority of costs (59%) occurred during an intensive 10-day period, when most of the contact tracing and prophylaxis recommendations were made. The elevated incidence of pertussis and the burden of response placed on health departments warrants exploring the impact of alternative response and chemoprophylaxis strategies.

Public Health Perspectives on the Rising Incidence of Pertussis

OBJECTIVES

Pertussis is one of the few vaccine-preventable diseases on the rise in the United States, particularly among adolescents. We analyzed the epidemiology of pertussis, focusing on disease burden in public health, and examined methods for controlling pertussis and reducing its incidence. DESIGN, SAMPLE, AND MEASUREMENTS: We evaluated current knowledge about pertussis, reported cases of pertussis in the United States, and the changing recognition, diagnosis, and management of the disease. The development of a pertussis vaccine, now licensed and recommended for use in adolescents and adults, was reviewed.

RESULTS

Of reported cases in 2004, 38% occurred in adolescents. The increased incidence of pertussis may be the result of better diagnosis, better reporting, and increased awareness of the disease. The burden of adolescent and adult pertussis is significant and includes medical visits, laboratory tests, treatment for cases and contacts, time lost from school and work, disruption of schools experiencing outbreaks, and public health and media turmoil. At current disease rates, the financial cost of adolescent pertussis in this decade is projected at $3.2 billion.

CONCLUSIONS

Efforts are needed to increase health care providers' knowledge of pertussis disease and vaccines, improve on-time infant immunization rates, promote immunization registries and public health surveillance, and ensure adequate compensation for vaccine purchase and administration. Universal recommendations for and widespread use of acellular pertussis vaccines in adolescents are the most effective measures in controlling the disease.

Impact of Bordetella pertussis exposures on a Massachusetts tertiary care medical system

OBJECTIVE

To assess the impact of outbreaks of Bordetella pertussis infection on a tertiary care medical system.

DESIGN

Retrospective study.

SETTING

Academic tertiary care medical center and affiliated ambulatory care settings.

SUBJECTS

All patients and healthcare workers (HCWs) who were in close contact with patients with laboratory-confirmed cases of B. pertussis infection from October 1, 2003, through September 30, 2004.

INTERVENTION

Direct and indirect medical center costs were determined, including low and high estimates of time expended in the evaluation and management of exposed patients and HCWs during outbreak investigations of laboratory-confirmed cases of B. pertussis infection.

RESULTS

During this period, 20 primary and 3 secondary laboratory-confirmed cases of B. pertussis infection occurred, with 2 primary pertussis cases and 1 secondary case occurring in HCWs. Outbreak investigations prompted screening of 353 medical center employees. Probable or definitive exposure was identified for 296 HCWs, and 287 subsequently received treatment or prophylaxis for B. pertussis infection. Direct medical center costs for treatment and prophylaxis were $13,416 and costs for personnel time were $19,500-$31,190. Indirect medical center costs for time lost from work were $51,300-$52,300. The total cost of these investigations was estimated to be $85,066-$98,456.

CONCLUSIONS

Frequent B. pertussis exposures had a major impact on our facility. Given the impact of exposures on healthcare institutions, routine vaccination for HCWs may be beneficial.

Two nosocomial pertussis outbreaks and their associated costs - King County, Washington, 2004

OBJECTIVE

Pertussis outbreaks in healthcare settings result in resource-intensive control activities, but studies have rarely evaluated the associated costs. We describe and estimate costs associated with 2 nosocomial pertussis outbreaks in King County, Washington, during the period from July 25 to September 15, 2004. One outbreak occurred at a 500-bed tertiary care hospital (hospital A), and the other occurred at a 250-bed pediatric hospital (hospital B).

METHODS

We estimated the costs of each outbreak from the hospitals' perspective through standardized interviews with hospital staff and review of contact tracing logs. Direct costs included personnel time and laboratory and medication costs, whereas indirect costs were those resulting from hospital staff furloughs.

RESULTS

Hospital A incurred direct costs of $195,342 and indirect costs of $68,015; hospital B incurred direct costs of $71,130 and indirect costs of $50,000. Cost differences resulted primarily from higher personnel costs at hospital A ($134,536), compared with hospital B ($21,645). Total cost per pertussis case was $43,893 for hospital A (6 cases) and $30,282 for hospital B (4 cases). Total cost per person exposed to a pertussis patient were $357 for hospital A (738 exposures) and $164 for hospital B (737 exposures).

CONCLUSIONS

Nosocomial pertussis outbreaks result in substantial costs to hospitals, even when the number of pertussis cases is low. The cost-effectiveness of strategies to prevent nosocomial pertussis outbreaks, including vaccination of healthcare workers, should be evaluated.

Resource consumption in the infection control management of pertussis exposure among healthcare workers in pediatrics

OBJECTIVE

To assess consumption of resources in the infection control management of healthcare workers (HCWs) exposed to pertussis and to assess avoidability of exposure.

SETTING

Tertiary care children's medical center.

METHODS

Analysis of the extent of and reasons for HCW exposure to pertussis during contact with children with the disease, whether exposures were avoidable (because of the failure to recognize a case or to order or adhere to isolation precautions) or unavoidable (because the case was not recognizable or because another diagnosis was confirmed), and the cost of implementing exposure management.

INTERVENTIONS

Interventions consisted of an investigation of every HCW encounter with any patient who was confirmed later to have pertussis from the time of hospital admission of the patient, use of azithromycin as postexposure prophylaxis (PEP) for exposed HCWs, performance of 21-day surveillance for cough illness, testing of symptomatic exposed HCWs for Bordetella pertussis, and enhanced preexposure education of HCWs.

RESULTS

From September 2003 through April 2005, pertussis was confirmed in 28 patients (median age, 62 days); 24 patients were admitted. For 11 patients, pertussis was suspected, appropriate precautions were taken, and no HCW was exposed. Inadequate precautions for 17 patients led to 355 HCW exposures. The median number of HCWs exposed per exposing patient was 9 (range, 1-86 HCWs; first quartile mean, 2; fourth quartile mean, 61). Exposure was definitely avoidable for only 61 (17%) of 355 HCWs and was probably unavoidable for 294 HCWs (83%). The cost of 20-month infection control management of HCWs exposed to pertussis was $69,770. The entire cohort of HCWs involved in direct patient care at the facility could be immunized for approximately $60,000.

CONCLUSIONS

Exposure of HCWs to pertussis during contact with children who have the disease is largely unavoidable, and management of this exposure is resource intensive. Universal preexposure vaccination of HCWs is a better utilization of resources than is case-based postexposure management.

Cost effectiveness of pertussis vaccination in adults

BACKGROUND

Prior economic analyses have reached disparate conclusions about whether vaccinating adults against pertussis would be cost effective. Newly available data on pertussis incidence were used to evaluate the cost effectiveness of one-time adult vaccination and adult vaccination with decennial boosters.

METHODS

A Markov model was used to calculate the health benefits, risks, costs, and cost effectiveness of the following strategies: (1) no adult pertussis vaccination, (2) one-time adult vaccination at 20-64 years, and (3) adult vaccination with decennial boosters. The impact of the severity of pertussis illness, vaccine adverse events, and herd immunity on model outcomes were also examined.

RESULTS

At a disease incidence of 360 per 100,000, the one-time adult vaccination strategy would prevent 2.8 million cases, and the decennial vaccination strategy would prevent 8.3 million cases. As disease incidence varied from 10 to 500 per 100,000, the one-time adult vaccination strategy was projected to prevent 79,000 to 3.8 million adult pertussis cases, while the decennial vaccination program would prevent 239,000 to 11.4 million cases. A one-time adult vaccination strategy would result in 106 million people vaccinated, or approximately 64% of the adult cohort, for a total program cost of $2.1 billion, while a decennial vaccination strategy would cost $6.7 billion. The one-time and decennial booster vaccination strategies result in cost-effectiveness ratios of <$50,000 per quality-adjusted life year saved if disease incidence in adults were greater than 120 cases per 100,000 population.

CONCLUSIONS

Routine vaccination of adults aged 20 to 64 years with combined tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis is cost effective if pertussis incidence in this age group is greater than 120 per 100,000 population.

[Pertussis: incidence, symptoms and costs]

BACKGROUND AND OBJECTIVE

A prospective sentinel study into the population-based incidence of pertussis in adults was done between 2001 and 2004 in Rostock (former East Germany) and Krefeld (former West Germany).

PATIENTS AND METHODS

971 outpatients, who consulted general practitioners or internists, were included. Clinical inclusion criteria were coughing for one week or more and no chronic respiratory diseases. Bordetella infection was diagnosed by PCR on nasopharyngeal swabs and ELISA for serology (IgG-anti-PT, IgA-anti-PT, IgG-anti-FHA, IgA-anti-FHA).

RESULTS

We found a total of 97 cases of pertussis in this cohort. The main symptom was coughing for a median of 7-8 weeks. Population-based incidence was estimated in Krefeld at 169 cases/100000 population per year, and in Rostock at 160/100000 per year. Resource use was 120 EUR of direct medical cost and 434 euro of indirect medical cost, not including hospitalization in this study.

CONCLUSIONS

Pertussis is a frequent cause of longer lasting cough in German adults, and it causes significant morbidity and costs.

Whooping cough: the current scene

Pertussis, a highly contagious disease caused by Bordetella pertussis, is making a comeback globally despite good immunization coverage. The developed countries have also shown a shift in the epidemiology of the disease to the adolescent and the adult age group, leading to a revision of their vaccination policies. The disease epidemiology in the South East Asian region seems poised for a similar change. Outbreaks have been reported among children and adults in countries such as Afghanistan, Israel, and Taipei. The anticipation and early recognition of this change in the epidemiology is important because the affected adolescents and adults act as reservoirs of the disease to the vulnerable population of infants, for whom the disease can be life threatening. The clinical presentation can be atypical in the adolescent age group, and the disease is often misdiagnosed. With the availability of polymerase chain reaction and serology, the disease can be diagnosed even later in the course of the disease when culture results are often negative. The whole-cell pertussis vaccine dramatically reduced the incidence of the disease but fell into disrepute due to the rare serious neurologic side effects that led to the introduction of the acellular pertussis vaccine, which led to fewer adverse reactions and also proved to be safe and effective in the adolescent age group when used as a booster. However, the cost of the acellular vaccine is may be prohibitive for widespread use in the developing nations of the South East Asian region.

Nosocomial pertussis: costs of an outbreak and benefits of vaccinating health care workers

BACKGROUND

In September 2003, 17 symptomatic cases of pertussis among health care workers (HCWs) resulted from a 1-day exposure to an infant who was later confirmed to have pertussis. These HCWs identified 307 close contacts. The hospital implemented extensive infection-control measures. The objective of this study was to determine direct and indirect costs incurred by the hospital and symptomatic HCWs as a result of the September 2003 outbreak and to estimate possible benefits of vaccinating HCWs from the hospital perspective.

METHODS

We determined costs by interviewing infection-control and hospital personnel, reviewing billing records, and surveying symptomatic HCWs. We calculated the benefits and costs of a vaccination program for HCWs, using a probabilistic model to estimate the number of pertussis exposures that would require control measures annually. Sensitivity and threshold analyses were performed.

RESULTS

The outbreak cost to the hospital was 74,870 dollars. The total measured cost of the outbreak was 81,382 dollars, including costs incurred by HCWs (6512 dollars). Our model predicted that vaccinating HCWs against pertussis would prevent >46% of exposures from HCWs with pertussis per year and would provide net savings. The benefit for the hospital was estimated to be 2.38 times the dollar amount invested in vaccinating HCWs. The number of exposures prevented and the benefit-cost ratio were sensitive to the number of exposures identified, the incidence of pertussis among HCWs, and HCW turnover.

CONCLUSIONS

A single nosocomial pertussis outbreak resulted in substantial disruption and costs to the hospital and to HCWs. Our model suggests that cost savings and benefits could be accrued by vaccinating HCWs against pertussis.

Hospitalization for pertussis: profiles and case costs by age

BACKGROUND

Pertussis, a highly contagious respiratory illness, affects people of all ages and can have serious clinical consequences. It has been reported that from 1997-2000, 20% of all pertussis cases required hospitalization in the US. This analysis examined demographics, case fatality rate, resource use and costs of hospital care related to pertussis by age.

METHODS

ICD-9 codes (033.0, 033.9) were used to identify cases of pertussis in hospital discharge databases from roughly 1,000 US hospitals in 4 states (California, Florida, Maryland, Massachusetts). Data from 1996-1999 were examined by age group. Separate analyses were done for infants (< 1 year) and children (1-11 years); however, adolescent and adult cases were combined into one group (12+ years), due to the small number of cases. Databases were used to determine demographics, health service utilization and care costs. Cost estimates include accommodations, ancillary and physician services, reported in 2002 USD.

RESULTS

Of the 2,518 cases identified, 90% were infants. The inpatient case fatality rate was < 1%. Of survivors, 99% were discharged home (6% with home health care); 1% required further sub-acute inpatient care. For the 2,266 infants, the mean LOS was 6 days at a cost of 9,586 dollars per stay. Children (n = 191) had a mean LOS of 3.7 and cost of 4,729 dollars; adolescents/adults (n = 61, mean age 40 years) stayed on average 3.4 days with a cost of 5,683 dollars per hospitalization.

CONCLUSION

Infants are responsible for the bulk of hospitalizations and generate higher inpatient costs. Costly hospital care occurs, however, in patients with pertussis at all ages.

Acellular pertussis vaccines for adolescents

BACKGROUND

The epidemiology of pertussis is changing, with a clear increase in the number of cases diagnosed in adolescents and adults. This development has spurred studies and anticipated licensure of safer diphtheria, tetanus, acellular pertussis combined (Tdap) vaccines for this older population.

METHODS

Literature review.

RESULTS

Tdap vaccines are safe and immunogenic when administered to adolescents and adults. Correlates of immunity to pertussis after Tdap vaccination have not been established, but various combinations of antibody to pertussis antigens (pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae) provide protection. The importance of the number of antigens in Tdap vaccines for protection against mild pertussis disease is unclear. Pertussis vaccination establishes herd immunity after sufficient uptake within communities and countries. As experience with TdaP vaccines has accumulated, a 1-2% occurrence of large, local injection-site reactions with all TdaP vaccine products have been observed for booster doses in children 4-6 years of age. The frequency of large local reactions appears lower in adolescents and adults. The pathophysiologic mechanisms for the local reactions are not established, but a majority appears to be immunoglobulin E-mediated-reactive edema, and a minority appears to be immunoglobulin G-mediated Arthus-type reactions.

CONCLUSIONS

Tdap vaccines appear safe and immunogenic. The economic impact of pertussis provides a cost-benefit justification for widespread use of Tdap vaccine boosting in adolescents.

Economic considerations for pertussis booster vaccination in adolescents

BACKGROUND

Despite good acellular pertussis vaccine safety and protective efficacy, as well as high vaccination rates among young children, the incidence of pertussis in the United States has steadily increased since the 1980s. This is especially true for adolescents and adults who are susceptible because of waning immunity, which is not long lived. Other populations are at increased risk for morbidity of infection, although infants younger than 6 months of age who have not completed the primary immunization series have the greatest morbidity and mortality. Other groups who might benefit from booster immunizations include hospital workers, family contacts, and individuals with compromised health. Although older individuals generally have milder illnesses, they are often the source of infection for younger children. An adolescent/adult formulation of acellular pertussis vaccine requires a lower dose of pertussis antigens and can be combined with currently recommended diphtheria and tetanus toxoids (Tdap). These new vaccines for adolescents and adults are safe, immunogenic, and protective.

METHODS

Through an extensive review of the literature, the direct and indirect costs associated with pertussis and its complications are examined, cost-benefit analyses of pertussis booster vaccination are evaluated for different groups, and the economic considerations involved in implementing a pertussis booster vaccination program in adolescents are discussed.

RESULTS

Pertussis infections cause outbreaks in schools, families, and workplaces, resulting in prolonged morbidity and significant costs for medical care, lost time, and wages. Physician visits, chest radiographs, and antibiotics comprise the majority of direct costs, and costs associated with work loss often comprise the majority of indirect costs related to pertussis illness. Adolescents and adults also transmit their infections to nonimmune children. A cost-benefit analysis evaluated the health and economic benefits of seven strategies for administering a pertussis booster. The most economical strategy is to immunize all adolescents 10-19 years of age, which may prevent 0.4-1.8 million cases of pertussis and save US 0.3-1.6 billion dollars in a decade. A tetanus and diphtheria booster (Td) is currently recommended for children 11-12 years of age. The Tdap vaccine offers an enhancement for the Td booster by providing protection against pertussis, and it will not require an additional injection or office visit.

CONCLUSIONS

Immunizing adolescents with a pertussis booster in the form of Tdap is the most economical and easiest-to-implement strategy and should provide significant health and economic benefits.

Clinical and economic effects of pertussis outbreaks

BACKGROUND

The reported incidence of pertussis is increasing, especially among the adolescent population. Current outbreak management strategies include investigating cases, contact follow-up, diagnostic testing, and antibiotic prophylaxis and treatment. The cost of these methods is substantial and can be attributed to the mobilization within public health departments to control the outbreaks.

METHODS

Through an extensive review of the literature, the clinical and economic effects of pertussis outbreaks in various nonhousehold settings are discussed.

RESULTS

The reported incidence of pertussis among adolescents and adults in the United States since the early 1980s continues to rise. The challenges of preventing and controlling pertussis outbreaks involve diagnosing pertussis in a timely, accurate, and standardized fashion and understanding the true burden of disease in different age and socioeconomic groups. The economic effects of pertussis have been demonstrated to be significant to individuals and communities, both locally and globally. Costs associated with pertussis often include diagnostic testing, hospitalization, emergency and/or medical office visits, antibiotic and symptomatic treatment, lost work days, and other reductions in productivity. In outbreak settings, increased surveillance, antibiotic prophylaxis, isolation of infected cases, and enhanced communication and education add to the economic burden of this disease. The potential opportunity to apply the use of pertussis booster vaccination to these populations, particularly among adolescents, likely would reduce the occurrence of pertussis and minimize the clinical and economic repercussions of pertussis outbreaks.

CONCLUSIONS

In the near future, it is anticipated that evaluating the effects of a licensed acellular pertussis booster vaccine in persons > or =10 years of age will become routine in pertussis prevention and outbreak-control activities.

Pertussis in adolescents and adults: should we vaccinate?

BACKGROUND

The incidence of reported pertussis among adolescents, adults, and young infants has increased sharply over the past decade. Combined acellular pertussis vaccines for adolescents and adults are available in Canada, Australia, and Germany and may soon be considered for use in the United States.

OBJECTIVE

To evaluate the potential health benefits, risks, and costs of a national pertussis vaccination program for adolescents and/or adults.

DESIGN, SETTING, AND POPULATION

The projected health states and immunity levels associated with pertussis disease and vaccination were simulated with a Markov model. The following strategies were examined from the health care payer and societal perspectives: (1) no vaccination; (2) 1-time adolescent vaccination; (3) 1-time adult vaccination; (4) adult vaccination with boosters; (5) adolescent and adult vaccination with boosters; and (6) postpartum vaccination. Data on disease incidence, costs, outcomes, vaccine efficacy, and adverse events were based on published studies, recent unpublished clinical trials, and expert panel input.

MAIN OUTCOME MEASURES

Cases prevented, adverse events, costs (in 2004 US dollars), cost per case prevented, and cost per quality-adjusted life-year (QALY) saved.

RESULTS

One-time adolescent vaccination would prevent 30800 cases of pertussis (36% of projected cases) and would result in 91000 vaccine adverse events (67% local reactions). If pertussis vaccination cost $15 and vaccine coverage was 76%, then 1-time adolescent vaccination would cost $1100 per case prevented (or $1200 per case prevented) or $20000 per QALY (or $23000 per QALY) saved, from the societal (or health care payer) perspective. With a threshold of $50000 per QALY saved, the adolescent and adult vaccination with boosters strategy became potentially cost-effective from the societal perspective only if 2 conditions were met simultaneously, ie, (1) the disease incidence for adolescents and adults was > or =6 times higher than base-case assumptions and (2) the cost of vaccination was less than $10. Adult vaccination strategies were more costly and less effective than adolescent vaccination strategies. The results were sensitive to assumptions about disease incidence, vaccine efficacy, frequency of vaccine adverse events, and vaccine costs.

CONCLUSIONS

Routine pertussis vaccination of adolescents results in net health benefits and may be relatively cost-effective.

Economic burden of pertussis and the impact of immunization

Although routine use of vaccines has diminished the incidence of pertussis disease, it has not eliminated the pathogen. Epidemiologic data confirm that pertussis remains a significant health problem in all age groups. Disease burden is highest in infants, in whom pertussis disease frequently leads to severe complications and mortality, although it is also a significant health burden in adolescents and adults, in whom the reported incidence of pertussis is increasing. The Global Pertussis Initiative reviewed the literature to find data that express the economic impact of this health burden and to review economic evaluations of pertussis immunization. Although only limited data on the direct and indirect costs of pertussis are available, they suggest that it poses a significant economic burden and indicate that the direct medical costs of pertussis depend on the rate of hospitalization and the severity of complications, and are highest in infants. The indirect costs of pertussis also appear to be considerable, particularly among adults, in whom the disease reduces work productivity, because of either personal illness or child care responsibilities. Several health economic models on the cost effectiveness of childhood immunization strategies have been published, and although constrained by missing data, have generally found childhood immunization strategies to be cost-effective. Economic analyses of adolescent and adult immunization strategies have also been conducted, but the findings of these studies have been inconsistent. The most recent evaluations, using much higher estimates of incidence than reported previously, suggest that immunization of adolescents and specific adult subgroups may be cost-effective. The literature review confirmed that the economic burden of pertussis is substantial, but there are gaps in existing information. In the short term, further economic analyses are required, particularly of adolescent and adult immunization. More importantly, collection of primary epidemiologic and economic data should be undertaken in parallel. Despite the existing gaps in data, further research using the most current data should facilitate decisions on new vaccination strategies by describing conditions for favorable results and quantifying the margin of uncertainty.

Pertussis immunization of adolescents in the United States: an economic evaluation

The incidence of reported pertussis has increased during the past decade and poses a growing health and economic burden in developed countries, despite high rates of primary vaccination. Administration of a booster dose of acellular pertussis vaccine to adolescents may help reduce this burden, not only by reducing infections in vaccinated individuals but also by reducing transmission of Bordetella pertussis to other individuals, particularly infants. An epidemiologic model was created to assess the health and economic impact of implementing a program of routine acellular pertussis immunization in adolescents 11-18 years of age in the United States, considering both the reduction in cases in those vaccinated and among the unvaccinated population (due to herd immunity). Inputs for the base case were defined according to information derived from published literature and were supplemented by estimates provided by members of the Global Pertussis Initiative. Both direct and indirect costs were included (in 2002 US dollars) using U.S. data. Outcomes were evaluated over the lifetime of a cohort of potential adolescent vaccine candidates. Because of uncertainty in many of the inputs, extensive sensitivity analyses were conducted. With 80% vaccination coverage of adolescents and a 20% reduction of other cases because of herd immunity, >68,000 cases and 41 pertussis-related deaths would be avoided in the subsequent 10 years by routine administration of acellular pertussis boosters to a single cohort of adolescents in the United States. This strategy would be cost-effective, incurring from 6000 US dollars to 22,000 US dollars per life-year gained. The level of herd immunity attained and the true incidence of pertussis are critical determinants of cost effectiveness, as is the duration of immunity resulting from immunization. The cost of immunization and the discount rate also play a role. Although there is considerable uncertainty surrounding key inputs, the results indicate that the conditions required for adolescent immunization to be economically warranted are realistic.

Health-state valuations for pertussis: methods for valuing short-term health states

BACKGROUND

The incidence of reported adolescent and adult pertussis continues to rise in the United States. Acellular pertussis vaccines for adolescents and adults have been developed and may be available soon for use in the U.S. Our objectives were: (1) to describe patient valuations of pertussis disease and vaccination; and (2) to compare valuations for short-term and long-term health states associated with pertussis.

METHODS

We conducted telephone surveys with 515 adult patients and parents of adolescent patients with pertussis in Massachusetts to determine valuations of pertussis-related health states for disease and vaccination using time trade-off (TTO) and contingent valuation (CV) techniques. Respondents were randomized to complete either a short-term or long-term TTO exercise. Discrimination between health states for each valuation technique was assessed using Tukey's method, and valuations for short-term vs. long-term health states were compared using the Wilcoxon rank-sum test.

RESULTS

Three hundred three (59%) and 309 (60%) respondents completed and understood the TTO and CV exercises, respectively. Overall, respondents gave lower valuations (lower TTO and higher CV values) to avoid a given state for adolescent/adult disease compared to vaccine adverse events. Infant complications due to pertussis were considered worse than adolescent/adult disease, regardless of the method of valuation. The short-term TTO resulted in lower mean valuations and larger mean differences between health states than the long-term TTO exercise.

CONCLUSION

Pertussis was considered worse than adverse events due to vaccination. Short-term health-state valuation is better able to discriminate among health states, which is useful for cost-utility analysis.

Acellular Pertussis Vaccine Safety and Efficacy in Children, Adolescents and Adults

This review offers a perspective on the acellular pertussis vaccine efficiency trials concluded in the 1990s and presents the main conclusions of a meta-analysis of 52 studies that assessed the safety and efficacy of the diphtheria-tetanus (DT)-whole cell pertussis (DTwP) and DT-acellular pertussis (DTaP) vaccines administered to children. A clear serological correlate of immunity to pertussis following DTaP vaccination was not identified despite an intensive analysis. It can be speculated that this may be because various combinations of antibody to agglutinogens (pertussis toxin, filamentous haemagglutinin, pertactin and fimbriae) provide protection, or because serum antibody levels and responses do not uniformly reflect mucosal IgA antibody levels.Long-term efficacy following DTaP vaccination is becoming characterised and cell-mediated immunity (T-cell memory) may have importance. DTaP vaccination appears to establish herd immunity after sufficient uptake within communities and countries. As experience with DTaP vaccine safety has accumulated, a 1-2% occurrence of large, local injection reactions with all products has been defined for booster doses. The pathophysiological mechanisms for the reactions are not established but a majority appear likely to be IgE-mediated reactive oedema and a minority to be IgG-mediated reactive Arthus-type reactions. DTwP and DTaP combinations with other vaccines have been studied and licensed; the most controversial combination products are the DTaP/Haemophilus influenzae type B polysaccharide conjugate vaccines. Pertussis epidemiology is changing with a clear increase in occurrence in adolescents and adults. This development has spurred studies and licensure of safer DTaP vaccines for this older population. The economic impact of pertussis and transmission from adults to vulnerable infants provides a cost-benefit justification for widespread use of DTaP vaccines in all age groups with routine boosting every 10 years.

Economic evaluation of an extended acellular pertussis vaccine programme for adolescents in Ontario, Canada

PURPOSE

Pertussis is a frequent cause of cough illness in adolescents. In Canada, until recently immunization against pertussis in public programmes has been restricted to children under the age of 7. The purpose of this analysis was to estimate the health and economic impact of an additional booster dose of the acellular vaccine in adolescents in Ontario.

METHODS

We performed a cost effectiveness analysis, based on a predictive spreadsheet dynamic model following a cohort of 144,000 adolescents in Ontario from the age of 12 years over a 10-year-period from the Ontario Ministry of Health (MoH) and societal perspectives. The model was used to compare costs and benefits of a combined vaccination programme (CVP) including tetanus, diphtheria, and acellular pertussis (dTacp) administered at age 12, compared to current practice.

RESULTS

From the MoH perspective, booster vaccination of dacpT at 12 years via the CVP would produce a yearly additional expected cost of CAD $0.52 per adolescent in Ontario with an incremental cost-effectiveness ratio of CAD $168 per pertussis case avoided based on a 10-year-period. If outcomes are discounted at 3%, the incremental cost-effectiveness ratio rises to $188/discounted pertussis case avoided. From the societal perspective, the CVP would be cost saving CAD $858,106 at 10 years for the cohort. Over the 10-year-period, more than 4400 cases of pertussis would be prevented with approximately 50 hospital admissions averted.

CONCLUSIONS

This study suggests that administering a booster dose of dTacp at 12 years of age to replace diphtheria and tetanus vaccination at 14 years may reduce the economic burden of pertussis treatment in the long term at a reasonable cost.

New Pertussis Vaccination Strategies beyond Infancy: Recommendations by the Global Pertussis Initiative

BACKGROUND

The Global Pertussis Initiative, an expert scientific forum, was established to address the ongoing problems associated with pertussis disease worldwide.

METHODS

The group analyzed pertussis disease trends, developed recommendations to improve disease control through expanded vaccination strategies, and proposed solutions to barriers to implementation and support of research activities.

RESULTS

Bordetella pertussis infection is endemic and continues to be a serious problem among unvaccinated or incompletely vaccinated infants. In addition, the reported incidence of pertussis disease is increasing in adolescents and adults, who not only experience a considerable health burden themselves but also infect vulnerable infants.

CONCLUSIONS

Current vaccination strategies need to be reinforced. Expanded vaccination should include adding booster doses to existing childhood schedules (preschool or adolescent) and booster doses for those specific adult subgroups that have the highest risk of transmitting B. pertussis infection to infants (i.e., new parents, other contacts of newborns, and health care workers). More epidemiological studies and studies of disease transmission and the cost-effectiveness of vaccination would be valuable, and surveillance, diagnostic improvements, and educational campaigns are needed for implementation. However, as a prelude to universal adult vaccination, immediate universal adolescent vaccination should be instituted in countries in which it is economically feasible.

Societal Costs and Morbidity of Pertussis in Adolescents and Adults

BACKGROUND

Since the 1980s, the reported incidence of pertussis among adolescents and adults has been steadily increasing. To understand whether the benefits of an acellular pertussis vaccine formulated for adolescents and adults might offset its costs, policy makers will need information about morbidity and societal (medical and nonmedical) costs of pertussis.

METHODS

Adolescents (age, 10-17 years) and adults (age, >or=18 years) with confirmed pertussis illness were identified by the Massachusetts enhanced pertussis surveillance system. We evaluated medical costs in a cohort of patients who had confirmed pertussis during the period of January 1998 through December 2000; nonmedical costs, by means of prospective interviews, in a cohort of patients who had confirmed pertussis during the period of December 2001 through January 2003; and morbidity in both cohorts. Our main outcome measures were mean costs per case, in 2002 US dollars.

RESULTS

In the analysis of medical costs, 1679 adolescents and 936 adults were found to have mean costs of 242 dollars and 326 dollars, respectively (P<.05). In interviews with 314 adolescents and 203 adults, adults had significantly higher nonmedical costs (447 dollars) than those of adolescents (155 dollars). A total of 83% of adolescents missed a mean of 5.5 days from school (range, 0.4-32 days), and 61% of adults missed a mean of 9.8 days from work (range, 0.1-180 days) because of pertussis. Thirty-eight percent of adolescents and 61% of adults were still coughing at the time of the interview, which occurred an average of 106 days and 94 days, respectively, after cough onset.

CONCLUSIONS

Pertussis causes significant morbidity in and costs for adolescents and adults, with time losses comprising the largest proportion of the cost. Societal costs should be considered when making decisions about potential vaccine use in the future.

Pertussis vaccination strategies for neonates—an exploratory cost-effectiveness analysis

Hospitalisation and death from pertussis in highly immunised populations largely occurs before the first vaccination at 2 months. A Markov model was constructed to estimate the costs and health consequences of three strategies to reduce pertussis over the first 6 months of an infant's life. Earlier vaccination (at either birth or 1 month in addition to current practice) or vaccination of the parents soon after birth was compared with the current practice of vaccination at 2, 4 and 6 months. The model was populated using data on the incidence and costs from Australia. Disability-adjusted life-years (DALYs) were used as the primary outcome measure. The cost to the Australian public health system was chosen as the economic perspective, and Monte-Carlo simulations were used to accommodate uncertainties in the variables. Vaccination at birth was estimated to cost (S.D.) an additional A$33.21 (A$1.60) per infant and to reduce cases, deaths and DALYs by 45%. Vaccination at 1 month was estimated to cost an additional A$43.24 (A$8.98) per infant and to reduce morbidity by approximately 25%. Parental vaccination at birth was the most expensive alternative, costing an additional A$73.38 (A$4.98) per infant and reducing pertussis morbidity by 38%. The costs per DALY averted were A$330,175 (A$15,461) A$735,994 (A$147,679) and A$787,504 (A$48,075) for the birth, 1 month and parental vaccination strategies, respectively. Changing the estimated factor by which hospitalisations and deaths are under-reported, and the efficacy of early vaccination, had large effects on results. Parental vaccination at birth was most cost-effective where protection persisted for subsequent children. The birth vaccination strategy appears to offer the greatest potential benefit for one-child families, but the efficacy at birth (and 1 month) needs to be established.

Evaluation of strategies for use of acellular pertussis vaccine in adolescents and adults: a cost-benefit analysis

Pertussis is increasingly recognized as a source of infection in adults who then commonly infect young children. Immunity to illness caused by Bordetella pertussis is not long-lived, so optimal control of pertussis may require booster immunizations. In a cost-benefit analysis, we evaluated the benefits of 7 independent strategies for administering a pertussis booster, in the form of a diphtheria-tetanus-acellular pertussis vaccine, to adolescents and adults. Break-even vaccine costs for each strategy were calculated by dividing costs preventable by vaccine by the number of persons eligible for vaccination. Of these strategies, the most economical would be to immunize adolescents 10-19 years of age, which would prevent 0.7-1.8 million pertussis cases and save 0.6 dollars-1.6 billion dollars over a decade. Although justified by our analysis, routine adult booster vaccinations every decade would be more expensive and more difficult to implement. A recommendation for booster vaccinations every 10 years requires more information about duration of immunity, program costs, compliance, and nonmedical costs associated with pertussis.

Pertussis vaccine controversies and acellular pertussis vaccine

Pertussis still continues to cause significant morbidity and mortality worldwide. Because of the high reactogenicity of whole cell pertussis vaccine, it had evoked public controversy in several countries. In 1970 Japan abandoned use of whole cell pertussis vaccine and mounted efforts to develop better vaccine. To date, nearly 24 acellular pertussis vaccines have been developed, using different number and quantity of components. No acellular vaccine is most or least immunogenic with respect to all included antigens. Vaccine efficacy and duration of immunity is comparable with whole cell pertussis vaccine. The adverse events are two thirds less compared to whole cell vaccine.

Estimating the potential health gain and cost consequences of introducing a pre-school DTPa pertussis booster into the UK child vaccination schedule

This work estimates the health and cost impacts of a pre-school booster vaccination for Bordetella pertussis, when added to existing UK primary vaccination. A transition state simulation model of pertussis infection in a closed population was constructed comprising of susceptible, infected and immune population sub-groups, across eight age bands. Epidemiological, service use and cost data were sourced from routine statistics, published literature and clinician estimates. The introduction of a pre-school booster is predicted to reduce the number of hospitalisations by approximately 1400 and pertussis cases suffered by up to 28,000 at a net investment of under 13 million pounds over a 5-year period.

Economic evaluation of a new acellular vaccine for pertussis in Canada

OBJECTIVE

Pertussis is a highly contagious infection affecting mainly children. Acellular pertussis vaccines were recently introduced in Canada based on evidence of improved safety and efficacy over whole cell vaccines, the current standard of care. The following study reports the economic impact of replacing the whole cell vaccine (wP) by a new acellular vaccine (aP) in the Ontario pertussis immunisation programme.

DESIGN

For a hypothetical cohort of 100,000 children from birth to the age of 8 years, the costs and consequences of pertussis vaccination with either aP or wP were compared. A decision analytical model was constructed for vaccine delivery, treatment of pertussis cases and vaccine adverse events, with analyses from the viewpoints of the Ontario Ministry of Health and society.

MAIN OUTCOME MEASURES AND RESULTS

The main outcomes were expected number of pertussis cases, hospitalisations, and workdays lost by parents. Data on vaccine effectiveness, pertussis incidence, and other parameters used in the model were from published literature. Costs were discounted at 5%, and extensive sensitivity analyses were undertaken. Over 8 years, in a cohort of 100,000 children, the introduction of aP would prevent 10,500 cases of pertussis, avoiding 504 hospital admissions and 73,500 days of work absence. For Ontario, healthcare cost savings over the same period would amount to 275,585 Canadian dollars ($Can), and societal savings to $Can9,752,864

Costs of illness due to Bordetella pertussis in families

OBJECTIVE

To assess costs of pertussis morbidity among families in a community setting.

DESIGN

Prospective survey.

RESULTS

Sixty-nine families (87 individuals) were studied. Twelve of 14 families with household contacts included an ill adolescent or parent. This individual was the first identified pertussis case within the household in 8 families. A family member required an average of 1.6 visits before (range, 0-7 visits) and after (range, 0-9 visits) pertussis was diagnosed; children younger than 1 year needed 2.5 and 2 visits, respectively. Symptomatic improvement occurred after a mean of 31 days (range, 4-134 days) after pertussis diagnosis and full recovery after a mean of 66 days (range, 5-383 days). Adults experienced the longest recovery time (median, 93 days) compared with other age groups. The average medical costs for an infant, child, adolescent, and adult were $2822, $308, $254, and $181, respectively. Parents lost an average of 6 workdays (range, 1-35 days) to care for an ill child; for these parents, costs associated with work loss averaged $767 per family. An average of 1.7 and 0.7 lost workdays accrued to bring an ill child to a physician's office and the emergency department, respectively. A majority (58%) of parents working while family members were ill with pertussis reported decreased work productivity ranging from 25% to 99%. Work-related costs contributed more than 60% of the overall costs of pertussis.

CONCLUSIONS

The adverse financial effect of pertussis on 69 families in Monroe County, New York, was $145,903 ($2115 per family) and supports the need for booster immunizations in adolescents and adults. Arch Fam Med. 2000;9:989-996

[Health and economic benefits of mandatory regular vaccination in the Slovak Republic. III. Diphtheria, tetanus and pertussis]

The authors tried to evaluate the cost-effectiveness and cost-benefit of regular vaccination of children against diphtheria, tetanus and pertussis in Slovakia. On the basis of model costs of treatment of these diseases before and after vaccination in 1996, the total saved expenditure (102.6 million Sk) and cost-effectiveness (31,619 Sk) were calculated, as well as the cost-benefit.

An economic evaluation of universal pertussis vaccination in Italy

An economic evaluation was performed of universal acellular pertussis vaccination in Italy, where until recently the overall coverage of pertussis vaccination was estimated at 50%. Over the last two years coverage seems to have increased rapidly. By means of a mathematical simulation model, the consequences of pertussis vaccination in terms of both health effects and economic costs were calculated for a single birth cohort followed for 6 years. Incremental analyses were performed for each additional 10% increase in coverage from 50-90%. The results indicate that a 50% coverage rate of pertussis vaccination in Italy was not optimal on the basis of cost-effectiveness and cost-benefit considerations. Additional increases in coverage were found to yield extra health gains at modest net costs or even potential net savings to the health care sector. For example, an increase in coverage to 90% would yield direct net savings of US$42 per extra vaccinee in comparison to a situation of 50% coverage. The total net savings for this strategy would be well over US$100 per additional vaccinee. In the sensitivity analysis, the positive relationship between incremental coverage and incremental efficiency remained unchanged.

Economic evaluation of pertussis prevention by whole-cell and acellular vaccine in Germany

Acellular pertussis vaccines are less reactogenic than whole cell pertussis vaccines, but they are also more expensive. Based on simulation models, we compared the costs and effects of three alternative pertussis vaccination strategies in German children to "no prevention": (1) vaccination with whole-cell vaccine at 45% coverage (vaccine efficacy 90%), (2) vaccination with acellular vaccine at 45% coverage (vaccine efficacy 85%), and (3) vaccination with acellular vaccine at 90% coverage. In the two low coverage scenarios expected annual savings in direct medical costs through prevention of disease were larger for whole-cell than for acellular vaccination (252 vs 216 million DM, respectively). Direct costs for treating the more important adverse events induced by whole-cell vaccination (16.9 million DM annually) did not outweigh the higher direct costs of pertussis infections not prevented with the acellular vaccine and the higher price of the acellular vaccine. However, vaccination with acellular pertussis vaccine rapidly becomes as cost saving as vaccination with whole-cell vaccine as soon as vaccination coverage can be raised from 45% to 52.5% with acellular vaccine. Acellular vaccination is also the superior alternative when considering indirect cost savings resulting from reduction in work-loss due to adverse events.

CONCLUSION

In our simulations, the most cost-effective pertussis prevention strategy was the use of an effective whole-cell vaccine with a high coverage rate. Introduction of the more expensive acellular pertussis vaccines becomes cost saving if at least a 7.5% increase in coverage is achieved. If also non-medical indirect costs to parents resulting from vaccine associated side-effects are accounted for, acellular vaccines may be more cost-effective also in countries with already high whole-cell vaccine coverage.

Economic impact of pertussis

OBJECTIVE

To assess the economic consequences of pertussis in Monroe County, New York (population, 713969), during a 6-year period (1989-1994).

METHODS

Cases of pertussis were identified retrospectively by passive reporting and diagnosis based on culture, positive results of direct fluorescent antibody testing, or Centers for Disease Control and Prevention clinical criteria (cough for > 14 days otherwise unexplained or for > 7 days with paroxysms or whoop epidemiologically linked to a laboratory-confirmed case). One hundred seven (50%) of 216 subjects with identified cases of pertussis completed questionnaires and had medical records reviewed to ascertain the costs of illness, including physician office visits, laboratory tests, medications, hospitalization, emergency department visits, additional child care, and lost days from school (children) or from work (parents or adult cases).

RESULTS

Ninety-three (87%) of the pertussis case occurred in children. The average duration of illness before diagnosis was 21.3 days (range, 12-37 days). One hundred one patients (94%) saw a physician at least once; overall, the average number of visits per case was 3.2 (range, 1-15). Ninety-seven patients (91%) received at least 1 course of antibiotic therapy (average cost for all antibiotics, $95/case), and all took symptomatic treatment (average cost, $48/case). Fifteen patients (14%) required hospitalization; average cost per admission was $13425 (range, $1732-$69637). Thirty patients (28%) were seen in emergency departments; average cost was $202 (range, $69-$289). Additional child care costs ranged from $12 to $2688. For 50 families, 1 adult lost workdays because of illness or to provide child care for an average of 8.3 days (range, 1-45 days). For 4 families, 2 adults lost an average of 44 days from work (range, 10-120 days). The cumulative number of lost workdays was 758 in association with the 107 cases of pertussis. The average full recovery time from illness was 72.9 days (range, 25-115 days).

CONCLUSIONS

Total direct and indirect cost for 107 cases of pertussis in Monroe County was $381052. The economic burden of pertussis is substantial and encourages broader use of vaccination to prevent disease.

Knowledge and attitudes of Minnesota primary care physicians about barriers to measles and pertussis immunization

BACKGROUND

Understanding the causes of low levels of childhood immunization is critical to preventing outbreaks of vaccine-preventable diseases. Hence, we examined physicians' knowledge and attitudes about measles and pertussis vaccines and barriers to immunization.

METHODS

We developed a telephone questionnaire, subjected it to a pilot test, and subsequently interviewed Minnesota pediatricians, general practitioners, rural family physicians, and urban family physicians. The physicians were selected by a random process.

RESULTS

The response rate was 76.4 percent (411 of 538 eligible physicians). Almost all physicians thought that vaccine efficacy was high and that the likelihood of serious side effects was low. Respondents were divided, however, about the likelihood of serious complications from pertussis disease and the role of adults as a pertussis reservoir. Many physicians inappropriately believed certain conditions were contraindications to vaccination; for instance, 33 percent of physicians would not administer measles, mumps, and rubella vaccine to a child whose mother was pregnant. Many physicians (31 percent) would not administer four vaccines simultaneously because of concerns that included parental acceptance and vaccine efficacy. Physicians were more likely to refer children without insurance (P < 0.001) or with Medicaid (P < 0.001) than children with insurance to health department vaccine clinics for immunization.

CONCLUSIONS

For immunization rates to reach high levels, changes are needed in health care system issues, such as vaccine reimbursement, and in provider practices, such as interpretation of vaccine contraindications.

Pertussis and pertussis vaccine. Reanalysis of benefits, risks, and costs

Using recently published information, we examined the experience of a hypothetical cohort of 1 million children followed up from birth to 6 years of age without and with a pertussis vaccination program. Costs associated with death or lost wages were not estimated. A vaccination program reaching 90% of children would reduce disease incidence and disease-related costs by 90%. Taking into account costs associated with vaccine and vaccine reactions, the costs are reduced 82%. The ratio of overall costs without a program to those with a program is 5.7:1. The benefit-cost ratio is 11.1:1. Because we did not include indirect costs, this is a conservative estimate. Until improved vaccines are available, continued use of our present vaccines, with careful attention to possible contraindications, seems the only prudent course to follow.

[Socioeconomic importance of diphtheria and whooping cough immunoprophylaxis]

The evaluation of the immunoprophylaxis of diphtheria and pertussis in the USSR in respect to its social and economic significance has shown that in 20 years (1957-1976) the damage caused by these diseases to the health of the population decreased 833 and 28-fold, and to the economy 333 and 17-fold, respectively. The economic effectiveness achieved by the realization of vaccinal prophylaxis was 1 : 87 for diphtheria and 1 : 119 for pertussis.

Pertussis vaccine--an analysis of benefits, risks and costs

Using decision analysis, we estimated the benefits, risks and costs of routine childhood immunization against pertussis. Without an immunization program, we predict that there would be a 71-fold increase in cases and an almost fourfold increase in deaths (2.0 to 7.6) per cohort of one million children. With a vaccination program, we predict 0.1 case of encephalitis associated with pertussis and five cases of post-vaccination encephalitis; without a program, there would be only 2.3 cases of encephalitis associated with pertussis. Community vaccination would reduce by 61 per cent the costs related to pertussis. Our analysis supports continuation of vaccination in routine childhood immunization programs, but suggests the need for more reliable data on complications from the vaccine, further study of the epidemiology of pertussis and development of a less toxic vaccine.