Clinical and economic effects of pertussis outbreaks

Interventions for increasing the uptake of immunisations in healthcare workers: A systematic review

OBJECTIVE

This systemic review aimed to evaluate the effectiveness of interventions for increasing the uptake of immunisation in healthcare workers (HCWs) compared to no or alternative interventions.

METHODS

A systematic review was undertaken (until March 2022) using a search strategy established a priori to capture studies that examined the effect of interventions on vaccination levels in HCWs. We included randomised controlled trials (RCT), cluster RCTs, controlled before-after (CBA) studies and interrupted time-series (ITS) studies. We described studies descriptively and synthesized results with a fixed-effect or random-effects model meta-analysis, where appropriate. The risk of bias was assessed for each study; the quality evidence per comparison was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

We identified three RCTs, six cluster RCTs and four ITS studies. There was a diverse range of interventions; many included an educational component. Based on the evidence examined the following may be effective strategies in increasing the proportion of HCWs vaccinated: policy interventions, targeted and multicomponent strategies, tailored programs directed at management, physician delivered education with a vaccine 'champion' and individual decision analysis. Limited eligible studies restricted synthesis and interpretation of findings. No studies evaluated the effectiveness of legislation. Nor did we find studies evaluating the effectiveness of incentives on their own or studies focusing solely on improving access to vaccination. We judged all the studies as either unclear or high risk of bias.

CONCLUSION

Few robust studies that evaluate interventions to increase vaccination in HCWs are available. A limitation of this systematic review is that interventions are diverse, poorly reported and few were sufficiently alike to combine in an evaluation. More research on the effects of interventions to increase vaccination in HCWs is required, this should address a variety of vaccines and not just influenza vaccination.

When Is Mass Prophylaxis Cost-Effective for Epidemic Control? A Comparison of Decision Approaches

BACKGROUND

For certain communicable disease outbreaks, mass prophylaxis of uninfected individuals can curtail new infections. When an outbreak emerges, decision makers could benefit from methods to quickly determine whether mass prophylaxis is cost-effective. We consider 2 approaches: a simple decision model and machine learning meta-models. The motivating example is plague in Madagascar.

METHODS

We use a susceptible-exposed-infectious-removed (SEIR) epidemic model to derive a decision rule based on the fraction of the population infected, effective reproduction ratio, infection fatality rate, quality-adjusted life-year loss associated with death, prophylaxis effectiveness and cost, time horizon, and willingness-to-pay threshold. We also develop machine learning meta-models of a detailed model of plague in Madagascar using logistic regression, random forest, and neural network models. In numerical experiments, we compare results using the decision rule and the meta-models to results obtained using the simulation model. We vary the initial fraction of the population infected, the effective reproduction ratio, the intervention start date and duration, and the cost of prophylaxis.

LIMITATIONS

We assume homogeneous mixing and no negative side effects due to antibiotic prophylaxis.

RESULTS

The simple decision rule matched the SEIR model outcome in 85.4% of scenarios. Using data for a 2017 plague outbreak in Madagascar, the decision rule correctly indicated that mass prophylaxis was not cost-effective. The meta-models were significantly more accurate, with an accuracy of 92.8% for logistic regression, 95.8% for the neural network model, and 96.9% for the random forest model.

CONCLUSIONS

A simple decision rule using minimal information about an outbreak can accurately evaluate the cost-effectiveness of mass prophylaxis for outbreak mitigation. Meta-models of a complex disease simulation can achieve higher accuracy but with greater computational and data requirements and less interpretability.

HIGHLIGHTS

We use a susceptible-exposed-infectious-removed model and net monetary benefit to derive a simple decision rule to evaluate the cost-effectiveness of mass prophylaxis.We use the example of plague in Madagascar to compare the performance of the analytically derived decision rule to that of machine learning meta-models trained on a stochastic dynamic transmission model.We assess the accuracy of each approach for different combinations of disease dynamics and intervention scenarios.The machine learning meta-models are more accurate predictors of mass prophylaxis cost-effectiveness. However, the simple decision rule is also accurate and may be a preferred substitute in low-resource settings.

Pertussis Morbidity in Children 12-59 Months of Age: A NSW Public Health Network Study

BACKGROUND

Pertussis continues to be a significant public health problem despite high levels of vaccination. Although hospitalizations and deaths among children greater than 12 months of age are much less frequent than among infants less than 6 months of age, only limited information is available for this age group on other measures of morbidity.

METHODS

A cross-sectional study with a 6-week follow-up component was conducted in New South Wales, Australia in 2017 to measure morbidity among children 12-59 months of age notified to health authorities. Measures used included cough duration, cough severity, constitutional symptoms and impacts on the family. Associations between these outcomes and age group, vaccination status, asthma, treatment and family structure were explored.

RESULTS

Three hundred and five of 472 (65%) notified cases were interviewed at baseline with approximately 20% having a severe cough with no trend in prevalence across age groups. Forty-eight percent of cases had experienced 3 or more constitutional symptoms with rates significantly higher among younger children. Children who had received an 18-month booster vaccination were significantly less likely to experience 3 or more constitutional symptoms (odds ratio: 0.46, 95% confidence interval: 0.22-0.97). Fifty-one percent of cases were still coughing at 6 weeks. One-third of carers initially reported having disrupted sleep 4 or more nights per week with substantial disruption to carers' sleep still recorded at 6 weeks.

CONCLUSIONS

Substantial morbidity was observed in this age group with some evidence that the reintroduction of an 18-month acellular pertussis booster lessened disease severity.

Predictors of pertussis outbreak in urban and rural municipalities of Saskatchewan, Canada

OBJECTIVES

Increased numbers of pertussis cases in September 2015 led to the declaration of an outbreak in the Saskatoon Health Region (SHR). SHR (population approximately 350,000) is a geographic area in central Saskatchewan consisting of both urban and rural municipalities. The purpose of this study was to describe the epidemiology and identify possible predictors of the outbreak.

METHODS

Confirmed cases of pertussis in SHR from 2010 to 2015 were extracted from the integrated Public Health Information System (iPHIS) database. Univariate and bivariate analyses and a comparison of the two outbreaks were conducted. Poisson regression modelling was used to estimate incidence rate ratios (IRRs) of factors associated with pertussis infection.

OUTCOMES

Two outbreaks between 2010 and 2015. Factors associated with the 2015 outbreak were residence in rural areas (IRR = 18.67, 95% CI 11.82-29.49; 11.37, 95% CI 6.40-20.21; and 6.31, 95% CI 3.43-11.62) for Humboldt, Watrous, and Rosthern areas, respectively, compared to the City of Saskatoon, and among children 11-14 years of age (IRR = 3.11, 95% CI 1.67-5.79) compared to children under 5 years of age. Unvaccinated persons had increased risk (IRR = 1.60, 95% CI 1.07-2.38). Multiple interventions, including enhanced contact tracing, supplemental immunization clinics, and cocooning, were employed in the 2015 outbreak.

CONCLUSION

Pertussis is a cyclical disease with outbreaks occurring every 3 to 5 years. Teenagers have increased risk of disease compared to younger children, likely due to waning immunity. Rural residents had a higher incidence of disease, possibly due to clusters of conscientious objectors. Control efforts require recognition of waning immunity and unvaccinated susceptibles.

Cost of a measles outbreak in a remote island economy: 2014 Federated States of Micronesia measles outbreak

After 20years with no reported measles cases, on May 15, 2014 the Centers for Disease Control and Prevention (CDC) was notified of two cases testing positive for measles-specific immunoglobulin M (IgM) antibodies in the Federated States of Micronesia (FSM). Under the Compact of Free Association, FSM receives immunization funding and technical support from the United States (US) domestic vaccination program managed by the Centers for Disease Control and Prevention (CDC). In a collaborative effort, public health officials and volunteers from FSM and the US government worked to respond and contain the measles outbreak through an emergency mass vaccination campaign, contact tracing, and other outbreak investigation activities. Contributions were also made by United Nations Children's Emergency Fund (UNICEF) and World Health Organization (WHO). Total costs incurred as a result of the outbreak were nearly $4,000,000; approximately $10,000 per case. Direct medical costs (≈$141,000) were incurred in the treatment of those individuals infected, as well as lost productivity of the infected and informal caregivers (≈$250,000) and costs to contain the outbreak (≈$3.5 million). We assessed the economic burden of the 2014 measles outbreak to FSM, as well as the economic responsibilities of the US. Although the US paid the majority of total costs of the outbreak (≈67%), examining each country's costs relative to their respective economy illustrates a far greater burden to FSM. We demonstrate that while FSM was heavily assisted by the US in responding to the 2014 Measles Outbreak, the outbreak significantly impacted their economy. FSM's economic burden from the outbreak is approximately equivalent to their entire 2016 Fiscal Year budget dedicated to education.

Suffer the Infants: A Severe Case of Pertussis in Oregon, 2012

Pertussis remains a public health concern in Oregon, especially among young infants. The disease can be severe in this age group and is associated with a high inpatient cost. This report describes an Oregon infant who was hospitalized with pertussis for 90 days, required extracorporeal oxygenation for 43 days, suffered complications including stroke, and had hospital charges totaling $1.5 million. Pertussis morbidity among young infants argues for vaccination of women during each pregnancy and of infants beginning promptly at two months of age.

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.

Tdap: The Need to Educate and Immunize

The resurgence of pertussis is puzzling, especially given the requirement that children complete recommended immunizations prior to school entry. Are adult carriers unknowingly infecting children? What do adult caregivers know about pertussis and the tetanus, diphtheria, and acellular pertussis (Tdap) booster vaccine? How can the incidence of pertussis in children younger than 2 years, a group most at risk for complications of the disease, be reduced? This article examines the incidence of pertussis and strategies to reduce pertussis incidence in the United States. If the need for Tdap vaccine is identified and favorably received by adults, immunization programs can be arranged at worksites to better protect infants who are most at risk for pertussis.

Relationship between the population incidence of pertussis in children in New South Wales, Australia and emergency department visits with cough: a time series analysis

Background

Little is known about the potential of syndromic surveillance to provide early warning of pertussis outbreaks. We conducted a time series analysis to assess whether an emergency department (ED) cough syndrome would respond to changes in the incidence of pertussis in children aged under 10 years in New South Wales (NSW), Australia, and to evaluate the timing of any association. A further aim was to assess the lag between the onset of pertussis symptoms and case notification in the infectious diseases surveillance system in NSW.

Methods

Using routinely collected data, we prepared a daily count time series of visits to NSW EDs assigned a provisional diagnosis of cough. Separate daily series were prepared for three independent variables: notifications of cases of pertussis and influenza and ED visits with bronchiolitis (a proxy measure of respiratory syncytial virus (RSV) infection). The study period was 1/1/2007-31/12/2010. A negative binomial multivariate model was used to assess associations between the outcome and independent variables. We also evaluated the median delay in days between the estimated onset of a case of pertussis and the date the local public health authority was notified of that case.

Results

When notified pertussis increased by 10 cases in one day, ED visits with cough increased by 5.2% (95% confidence interval (CI): 0.5%-10.0%) seven days later. Daily increases in the other independent variables had a smaller impact on cough visits. When notified influenza increased by 10 cases in one day, ED visits with cough increased by 0.8% (95% CI: 0%-1.7%) seven days later. When ED visits with bronchiolitis increased by 10 visits in one day, ED visits with cough increased by 4.8% (95% CI: 1.2%-8.6%) one day earlier. The median interval between estimated onset of pertussis and case notification was seven days.

Conclusions

Pertussis appears to be an important driver of ED visits with cough in children aged under 10 years. However, the median delay in notification of cases of pertussis was similar to the lag in the pertussis-associated short-term increases in ED visits with cough. Elevations in RSV and influenza activity may also explain increases in the ED cough syndrome. Real time monitoring of ED visits with cough in children is therefore unlikely to consistently detect a potential outbreak of pertussis before passive surveillance.

US hospital requirements for pertussis vaccination of healthcare personnel, 2011

In 2011, institutional requirements for pertussis vaccination of healthcare personnel were reported by nearly one-third of surveyed US hospitals. Requirements often applied to personnel with certain clinical responsibilities, such as those caring for infants. Healthcare personnel who were not on an institution's payroll were rarely subject to pertussis vaccination requirements.

Pertussis knowledge, attitude and practices among European health care professionals in charge of adult vaccination

Despite successful infant vaccination programmes, pertussis remains endemic in many countries. Waning immunity leaves adolescents and adults susceptible to disease and potential reservoirs of infection allowing transmission to vulnerable infants. Misdiagnosis leads to significant underestimation of disease burden and inappropriate treatment. This online survey of 517 European health care professionals (HCP) examined their knowledge, attitudes and practices regarding pertussis and adult vaccination. Compared with other vaccine-preventable diseases, HCPs did not perceive pertussis as a serious disease in adults and there was a low perceived need for adult vaccination; only 17% mentioned pertussis as a disease they would usually vaccinate adults against. Pertussis incidence was considered to be low. Although the majority of HCPs agreed that vaccination is useful to prevent pertussis transmission from adults to susceptible infants, respondents discussed pertussis vaccination with ≤5% of patients; 58% respondents had never prescribed a pertussis vaccine to adults. The perceived low incidence of pertussis in adults and the lack of official guidelines/ recommendations were cited as key reasons for not administering pertussis boosters. Despite only taking place in four countries, our results suggest that the incidence and burden of adult pertussis is not reflected in the attitudes of European HCPs to the disease. Awareness of adult pertussis, its diagnosis and guidance on pertussis boosters should be raised to protect adults and vulnerable infants and to manage the consequences of waning pertussis immunity.

Pertussis-the case for universal vaccination

PURPOSE

Does the literature support universal vaccination of adolescents and adults, reducing disease incidence in infants and young children?

DESIGN & METHODS

An extensive literature review and a meta-analysis of four case-control studies, evaluating effects of missed or late vaccine doses, was conducted.

RESULTS

The literature confirms (a) increasing pertussis rates; (b) adults and adolescents are the primary carriers; (c) vaccine effectiveness wanes over time; and (d) pertussis persists despite disease control efforts.

PRACTICE IMPLICATIONS

Missed or late doses mean an increase in likelihood of contracting pertussis, supporting full vaccination for children and boosters for adolescents/adults.

Use of population health data to refine diagnostic decision-making for pertussis

OBJECTIVE

To improve identification of pertussis cases by developing a decision model that incorporates recent, local, population-level disease incidence.

DESIGN

Retrospective cohort analysis of 443 infants tested for pertussis (2003-7).

MEASUREMENTS

Three models (based on clinical data only, local disease incidence only, and a combination of clinical data and local disease incidence) to predict pertussis positivity were created with demographic, historical, physical exam, and state-wide pertussis data. Models were compared using sensitivity, specificity, area under the receiver-operating characteristics (ROC) curve (AUC), and related metrics.

RESULTS

The model using only clinical data included cyanosis, cough for 1 week, and absence of fever, and was 89% sensitive (95% CI 79 to 99), 27% specific (95% CI 22 to 32) with an area under the ROC curve of 0.80. The model using only local incidence data performed best when the proportion positive of pertussis cultures in the region exceeded 10% in the 8-14 days prior to the infant's associated visit, achieving 13% sensitivity, 53% specificity, and AUC 0.65. The combined model, built with patient-derived variables and local incidence data, included cyanosis, cough for 1 week, and the variable indicating that the proportion positive of pertussis cultures in the region exceeded 10% 8-14 days prior to the infant's associated visit. This model was 100% sensitive (p<0.04, 95% CI 92 to 100), 38% specific (p<0.001, 95% CI 33 to 43), with AUC 0.82.

CONCLUSIONS

Incorporating recent, local population-level disease incidence improved the ability of a decision model to correctly identify infants with pertussis. Our findings support fostering bidirectional exchange between public health and clinical practice, and validate a method for integrating large-scale public health datasets with rich clinical data to improve decision-making and public health.

Keeping vulnerable children safe from pertussis: preventing nosocomial pertussis transmission in the neonatal intensive care unit

OBJECTIVE

To examine the impact of different acellular pertussis booster vaccination strategies on the probability of a nosocomial pertussis outbreak occurring and the distribution of outbreak sizes observed for each intervention strategy.

SETTING

Neonatal intensive care unit.

METHODS

We developed a stochastic, agent-based simulation model to examine the impact of booster vaccination strategies for pertussis on health care-related transmission.

RESULTS

Our results demonstrate that healthcare worker booster vaccination decreases the probability of secondary transmission from 49% (base case, no boosting) to 2% (if 95% of healthcare workers are boosted) and decreases final outbreak size. Boosting family caregivers did not have a clinically significant impact on nosocomial disease transmission.

CONCLUSION

The provision of booster vaccine to healthcare workers in the neonatal intensive care unit substantially reduces the risk of hospital-centered pertussis outbreaks in a manner that enhances the health of hospitalized children. A formal health economic analysis of this finding is currently under way. Policies to protect patient safety in pediatric facilities should include compliance with the United States Advisory Committee on Immunization Practices, which recommends provision of pertussis booster vaccination to healthcare workers.

Boostrix: a reduced-dose acellular pertussis vaccine for use in adolescents and adults

Pertussis remains a serious problem in many countries. Even in countries with high vaccine coverage and a long vaccination history, pertussis outbreaks occur periodically. Rather than being a disease of young children, pertussis has shifted to affect adolescents and adults. Increased pertussis burden in adolescents and adults is the major source of severe infection for young infants. An effective vaccine is needed to control the spread of pertussis beyond preschool children. Boostrix is a reduced-dose acellular pertussis vaccine with diphtheria and tetanus toxoids, and is designed for use in adolescents and adults. Current evidence suggests that Boostrix is immunogenic and well tolerated. The pertussis component of Boostrix has been shown to be efficacious in a large-scale Phase III trial. More than 50 countries have given permit to the use of Boostrix, and many of them formally recommend the use of Boostrix in adolescents and adults. Designed as a vaccine for adolescence and adults, Boostrix has a long way to go to achieve large-scale use in those target groups. Nevertheless, we expect that the advent of Boostrix will lead to a much better control of pertussis in the general population.

Urgent care providers' knowledge and attitude about public health reporting and pertussis control measures: implications for informatics

OBJECTIVES

We assessed urgent care providers' knowledge about public health reporting, guidelines, and actions for the prevention and control of pertussis; attitudes about public health reporting and population-based data; and perception of reporting practices in their clinic.

METHODS

We identified the 106 providers (95% are physicians) employed in 28 urgent care clinics owned by Intermountain Healthcare located throughout Utah and Southern Idaho. We performed a descriptive, cross-sectional survey and assessed providers' knowledge, attitudes, beliefs, and behaviors associated with population-based data and public health mandates and recommendations. The online survey was completed between November 1, 2007, and February 29, 2008.

RESULTS

Among 63 practicing urgent care providers (60% response rate), 19 percent knew that clinically diagnosed pertussis was reportable, and only half (52%) the providers correctly responded about current pertussis vaccination recommendations. Most (35%-78%) providers did not know the prevention and control measures performed by public health practitioners after reporting occurs, including contact tracing, testing, treatment, and prophylaxis. Half (48%) the providers did not know that health department personnel can prescribe antibiotics for contacts of a reported case, and only 22 percent knew that health department personnel may perform diagnostic testing on contacts. Attitudes about reporting are variable, and reporting responsibility is diffused.

CONCLUSION

To improve our ability to meet public health goals, systems need to be designed that engage urgent care providers in the public health process, improve their knowledge and attitude about reporting, and facilitate the flow of information between urgent care and public health settings.

Pertussis vaccination for health care workers

Pertussis, an acute respiratory infection caused by Bordetella pertussis, classically manifests as a protracted cough illness. The incidence of pertussis in the United States has been increasing in recent years. Immunity wanes after childhood vaccination, leaving adolescents and adults susceptible to infection. The transmission of pertussis in health care settings has important medical and economic consequences. Acellular pertussis booster vaccines are now available for use and have been recommended for all adolescents and adults. These vaccines are safe, immunogenic, and effective. Health care workers are a priority group for vaccination because of their increased risk of acquiring infection and the potential to transmit pertussis to high-risk patients. Health care worker vaccination programs are likely to be cost-effective, but further research is needed to determine the acceptability of pertussis vaccines among health care workers, the duration of immunity after booster doses, and the impact of vaccination on the management of pertussis exposures in health care settings.

Current issues in adolescent immunization

Based on the December 2006 Fondation Mérieux International Scientific Symposium, the current state of adolescent immunization is reviewed with a focus on the policy and programmatic issues that impact the acceptability, initiation, and successful implementation. Key questions are identified with proposed strategies to help achieve successful adolescent immunization programs. The role of current vaccines targeted to adolescents, such as those directed against invasive meningitis, pertussis, and the human papillomavirus, is reviewed as well as their role in rejuvenating interest in adolescent immunization, and more importantly, adolescent health as a whole.

New, and some not-so-new, vaccines for adolescents and diseases they prevent

Adolescents in the United States now have the opportunity to receive new vaccines that prevent invasive meningococcal infections, pertussis (whooping cough), and cervical cancer. Except for their potential to cause serious illness, these infections could not be more different. Their incidence ranges from extremely low to quite high. Early clinical manifestations of infection range from none to life-threatening illness. Two of the vaccines are similar to those already in use, whereas 1 is completely new. In conjunction with the 4 vaccines previously recommended for adolescents (the tetanus and diphtheria booster, hepatitis B, measles-mumps-rubella, and varicella), the 3 new vaccines (meningococcal, human papillomavirus, and the tetanus-diphtheria-pertussis booster [which replaced the tetanus-diphtheria booster]) bring the number recommended for adolescents to 6. In this article, we describe key characteristics of the 3 new vaccines and infections they were designed to prevent. We also briefly discuss other vaccines recommended for all adolescents who have not already received them and new vaccines that are still under development.

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.

Predicting pertussis in a pediatric emergency department population

Cases of pertussis, a potentially life-threatening illness in infants younger than 6 months of age, are at a 40-year high. Children frequently present to emergency departments for initial evaluation. Quick recognition of the illness allows rapid triage, isolation, and prevention of nosocomial transmission. A retrospective, case-control chart review was conducted of pediatric emergency department patients (0 to 18 years of age) presenting between January 1, 2003, and December 31, 2004. Analysis focused on the exploration of medical history and physical examination variables as predictors using laboratory verification of the presence of pertussis as a binary outcome variable. Infants younger than 2 months who have a cough or choking associated with cyanosis, as well as a cough and rhonchi on physical examination, have a high likelihood of pertussis and should be identified in triage, isolated immediately, and tested for pertussis. This may lead to appropriate therapy for this population and decrease the transmission of pertussis to other patients and staff in the pediatric emergency department.

Children with pertussis inform the investigation of other pertussis cases among contacts

Background

The number of reported pertussis has increased in the last two decades. However, many cases of pertussis may be underreported or not diagnosed. The World Health Organization estimates that pertussis causes 200.000 – 400.000 deaths each year, most deaths are in infants and in developing countries. Infants with pertussis can indicate an undetected source cases in the community.

Methods

At a University Hospital in Brazil individuals that had frequent contacts with a child with confirmed pertussis (the index case) and had recent history of cough were enrolled into the study. Nasopharyngeal swabs were collected from every contact that had cough within the last 21 days. Cases confirmation followed the guidelines of the Center for Disease Control and Prevention – Atlanta, U.S.A.

Results

Pertussis diagnosis was confirmed in 51 children, (considered the index cases). Among the index cases, 72.5% (37/51) were under 6 months of age; culture for Bordetella pertussis was positive in 78.4% (40/51). Pertussis was confirmed in 39% (107/276) of the contacts of 51 index cases. Among these contacts identified as a pertussis case, 40.2% (43/107) were between 6 months and 11¹/₂ years of age and 59.8% (64/107) were older than 11¹/₂ years of age. Pertussis was confirmed by culture in 11.2% (12/107) of them and by epidemiologic linkage in 88.8% (95/107). Each index case allowed identifying two new cases of pertussis.

Conclusion

Public health authorities should consider implementing early recognition of pertussis index cases and searching for pertussis cases among the contacts. Treatment of the cases and prophylaxis of the contacts is fundamental to control outbreaks in the community.

Update on adolescent immunization: review of pertussis and the efficacy, safety, and clinical use of vaccines that contain tetanus-diphtheria-acellular pertussis

Adolescents, who comprise 14% of the US population, are historically resistant to receiving health care. As a result, adolescents have low immunization rates and are becoming more susceptible to diseases that are preventable by vaccine, such as pertussis. The incidence of pertussis has increased during the past 25 years, with a notable shift in incidence from young children to adolescents and young adults. New vaccines that provide protection against pertussis for use in adolescents have been proven to be safe, effective, and cost-beneficial. Regional epidemics among infants and other vulnerable populations can be reduced or eliminated with improved immunity in adolescents.

Prevention of pertussis among adolescents: recommendations for use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine

The purpose of this statement is to provide the rationale and recommendations for adolescent use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines. Despite universal immunization of children with multiple doses of pediatric diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccine, pertussis remains endemic with a steady increase in the number of reported cases. Two peaks in the incidence of pertussis occur in pediatric patients: infants younger than 6 months of age who are inadequately protected by the current immunization schedule and adolescents 11 through 18 years of age whose vaccine-induced immunity has waned. Significant medical and public health resources are being consumed in postexposure management of adolescent cases, contacts, and outbreaks with little beneficial effect on individuals or the epidemiology of disease. Two Tdap products were licensed in 2005 for use in people 10 through 18 years of age (Boostrix) and 11 through 64 years of age (Adacel). The American Academy of Pediatrics recommends the following: 1. Adolescents 11 to 18 years of age should receive a single dose of Tdap instead of tetanus and diphtheria toxoids (Td) vaccine for booster immunization. The preferred age for Tdap immunization is 11 to 12 years. 2. Adolescents 11 to 18 years of age who have received Td but not Tdap are encouraged to receive a single dose of Tdap. An interval of at least 5 years between Td and Tdap is suggested to reduce the risk of local and systemic reactions; however, intervals of less than 5 years can be used, particularly in settings of increased risk of acquiring pertussis, having complicated disease, or transmitting infection to vulnerable contacts. Data support acceptable safety with an interval as short as approximately 2 years. 3. Tdap and tetravalent meningococcal conjugate vaccine (MCV4 [Menactra]) should be administered during the same visit if both vaccines are indicated. If this is not feasible, MCV4 and Tdap can be administered using either sequence. When not administered simultaneously, the American Academy of Pediatrics suggests a minimum interval of 1 month between vaccines. The rationale for this strategy is to provide direct protection of immunized adolescents. With implementation of vaccine recommendations, indirect benefitalso is likely to extend to unimmunized peers and other age groups. The strategy of universal Tdap immunization at 11 to 12 years of age is cost-effective.

Pertussis in Infants, Children, and Adolescents: Diagnosis, Treatment, and Prevention

Pertussis, or "whooping cough," caused by the gram-negative pleomorphic bacillus Bordetella pertussis, is a highly contagious, potentially life-threatening respiratory tract illness that has re-emerged worldwide as a cause of substantial morbidity and mortality in infants, children, and adolescents, despite high vaccination rates. Increased awareness and reporting, in addition to the availability of better diagnostic tests, partially explain the recent resurgence of pertussis. However, waning immunity after childhood immunization has resulted in a growing pool of susceptible adolescents and adults who are capable of transmitting pertussis to vulnerable unvaccinated or incompletely vaccinated infants. An acellular pertussis vaccine booster for adolescents has been recommended in the United States and other industrialized countries. Active immunization and early diagnosis are crucial in the management of pertussis.