Clinical findings in Bordetella pertussis infections: results of a prospective multicenter surveillance study

Pertussis outbreak in children hospitalized in Rabat (Morocco)

INTRODUCTION

Cyclical pertussis epidemics primarily affect young infants. This study aims to estimate pertussis prevalence during the ongoing 2023 outbreak at our institution, focusing on affected age groups and clinical presentations.

MATERIEL AND METHODS

This retrospective study includes patients admitted to Rabat University Hospital Center from 1st January 2021 to 30th June 2023. Symptomatic patients underwent Multiplex Respiratory Panel PCR testing for respiratory infections. The analysis included cases where RT-PCR identified Bordetella spp., with data analysed using SPSS 15.0.

RESULTS

Pertussis cases sharply increased from December 2022, constituting 85.4 % of positive samples. Most cases (78.2 %) occurred in infants under 3 months, presenting symptoms such as coughing (94.5 %) and dyspnoea (94.5 %). Pertussis was suspected in 60 % of RT-PCR confirmed cases. B. pertussis DNA was identified in 81.8 % of cases and B. parapertussis DNA in 18.2 % of cases.

CONCLUSION

The study exposes a significant pertussis outbreak affecting predominantly young infants.

Burden of whooping cough in China (PertussisChina): study protocol of a prospective, population-based case-control study

INTRODUCTION

Pertussis is one of the top 10 diseases of children under 10 years of age, and the few vaccine-preventable diseases who is on a rise in China in recent years; however, the true burden of pertussis, including age-stratified incidence and risk factors of severe sequelae, are under-recognised. We aim to estimate the health burden of laboratory-confirmed pertussis by age groups, considering the setting of illness onset (ie, in community, outpatient and inpatient), in a Chinese population (~2.23 million in total) at two sites.

METHODS AND ANALYSIS

This paper describes the study design of a 1-year, prospective, age-stratified and population-based case-control study, including site selection, study population, case registry, ascertainment and enrolment, control recruitment, follow-up of case, microbiological methods, data collection, quality control activities and statistical methods used to generate incidence estimates. During June 2021 through May 2022, registry of suspected pertussis cases (namely chronic/persistent cough) will be conducted in several participating hospitals (SHs) at the two sites, which are selected based on Healthcare Utilisation and Attitudes Surveys (HUAS) carried out before study initiation. A case-control study will be conducted in the SHs and we aim to enrol a total of 1000 suspected pertussis cases (ie, all hospital admissions and the first 1-3 outpatient visits each week each hospital) and 2000 frequency matched healthy controls in community. Our primary study outcome, the laboratory-confirmed Bordetella pertussis infection, will be determined by a comprehensive laboratory methods and procedures (ie, culture, PCR and serological tests) in both cases and controls at enrolment and during 60-day's follow-up visits. Finally, data from HUAS (ie, population size), case registry (ie, the total number of suspected pertussis cases) and case-control study (ie, the prevalence or population attributable fraction of Bordetella pertussis) will be combined to calculate incidence and its 95% CI through bootstrap method. Epidemiological analyses will be conducted to determine the risk factors associated with severe sequelae of pertussis.

ETHICS AND DISSEMINATION

This study has been approved by Chinese Centre for Disease Control and Prevention's Institutional Review Board (no. ICDC-202110). Results will be disseminated via academic presentations and publication in peer-reviewed journals, and will provide valuable scientific data and some new insights into the incidence, aetiology and risk factors for severe sequelae of pertussis to academic societies and the public health authorities who is currently struggling and fighting against this burdensome disease worldwide.

Mucosal Immunization with DTaP Confers Protection against Bordetella pertussis Infection and Cough in Sprague-Dawley Rats

Pertussis is a respiratory disease caused by the Gram-negative pathogen, Bordetella pertussis. The transition from a whole-cell pertussis vaccine (wP and DTP) to an acellular pertussis vaccine (aP, DTaP, and Tdap) correlates with an increase in pertussis cases, despite widespread vaccine implementation and coverage, and it is now appreciated that the protection provided by aP rapidly wanes. To recapitulate the localized immunity observed from natural infection, mucosal vaccination with aP was explored using the coughing rat model of pertussis. Overall, our goal was to evaluate the route of vaccination in the coughing rat model of pertussis. Immunity induced by both oral gavage and intranasal vaccination of aP in B. pertussis challenged rats over a 9-day infection was compared to intramuscular wP (IM-wP)- and IM-aP-immunized rats that were used as positive controls. Our data demonstrate that mucosal immunization of aP resulted in the production of anti-B. pertussis IgG antibody titers similar to IM-wP- and IM-aP-vaccinated controls postchallenge. IN-aP also induced anti-B. pertussis IgA antibodies in the nasal cavity. Immunization with IM-wP, IM-aP, IN-aP, and OG-aP immunization protected against B. pertussis-induced cough, whereas OG-aP immunization did not protect against respiratory distress. Mucosal immunization by both intranasal and oral gavage administration protected against acute inflammation and decreased bacterial burden in the lung compared to mock-vaccinated challenge rats. The data presented in this study suggest that mucosal vaccination with aP can induce a mucosal immune response and provide protection against B. pertussis challenge. This study highlights the potential benefits and uses of the coughing rat model of pertussis; however, further questions regarding waning immunity still require additional investigation.

Pharmacological targeting of host chaperones protects from pertussis toxin in vitro and in vivo

Whooping cough is caused by Bordetella pertussis that releases pertussis toxin (PT) which comprises enzyme A-subunit PTS1 and binding/transport B-subunit. After receptor-mediated endocytosis, PT reaches the endoplasmic reticulum from where unfolded PTS1 is transported to the cytosol. PTS1 ADP-ribosylates G-protein α-subunits resulting in increased cAMP signaling. Here, a role of target cell chaperones Hsp90, Hsp70, cyclophilins and FK506-binding proteins for cytosolic PTS1-uptake is demonstrated. PTS1 specifically and directly interacts with chaperones in vitro and in cells. Specific pharmacological chaperone inhibition protects CHO-K1, human primary airway basal cells and a fully differentiated airway epithelium from PT-intoxication by reducing intracellular PTS1-amounts without affecting cell binding or enzyme activity. PT is internalized by human airway epithelium secretory but not ciliated cells and leads to increase of apical surface liquid. Cyclophilin-inhibitors reduced leukocytosis in infant mouse model of pertussis, indicating their promising potential for developing novel therapeutic strategies against whooping cough.

Pertussis in early life: underdiagnosed, severe, and risky disease. A seven-year experience in a pediatric tertiary-care hospital

AIM

Pertussis continues to be a common worldwide infection in pediatric and adult populations.We aimed to study epidemiological and clinical characteristics of infants and children admitted for pertussis to a tertiary-care hospital and to investigate the risk factors for pediatric intensive care unit (PICU) admission.

MATERIALS AND METHODS

With a retrospective study, we analyzed all medical reports of patients admitted to Bambino Gesù Children's Hospital in Rome from January 2011 to December 2018 with a diagnosis of pertussis.

RESULTS

We examined 195 patients. The majority of hospitalized children (66.15%) were <3 months of age. No mother had received pertussis containing vaccine during pregnancy. Ten cases required admission in PICU. The age at admission was lower in PICU patients with respect to ward patients (42.8 vs 240 days; p < .0007), length of hospital stay was longer in PICU group (24.7 vs 7.52 days; p < .003). Patients who needed PICU admission had greater white blood cell count at hospital admission compared with those hospitalized in the pediatric ward. One infant died and one had encephalitis.

CONCLUSIONS

Pertussis is a remerging disease. In infants, it is associated with significant morbidity and mortality. In recent years, many countries have implemented different vaccination strategies and public health measures to prevent the increase in pertussis cases. Maternal vaccination has been shown to be highly protective for infants <3 months of age before they can develop their own immunity via vaccination.

Neurologic alterations in an HIV adult patient with pertussis: a case report

Background

Pertussis is a highly contagious disease of public health interest caused by the bacterium Bordetella pertussis. Although its incidence has decreased substantially after the introduction of a vaccination, the burden of the disease remains high. Although the paroxysmal phase is highly disabling, complications are uncommon and more prevalent in children than in adults. The most frequent neurological complication is encephalopathy, but seizures, paresis, paraplegia, ataxias, aphasias, and decerebration postures have also been described. The complication of decerebration postures has not been previously reported in adults.

Case presentation

We present a video case of an adult HIV patient with severe coughing paroxysms, post-tussive emesis and syncope, whose workup confirmed the diagnosis of a B. pertussis respiratory infection. During hospitalization, he had fluctuant encephalopathy and post-tussive decerebration postures following paroxysms. He was treated with antibiotic therapy and finally sent home without residual neurological deficits.

Conclusion

This case illustrates the biological plausibility of neurologic complications of pertussis in adults, which, albeit rare, can cause important morbidities. Future research should explore whether there are differences in the clinical presentation, risk factors and pathophysiology of the disease among adults or interventions aimed at preventing or treating pertussis encephalopathy.

Analysis of Multiple Factors Involved in Pertussis-Like Coughing

Objectives. To identify risk factors associated with the prognosis of pertussis-like coughing. Methods. A retrospective study on children hospitalized with pertussis-like coughing from 2018 to 2019. We collected all the case data from medical records including age, gender, vaccination, clinical symptoms, complication, pathogens, white blood cell (WBC) count, lymphocyte ratio, application of macrolide antibiotics, usage of sulfamethoxazole, and usage of inhaled glucocorticoids. Logistic regression was used in this study. Results. A total of 213 hospitalized children with pertussis-like coughing were included in this study. About 70 children were cured within 2 weeks. One120 children were cured from 2 weeks to 3 months, including cases of initial attack and relapse. Symptoms lasting longer than 3 months accounts for 10.8%. Bordetella pertussis, WBC count >20 × 10⁹/L and lymphocyte ratio >60% were associated with poor prognosis (P < .05). Conclusions. Bordetella pertussis, WBC count, and lymphocyte ratio are independent risk factors for poor prognosis.

Age-Dependent Effects of Type I and Type III IFNs in the Pathogenesis of Bordetella pertussis Infection and Disease

Type I and III IFNs play diverse roles in bacterial infections, being protective for some but deleterious for others. Using RNA-sequencing transcriptomics we investigated lung gene expression responses to Bordetella pertussis infection in adult mice, revealing that type I and III IFN pathways may play an important role in promoting inflammatory responses. In B. pertussis-infected mice, lung type I/III IFN responses correlated with increased proinflammatory cytokine expression and with lung inflammatory pathology. In mutant mice with increased type I IFN receptor (IFNAR) signaling, B. pertussis infection exacerbated lung inflammatory pathology, whereas knockout mice with defects in type I IFN signaling had lower levels of lung inflammation than wild-type mice. Curiously, B. pertussis-infected IFNAR1 knockout mice had wild-type levels of lung inflammatory pathology. However, in response to infection these mice had increased levels of type III IFN expression, neutralization of which reduced lung inflammation. In support of this finding, B. pertussis-infected mice with a knockout mutation in the type III IFN receptor (IFNLR1) and double IFNAR1/IFNLR1 knockout mutant mice had reduced lung inflammatory pathology compared with that in wild-type mice, indicating that type III IFN exacerbates lung inflammation. In marked contrast, infant mice did not upregulate type I or III IFNs in response to B. pertussis infection and were protected from lethal infection by increased type I IFN signaling. These results indicate age-dependent effects of type I/III IFN signaling during B. pertussis infection and suggest that these pathways represent targets for therapeutic intervention in pertussis.

Clinical Findings and Management of Pertussis

Pertussis is an endemic highly infectious vaccine-preventable disease. The disease is a major cause of childhood morbidity and mortality. In the most recent years, the re-emergence of pertussis occurred, and many efforts were done to identify the possible causes. Certainly, more effective laboratory methods have a role in making the diagnosis easier. However, sub-optimal efficacy of available vaccines as well as their limited duration of protection could explain the resurgence of the disease. Many forms and clinical features of the disease, ranging from the most classical to atypical and very nuanced forms, have been reported. There are many aspects that influence the clinical features of the pathology, such as a previous immunization or infection, patient's age, gender and antibiotic treatment. A prompt suspect and a rapid diagnosis of pertussis is fundamental for an appropriate clinical management and for preventing pertussis complications, especially in children. However, under a clinical point of view, pertussis is often difficult to be diagnosed. A prompt treatment may decrease the duration and severity of cough; the cornerstone drugs are the macrolides. Although prompt diagnosis and effective therapy are important for pertussis control, only with a broad vaccination coverage will be possible to reduce circulation of Bordetella pertussis.

Pertussis hospitalizations among term and preterm infants: clinical course and vaccine effectiveness

BACKGROUND

Pertussis causes severe disease in young unvaccinated infants, with preterms potentially at highest risk. We studied pertussis in hospitalized infants as related to gestational age (GA) and vaccination history.

METHODS

Medical record data of 0-2y old patients hospitalized for pertussis during 2005-2014 were linked to vaccination data. Multivariable logistic regression was used to study the association between GA and vaccination history on the clinical disease course. We compared vaccine effectiveness (VE) against hospitalization for pertussis between term and preterm infants (i.e., <37w GA) using the screening method as developed by Farrington.

RESULTS

Of 1187 records, medical data from 676 were retrieved. Of these, 12% concerned preterms, whereas they are 8% of Dutch birth cohorts. Median age at admission was 3 m for preterms and 2 m for terms (p < 0.001). Preterms more often had received pertussis vaccination (62% vs 44%; p = 0.01) and more often had coinfections (37% vs 21%; p = 0.01). Preterms tended more often to have complications, to require artificial respiration or to need admittance to the intensive care unit (ICU). Preterms had longer ICU stays (15d vs 9d; p = 0.004). Vaccinated preterms and terms had a lower median length of hospital stay and lower crude risks of apneas and the need for artificial respiration, additional oxygen, and ICU admittance than those not vaccinated. After adjustment for presence of coinfections and age at admittance, these differences were not significant, except the lower need of oxygen treatment in vaccinated terms. Effectiveness of the first vaccination against pertussis hospitalizations was 95% (95% CI 93-96%) and 73% (95% CI 20-91%) in terms and preterms, respectively. Effectiveness of the second dose of the primary vaccination series was comparable in both groups (86 and 99%, respectively).

CONCLUSIONS

Infants hospitalized for pertussis suffer from severe disease. Preterms were overrepresented, with higher need for intensive treatment and less VE of first vaccination. These findings stress the need for alternative prevention, in particular prenatal vaccination of mothers, to reduce pertussis in both groups.

SEVERE PERTUSSIS IN CHILDHOOD: UPDATE AND CONTROVERSY - SYSTEMATIC REVIEW

Objective:

Through a systematic review, this essay aimed at revising the concepts of severe pertussis, updating the epidemiology, pathophysiology, clinical presentation, antibiotic therapy and auxiliary therapeutic options for symptomatology and complications.

Data sources:

This review considered publications from the last 30years in the databases US National Library of Medicine (PubMed), Scientific Electronic Library Online (SciELO), Literatura Latino-americana e do Caribe em Ciências da Saúde (LILACS), Cochrane, Google Scholar, as well as protocols of the Ministry of Health and recommendations of the Centers for Disease Control and Prevention, related to childhood pertussis (whooping cough), with emphasis on its severe form. This research was based on keywords derived from the terms “pertussis”, “azithromycin”, “antitussives”, “leukocyte reduction” in Portuguese and English. Duplicate studies and those with unavailable full-text were excluded.

Data synthesis:

Among 556 records found, 54 were selected for analysis. Pertussis, as a reemerging disease, has affected all age groups, evidencing the transient immunity conferred by infection and vaccination. Severe cases occur in neonates and infants, with secondary viral and bacterial complications and malignant pertussis, a longside hyperleukocytosis, respiratory failure and shock. Macrolides continue to be the chosen antibiotics, while antitussives for coughing remain without efficacy. The prompt treatment in Intensive Care Units improved the prognostic in severe cases, and transfusion was promising among procedures for leukoreduction.

Conclusions:

Approaching severe pertussis in childhood remains a challenge for diagnostic and therapy, as the available therapeutic options are still unsatisfactory. Strategies of prevention are expected to reduce the occurrence of severe cases, while new studies should confirm the role of auxiliary therapies.

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.

Disparities in Tdap Vaccination and Vaccine Information Needs Among Pregnant Women in the United States

Objectives The Advisory Committee on Immunization Practices (ACIP) and the American College of Obstetricians and Gynecologists (ACOG) recommend that pregnant women receive the Tdap vaccine during every pregnancy. The objectives of this paper are to evaluate disparities in Tdap vaccination among pregnant women in the U.S., and to assess whether race/ethnicity and other characteristics are associated with factors that inform pregnant women's decisions about Tdap vaccination. Methods We conducted a nationwide cross-sectional web-based survey of pregnant women in the U.S. during June-July 2014. The primary outcome was self-reported vaccination status with Tdap during pregnancy, categorized as vaccinated, unvaccinated with intent to be vaccinated during the current pregnancy, and unvaccinated with no intent to be vaccinated during the current pregnancy. Secondary outcomes included factors that influenced women's decisions about vaccination and information needs. We used multivariable logistic regression models to estimate odds ratios for associations between race/ethnicity and the outcomes. Results Among pregnant women who completed the survey, 41% (95% CI 36-45%) reported that they had received Tdap during the current pregnancy. Among those women in the third trimester at the time of survey, 52% (95% CI 43-60%) had received Tdap during the current pregnancy. Hispanic women had higher Tdap vaccination than white women and black women (53%, p < 0.05, compared with 38 and 36%, respectively). In logistic regression models adjusting for maternal age, geographic region, education, and income, Hispanic women were more likely to have been vaccinated with Tdap compared with white women (aOR 2.29, 95% CI 1.20-4.37). Higher income and residing in the western U.S. were also independently associated with Tdap vaccination during pregnancy. Twenty-six percent of surveyed women had not been vaccinated with Tdap yet but intended to receive the vaccine during the current pregnancy; this proportion did not differ significantly by race/ethnicity. The most common factor that influenced women to get vaccinated was a health care provider (HCP) recommendation. The most common reason for not getting vaccinated was a concern about safety of the vaccine. Conclusions This study found that some disparities exist in Tdap vaccination among pregnant women in the U.S., and HCPs have an important role in providing information and recommendations about the maternal Tdap recommendation to pregnant women so they can make informed vaccination decisions.

Peptidoglycan Recognition Protein 4 Suppresses Early Inflammatory Responses to Bordetella pertussis and Contributes to Sphingosine-1-Phosphate Receptor Agonist-Mediated Disease Attenuation

Incidence of whooping cough (pertussis), a bacterial infection of the respiratory tract caused by the bacterium Bordetella pertussis, has reached levels not seen since the 1950s. Antibiotics fail to improve the course of disease unless administered early in infection. Therefore, there is an urgent need for the development of antipertussis therapeutics. Sphingosine-1-phosphate receptor (S1PR) agonists have been shown to reduce pulmonary inflammation during Bordetella pertussis infection in mouse models. However, the mechanisms by which S1PR agonists attenuate pertussis disease are unknown. We report the results of a transcriptome sequencing study examining pulmonary transcriptional responses in B. pertussis-infected mice treated with S1PR agonist AAL-R or vehicle control. This study identified peptidoglycan recognition protein 4 (PGLYRP4) as one of the most highly upregulated genes in the lungs of infected mice following S1PR agonism. PGLYRP4, a secreted, innate mediator of host defenses, was found to limit early inflammatory pathology in knockout mouse studies. Further, S1PR agonist AAL-R failed to attenuate pertussis disease in PGLYRP4 knockout (KO) mice. B. pertussis virulence factor tracheal cytotoxin (TCT), a secreted peptidoglycan breakdown product, induces host tissue damage. TCT-oversecreting strains were found to drive an early inflammatory response similar to that observed in PGLYRP4 KO mice. Further, TCT-oversecreting strains induced significantly greater pathology in PGLYRP4-deficient animals than their wild-type counterparts. Together, these data indicate that S1PR agonist-mediated protection against pertussis disease is PGLYRP4 dependent. Our data suggest PGLYRP4 functions, in part, by preventing TCT-induced airway damage.

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

The reemergence of pertussis in the last two decades led to the introduction of adolescents and adults immunization strategies of tetanus–diphtheria–acellular pertussis vaccines (Tdap) in several countries. The health authorities must consider economic aspects when deciding to recommend and fund new programs. Here we present a systematic review of worldwide full economic evaluations of pertussis vaccination targeting adolescents or adults published from 2000. Studies were identified by searching MEDLINE, Excerpta Medica, CRD, and Lilacs databases. Twenty-seven economic evaluations of different strategies with Tdap were identified. Booster vaccination for adolescents and adults were the most frequent, followed by cocooning and pregnant women vaccination. Strategies performance varied considerably among different studies. Assumptions regarding underreporting correction, herd protection and vaccine coverage were crucial to cost-effectiveness results. Understanding the model and the parameters used is essential to understand the results, and identify the major issues important to public health decisions.

Challenges of interpreting epidemiologic surveillance pertussis data with changing diagnostic and immunization practices: the case of the state of São Paulo, Brazil

Background

A significant increase in pertussis incidence occurred in Brazil, from 2011 to 2014, despite high coverage of childhood immunization with whole-cell-pertussis (wP) containing vaccines. This study presents pertussis surveillance data from São Paulo state and discusses the challenges to interpret them considering pertussis cyclic epidemic behavior, the introduction of new diagnostic techniques and new vaccination strategies, and enhanced disease awareness during epidemics.

Methods

Observational study including pertussis cases reported to the Surveillance System in São Paulo state, from January 2001 to December 2015. Pertussis cases data were retrieved from the National Notifiable Diseases Information System (SINAN) website and from São Paulo state Epidemiological Surveillance Center (CVE/SP) database. Vaccination coverage and homogeneity data were collected from the Unified Health System Department of Informatics (DATASUS). We presented cases distribution by year, age group and diagnostic criteria and calculated pertussis incidence rates. The proportions of cases among different age groups were compared using chi-square test for trend.

Results

Infants less than 1 year of age were the most affected during the whole period, but the proportions of cases in this age group had a significant decreasing trend, with significant increase in the proportions of cases reported among older age groups (1–4, 5–10 and ≥20 years). Cases among infants aged less than 6 months represented ≥90% of all cases in children less than 1 year of age in all but 2 years (2012 and 2015). A non-significant decrease in the proportion of cases among infants aged < 2 months was observed in parallel to a significant increase in the proportion of cases in infants aged 6–11 months.

Conclusions

A pertussis outbreak has occurred in a state with universal use of wP vaccine. The disease cyclic behavior has probably had a major role in the increased incidence rates registered in São Paulo state, from 2011 to 2014, as well as in the decreased incidence in 2015. Maternal vaccination cannot explain the drop in the number of cases among all age groups, in 2015, as herd protection is not expected, but may have had an impact on the number of cases in infants aged < 2 months.

Pertussis in Young Infants Throughout the World

In typical pertussis in young infants, the child will appear deceptively well; he or she will have coryza, sneezing, and a mild cough. There is no fever. This progresses to gagging, gasping, eye bulging, bradycardia, cyanosis, and vomiting. There is leukocytosis with lymphocytosis and apneic episodes. Deaths relate to leukocytosis, pulmonary hypertension, and pneumonia. The source of pertussis in young infants is most often a family member with cough illness that is not recognized as pertussis. Diagnosis is based on culture/polymerase chain reaction and leukocytosis with lymphocytosis. Treatment depends on macrolide antibiotic therapy and intubation, with assisted ventilation and oxygen. Prevention is based on prophylactic macrolide treatment, immunization starting at 6 weeks of age, and immunization of all pregnant women in the second or third trimester.

Fatal Pertussis in the Neonatal Mouse Model Is Associated with Pertussis Toxin-Mediated Pathology beyond the Airways

In infants, Bordetella pertussis can cause severe disease, manifested as pronounced leukocytosis, pulmonary hypertension, and even death. The exact cause of death remains unknown, and no effective therapies for treating fulminant pertussis exist. In this study, a neonatal mouse model of critical pertussis is characterized, and a central role for pertussis toxin (PT) is described. PT promoted colonization, leukocytosis, T cell phenotypic changes, systemic pathology, and death in neonatal but not adult mice. Surprisingly, PT inhibited lung inflammatory pathology in neonates, a result which contrasts dramatically with observed PT-promoted pathology in adult mice. Infection with a PT-deficient strain induced severe pulmonary inflammation but not mortality in neonatal mice, suggesting that death in these mice was not associated with impaired lung function. Dissemination of infection beyond the lungs was also detected in neonatal mice, which may contribute to the observed systemic effects of PT. We propose that it is the systemic activity of pertussis toxin and not pulmonary pathology that promotes mortality in critical pertussis. In addition, we observed transmission of infection between neonatal mice, the first report of B. pertussis transmission in mice. This model will be a valuable tool to investigate causes of pertussis pathogenesis and identify potential therapies for critical pertussis.

Reduction of Pertussis Inflammatory Pathology by Therapeutic Treatment With Sphingosine-1-Phosphate Receptor Ligands by a Pertussis Toxin-Insensitive Mechanism

Recent data have demonstrated the potential of sphingosine 1-phosphate (S1P) receptor (S1PR) agonism in the treatment of infectious diseases. A previous study used a murine model of Bordetella pertussis infection to demonstrate that treatment with the S1PR agonist AAL-R reduces pulmonary inflammation during infection. In the current study, we showed that this effect is mediated via the S1PR1 on LysM+ (myeloid) cells. Signaling via this receptor results in reduced lung inflammation and cellular recruitment as well as reduced morbidity and mortality in a neonatal mouse model of disease. Despite the fact that S1PRs are pertussis toxin-sensitive G protein-coupled receptors, the effects of AAL-R were pertussis toxin insensitive in our model. Furthermore, our data demonstrate that S1PR agonist administration may be effective at therapeutic time points. These results indicate a role for S1P signaling in B. pertussis-mediated pathology and highlight the possibility of host-targeted therapy for pertussis.

Characteristics of Bordetella pertussis infection among infantsand children admitted to paediatric intensive care units in Greece: A multicentre, 11-year study

AIM

To describe children with pertussis who required intensive care.

METHODS

This is a retrospective analysis of pertussis admissions to all (six) national intensive care units in Greece from 2003 to 2013.

RESULTS

A total of 31 children were included, 28 of whom were younger than 12 months old. Cough was the most prominent symptom, being present in 27 of 31 (87%) patients, and on admission, only 7 (22.6%) satisfied the case definition. Mechanical ventilation was initiated in 13 (42%) patients. Six patients died because of respiratory failure (two) or multi-organ system failure (four). The patients who died had significantly higher white blood cell counts (WBC) (77 800-31 600, P = 0.031) and neutrophils (29 016-12 795, P = 0021) than those who survived and lower minimum values of serum sodium (125-133, P = 0002). They also had a longer duration of hospitalisation prior to their paediatric intensive care unit admission (6-1 days, P = 0022). Three patients were diagnosed with pulmonary hypertension, and only one of them survived. Age, gender and immunisation status did not differ between survivors and non-survivors. Two patients received exchange blood transfusion, and survival benefit was not apparent.

CONCLUSION

Young infants are at risk of severe pertussis, resulting in serious complications or death. Elevated WBC and low serum sodium are associated with higher mortality. Despite advances in life support and treatment of organ failure in childhood critical illness, pertussis still has substantial mortality.

Evaluation of two vaccine education interventions to improve pertussis vaccination among pregnant African American women: A randomized controlled trial

BACKGROUND

Vaccination coverage with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine in pregnancy or immediately postpartum has been low. Limited data exist on rigorously evaluated interventions to increase maternal vaccination, including Tdap. Tailored messaging based on the Elaboration Likelihood Model (ELM) framework has been successful in improving uptake of some public health interventions. We evaluated the effect of two ELM-based vaccine educational interventions on Tdap vaccination among pregnant African American women, a group of women who tend to have lower vaccine uptake compared with other groups.

METHODS

We conducted a prospective randomized controlled trial to pilot test two interventions - an affective messaging video and a cognitive messaging iBook - among pregnant African American women recruited during routine prenatal care visits. We measured Tdap vaccination during the perinatal period (during pregnancy and immediately postpartum), reasons for non-vaccination, and intention to receive Tdap in the next pregnancy.

RESULTS

Among the enrolled women (n=106), 90% completed follow-up. Tdap vaccination in the perinatal period was 18% in the control group; 50% in the iBook group (Risk Ratio [vs. control group]: 2.83; 95% CI, 1.26-6.37), and 29% in the video group (RR: 1.65; 95% CI, 0.66-4.09). From baseline to follow-up, women's reported intention to receive Tdap during the next pregnancy improved in all three groups. Among unvaccinated women, the most common reason reported for non-vaccination was lack of a recommendation for Tdap by the woman's physician.

CONCLUSIONS

Education interventions that provide targeted information for pregnant women in an interactive manner may be useful to improve Tdap vaccination during the perinatal period. However, larger studies including multiple racial and ethnic groups are needed to evaluate robustness of our findings.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01740310.

[Clinical, laboratorial and radiographic predictors of Bordetella pertussis infection]

OBJECTIVE

To identify clinical, laboratorial and radiographic predictors for Bordetella pertussis infection.

METHODS

This was a retrospective study, which analyzed medical records of all patients submitted to a molecular diagnosis (qPCR) for B. pertussis from September 2011 to January 2013. Clinical and laboratorial data were reviewed, including information about age, sex, signs/symptoms, length of hospitalization, blood cell counts, imaging findings, coinfection with other respiratory pathogens and clinical outcome.

RESULTS

222 cases were revised. Of these, 72.5% had proven pertussis, and 60.9% were under 1 year old. In patients aging up to six months, independent predictors for B. pertussis infection were cyanosis (OR 8.0, CI 95% 1.8-36.3; p=0.007) and lymphocyte count >10(4)/μL (OR 10.0, CI 95% 1.8-54.5; p=0.008). No independent predictors of B. pertussis infection could be determined for patients older than six months. Co-infection was found in 21.4% of patients, of which 72.7% were up to six months of age. Adenovirus was the most common agent (40.9%). In these patients, we were not able to identify any clinical features to detect patients presenting with a respiratory co-infection, even though longer hospital stay was observed in patients with co-infections (12 vs. 6 days; p=0.009).

CONCLUSIONS

Cyanosis and lymphocytosis are independent predictors for pertussis in children up to 6 months old.

Seroprevalence of Bordetella pertussis specific Immunoglobulin G antibody levels among asymptomatic individuals aged 4 to 24 years: a descriptive cross sectional study from Sri Lanka

Background

In Sri Lanka pertussis continues to circulate in the community and cases among adolescents and adults have been reported despite 95% coverage of the four dose pertussis vaccination during early childhood. Waning of immunity following natural infection or immunization may contribute to the persistent circulation. An adolescent booster dose is not included in the national immunization schedule of Sri Lanka, although this is routine practice in many countries. Therefore information on immunity to pertussis in the adolescent group is needed prior to considering vaccination schedule changes.

Methods

The quantitative determination of specific Immunoglobulin G antibodies to Bordetella pertussis toxin was done using a commercially available validated ELISA method. The antibody values were categorized into groups according to the interpretive criteria provided by the manufacturer. The values were <55 IU/mL, negative; 55–<60 IU/mL, borderline; 60–125 IU/mL, positive; >125, strongly positive respectively. Sera of 385 asymptomatic individuals aged 4 to 24 years admitted to surgical units of Lady Ridgeway Hospital, Colombo and Colombo South Teaching Hospital were used for the study. Mann-Whitney U and Kruskal-Wallis tests were used in analysis of results and p ≤0.05 was considered as statistically significant. Details of epidemiological variables were collected using a questionnaire and correlation with significant levels of pertussis antibodies was determined.

Results

Median age of the study population was 12 years with 212 (55.1%) females. The median anti PT antibody level was 3.31 IU/mL and 352 (91%) had anti PT levels ≤55 IU/mL. Median of anti PT levels were 3.18 IU/mL for 4–7 years, 1.43 IU/mL (IQR 0.336–6.27) for 8–11 years, 4.28 IU/mL (IQR 0.978–13.39) for 12–15 years, 6.14 IU/mL for 16–19 years and 4.89 IU/mL for 20–24 years and the differences were statistically significant (p = 0.000). Females (p < 0.003) and those having a sibling aged ≥12 years (p = 0.017) had significantly higher anti PT levels.

Conclusions

The majority of the study population, especially 8 to 11 year age group had low anti PT IgG levels. The higher antibody titers in the 12–15 year age group seem to indicate infection in early adolescence. A booster dose of acellular pertussis vaccine need to be considered.

Pertussis leukocytosis: mechanisms, clinical relevance and treatment

The significant and sometimes dramatic rise in the number of circulating white blood cells (leukocytosis) in infants suffering from pertussis (whooping cough) has been recognized for over a century. Although pertussis is a disease that afflicts people of all ages, it can be particularly severe in young infants, and these are the individuals in whom leukocytosis is most pronounced. Very high levels of leukocytosis are associated with poor outcome in infants hospitalized with pertussis and modern treatments are often aimed at reducing the number of leukocytes. Pertussis leukocytosis is caused by pertussis toxin, a soluble protein toxin released by Bordetella pertussis during infection, but the exact mechanisms by which this occurs are still unclear. In this minireview, I discuss the history of clinical and experimental findings on pertussis leukocytosis, possible contributing mechanisms causing this condition and treatments aimed at reducing leukocytosis in hospitalized infants. Since recent studies have detailed significant associations between specific levels of pertussis leukocytosis and fatal outcome, this is a timely review that may stimulate new thinking on how to understand and combat this problem.

Pertussis: Microbiology, Disease, Treatment, and Prevention

Pertussis is a severe respiratory infection caused by Bordetella pertussis, and in 2008, pertussis was associated with an estimated 16 million cases and 195,000 deaths globally. Sizeable outbreaks of pertussis have been reported over the past 5 years, and disease reemergence has been the focus of international attention to develop a deeper understanding of pathogen virulence and genetic evolution of B. pertussis strains. During the past 20 years, the scientific community has recognized pertussis among adults as well as infants and children. Increased recognition that older children and adolescents are at risk for disease and may transmit B. pertussis to younger siblings has underscored the need to better understand the role of innate, humoral, and cell-mediated immunity, including the role of waning immunity. Although recognition of adult pertussis has increased in tandem with a better understanding of B. pertussis pathogenesis, pertussis in neonates and adults can manifest with atypical clinical presentations. Such disease patterns make pertussis recognition difficult and lead to delays in treatment. Ongoing research using newer tools for molecular analysis holds promise for improved understanding of pertussis epidemiology, bacterial pathogenesis, bioinformatics, and immunology. Together, these advances provide a foundation for the development of new-generation diagnostics, therapeutics, and vaccines.

Serum reactome induced by Bordetella pertussis infection and Pertussis vaccines: qualitative differences in serum antibody recognition patterns revealed by peptide microarray analysis

Background

Pertussis (whooping cough) remains a public health problem despite extensive vaccination strategies. Better understanding of the host-pathogen interaction and the detailed B. pertussis (Bp) target recognition pattern will help in guided vaccine design. We characterized the specific epitope antigen recognition profiles of serum antibodies (‘the reactome’) induced by whooping cough and B. pertussis (Bp) vaccines from a case–control study conducted in 1996 in infants enrolled in a Bp vaccine trial in Sweden (Gustafsson, NEJM, 1996, 334, 349–355).

Methods

Sera from children with whooping cough, vaccinated with Diphtheria Tetanus Pertussis (DTP) whole-cell (wc), acellular 5 (DPTa5), or with the 2 component (a2) vaccines and from infants receiving only DT (n = 10 for each group) were tested with high-content peptide microarrays containing 17 Bp proteins displayed as linear (n = 3175) peptide stretches. Slides were incubated with serum and peptide-IgG complexes detected with Cy5-labeled goat anti-human IgG and analyzed using a GenePix 4000B microarray scanner, followed by statistical analysis, using PAM (Prediction Analysis for Microarrays) and the identification of uniquely recognized peptide epitopes.

Results

367/3,085 (11.9%) peptides were recognized in 10/10 sera from children with whooping cough, 239 (7.7%) in DTPwc, 259 (8.4%) in DTPa5, 105 (3.4%) DTPa2, 179 (5.8%) in the DT groups. Recognition of strongly recognized peptides was similar between whooping cough and DPTwc, but statistically different between whooping cough vs. DTPa5 (p < 0.05), DTPa2 and DT (p < 0.001 vs. both) vaccines. 6/3,085 and 2/3,085 peptides were exclusively recognized in (10/10) sera from children with whooping cough and DTPa2 vaccination, respectively. DTPwc resembles more closely the whooping cough reactome as compared to acellular vaccines.

Conclusion

We could identify a unique recognition signature common for each vaccination group (10/10 children). Peptide microarray technology allows detection of subtle differences in epitope signature responses and may help to guide rational vaccine development by the objective description of a clinically relevant immune response that confers protection against infectious pathogens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-015-0090-3) contains supplementary material, which is available to authorized users.

Clinical, laboratorial and radiographic predictors of Bordetella pertussis infection

OBJECTIVE: To identify clinical, laboratorial and radiographic predictors for Bordetella pertussis infection.METHODS: This was a retrospective study, which analyzed medical records of all patients submitted to a molecular dignosis (qPCR) for B. pertussis from September 2011 to January 2013. Clinical and laboratorial data were reviewed, including information about age, sex, signs/symptoms, length of hospitalization, blood cell counts, imaging findings, coinfection with other respiratory pathogens and clinical outcome.RESULTS: 222 cases were revised. Of these, 72.5% had proven pertussis, and 60.9% were under 1 year old. In patients aging up to six months, independent predictors for B. pertussisinfection were (OR 8.0, CI 95% 1.8-36.3; p=0.007) and lymphocyte count >104/µL (OR 10.0, CI 95% 1.8-54.5; p=0.008). No independent predictors of B. pertussisinfection could be determined for patients older than six months. Co-infection was found in 21.4% of patients, of which 72.7% were up to six months of age. Adenovirus was the most common agent (40.9%). In these patients, we were not able to identify any clinical features to detect patients presenting with a respiratory co-infection, even though longer hospital stay was observed in patients with co-infections (12 vs. 6 days; p=0.009).CONCLUSIONS: Cyanosis and lymphocytosis are independent predictors for pertussis in children up to 6 months old.

A 6-month-old with vaccine-hesitant parents

Many primary care pediatricians find vaccine hesitancy to be one of the most frustrating situations that they face. Parents who refuse to vaccinate their children implicitly call into question an intervention that most pediatricians see as one of the safest and most effective health care interventions of all time. Many pediatricians respond by refusing to care for children whose parents refuse vaccines, and some may consider that the parent's refusal warrants referral to child protective services. We present a case in which a pediatrician faces this dilemma, with responses from pediatricians in academia and private practice.

Prospective nationwide surveillance of hospitalizations due to pertussis in children, 2006-2010

BACKGROUND

Frequency of pertussis is highly variable from country to country and it depends on multiple factors including case definitions and type of surveillance systems used. Many countries recently reported an increase of pertussis cases especially in infants and adolescents.

METHODS

From April 2006 to March 2011, 15-year-old patients hospitalized with suspected or proven pertussis were reported to the Swiss Pediatric Surveillance Unit. Patients with ≥14 days of cough plus paroxysms, whooping or post-tussive vomiting fulfilled the clinical case definition of pertussis. For laboratory confirmation, Bordetella pertussis polymerase chain reaction was offered free of charge.

RESULTS

Data were available from 159 of 173 reported cases and 130 (90% of them <12 months old) were eligible including 125 laboratory-confirmed B. pertussis infections. Rates per 100,000 population were 2.6 (<16 years) and 38.8 (<12 months), respectively. Most frequent complications were cyanosis (63%) and sleep disturbance (60%); 35 (27%) patients received intensive care and 1 patient died. Source of infection was known in 79 (61%) patients and was mainly a sibling, parent or both. Most patients were unimmunized (65%) or incompletely immunized (30%).

CONCLUSIONS

The high rate of pertussis hospitalization in young infants established in this surveillance project and the incomplete pertussis immunization status in almost all hospitalized patients require further efforts for improvement. In addition, introduction of pertussis immunizations for all adolescents (in 2013), young adults (in 2012) and pregnant women (in 2013) in Switzerland should increase indirect protection of vulnerable newborns and infants too young to be fully immunized.

Bronchoscopy with N-acetylcysteine lavage in severe respiratory failure from pertussis infection

Pertussis is an illness that causes significant morbidity and mortality, especially in infants younger than 3 months old. In the most severe cases, it can cause pneumonia, respiratory failure, acute respiratory distress syndrome, pulmonary hypertension, and death. There are reports of using rescue extracorporeal membrane oxygenation (ECMO) as a rescue therapy. However, the mortality of ECMO with pertussis is higher than with other causes of pediatric respiratory failure. We report here the case of a 2-month-old boy with severe respiratory failure and pulmonary hypertension who satisfied ECMO criteria but was successfully treated with repeated bronchoscopy with instillation of N-acetylcysteine. Our patient's respiratory failure was refractory to multiple therapies that have shown benefit in pediatric hypoxemic respiratory failure, including open lung strategies, prone positioning, intratracheal surfactant, and inhaled nitric oxide. Although pulmonary hypertension is a key factor in most cases of fatal pertussis, the adverse effects of hyperinflation and air leaks were more important in this patient's clinical course. Because bronchiolar obstruction from inflammatory, mucous, and airway epithelial debris can be seen in severe pertussis, a regimen of repeated therapeutic bronchoscopy was initiated, and thick, inspissated secretions were retrieved. The patient's airway obstruction gradually resolved, and he eventually recovered with minimal sequelae.

Quantification of the adenylate cyclase toxin of Bordetella pertussis in vitro and during respiratory infection

Whooping cough results from infection of the respiratory tract with Bordetella pertussis, and the secreted adenylate cyclase toxin (ACT) is essential for the bacterium to establish infection. Despite extensive study of the mechanism of ACT cytotoxicity and its effects over a range of concentrations in vitro, ACT has not been observed or quantified in vivo, and thus the concentration of ACT at the site of infection is unknown. The recently developed baboon model of infection mimics the prolonged cough and transmissibility of pertussis, and we hypothesized that measurement of ACT in nasopharyngeal washes (NPW) from baboons, combined with human and in vitro data, would provide an estimate of the ACT concentration in the airway during infection. NPW contained up to ≈ 10(8) CFU/ml B. pertussis and 1 to 5 ng/ml ACT at the peak of infection. Nasal aspirate specimens from two human infants with pertussis contained bacterial concentrations similar to those in the baboons, with 12 to 20 ng/ml ACT. When ≈ 10(8) CFU/ml of a laboratory strain of B. pertussis was cultured in vitro, ACT production was detected in 60 min and reached a plateau of ≈ 60 ng/ml in 6 h. Furthermore, when bacteria were brought into close proximity to target cells by centrifugation, intoxication was increased 4-fold. Collectively, these data suggest that at the bacterium-target cell interface during infection of the respiratory tract, the concentration of ACT can exceed 100 ng/ml, providing a reference point for future studies of ACT and pertussis pathogenesis.

Childhood infections and the risk of asthma: a longitudinal study over 37 years

BACKGROUND

Few studies have examined common childhood infections and adult asthma. We examined associations between childhood infectious diseases, childhood pneumonia, and current, persisting, and incident asthma to middle age.

METHODS

We analyzed data from the Tasmanian Longitudinal Health Study (TAHS). A history of pneumonia was ascertained from their parents when the TAHS participants were 7 years old. Measles, rubella, mumps, chickenpox, diphtheria, and pertussis were identified from school medical records. Associations with current, persisting, or incident asthma were examined using regression techniques.

RESULTS

Greater infectious diseases load was negatively associated with persisting asthma at all ages. Individually, pertussis (adjusted OR [aOR], 0.53; 95% CI, 0.28-1.00) was negatively associated with asthma persisting to age 13 years, chickenpox (aOR, 0.58; 95% CI, 0.38-0.88) was negatively associated with asthma persisting to age 32 years, and rubella was negatively associated with asthma persisting to ages 32 (aOR, 0.61; 95% CI, 0.31-0.96) and 44 years (aOR 0.53; 95% CI, 0.35-0.82). Pertussis was associated with preadolescent incident asthma (adjusted hazard ratio [aHR], 1.80; 95% CI, 1.10-2.96), whereas measles was associated with adolescent incident asthma (aHR, 1.66; 1.06-2.56). Childhood pneumonia was associated with current asthma at ages 7 (aOR, 3.12; 95% CI, 2.61-3.75) and 13 years (aOR, 1.32; 95% CI, 1.00-1.75), an association stronger in those without than those with eczema (aOR, 3.46; 95% CI, 2.83-4.24 vs aOR, 2.08; 95% CI, 1.38-3.12).

CONCLUSIONS

Overall, childhood infectious diseases protected against asthma persisting in later life, but pertussis and measles were associated with new-onset asthma after childhood. Measles and pertussis immunization might lead to a reduction in incident asthma in later life.

Finding the proper balance between freedom and justice: why we should not eliminate personal belief exemptions to vaccine mandates

Lantos and colleagues (this issue) propose to eliminate personal belief exemptions from school vaccine mandates, particularly for those vaccines that target deadly contagious childhood disease. They argue that not doing so would be unjust. In this counterpoint, we argue that, for reasons grounded in both health policy and morality, a just vaccine policy need not prohibit parents from claiming personal belief exemptions.

Risk factors for complications in hospitalized young infants presenting with uncomplicated pertussis

OBJECTIVE

We sought to identify risk factors for complications in hospitalized young infants with uncomplicated pertussis.

METHODS

Retrospective cohort study of hospitalized infants 0 to 6 months of age with confirmed pertussis from 2005 to 2009. Subjects presenting without complications or need for initial intensive care admission were deemed to have uncomplicated pertussis. Complications during hospitalization were defined as apnea, pneumonia, seizures, or encephalopathy. Univariate analysis was performed by estimating odds ratios (OR) and 95% confidence intervals (CI) for the association between each variable and the occurrence of complications. Multivariable analysis was performed using logistic regression. Clinical variables included demographics, historical, laboratory, and imaging data.

RESULTS

Of 126 study subjects, 46 (36.5%) developed complications in the hospital: 43 with apnea (two required endotracheal intubation), seven with pneumonia, and three with seizures; there were no cases of encephalopathy and no deaths. Age less than 60 days (OR, 2.71; 95% CI, 1.08-6.82), cough duration less than 7 days (OR, 5.38; 95% CI, 1.79-16.18), history of color change (OR, 5.24; 95% CI, 1.14-24.07), parental intervention (OR, 10.05; 95% CI, 1.67-60.39), and need for oxygen in the emergency department (OR. 3.94; 95% CI. 1.37-11.36) were associated with development of complications. The median duration of cough at the time of complication was 9 days (range 2-30 days). Initial complete blood cell count and radiographic findings were not associated with complications.

CONCLUSIONS

Infants with uncomplicated pertussis may be at low risk for developing respiratory failure or death. Historical information may assist practitioners in determining risk for serious complications.

Posttussive emesis as a symptom of asthma in children

BACKGROUND

Emesis can be triggered by cough in children, and cough is a common symptom of asthma.

OBJECTIVE

To explore the association between posttussive emesis and asthma in the pediatric population.

METHODS

A questionnaire was distributed to parents of children between the ages of 2 and 17 years in the pediatric and allergy-immunology clinics at our institution from August 16 through November 3, 2008. Prevalence of posttussive emesis was determined and compared among children with physician-diagnosed asthma, children with no evidence of asthma, and those not formally diagnosed as having asthma but with surrogate markers suggestive of asthma. The predictive value of posttussive emesis was compared with those of known markers of asthma. The prevalence of gastroesophageal reflux and pertussis was evaluated because these conditions might also cause posttussive emesis.

RESULTS

The prevalence of posttussive emesis was 33% in our study population of 500 children. Among those with physician-diagnosed asthma (n = 122), 56% reported a history of posttussive emesis. For patients not formally diagnosed as having asthma but with surrogate markers suggestive of asthma (n = 62), 71% had a history of posttussive emesis. Both of these were significantly higher than in those with no evidence of asthma (n = 316), in whom 16% reported a history of posttussive emesis (P < .0005). Children with posttussive emesis were significantly more likely to have asthma than those without posttussive emesis (odds ratio, 7.9; 95% confidence interval, 5.2-12). Neither pertussis nor gastroesophageal reflux accounted for the degree of posttussive emesis reported.

CONCLUSIONS

Posttussive emesis is more common among children with asthma than among nonasthmatic children. In children with cough and a history of posttussive emesis, asthma should be strongly considered in the differential diagnosis.

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.

The epidemiology of pertussis in Germany: past and present

BACKGROUND

Current and past pertussis epidemiology in the two parts of Germany is compared in the context of different histories of vaccination recommendations and coverage to better understand patterns of disease transmission.

METHODS

Available regional pertussis surveillance and vaccination coverage data, supplemented by a literature search for published surveys as well as official national hospital and mortality statistics, were analyzed in the context of respective vaccination recommendations from 1964 onwards.

RESULTS

Routine childhood pertussis vaccination was recommended in the German Democratic Republic (GDR) from 1964 and in former West German states (FWG) from 1969, but withdrawn from 1974-1991 in FWG. Pertussis incidence declined to <1 case/100,000 inhabitants in GDR prior to reunification in 1991, while in FWG, where pertussis was not notifiable after 1961, incidence was estimated at 160-180 cases/100,000 inhabitants in the 1970s-1980s. Despite recommendations for universal childhood immunization in 1991, vaccination coverage decreased in former East German States (FEG) and increased only slowly in FWG. After introduction of acellular pertussis vaccines in 1995, vaccination coverage increased markedly among younger children, but remains low in adolescents, especially in FWG, despite introduction of a booster vaccination for 9-17 year olds in 2000. Reported pertussis incidence increased in FEG to 39.3 cases/100,000 inhabitants in 2007, with the proportion of adults increasing from 20% in 1995 to 68% in 2007. From 2004-2007, incidence was highest among 5-14 year-old children, with a high proportion fully vaccinated according to official recommendations, which did not include a preschool booster until 2006. Hospital discharge statistics revealed a ~2-fold higher pertussis morbidity among infants in FWG than FEG.

CONCLUSION

The shift in pertussis morbidity to older age groups observed in FEG is similar to reports from other countries with longstanding vaccination programs and suggests that additional booster vaccination may be necessary beyond adolescence. The high proportion of fully vaccinated cases in older children in FEG suggests waning immunity 5-10 years after primary immunisation in infancy. The higher incidence of pertussis hospitalisations in infants suggests a stronger force of infection in FWG than FEG. Nationwide pertussis reporting is required for better evaluation of transmission patterns and vaccination policy in both parts of Germany.

Pertussis: severe clinical presentation in pediatric intensive care and its relation to outcome

OBJECTIVE

To describe our institutional experience in the management of infants and children with pertussis admitted during a 20-yr period (January 1985 through December 2004) and also to study the relation between method of presentation and outcome.

SETTING

Pediatric intensive care unit in a university-affiliated tertiary pediatric hospital in Melbourne, Australia.

DESIGN/METHODS

Retrospective review of medical records and radiology reports of patients with a diagnosis of pertussis identified from the pediatric intensive care unit database.

RESULTS

A total of 49 patients (median age, 6 wks; interquartile range, 4-8 wks) required 55 admission episodes to the pediatric intensive care unit. Main reasons for admission were apnea with or without cough paroxysms (63%), pneumonia (18%), and seizures (10%). None of the infants had completed the primary course of immunization, and 94% had not received a single dose of pertussis vaccine. Infants presenting with pneumonia presented earlier (p = .001), had longer intensive care stay (p = .007), higher white cell count (p < or = .001), lower Pao2 at admission (p = .020), and higher mortality. Six infants out of seven needing circulatory support died (including all four treated with extracorporeal membrane oxygenation), and all deaths (n = 7) occurred in infants who had pneumonia at presentation.

CONCLUSION

Patients with pertussis, presenting as apnea (with or without cough paroxysms), treated in the pediatric intensive care unit had 100% survival. However, pneumonia as the main reason for admission and the need for circulatory support is associated with a very poor outcome. A deeper understanding of the molecular basis of Bordetella pertussis and its relation to the human host might offer means for future therapies.