Pertussis requiring intensive care

Alpha-1 antitrypsin inhibits pertussis toxin

Pertussis (whooping cough) is a vaccine-preventable but re-emerging, highly infectious respiratory disease caused by Bordetella pertussis. There are currently no effective treatments for pertussis, complicating care for nonvaccinated individuals, especially newborns. Disease manifestations are predominantly caused by pertussis toxin (PT), a pivotal virulence factor classified as an ADP-ribosylating AB-type protein toxin. In this work, an unbiased approach using peptide libraries, bioassay-guided fractionation and mass spectrometry revealed α1-antitrypsin (α1AT) as a potent PT inhibitor. Biochemistry-, cell culture-, and molecular modeling-based in vitro experimentation demonstrated that the α1AT mode of action is based on blocking PT-binding to the host target cell surface. In the infant mouse model of severe pertussis, α1AT expression was reduced upon infection. Further, systemic administration of α1AT significantly reduced B. pertussis-induced leukocytosis, which is a hallmark of infant infection and major risk factor for fatal pertussis. Taken together our data demonstrates that α1AT is a novel PT inhibitor and that further evaluation and development of α1AT as a therapeutic agent for pertussis is warranted. Importantly, purified α1AT is already in use clinically as an intravenous augmentation therapy for those with genetic α1AT deficiency and could be repurposed to clinical management of pertussis.

The Chaperonin TRiC/CCT Inhibitor HSF1A Protects Cells from Intoxication with Pertussis Toxin

Pertussis toxin (PT) is a bacterial AB5-toxin produced by Bordetella pertussis and a major molecular determinant of pertussis, also known as whooping cough, a highly contagious respiratory disease. In this study, we investigate the protective effects of the chaperonin TRiC/CCT inhibitor, HSF1A, against PT-induced cell intoxication. TRiC/CCT is a chaperonin complex that facilitates the correct folding of proteins, preventing misfolding and aggregation, and maintaining cellular protein homeostasis. Previous research has demonstrated the significance of TRiC/CCT in the functionality of the Clostridioides difficile TcdB AB-toxin. Our findings reveal that HSF1A effectively reduces the levels of ADP-ribosylated Gαi, the specific substrate of PT, in PT-treated cells, without interfering with enzyme activity in vitro or the cellular binding of PT. Additionally, our study uncovers a novel interaction between PTS1 and the chaperonin complex subunit CCT5, which correlates with reduced PTS1 signaling in cells upon HSF1A treatment. Importantly, HSF1A mitigates the adverse effects of PT on cAMP signaling in cellular systems. These results provide valuable insights into the mechanisms of PT uptake and suggest a promising starting point for the development of innovative therapeutic strategies to counteract pertussis toxin-mediated pathogenicity.

Domperidone Inhibits Clostridium botulinum C2 Toxin and Bordetella pertussis Toxin

Bordetella pertussis toxin (PT) and Clostridium botulinum C2 toxin are ADP-ribosylating toxins causing severe diseases in humans and animals. They share a common translocation mechanism requiring the cellular chaperones Hsp90 and Hsp70, cyclophilins, and FK506-binding proteins to transport the toxins' enzyme subunits into the cytosol. Inhibitors of chaperone activities have been shown to reduce the amount of transported enzyme subunits into the cytosol of cells, thus protecting cells from intoxication by these toxins. Recently, domperidone, an approved dopamine receptor antagonist drug, was found to inhibit Hsp70 activity. Since Hsp70 is required for cellular toxin uptake, we hypothesized that domperidone also protects cells from intoxication with PT and C2. The inhibition of intoxication by domperidone was demonstrated by analyzing the ADP-ribosylation status of the toxins' specific substrates. Domperidone had no inhibitory effect on the receptor-binding or enzyme activity of the toxins, but it inhibited the pH-driven membrane translocation of the enzyme subunit of the C2 toxin and reduced the amount of PTS1 in cells. Taken together, our results indicate that domperidone is a potent inhibitor of PT and C2 toxins in cells and therefore might have therapeutic potential by repurposing domperidone to treat diseases caused by bacterial toxins that require Hsp70 for their cellular uptake.

Inhibition of Pertussis Toxin by Human α-Defensins-1 and -5: Differential Mechanisms of Action

Whooping cough is a severe childhood disease, caused by the bacterium Bordetella pertussis, which releases pertussis toxin (PT) as a major virulence factor. Previously, we identified the human antimicrobial peptides α-defensin-1 and -5 as inhibitors of PT and demonstrated their capacity to inhibit the activity of the PT enzyme subunit PTS1. Here, the underlying mechanism of toxin inhibition was investigated in more detail, which is essential for developing the therapeutic potential of these peptides. Flow cytometry and immunocytochemistry revealed that α-defensin-5 strongly reduced PT binding to, and uptake into cells, whereas α-defensin-1 caused only a mild reduction. Conversely, α-defensin-1, but not α-defensin-5 was taken up into different cell lines and interacted with PTS1 inside cells, based on proximity ligation assay. In-silico modeling revealed specific interaction interfaces for α-defensin-1 with PTS1 and vice versa, unlike α-defensin-5. Dot blot experiments showed that α-defensin-1 binds to PTS1 and even stronger to its substrate protein Gαi in vitro. NADase activity of PTS1 in vitro was not inhibited by α-defensin-1 in the absence of Gαi. Taken together, these results suggest that α-defensin-1 inhibits PT mainly by inhibiting enzyme activity of PTS1, whereas α-defensin-5 mainly inhibits cellular uptake of PT. These findings will pave the way for optimization of α-defensins as novel therapeutics against whooping cough.

Clinical evaluation of a new rapid immunochromatographic test for detection of Bordetella pertussis antigen

A more rapid and less complicated test to diagnose pertussis is required in clinical settings. We need to detect Bordetella pertussis, which mainly causes pertussis, as early as possible, because pertussis is more likely to become severe in infants, and people around them can easily become a source of infection due to its strong infectivity. Nevertheless, methods that can detect B. pertussis rapidly and efficiently are lacking. Therefore, we developed a new immunochromatographic antigen kit (ICkit) for the early diagnosis of pertussis. The ICkit detects B. pertussis antigens in a nasopharyngeal swab without equipment and provides the result in about 15 min with a simple procedure. Additionally, a prospective study to evaluate the ICkit was conducted in 11 medical institutions, involving 195 cases with suspected pertussis. Compared with the real-time polymerase chain reaction (rPCR), the sensitivity and specificity of the ICkit were 86.4% (19/22) and 97.1% (168/173), respectively. The ICkit detected the antigen in both children and adults. Furthermore, the ICkit detected the antigen until the 25th day from the onset of cough, when rPCR detected the antigen. Thus, the ICkit demonstrated a high correlation with rPCR and would help diagnose pertussis more rapidly and efficiently.

Evaluating the impact of a continued maternal pertussis immunisation programme in England: A modelling study and cost-effectiveness analysis

INTRODUCTION

An unexpected resurgence of pertussis cases and infant deaths was observed in some countries that had switched to acellular pertussis vaccines in the primary immunisation schedule. In response to the outbreaks, maternal pertussis vaccination programmes in pregnant women have been adopted worldwide, including the USA in 2011 and the UK in 2012. Following the success of the programme in England, we evaluated the health and economic impact of stopping versus continuing the maternal pertussis immunisation to inform public health policy making.

METHODS

We used a mathematical model to estimate the number of infant hospitalisations and deaths related to pertussis in England over 2019-2038. Losses in quality-adjusted life years, QALYs, were considered for infants (aged 0-2 months) who survived or died from pertussis, bereaved parents (of infants who died from pertussis), and women with pertussis (aged 20-44 years). Direct medical costs to the National Health Service included infant hospitalisations, maternal vaccinations, and disease in women. Costs and QALYs were discounted at 3.5%. Changes in the incremental cost-effectiveness ratio, ICER, were explored in sensitivity analyses.

RESULTS

The model supports continuing the maternal pertussis immunisation programme as a cost-effective intervention at an ICER of £14,500/QALY (2.5% and 97.5%-quantile: £7,300/QALY to £32,400/QALY). Stopping versus continuing the maternal programme results in an estimated mean of 972 (range 582 to 1489) versus 308 (184 to 471) infant hospitalisations annually. Results were most sensitive to the number of hospitalisations and deaths when stopping the maternal programme. At a cost-effectiveness threshold of £30,000/QALY, the probability of the maternal programme being cost-effective was 96.2%.

CONCLUSION

Our findings support continuing the maternal pertussis vaccination programme as otherwise higher levels of disease activity and infant mortality are expected to return. These results have led policy makers to decide to continue the maternal programme in the UK routine immunisation schedule.

Infant Hospitalizations and Fatalities Averted by the Maternal Pertussis Vaccination Program in England, 2012-2017: Post-implementation Economic Evaluation

In October 2012, a maternal pertussis vaccination program was implemented in England following an increased incidence and mortality in infants. We evaluated the cost-effectiveness of the program by comparing pertussis-related infant hospitalizations and deaths in 2012-2017 with nonvaccination scenarios. Despite considerable uncertainties, findings support the cost-effectiveness of the program.

Critical pertussis: A multi-centric analysis of risk factors and outcomes in Oman

OBJECTIVES

To identify risk factors and outcomes of patients with critical pertussis.

DESIGN

Retrospective observational cohort study.

SETTING

Sultan Qaboos University Hospital and The Royal Hospital, Muscat, Oman.

SUBJECTS

Children aged <13 years presenting to the emergency departments and diagnosed with laboratory-confirmed pertussis by polymerase chain reaction between January 2013 and December 2018.

MEASUREMENTS AND MAIN RESULTS

In total, 157 patients were diagnosed with pertussis, of which 12% (n = 19) had critical pertussis. Patients with critical pertussis had a higher white blood cell count (WBCC) [adjusted odds ratio (aOR) 1.05; 95% confidence interval (CI) 1.02-1.08; P = 0.003], absolute lymphocyte count (ALC) (aOR 1.08; 95% CI 1.03-1.15; P = 0.004) and absolute neutrophil count (ANC) (aOR 1.05; 95% CI 1.01-1.10; P = 0.032) than patients with non-critical pertussis, even after multi-variate adjustment. The area under the curve for discriminatory accuracy of laboratory variables was 0.75 (95% CI 0.65-0.85), 0.74 (95% CI 0.64-0.84) and 0.72 (95% CI 0.60-0.83) for maximum WBCC, ALC and ANC, respectively, with Youden's cut-off values of 31.5 × 10⁹/L, 19.9 × 10⁹/L and 5.0 × 10⁹/L, respectively.

CONCLUSIONS

In children, higher WBCC, ALC and ANC were significant predictors of critical pertussis. A cut-off level of 31.5 × 10⁹/L for WBCC was associated with critical pertussis.

A Qualitative Study of Views and Experiences of Women and Health Care Professionals about Free Maternal Vaccinations Administered at Community Pharmacies

Background: A policy to extend funding of maternal pregnancy influenza and pertussis vaccinations to community pharmacies could address low pregnancy vaccine uptake. The policy has been implemented in one region in New Zealand. This study explored the views and experiences of women eligible for the vaccines and health care professionals regarding funded maternal vaccinations in pharmacy. Methods: Women in late pregnancy or with an infant, and midwives, pharmacists, and general practice staff were selected purposively and interviewed regarding maternal vaccinations and the new policy, including their awareness and views of the funded vaccinations in pharmacies, and how this policy worked in practice. Enablers and barriers to vaccination by pharmacists were explored. Interviews were transcribed and analysed using a framework approach. Results: Fifty-three interviews were conducted. Most women and health care professionals viewed funded maternal vaccinations in pharmacies positively with respect to increasing awareness and providing delivery options. Many women received messages from pharmacies. Most pharmacies used posters, leaflets and/or verbal explanation to pregnant women to raise awareness of the vaccinations. Not all pharmacies provided these vaccinations, and frontline staff could help to raise awareness. Conclusion: Funded maternal vaccinations in pharmacies are generally well accepted and provide an opportunity to increase uptake and prevent disease.

Five-Year Follow-up of a Severe Case of Pertussis in Oregon, 2012

Oregon continues to face epidemics of pertussis, and infants younger than 2 months of age have the highest incidence and rates of hospitalization and complications. We describe the medical course and sequelae of an infant's severe pertussis illness through age 5½ years. The child has failed to meet developmental milestones, requires substantial medical care, and bears the burdens of chronic lung disease, stroke, epilepsy, impaired neurodevelopment, and problems with vision. The medical and social burden of pertussis among infants too young to be vaccinated underscores the importance of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccination during pregnancy.

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.

Hemolytic uremic syndrome associated with Bordetella pertussis infection in a 2-month-old infant carrying a pathogenic variant in complement factor H

BACKGROUND

Hemolytic uremic syndrome (HUS) has been associated with a number of infectious agents. We report here the case of an infant with severe Bordetella pertussis infection who developed HUS.

CASE DIAGNOSIS/TREATMENT

A 2-month-old preterm male was admitted for severe Bordetella pertussis infection. Symptoms leading to a diagnosis of hemolytic uremic syndrome (HUS) rapidly appeared: hemolytic anemia, thrombocytopenia, and acute kidney injury. He was treated with 25 days of peritoneal dialysis and received complement-targeting therapy with eculizumab (five injections over 2 months), in addition to blood transfusions, antibiotics, and respiratory support. The outcome was favorable. The genetic workup found a complement factor H gene variant which has been associated with atypical HUS. This variant was located in the C3b-binding site and functional tests revealed that it perturbed the regulatory activity of factor H.

CONCLUSION

This case suggests that pertussis is a strong trigger of HUS and that complement investigations are necessary to guide treatment and understand the pathophysiology.

[Prevalence of Bordetella pertussis infection in children with chronic cough and its clinical features]

OBJECTIVE

To investigate the prevalence of Bordetella pertussis infection in children with chronic cough and its clinical features.

METHODS

A total of 106 children who were treated at the outpatient service or hospitalized from January 1, 2016 to May 31, 2017 were enrolled. Their nasopharyngeal swabs and venous blood samples were collected for Bordetella pertussis culture, multiple PCR and serum anti-pertussis toxin antibody detection. According to these results, the children were divided into pertussis group with 26 children and control group with 80 children, and clinical features were analyzed for both groups. E-test stripes were used to determine the sensitivity of Bordetella pertussis strains to erythromycin, azithromycin, doxycycline, levofloxacin, sulfamethoxazole/trimethoprim and amoxicillin.

RESULTS

Of the 106 children with chronic cough, 26 (24.5%) were found to have Bordetella pertussis infection. There were no significant differences in the incidence rates of typical symptoms of pertussis between the pertussis and control groups (P>0.05). E-test showed that erythromycin and azithromycin had a minimal inhibitory concentration (MIC) of >256 mg/L against five Bordetella pertussis strains, while amoxicillin had an MIC of 0.5-1 mg/L.

CONCLUSIONS

The presence of Bordetella pertussis infection in children with chronic cough should be taken seriously by clinicians, and children with chronic cough and Bordetella pertussis infection may not have the typical symptoms of pertussis and are mainly manifested as chronic cough. Amoxicillin may be an alternative drug for macrolide-resistant Bordetella pertussis infection.

Role of Major Toxin Virulence Factors in Pertussis Infection and Disease Pathogenesis

Bordetella pertussis produces several toxins that affect host-pathogen interactions. Of these, the major toxins that contribute to pertussis infection and disease are pertussis toxin, adenylate cyclase toxin-hemolysin and tracheal cytotoxin. Pertussis toxin is a multi-subunit protein toxin that inhibits host G protein-coupled receptor signaling, causing a wide array of effects on the host. Adenylate cyclase toxin-hemolysin is a single polypeptide, containing an adenylate cyclase enzymatic domain coupled to a hemolysin domain, that primarily targets phagocytic cells to inhibit their antibacterial activities. Tracheal cytotoxin is a fragment of peptidoglycan released by B. pertussis that elicits damaging inflammatory responses in host cells. This chapter describes these three virulence factors of B. pertussis, summarizing background information and focusing on the role of each toxin in infection and disease pathogenesis, as well as their role in pertussis vaccination.

[Prevalence of Bordetella pertussis infection in children with chronic cough and its clinical features]

OBJECTIVE

To investigate the prevalence of Bordetella pertussis infection in children with chronic cough and its clinical features.

METHODS

A total of 106 children who were treated at the outpatient service or hospitalized from January 1, 2016 to May 31, 2017 were enrolled. Their nasopharyngeal swabs and venous blood samples were collected for Bordetella pertussis culture, multiple PCR and serum anti-pertussis toxin antibody detection. According to these results, the children were divided into pertussis group with 26 children and control group with 80 children, and clinical features were analyzed for both groups. E-test stripes were used to determine the sensitivity of Bordetella pertussis strains to erythromycin, azithromycin, doxycycline, levofloxacin, sulfamethoxazole/trimethoprim and amoxicillin.

RESULTS

Of the 106 children with chronic cough, 26 (24.5%) were found to have Bordetella pertussis infection. There were no significant differences in the incidence rates of typical symptoms of pertussis between the pertussis and control groups (P>0.05). E-test showed that erythromycin and azithromycin had a minimal inhibitory concentration (MIC) of >256 mg/L against five Bordetella pertussis strains, while amoxicillin had an MIC of 0.5-1 mg/L.

CONCLUSIONS

The presence of Bordetella pertussis infection in children with chronic cough should be taken seriously by clinicians, and children with chronic cough and Bordetella pertussis infection may not have the typical symptoms of pertussis and are mainly manifested as chronic cough. Amoxicillin may be an alternative drug for macrolide-resistant Bordetella pertussis infection.

Pharmacological Cyclophilin Inhibitors Prevent Intoxication of Mammalian Cells with Bordetella pertussis Toxin

The Bordetella pertussis toxin (PT) is one important virulence factor causing the severe childhood disease whooping cough which still accounted for approximately 63,000 deaths worldwide in children in 2013. PT consists of PTS1, the enzymatically active (A) subunit and a non-covalently linked pentameric binding/transport (B) subunit. After endocytosis, PT takes a retrograde route to the endoplasmic reticulum (ER), where PTS1 is released into the cytosol. In the cytosol, PTS1 ADP-ribosylates inhibitory alpha subunits of trimeric GTP-binding proteins (Giα) leading to increased cAMP levels and disturbed signalling. Here, we show that the cyclophilin (Cyp) isoforms CypA and Cyp40 directly interact with PTS1 in vitro and that Cyp inhibitors cyclosporine A (CsA) and its tailored non-immunosuppressive derivative VK112 both inhibit intoxication of CHO-K1 cells with PT, as analysed in a morphology-based assay. Moreover, in cells treated with PT in the presence of CsA, the amount of ADP-ribosylated Giα was significantly reduced and less PTS1 was detected in the cytosol compared to cells treated with PT only. The results suggest that the uptake of PTS1 into the cytosol requires Cyps. Therefore, CsA/VK112 represent promising candidates for novel therapeutic strategies acting on the toxin level to prevent the severe, life-threatening symptoms caused by PT.

Cognitive Development One Year After Infantile Critical Pertussis

OBJECTIVES

Pertussis can cause life-threatening illness in infants. Data regarding neurodevelopment after pertussis remain scant. The aim of this study was to assess cognitive development of infants with critical pertussis 1 year after PICU discharge.

DESIGN

Prospective cohort study.

SETTING

Eight hospitals comprising the Eunice Kennedy Shriver National Institute for Child Health and Human Development Collaborative Pediatric Critical Care Research Network and 18 additional sites across the United States.

PATIENTS

Eligible patients had laboratory confirmation of pertussis infection, were less than 1 year old, and were admitted to the PICU for at least 24 hours.

INTERVENTIONS

The Mullen Scales of Early Learning was administered at a 1-year follow-up visit. Functional status was determined by examination and parental interview.

MEASUREMENTS AND MAIN RESULTS

Of 196 eligible patients, 111 (57%) completed the Mullen Scales of Early Learning. The mean scores for visual reception, receptive language, and expressive language domains were significantly lower than the norms (p < 0.001), but not fine and gross motor domains. Forty-one patients (37%) had abnormal scores in at least one domain and 10 (9%) had an Early Learning Composite score 2 or more SDs below the population norms. Older age (p < 0.003) and Hispanic ethnicity (p < 0.008) were associated with lower mean Early Learning Composite score, but presenting symptoms and PICU course were not.

CONCLUSIONS

Infants who survive critical pertussis often have neurodevelopmental deficits. These infants may benefit from routine neurodevelopmental screening.

Leukemoid Reaction in Infant Pertussis: Is There a Place for Hydroxyurea? A Case Report

A 73-days old infant of 34 weeks' gestation was hospitalized with a co-infection of respiratory syncytial virus (RSV) and Bordetella pertussis (BP). She required invasive ventilation for 9 days in the context of malignant pertussis with persistent hypoxemia and hypercapnia secondary to a leukemoid reaction. Despite an increase of white blood cell (WBC) count up to 70 G/L and ensuing pulmonary hypertension, no hemodynamic compromise occurred. Without clear indication for leukapheresis nor exchange transfusion, an off-label treatment with hydroxyurea was given for 5 days with gradual decrease of WBC count, without any complication and hospital discharge on day 29. To our knowledge, no effective therapy for malignant pertussis has been described in the literature and complications are frequent with leukoreduction procedures. We discuss an alternative to invasive procedures in young infants to fulfill the need to decrease rapidly leukocyte counts in a leukemoid reaction associated with Bordetella pertussis infection. To our knowledge, hydroxyurea has never been used in malignant pertussis but is a well-known medication for oncologic and hematologic diseases such as acute myeloid leukemia or sickle cell anemia. Its effects in this setting are not well understood but the positive outcome in our patient supports the need for further studies.

Pertussis and Pertussis like Illness: Pediatric Experience in Oman

OBJECTIVES

A resurgence of pertussis or whooping cough has been observed worldwide despite broad vaccination coverage. Pertussis like illness (PLI) refers to a clinical syndrome compatible with pertussis infection but lacking laboratory confirmation or an epidemiological link to a confirmed case. Our study aimed to estimate the contribution of Bordetella pertussis infection and identifying predictors of its diagnosis in a cohort of children with PLI.

METHODS

Demographic and clinical information were retrospectively collected from the medical records of children < 13 years old and hospitalized for PLI in two pediatric units in Oman from 1 January 2012 to 31 December 2013. The laboratory data of all cases were reviewed and confirmed cases of pertussis were identified, analyzed, and compared with non-confirmed cases.

RESULTS

A total of 131 patients were enrolled in this study. The majority (95.4% [125/131]) were infants. Only 54.1% (71/131) of admitted children with PLI were tested for pertussis. The incidence of pertussis infection among the tested group was 16.9% (12/71) with a 95% confidence interval 8.2-25.6. Severe illness occurred in 56.4% (74/131) of patients, and six were confirmed to have pertussis. Pediatric intensive care unit admission was required for one confirmed case of pertussis and eight cases from the PLI group (three were negative for pertussis, and five were not tested). Receiver operator characteristic curve analysis revealed that a white blood cell count ³ 23.5 × 10⁹/L had 96.6% specificity and lymphocytes ³ 17 × 10⁹/L had 98.3% specificity.

CONCLUSIONS

Taking into consideration that the number tested for pertussis was limited, the incidence of pertussis was 16.9% (12 out of 71 patients). Lymphocytosis can be used as a reliable predictor for the diagnosis of pertussis especially in the absence of specific confirmatory tests or until their results are available.

Apnea in the term infant

Whereas apnea of prematurity has been well defined and its pathophysiology extensively studied, apnea in the term infant remains a greater challenge. Unfortunately, clear diagnostic criteria are lacking and pathogenesis and management vary widely. In this review we have arbitrarily organized the discussion chronologically into earlier and later postnatal periods. In the first days of life, presumed apnea may reflect physiologic events such as positional or feeding etiologies, or may be a manifestation of serious pathophysiology, such as a seizure disorder. Beyond the neonatal period, presumed apnea may be characterized as a BRUE event (brief resolved unexplained event; formerly referred to as ALTE: apparent life-threatening event) and most frequently a precipitating event cannot be identified. Medical providers are left with somewhat of a dilemma regarding the need to hospitalize and/or work up such patients.

Increasing Incidence of Life-threatening Pertussis: A Retrospective Cohort Study in New Zealand

BACKGROUND

Pertussis immunization programs aim to prevent severe infant disease. We investigated temporal trends in infant pertussis deaths and pediatric intensive care unit (PICU) admissions and associations of changes in disease detection and vaccines used with death and PICU admission rates.

METHODS

Using national data from New Zealand (NZ), we described infant pertussis deaths and PICU admissions from 1991 to 2013, over which time national immunization coverage at 2 years of age increased from <80% to 92%. In NZ, pertussis became a notifiable disease with polymerase chain reaction (PCR) diagnosis available in 1997 and acellular replaced whole-cell vaccine in 2000. We used Poisson regression to model temporal trends and compared rates in time intervals using rate ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

There were 10 pertussis deaths and 159 infant PICU admissions with pertussis from 1991 to 2013. The annual number of infant pertussis PICU admissions increased from 1991 to 2013 (P = 0.02) but the number of pertussis deaths did not (P = 0.09). The risk of PICU admission during infancy with pertussis was increased in the notification/PCR versus the non-notification/PCR era (RR: 1.12; 95% CI: 1.02-1.19) and when acellular replaced whole-cell vaccine (RR: 1.19; 95% CI: 1.06-1.31). Median Pediatric Index of Mortality scores during 2001-2013 were lower than during 1991-1999 (P < 0.001).

CONCLUSIONS

Infant PICU pertussis admission rates have increased in NZ despite improvements in immunization coverage. Higher rates have occurred since pertussis notification/PCR became available and since acellular replaced whole-cell vaccine. The severity of disease in infants admitted to PICU with pertussis has decreased in recent years.

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.

Identifying Children at Risk of Malignant Bordetella pertussis Infection

OBJECTIVE

To identify factors associated with malignant pertussis.

DESIGN

A retrospective case notes review from January 2003 to August 2013. Area under the receiver-operator characteristic curve was used to determine how well vital sign and white cell characteristics within 48 hours of hospital presentation identified children with malignant pertussis.

SETTING

The national children's hospital in Auckland, New Zealand.

PATIENTS

One hundred fifty-two children with pertussis.

MEASUREMENTS AND MAIN RESULTS

There were 152 children with confirmed pertussis identified, including 11 children with malignant pertussis. The area under the receiver-operator characteristic curve was 0.88 (95% CI, 0.78-0.97) for maximum heart rate. The optimal cut-point was 180 beats/min, which predicted malignant pertussis with a sensitivity of 73% and a specificity of 91%. The area under the receiver-operator characteristic curve was 0.92 (95% CI, 0.81-1.0) for absolute neutrophil count, 0.85 (95% CI, 0.71-0.99) for total WBC count, 0.80 (95% CI, 0.63-0.96) for neutrophil-to-lymphocyte ratio, and 0.77 (95% CI, 0.58-0.92) for absolute lymphocyte count. All children with malignant pertussis had one or more of heart rate greater than 180 beats/min, total WBC count greater than 25 × 10/L, and neutrophil-to-lymphocyte ratio greater than 1.0 with an area under the receiver-operator characteristic curve of 0.96 (95% CI, 0.91-1.0) for a multivariate model that included these three variables.

CONCLUSIONS

Clinical predictors of malignant pertussis are identifiable within 48 hours of hospital presentation. Early recognition of children at risk of malignant pertussis may facilitate early referral to a PICU for advanced life support and selection for trials of investigational therapies.

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.

[Recent progress in clinical research on pertussis]

Pertussis is a highly contagious respiratory disease. Despite the high vaccination coverage, re-emergence of pertussis has been reported in many countries over the past two decades. With the increase in the incidence of pertussis, there has been a shift in the epidemiological features: an increased incidence of pertussis has been noted in older children and adults, who normally lack typical clinical manifestations, and who may be easily missed according to current diagnostic references for pertussis. In order to achieve better prevention and treatment of pertussis, this review article summarized the recent research progress in the epidemiology, clinical features, etiology, diagnosis, treatment, and prevention of pertussis, particularly focusing on the diagnosis of pertussis in older children and adults.

[Recent progress in clinical research on pertussis]

Pertussis is a highly contagious respiratory disease. Despite the high vaccination coverage, re-emergence of pertussis has been reported in many countries over the past two decades. With the increase in the incidence of pertussis, there has been a shift in the epidemiological features: an increased incidence of pertussis has been noted in older children and adults, who normally lack typical clinical manifestations, and who may be easily missed according to current diagnostic references for pertussis. In order to achieve better prevention and treatment of pertussis, this review article summarized the recent research progress in the epidemiology, clinical features, etiology, diagnosis, treatment, and prevention of pertussis, particularly focusing on the diagnosis of pertussis in older children and adults.

Burden and Outcomes of Severe Pertussis Infection in Critically Ill Infants

OBJECTIVES

Despite World Health Organization endorsed immunization schedules, Bordetella pertussis continues to cause severe infections, predominantly in infants. There is a lack of data on the frequency and outcome of severe pertussis infections in infants requiring ICU admission. We aimed to describe admission rates, severity, mortality, and costs of pertussis infections in critically ill infants.

DESIGN

Binational observational multicenter study.

SETTING

Ten PICUs and 19 general ICUs in Australia and New Zealand contributing to the Australian and New Zealand Paediatric Intensive Care Registry.

PATIENTS

Infants below 1 year of age, requiring intensive care due to pertussis infection in Australia and New Zealand between 2002 and 2014.

MEASUREMENTS AND MAIN RESULTS

During the study period, 416 of 42,958 (1.0%) infants admitted to the ICU were diagnosed with pertussis. The estimated population-based ICU admission rate due to pertussis ranged from 2.1/100,000 infants to 18.6/100,000 infants. Admission rates were the highest among infants less than 60 days old (p < 0.0001). Two hundred six infants (49.5%) required mechanical ventilation, including 20 (4.8%) treated with high-frequency oscillatory ventilation, 16 (3.8%) with inhaled nitric oxide, and 7 (1.7%) with extracorporeal membrane oxygenation. Twenty of the 416 children (4.8%) died. The need for mechanical ventilation, high-frequency oscillatory ventilation, nitric oxide, and extracorporeal membrane oxygenation were significantly associated with mortality (p < 0.01). Direct severe pertussis-related hospitalization costs were in excess of USD$1,000,000 per year.

CONCLUSIONS

Pertussis continues to cause significant morbidity and mortality in infants, in particular during the first months of life. Improved strategies are required to reduce the significant healthcare costs and disease burden of this vaccine-preventable disease.

Epidemiology of pertussis-related paediatric intensive care unit (ICU) admissions in Australia, 1997-2013: an observational study

OBJECTIVE

To review the epidemiology of pertussis-related intensive care unit (ICU) admissions across Australia, over a 17-year period.

DESIGN

Retrospective descriptive study.

SETTING

Australian ICUs contributing data to the Australian and New Zealand Paediatric Intensive Care (ANZPIC) Registry. The number of contributing ICUs increased over the study period, from 8 specialist paediatric ICUs in 1997 to 8 specialist paediatric and 13 general ICUs in 2013.

PARTICIPANTS

All paediatric (<16 years) ICU admissions, coded as pertussis-related, between 1 January 1997 and 31 December 2013.

RESULTS

A total of 373 pertussis-coded ICU admissions were identified in the ANZPIC Registry over the study period. Of these cases, 52.8% occurred during the 4 years of the recent Australian epidemic (2009-2012). ICU admissions were most likely to occur in infants aged younger than 6 weeks (41.8%, n=156) and aged 6 weeks to 4 months (42.9%, n=160). The median length of stay for pertussis-related ICU admissions was 3.6 days, with 77.5% of cases staying in ICU for <7 days. Approximately half of all admissions (54.8%) required some form of respiratory support, with 32.7% requiring invasive respiratory support. Over the study period, 23 deaths were recorded (6.2% of pertussis-related ICU admissions), of which 20 (87.0%) were infants <4 months old.

CONCLUSIONS

Pertussis-related ICU admissions occur primarily in infants too young to be fully protected from active immunisation. More needs to be done to protect these high-risk infants, such as maternal immunisation.

Finnish guidelines for the treatment of community-acquired pneumonia and pertussis in children

Evidence-based guidelines are needed to harmonise and improve the diagnostics and treatment of children's lower respiratory tract infections. Following a professional literature search, an interdisciplinary working group evaluated and graded the available evidence and constructed guidelines for the treatment of community-acquired pneumonia and pertussis.

CONCLUSION

The clinical guidelines state that chest radiography is not needed if the child is diagnosed with pneumonia and treated at home. Complications should be considered if there is no improvement after antimicrobial therapy and a paroxysmal cough can indicate pertussis, which is life-threatening in unvaccinated infants and can lead to respiratory failure.

Hospitalizations and deaths due to pertussis in children from 1996 to 2013

OBJECTIVES

To assess temporal trends of hospitalizations and deaths from pertussis in Brazilian children in the period of 1996-2013.

METHODS

This was a descriptive ecological study of temporal trends, based on the DATASUS database. The number of hospitalizations and deaths from pertussis in children up to 19 years of age from January 1996 to December 2013 was obtained. Descriptive statistics were applied for data analysis.

RESULTS

During the study period, a total of 19,047 hospital admissions from pertussis were recorded, of which 88.2% occurred in infants younger than 1 year. In the period 1996-2010, the mean annual number of admissions was 755, ranging from a maximum of 1179 in 2004 to a minimum of 400 in 2010. There was an increase of admissions in the last three consecutive years (2011, 2012, and 2013) with 1177, 2954 and 3589 hospitalizations, respectively. There were 498 deaths from pertussis throughout the study period, of which 96.8% occurred in children younger than one year. There was an increase in the number of deaths from pertussis in children in the years 2011, 2012, and 2013, with 40, 93, and 87 recorded deaths, respectively. The increase in hospitalizations and deaths from pertussis in children occurred in all regions of the country, with the highest increase observed in the Southeast, North and Northeast regions.

CONCLUSIONS

There was a substantial increase in hospitalizations and deaths from pertussis in children for three consecutive years (2011, 2012, and 2013) in all Brazilian regions. The most affected age group was that of children younger than one year.

Highly differentiated human airway epithelial cells: a model to study host cell-parasite interactions in pertussis

BACKGROUND

Bordetella pertussis colonizes the human respiratory mucosa. Most studies on B. pertussis adherence have relied on cultured mammalian cells that lack key features present in differentiated human airway cells or on animal models that are not natural hosts of B. pertussis. The objectives of this work were to evaluate B. pertussis infection in highly differentiated human airway cells in vitro and to show the role of B. pertussis fimbriae in cell adherence.

METHODS

Primary human airway epithelial (PHAE) cells from human bronchi and a human bronchial epithelial (HBE) cell line were grown in vitro under air-liquid interface conditions.

RESULTS

PHAE and HBE cells infected with B. pertussis wild-type strain revealed bacterial adherence to the apical surface of cells, bacteria-induced cytoskeleton changes, and cell detachment. Mutations in the major fimbrial subunits Fim2/3 or in the minor fimbrial adhesin subunit FimD affected B. pertussis adherence to predominantly HBE cells. This cell model recapitulates the morphologic features of the human airway infected by B. pertussis and confirms the role of fimbriae in B. pertussis adherence. Furthermore, HBE cells show that fimbrial subunits, and specifically FimD adhesin, are critical in B. pertussis adherence to airway cells.

CONCLUSIONS

The relevance of this model to study host-parasite interaction in pertussis lies in the striking physiologic and morphologic similarity between the PHAE and HBE cells and the human airway ciliated and goblet cells in vivo. These cells can proliferate in vitro, differentiate, and express the same genetic profile as human respiratory cells in vivo.

Contribution of pertussis toxin to the pathogenesis of pertussis disease

Pertussis toxin (PT) is a multisubunit protein toxin secreted by Bordetella pertussis, the bacterial agent of the disease pertussis or whooping cough. PT in detoxified form is a component of all licensed acellular pertussis vaccines, since it is considered to be an important virulence factor for this pathogen. PT inhibits G protein-coupled receptor signaling through Gi proteins in mammalian cells, an activity that has led to its widespread use as a cell biology tool. But how does this activity of PT contribute to pertussis, including the severe respiratory symptoms of this disease? In this minireview, the contribution of PT to the pathogenesis of pertussis disease will be considered based on evidence from both human infections and animal model studies. Although definitive proof of the role of PT in humans is lacking, substantial evidence supports the idea that PT is a major contributor to pertussis pathology, including the severe respiratory symptoms associated with this disease.

Predictors of disease severity in children hospitalized for pertussis during an epidemic

BACKGROUND

Australia recently experienced its worst pertussis epidemic since introduction of pertussis vaccine into the National Immunisation Program. This study aimed to determine factors associated with severe pertussis in hospitalized children during an epidemic using a novel pertussis severity scoring (PSS) system.

METHODS

This prospective, observational, multicenter study enrolled children hospitalized with laboratory confirmed pertussis from 8 tertiary pediatric hospitals during a 12 month period (May 2009-April 2010). Variables assessed included demographics, clinical symptoms and relevant medical and immunization history. Cases were scored using objective clinical findings with cases classified as either severe (PSS > 5) or not severe (PSS ≤ 5). Logistic regression models were used to predict variables associated with severe disease.

RESULTS

One hundred twenty hospitalized children 0-17 years of age were enrolled with a median PSS of 5 (interquartile range 3-7). Most (61.7%) were classified as not severe with 38.3% (46/120) severe. Most severe cases (54.3%) were <2 months of age. Presence of coinfection [odds ratio (OR): 4.82, CI: 1.66-14.00], <2 months old (OR: 4.76, CI: 1.48-15.32), fever >37.5°C (OR: 5.97, CI: 1.19-29.96) and history of prematurity (OR: 5.00, CI: 1.27-19.71) were independently associated with severe disease. A total of 70 cases in children ≥2 months of age, almost a third (n = 23) had not received pertussis vaccine.

CONCLUSIONS

Most severe pertussis occurred in young, unimmunized infants, although severe disease was also observed in children >12 months of age and previously vaccinated children. Children admitted with pertussis with evidence of coinfection, history of prematurity or fever on presentation need close monitoring.

Association between sudden infant death syndrome and diphtheria-tetanus-pertussis immunisation: an ecological study

BACKGROUND

Sudden infant death syndrome (SIDS) continues to be one of the main causes of infant mortality in the United States. The objective of this study was to analyse the association between diphtheria-tetanus-pertussis (DTP) immunisation and SIDS over time.

METHODS

The Centers for Disease Control and Prevention provided the number of cases of SIDS and live births per year (1968-2009), allowing the calculation of SIDS mortality rates. Immunisation coverage was based on (1) the United States Immunization Survey (1968-1985), (2) the National Health Interview Survey (1991-1993), and (3) the National Immunization Survey (1994-2009). We used sleep position data from the National Infant Sleep Position Survey. To determine the time points at which significant changes occurred and to estimate the annual percentage change in mortality rates, we performed joinpoint regression analyses. We fitted a Poisson regression model to determine the association between SIDS mortality rates and DTP immunisation coverage (1975-2009).

RESULTS

SIDS mortality rates increased significantly from 1968 to 1971 (+27% annually), from 1971 to 1974 (+47%), and from 1974 to 1979 (+3%). They decreased from 1979 to 1991 (-1%) and from 1991 to 2001 (-8%). After 2001, mortality rates remained constant. DTP immunisation coverage was inversely associated with SIDS mortality rates. We observed an incidence rate ratio of 0.92 (95% confidence interval: 0.87 to 0.97) per 10% increase in DTP immunisation coverage after adjusting for infant sleep position.

CONCLUSIONS

Increased DTP immunisation coverage is associated with decreased SIDS mortality. Current recommendations on timely DTP immunisation should be emphasised to prevent not only specific infectious diseases but also potentially SIDS.

Whooping cough in 2014 and beyond: an update and review

Pertussis, or whooping cough, has had a dramatic resurgence in the past several years and is the most common vaccine-preventable disease in the world. The year 2012 marked the most cases in the United States in &gt; 50 years. Large outbreaks have occurred in multiple states, and infant deaths have drawn the attention of not only health-care providers but also the media. Although the disease is theoretically preventable by vaccination, it remains a challenge to control. New vaccination strategies have been implemented across different age groups and populations of patients, but vaccine coverage remains dismally low. Acellular vaccines, although safe, do not afford the same long-lasting immunity as the previously used whole-cell vaccine. Ultimately, improvements in the development of vaccines and in vaccination coverage will be essential to decrease the burden of pertussis on society. This article provides a review of pertussis infection and discusses advances related to the epidemiology, diagnosis, treatment, and prevention of infection, as well as continued areas of uncertainty.

Predictors of Mortality in Mechanically Ventilated Critical Pertussis in a low Income Country

BACKGROUND

Critical pertussis is characterized by severe respiratory failure, important leukocytosis, pulmonary hypertension, septic shock and encephalopathy.

AIM

To describe the clinical course of critical pertussis, and identify predictors of death at the time of presentation for medical care.

METHODOLOGY

Retrospective study conducted in children's hospital Tunisian PICU between 01 January and 31 October 2013. Patients with critical pertussis confirmed by RT-PCR and requiring mechanical ventilation were included. Predictors of death were studied.

RESULTS

A total of 17 patients was studied. Median age was 50 days. Mortality was 23%. Predictors risk of mortality were : high PRISM score (Pediatric Risk of Mortality Score) (p=0,007), shock (p=0,002), tachycardia (p=0,005), seizures (p=0,006), altered mental status (p=0,006), elevated WBC count (p=0,003) and hemodynamic support (p=0022). However, the difference did not reach statistical significance in comorbidity, pneumoniae, high pulmonary hypertension or exchange transfusion. Concomitant viral or bacterial co-infection was not related to poor outcome.

CONCLUSION

Young infants are at high risk to have critical pertussis. Despite advances in life support and the treatment of organ failure in childhood critical illness, critical pertussis remains difficult to treat.

Critical pertussis illness in children: a multicenter prospective cohort study

OBJECTIVE

Pertussis persists in the United States despite high immunization rates. This report characterizes the presentation and acute course of critical pertussis by quantifying demographic data, laboratory findings, clinical complications, and critical care therapies among children requiring admission to the PICU.

DESIGN

Prospective cohort study.

SETTING

Eight PICUs comprising the Eunice Kennedy Shriver National Institute for Child Health and Human Development Collaborative Pediatric Critical Care Research Network and 17 additional PICUs across the United States.

PATIENTS

Eligible patients had laboratory confirmation of pertussis infection, were younger than 18 years old, and died in the PICU or were admitted to the PICU for at least 24 hours between June 2008 and August 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 127 patients were identified. Median age was 49 days, and 105 (83%) patients were less than 3 months old. Fifty-five (43%) patients required mechanical ventilation and 12 patients (9.4%) died during initial hospitalization. Pulmonary hypertension was found in 16 patients (12.5%) and was present in 75% of patients who died, compared with 6% of survivors (p < 0.001). Median WBC was significantly higher in those requiring mechanical ventilation (p < 0.001), those with pulmonary hypertension (p < 0.001), and nonsurvivors (p < 0.001). Age, sex, and immunization status did not differ between survivors and nonsurvivors. Fourteen patients received leukoreduction therapy (exchange transfusion [12], leukopheresis [1], or both [1]). Survival benefit was not apparent.

CONCLUSIONS

Pulmonary hypertension may be associated with mortality in pertussis critical illness. Elevated WBC is associated with the need for mechanical ventilation, pulmonary hypertension, and mortality risk. Research is indicated to elucidate how pulmonary hypertension, immune responsiveness, and elevated WBC contribute to morbidity and mortality and whether leukoreduction might be efficacious.

Characteristics of Severe Bordetella pertussis Infection Among Infants ≤90 Days of Age Admitted to Pediatric Intensive Care Units - Southern California, September 2009-June 2011

BACKGROUND

Bordetella pertussis infection can cause severe illness and death among young infants.

METHODS

We collected demographic and clinical information from the medical records of infants who were ≤90 days of age and hospitalized for pertussis in 5 Southern California pediatric intensive care units (PICUs) from September 1, 2009 to June 30, 2011. Infants who died or were diagnosed with pulmonary hypertension were considered to have more severe pertussis.

RESULTS

Thirty-one infants were admitted to a participating PICU. Eight infants had more severe infections, 6 infants had pulmonary hypertension, and 4 infants died. The 8 infants with more severe infections had white blood cell counts that exceeded 30 000, heart rates that exceeded 170, and respiratory rates that exceeded 70 more rapidly after cough onset than the 23 infants with less severe illness.

CONCLUSIONS

Identifying higher-risk infants earlier might allow for more rapid implementation of interventions.

Leukoreduction in patients with severe pertussis with hyperleukocytosis

When pertussis is associated with hyperleukocytosis, mortality approaches to 80%. Immature leukocytes have been identified in pulmonary arterioles, small arteries and venules. Techniques aimed at reducing leukocyte mass might improve the prognosis of these patients. We report our experience with 3 patients in whom a leukoreduction was performed in the context of severe pertussis and hyperleukocytosis.

Pertussis in infancy and the association with respiratory and cognitive disorders at toddler age

Pertussis in unvaccinated infants can run a severe course and is often accompanied by complications. In this pilot study, we studied whether there is an association between pertussis hospitalisation in infancy and, respiratory symptoms, growth and cognitive development in early childhood. A group of 89 children aged 13-45 months and hospitalised for laboratory confirmed pertussis within the first six months of their life were compared with 172 children without a history of pertussis. Risk ratios (RR) with 95% confidence intervals (CI) of the association between health outcomes and pertussis in infancy were calculated. Weight-for-length and length-for-age z-scores were calculated to investigate growth. Van Wiechen scores were compared to study cognitive development. Children with a history of pertussis in infancy had a greater chance on "asthma symptoms" (RR 2.8 95%CI 1.1-7.0) on toddler age and were more likely to report "respiratory infections" (RR 3.3 95%CI 1.6-6.6). In addition, children with a history of pertussis in infancy had significantly lower weight-for-height in the first 40 months of life. No significant differences in cognitive development were found. We found an association between severe pertussis in infancy and respiratory symptoms on toddler age. The mechanisms that may underlie this association require further investigation.