Clinical and laboratory features of pertussis in hospitalized infants with confirmed versus probable pertussis cases

Burden of pertussis in infants in the Eastern Mediterranean Region and the impact of maternal vaccination: a systematic review

BACKGROUND

Despite vaccine availability, Pertussis remains a global public health challenge, especially among infants. The Eastern Mediterranean Region (EMR) presents a diverse epidemiological landscape with varying vaccination coverages and healthcare infrastructures. This systematic review aimed to assess the burden of pertussis in infants < 1 year of age in the EMR and evaluate the use and impact of pertussis vaccination during pregnancy.

METHODS

Following PRISMA guidelines, we conducted a systematic search of Scopus, Embase, CINAHL Ultimate, and PubMed from inception until April 30, 2024. Studies included reported on pertussis burden in infants or maternal vaccination. Data extraction and quality assessment were performed in duplicate, focusing on incidence, age distribution, disease severity, and vaccination uptake and impact when data were available.

RESULTS

Thirty-six studies were included, the majority from Iran (N = 11), Morocco (N = 5), Tunisia (N = 5), and Oman (N = 3), with underrepresentation of other EMR countries. The incidence of PCR-confirmed pertussis among children with suspected pertussis varied significantly, from 6.7% to 8.9% (Morocco 2018-2019) to 50.4% and 51.6% (Palestine 2004-2008) among children < 12 and < 6 months, respectively, and between 16.3% (Tunisia 2007-2016) to 73.0% (Morocco 2013-2015) in children < 2 months. Age distribution data indicated the highest burden was in infants < 2 months regardless of the population studied. High hospitalization rates and severe complications, including seizures and the need for ventilatory support, were frequently reported in infants < 6 months of age. Only one study from Saudi Arabia addressed maternal pertussis vaccination, reflecting low vaccine uptake and awareness among pregnant women.

CONCLUSIONS

This review underscores the substantial burden of pertussis among infants in the EMR and the lack of data on maternal immunization. The findings emphasize the need for enhanced surveillance and targeted public health interventions to reduce disease incidence. Future research should prioritize underrepresented countries to ensure comprehensive data for informed public health strategies.

TRIAL REGISTRATION

PROSPERO (CRD42024573471).

Prevalence and Outpatient Clinical Diagnostic Approaches for Common Acute Respiratory Tract Infections in Children Under Five Years of Age: A Cross-Sectional Study

Background

Acute respiratory tract infections are among the leading causes of child morbidity and mortality worldwide. Although the diagnosis of acute respiratory tract infections requires simple outpatient medical techniques and care, it is still misdiagnosed among primary care physicians, leading to delayed treatment and increased mortality. This study described the prevalence of common acute respiratory tract infections and simple techniques that effectively detect and diagnose children presenting with acute respiratory symptoms to primary healthcare physicians in remote settings.

Patients and Methods

This descriptive cross-sectional study was conducted at the pediatric outpatient clinic of a tertiary hospital in western Uganda in April, May and June 2019. A total of 896 children aged 2-59 months attending the clinic were recruited consecutively into the study and examined for the presence of acute respiratory infection. Participants' sociodemographic and clinical data were collected through history taking and clinical examination using a validated Uganda Ministry of Health Uganda outpatient clinical checklist (FORM 5). The outcome variable was the presence of an acute upper or lower respiratory condition. Data was analyzed using STATA version 13.0 (StataCorp, College Station, USA) and summarized using descriptive statistics.

Results

The overall period prevalence of acute respiratory tract infections among children aged 2 to 59 months was 36.9% (36,942 per 100,000 population). Upper respiratory tract infections with a prevalence of 24.8% were more common than lower respiratory tract infections. The most frequent upper respiratory tract infection in this setting was common cold (52%), followed by tonsillopharyngitis (10.7%), while pneumonia (26%) was the most frequent lower respiratory tract infection.

Conclusion

Acute respiratory tract infections contribute to the high burden of disease in pediatric outpatient clinics. Simple, affordable, and approved diagnostic clinical techniques that involve physical examination of the upper and lower respiratory systems can precisely diagnose acute respiratory tract infections in resource-limited settings where there is no access to sophisticated diagnostic equipment.

Metagenomics next-generation sequencing assists in the diagnosis of infant pertussis encephalopathy: A case report

RATIONALE

Pertussis is an acute respiratory infection that often occurs in the pediatric population, especially in infants under 3 months old. Bordetella pertussis is the causative agent of pertussis, which can lead to pneumonia, encephalopathy, and pulmonary hypertension, causing death in severe cases. Therefore, an accurate and comprehensive diagnosis of the pathogen is essential for effective treatment.

PATIENT CONCERNS

We report a case of 2-month-old male infant admitted to the pediatric intensive care unit of West China Second University due to hoarse cough for 7 days, accompanied by a crowing-like echo, fever and listlessness, occasional nonprojectile vomiting with anorexia, shortness of breath, accelerated heart rate, cyanosis of the lips, and convulsions. B pertussis was identified by metagenomic next-generation sequencing in blood and cerebrospinal fluid and polymerase chain reaction assay using blood.

DIAGNOSES

The infant was diagnosed with pertussis.

INTERVENTIONS

Intravenous infusion of erythromycin (50 mg/kg/d) for anti-infection and dexamethasone for alleviating intracranial inflammatory reaction were given.

OUTCOMES

The patient was eventually recovered and discharged.

LESSONS

This case report emphasized the importance of metagenomic next-generation sequencing using cerebrospinal fluid and blood for early diagnosis of pertussis-associated encephalopathy.

The role of Bordetella pertussis in the development of multiple sclerosis

Background

Multiple sclerosis (MS) is one of the most common neurological disorders which main cause is not identified yet. Some studies mentioned the possible role of infectious agents such as chlamydia pneumonia, mycoplasma and also, B. pertussis via asymptomatic nasopharyngeal colonization. The current study aimed to investigate and compared the serum level of B. pertussis antibody and the rate of nasopharyngeal colonization by this pathogen in subjects with and without MS.

Methods

In this case-control study, 109 patients with MS and 114 subjects without MS referred to Sina Hospital in Hamadan in 2019 are studied and compared in terms of serum titer of B. pertussis antibody and nasopharyngeal colonization by this bacterium. Colonization was evaluated using culture and real-time PCR techniques. Data were analyzed using SPSS version 16 with a 95% confidence interval.

Results

The serum titer of B. pertussis antibody in case and control groups was 37.8 and 35.1%, respectively (P = 0.74). Culture and real-time PCR techniques revealed no case of nasopharyngeal colonization by B. pertussis.

Conclusion

There was no difference between B. pertussis antibody titer and the rate of nasopharyngeal colonization between both MS patients and the healthy control group. Therefore, it seems that probably B. pertussis has not a role in MS development.

Hospital-based prospective study of pertussis in infants and close contacts in Tehran, Iran

Background

Pertussis remain a global health concern, especially in infants too young to initiate their vaccination. Effective vaccination and high coverage limit the circulation of the pathogen, yet duration of protection is limited and boosters are recommended during a lifetime. In Iran, boosters are given at 18 months and 6 years old using whole pertussis vaccines for which efficacy is not known, and pertussis surveillance is scant with only sporadic biological diagnosis. Burden of pertussis is not well understood and local data are needed.

Methods

Hospital-based prospective study implementing molecular laboratory testing in infants aged ≤6 months and presenting ≥5 days of cough associated to one pertussis-like symptom in Tehran. Household and non-household contact cases of positive infants were evaluated by comprehensive pertussis diagnosis (molecular testing and serology) regardless of clinical signs. Clinical evaluation and source of infection were described.

Results

A total of 247 infants and 130 contact cases were enrolled. Pertussis diagnosis result was obtained for 199 infants and 104 contact cases. Infant population was mostly < 3 months old (79.9%; 157/199) and unvaccinated (62.3%; 124/199), 20.1% (40/199) of them were confirmed having B. pertussis infection. Greater cough duration and lymphocyte counts were the only symptoms associated to positivity. Half of the contact cases (51.0%; 53/104) had a B. pertussis infection, median age was 31 years old. A proportion of 28.3% (15/53) positive contacts did not report any symptom. However, 67.9% (36/53) and 3.8% (2/53) of them reported cough at inclusion or during the study, including 20.8% (11/53) who started coughing ≥7 days before infant cough onset. Overall, only five samples were successfully cultured.

Conclusion

These data evidenced the significant prevalence of pertussis infection among paucy or poorly symptomatic contacts of infants with pertussis infection. Widespread usage of molecular testing should be implemented to identify B. pertussis infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06266-6.

Pertussis-like syndrome often not associated with Bordetella pertussis: 5-year study in a large children's hospital

Background: Recently, a resurgence of pertussis has been observed worldwide despite broad vaccination coverage. The purpose of this study was to identify the clinical characteristics and the aetiological agent of pertussis-like syndrome (PLS) in Eastern China.Methods: 1168 patients who were diagnosed with a suspected Bordetella pertussis in Shanghai Children's Hospital from 2013 to 2017 were included in the study. Clinical features and aetiologies were analysed. Aetiological analyses in sub-cohorts of age, seasons and years were also investigated.Results: 96.0% (1121) of the patients were less than 12 months old. 59.0% (689) of the patients were male. The Top 5 pathogens were respiratory syncytial virus (RSV; n = 125; 10.7%), Streptococcus pneumonia (SP; n = 109; 9.3%), Haemophilus influenzae type b (HIB; n = 86; 7.4%), Bordetella pertussis (B. pertussis; n = 84; 7.2%), and Mycoplasma pneumonia (MP; n = 80; 6.9%), respectively. The percentage of SP in the age group of 0-3 months was significantly lower than that in other age groups. The percentage of B. pertussis in the age group of 3-6 months was significantly lower than that in the group of 6-12 months. The percentage of MP in 0-3 months' group was significantly lower than that in >12 months group. RSV peaked in winter (n = 52), while HIB peaked in spring (n = 38).Conclusion: PLS occurred most often in infants. RSV, SP, HIB, B. pertussis, and MP were the most prevalent pathogens. Since patients with B. pertussis and other pathogens have similar clinical manifestations, diagnosis of pertussis should be based on both clinical symptoms and laboratory confirmation.

Pathogen analysis of pertussis-like syndrome in children

Background

The aim of the study was to identify the pathogens, in addition to bordetella pertussis (B. pertussis), which cause pertussis-like syndrome in children and to compare clinical presentation between those with B. pertussis and pertussis-like syndrome.

Methods

A cross-sectional analysis was conducted from March 2016 to September 2018. In total, 281 children with suspected pertussis infections were enrolled in this study. Multi-pathogen detection was performed.

Results

In total, 281 children were enrolled including 139 males and 142 females. Among them, 149 (53.0%) were B. pertussis positive, and 72 (15.6%) children tested positive for other pathogens. Mycoplasma pneumoniae (MP, 27 cases) was the most common causative pathogen in pertussis-like syndrome, followed by human rhinovirus (HRV, 23 cases), Streptococcus pneumoniae (SP, 13 cases), Haemophilus influenzae (HI, 12 cases) and parainfluenza virus 3 (Pinf-3, 9 cases). Children in the B. pertussis group had a higher rate of vaccination and longer hospital stay (P < 0.05). B. pertussis was more likely to be detected in winter than other pathogens, but this difference was not significant (P = 0.074). The number of white blood cells, neutrophils and blood platelets was significantly higher in children in the B. pertussis than in the pertussis-like group (P < 0.05). In addition, the percentage of CD3-CD19+ cells was significantly higher in the B. pertussis group (P = 0.018).

Conclusion

About half of the children with pertussis-like syndrome were B. pertussis positive. MP was the second most common causative pathogen followed by HRV, SP, HI and Pinf-3. Children infected with B. pertussis had longer hospital stay and higher numbers of white blood cells, neutrophil and blood platelets compared with other pathogens.

Genomic epidemiology of Iranian Bordetella pertussis: 50 years after the implementation of whole cell vaccine

Pertussis caused by Bordetella pertussis, remains a public health problem worldwide, despite high vaccine coverage in infants and children in many countries. Iran has been using whole cell vaccine for the last 50 years with more than 95% vaccination rate since 1988 and has experienced pertussis resurgence in recent years. Here, we sequenced 55 B. pertussis isolates mostly collected from three provinces with the highest number of pertussis cases in Iran, including Tehran, Mazandaran, and Eastern-Azarbayjan from the period of 2008-2016. Most isolates carried ptxP3/prn2 alleles (42/55, 76%), the same genotype as isolates circulating in acellular vaccine-administrating countries. The second most frequent genotype was ptxP3/prn9 (8/55, 14%). Only three isolates (5%) were ptxP1. Phylogenetic analysis showed that Iranian ptxP3 isolates can be divided into eight clades (Clades 1-8) with no temporal association. Most of the isolates from Tehran grouped together as one distinctive clade (Clade 8) with six unique single nucleotide polymorphisms (SNPs). In addition, the prn9 isolates were grouped together as Clade 5 with 12 clade-supporting SNPs. No pertactin deficient isolates were found among the 55 Iranian isolates. Our findings suggest that there is an ongoing adaptation and evolution of B. pertussis regardless of the types of vaccine used.

Identification of etiologic agents and clinical characteristics for patients suspected of having pertussis in a large Children's Hospital in China

BACKGROUND

In China, pertussis is a major health problem with an increasing incidence despite immunization efforts. Timely and accurate diagnosis is essential for the optimal management of pertussis, especially in severe cases.

METHODS

Nasopharyngeal swabs or sputum specimens were obtained from patients suspected of having pertussis on the day of hospitalization at Shanghai Children's Medical Center from December 01, 2016, to November 30, 2017. The specimens were tested with the FilmArray Respiratory Panel, a multiplex polymerase chain reaction (PCR) assay that detects 16 viruses, Bordetella pertussis (B. pertussis), Mycoplasma pneumoniae (M. pneumoniae), and Chlamydophila pneumoniae (C. pneumoniae).

RESULTS

Among the 140 children studied, 50.0% (70/140) were detected with a single pathogen, 45.0% (63/140) were detected with multiple pathogens, and 5.0% (7/140) had no detected pathogens. Forty-nine (35%, 49/140) patients tested positive for B. pertussis. Respiratory syncytial virus (RSV), parainfluenza virus (Para) and rhinovirus/enterovirus (Rhino/Entero) were the most prevalent pathogens in patients with pertussis-like syndrome. No significant differences between the groups with pertussis and pertussis-like syndrome were observed regarding the clinical symptoms. Severe cases were more frequently observed in unvaccinated, premature and pertussis/RSV co-infection patients.

CONCLUSIONS

Our study highlights the importance of the timely and accurate diagnosis of pertussis based on both clinical symptoms and laboratory methods.

Pertussis clinical case definition: Time for change in developing countries?

Background

Developing countries still struggle with late detection and mortality from pertussis. A review of clinical case definitions is necessary for early disease detection. This paper aimed to study possible clinical characteristics for earlier pertussis detection in a sporadic setting.

Methods

We conducted a retrospective review of medical and laboratory records in a general paediatric ward of a district hospital in a developing country. Inclusion criteria were all children hospitalised with nasopharyngeal swab taken for Bordetella pertussis. We compared sensitivity and specificity of World Health Organization diagnostic criteria with other clinical characteristics. Polymerase chain reaction Bordetella pertussis was the gold standard used.

Results

Out of 207 eligible admissions, the study retrieved 128 complete records. Approximately half of the children were less than 3 months old. The World Health Organization diagnostic criteria had a low sensitivity (15%), but high specificity (92%). In comparison, combinations that included paroxysmal cough, ill contact and facial congestion had higher sensitivity. Increasing cough duration improved specificity while compromising sensitivity.

Conclusion

Several clinical characteristics such as paroxysmal cough, facial congestion and a history of ill contact have potential for early clinical detection. Conventional emphasis on cough duration may hamper early detection.

Role of Evolutionary Selection Acting on Vaccine Antigens in the Re-Emergence of Bordetella Pertussis

Pertussis (“whooping cough”) is a re-emerging disease with increasing incidence among fully vaccinated individuals. We explored the genetic diversity of five Bordetella pertussis proteins used to generate the subunit vaccine across ancestral and newly emergent strains using immunoinformatics and evolutionary selection measurements. The five subunits of pertussis toxin (Ptx1–Ptx5) were highly conserved with regard to sequence, predicted structure, predicted antigenicity, and were under purifying selection. In contrast, the adhesin proteins pertactin (Prn) and filamentous hemagglutinin (FHA) were under statistically significant (p < 0.01) diversifying selection. Most heavily diversified sites of each protein fell within antigenic epitopes, and the functional adhesin motifs were conserved. Protein secondary structure was conserved despite sequence diversity for FHA but was changeable in Prn. These findings suggest that subunit vaccine-derived immunity does not impact Ptx1–Ptx5 but may apply evolutionary pressure to Prn and FHA to undergo diversifying selection. These findings offer further insight into the emergence of vaccine-resistant strains of B. pertussis.

Pertussis: New preventive strategies for an old disease

In the last twenty years, despite high vaccination coverage, epidemics of pertussis are occurring in both developing and developed countries. Many reasons could explain the pertussis resurgence: the increasing awareness of the disease, the availability of new diagnostic tests with higher sensitivity, the emergence of new Bordetella pertussis (B. pertussis) strains different from those contained in the current vaccines, the asymptomatic transmission of B. pertussis in adolescents and adults and the shorter duration of protection given by the acellular pertussis (aP) vaccine. New preventive strategies have already been implemented, such as booster doses of aP vaccine in adolescents and adults, maternal immunisation during pregnancy and the "cocooning" strategy, but more are still needed. Knowing what is new about this old disease is necessary to reduce its incidence and to protect infants too young to be vaccinated, which have the highest risk of complications and death.

Diversity of upper respiratory tract infections and prevalence of Streptococcus pneumoniae colonization among patients with fever and flu-like symptoms

BACKGROUND

Many upper respiratory pathogens cause similar symptoms. In China, routine molecular tests for upper respiratory pathogens are not widely performed and antibiotics abuse in treating upper respiratory tract infections (URTIs) is a major public health concern.

METHODS

We performed qualitative real-time PCR tests to detect common upper respiratory tract pathogens including 9 viruses and 3 bacteria in 1221 nasopharyngeal swabs from patients with fever and influenza-like symptoms in a Chinese city. A quantitative real-time PCR was also performed to measure the bacterial density of the colonizing Streptococcus pneumoniae in these samples.

RESULTS

We found very diverse pathogens including 81.7% viruses, 11.6% bacteria and 6.7% mixed viruses and bacteria. S. pneumoniae colonization was found in 8.0% of the cases but most of them had low bacterial density (Mean = 3.9 log cfu/ml). We also discovered an increase of S. pneumoniae colonization frequency (but not the density) in patients with detectable upper respiratory tract pathogens, in a pathogen variety-dependent manner.

CONCLUSIONS

Our study provided strong evidence against empiric antibiotic use for treating URTIs, and highlighted a strong need for improving the diagnostic capacity for URTIs by using more molecular testing in China.

Identification of Etiologic Agents of the Pertussis-like Syndrome in Children by Real-time PCR Method

The aim of this study was to recognize the identity and frequency of etiologic agents of the pertussis-like syndrome in children &lt; 2 years of age. A cross-sectional hospital-based study conducted from August 2014 to August 2015. All children &lt; 2 years of age (n=100) who were suspected as pertussis infected were enrolled in this study and tested for Bordetella pertussis, adenovirus (Adv), respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and influenza virus A (INF-A) by real-time PCR technique. RSV was the most detected pathogen (20%), followed by B. pertussis (18%), Adv (16%), INF-A (11%), and hMPV (10%). Co-infection was observed in 8 patients (11%) and the combinations of RSV/INF-A (n=3, 4%), and AdV/B. pertussis (n=3, 4%) were more frequent. RSV, B. pertussis, and hMPV were more frequent pathogens among infants &lt; 4 months of age. However, Adv and INF-A were more frequent pathogens among children &gt; 6 months of age. In this study, RSV was the most frequent identified pathogen (n=20, 20%), followed by B. pertussis (n=18, 18%) and AdV (n=16, 16%). Pertussis was more frequent in spring (8%) and summer (6%). In addition, clinical symptoms of pertussis were the same as some viral pathogens, which can lead to misdiagnosis of infection. Therefore, diagnosis of pertussis should be established on the bases of both the clinical symptoms and the laboratory methods.

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.

Bordetella pertussis

Pertussis is a highly infectious vaccine-preventable cough illness that continues to be a significant source of morbidity and mortality around the world. The majority of human illness is caused by Bordetella pertussis, and some is caused by Bordetella parapertussis. Bordetella is a Gram-negative, pleomorphic, aerobic coccobacillus. In the past several years, even countries with high immunization rates in early childhood have experienced rises in pertussis cases. Reasons for the resurgence of reported pertussis may include molecular changes in the organism and increased awareness and diagnostic capabilities, as well as lessened vaccine efficacy and waning immunity. The most morbidity and mortality with pertussis infection is seen in infants too young to benefit from immunization. Severe infection requiring hospitalization, including in an intensive care setting, is mostly seen in those under 3 months of age. As a result, research and public health actions have been aimed at better understanding and reducing the spread of Bordetella pertussis. Studies comparing the cost benefit of cocooning strategies versus immunization of pregnant women have been favorable towards immunizing pregnant women. This strategy is expected to prevent a larger number of pertussis cases, hospitalizations, and deaths in infants <1 year old while also being cost-effective. Studies have demonstrated that the source of infection in infants usually is a family member. Efforts to immunize children and adults, in particular pregnant women, need to remain strong.

Clinical Characteristics of Pertussis-Associated Cough in Adults and Children: A Diagnostic Systematic Review and Meta-Analysis

BACKGROUND

Pertussis (whooping cough) is a highly infective cause of cough that causes significant morbidity and mortality. Existing case definitions include paroxysmal cough, whooping, and posttussive vomiting, but diagnosis can be difficult. We determined the diagnostic accuracy of clinical characteristics of pertussis-associated cough.

METHODS

We systematically searched CINAHL, Embase, Medline, and SCI-EXPANDED/CPCI-S up to June 2016. Eligible studies compared clinical characteristics in those positive and negative for Bordetella pertussis infection, confirmed by laboratory investigations. Two authors independently completed screening, data extraction, and quality and bias assessments. For each characteristic, RevMan was used to produce descriptive forest plots. The bivariate meta-analysis method was used to generate pooled estimates of sensitivity and specificity.

RESULTS

Of 1,969 identified papers, 53 were included. Forty-one clinical characteristics were assessed for diagnostic accuracy. In adult patients, paroxysmal cough and absence of fever have a high sensitivity (93.2% [CI, 83.2-97.4] and 81.8% [CI, 72.2-88.7], respectively) and low specificity (20.6% [CI, 14.7-28.1] and 18.8% [CI, 8.1-37.9]), whereas posttussive vomiting and whooping have low sensitivity (32.5% [CI, 24.5-41.6] and 29.8% [CI, 8.0-45.2]) and high specificity (77.7% [CI, 73.1-81.7] and 79.5% [CI, 69.4-86.9]). Posttussive vomiting in children is moderately sensitive (60.0% [CI, 40.3-77.0]) and specific (66.0% [CI, 52.5-77.3]).

CONCLUSIONS

In adult patients, the presence of whooping or posttussive vomiting should rule in a possible diagnosis of pertussis, whereas the lack of a paroxysmal cough or the presence of fever should rule it out. In children, posttussive vomiting is much less helpful as a clinical diagnostic test.

Underdetection and underreporting of pertussis in children attended in primary health care centers: Do surveillance systems require improvement?

BACKGROUND

Pertussis is an underestimated disease. Several European countries have developed models to account for underreporting of pertussis. The aim of this study was to estimate pertussis underdetection and underreporting in pediatric patients attending primary health care centers (PHCCs).

METHODS

We reviewed clinical records of PHCCs in Barcelona in 2012. Factors associated with underdetection and underreporting were analyzed by logistic regression. Adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

We included 3,505 children aged < 7 years (mean age, 34  ±  20.7 months; range, 0-82 months) presenting with cough; 9.3% (326 out of 3,505) of patients also had ≥ 1 symptoms related to pertussis accompanied by cough for a duration ≥ 2 weeks. Of the 326 children receiving clinical criteria, only 31 (9.5%) were laboratory-confirmed and 6 (1.8%) were detected but not reported. There were 295 (90.5%) undetected suspected pertussis cases. Age ≥ 18 months (aOR, 8.51; 95% CI, 1.82-39.86), cyanosis (aOR, 6.71; 95% CI, 1.43-31.39), request for chest radiograph (aOR, 0.26; 95% CI, 0.07-0.99), and request for other laboratory tests (aOR, 5.39; 95% CI, 2.19-13.27) were associated with underdetection. Paroxysmal cough (aOR, 5.77; 95% CI, 1.05-31.76) and request for other laboratory tests (aOR, 2.91; 95% CI, 1.11-7.62) were associated with underreporting.

CONCLUSIONS

Both underdetection and underreporting complicate the understanding of pertussis epidemiology. Correct assessment of pertussis symptoms and notification of cases must be improved to control pertussis.

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 diagnosis: the limitation of the currently used criteria and the suggestion of Global Pertussis Initiative]

It has been recognized that pertussis is a disease that affects all age groups. There are obvious limitations in the currently used diagnostic criteria with "one-size-fits-all" definition, which is not advantageous to start individual treatment and perform strategies for preventing the transmission. Therefore, the expert group of Global Pertussis Initiative gives a suggestion for the diagnosis of pertussis. Based on the related published studies, the present article analyzes the limitations of the current criteria, and introduces the GPI's suggestion in detail.

Pertussis in infants: an underestimated disease

BACKGROUND

The clinical diagnosis of pertussis is not easy in early infancy since clinical manifestations can overlap with several different diseases. Many cases are often misclassified and underdiagnosed. We conducted a retrospective study on infants to assess how often physicians suspected pertussis and the actual frequency of Bordetella pertussis infections.

METHODS

We analyzed all infants with age ≤90 days hospitalized from March 2011 until September 2013 for acute respiratory symptoms tested with a Real Time Polymerase Chain Reaction able to detect Bordetella pertussis and with a Real Time Polymerase Chain Reaction for a multipanel respiratory virus. Therefore, we compared patients with pertussis positive aspirate, patients with respiratory virus positive aspirate and patients with negative aspirate to identify symptoms or clinical findings predictive of pertussis.

RESULTS

Out of 215 patients analyzed, 53 were positive for pertussis (24.7 %), 119 were positive for respiratory virus (55.3 %) and 43 had a negative aspirate (20 %). Pertussis was suspected in 22 patients at admission and 16 of them were confirmed by laboratory tests, while 37 infants with different admission diagnosis resulted positive for pertussis. The sensitivity of clinical diagnosis was 30.2 % and the specificity 96.3 %. Infants with pertussis had more often paroxysmal cough, absence of fever and a higher absolute lymphocyte count than infants without pertussis.

CONCLUSIONS

Pertussis is a serious disease in infants and it is often unrecognized; some features should help pediatricians to suspect pertussis, but clinical suspicion has a low sensitivity. We suggest a systematic use of Real Time Polymerase Chain Reaction to support the clinical suspicion of pertussis in patients with less than 3 months of age hospitalized with acute respiratory symptoms.

Old Disease and New Challenges: Major Obstacles of Current Strategies in the Prevention of Pertussis

Context

Universal immunization against Bordetella pertussis has partially controlled the burden of the disease and its transmission. However, according to recent data, the epidemiology of this vaccine-preventable disease has changed. Now, younger infants, adolescents, and adults are at greater risk of infection. This article has studied the interaction between the various factors involved in the changing epidemiology of pertussis and the major obstacles faced by the current strategies in its prevention.

Evidence Acquisition

In this narrative review, the most recently published sources of information on pertussis control measures, consisting of textbooks and articles, have been reviewed. We focused on the more recent data about the changing epidemiology or pertussis in Scopus through the use of the MeSH-term words [pertussis] or [whooping cough] and [epidemiology] or [outbreak] or [resurgence], but our search was not restricted to this particular strategy; we also tried to find all of the most recent available data in the general field through other means.

Results

Primary and booster doses of the pertussis vaccine seem to partially control transmission of the disease, but despite the different preventive strategies available, pertussis continues to cause mortality and morbidity among high-risk groups.

Conclusions

Adding booster doses of acellular pertussis vaccine to the current national immunization practices with whole-cell vaccines for young adults and pregnant women seems to be a good option for controlling mortality and morbidity among high-risk groups such as very young infants.

Pertussis: the resurgence of a public health threat

Pertussis is an acute and very contagious pulmonary disease, clinically characterized by periods of coughing and paroxysms that may cause death. The disease afflicts mainly the pediatric population and is life threatening to children under the age of 1 year. Since the beginning of the second millennium, the number of cases of pertussis has increased, menacing public health, despite the availability of the pertussis vaccine. The resurgence of the disease among adults and older children creates a reservoir of infection that will afflict the unimmunized or incompletely immunized children. As newborns and infants show the highest mortality rate, immunization during pregnancy is a new strategy to reduce the burden of pertussis. The authors report the case of a newborn that presented respiratory distress accompanied by marked leukocytosis. Bronchiolitis was the initial diagnostic hypothesis, but the clinical picture became typical of pertussis when paroxysmal coughing ensued. Isolation of the Bordetella pertussis and antigenic demonstration by polymerase chain reaction were positive from respiratory secretion. Despite appropriate antibiotic therapy and intensive care management the child died and the autopsy showed characteristic diagnostic findings. The authors call attention to this diagnosis when facing respiratory failure among young children, mainly in the presence of marked leukocytosis. Thorough research on the immunization status of the patient's social environment is of crucial importance.