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

Pertussis Notification Rate and Tdpa Vaccine/Booster Coverage in Adults: An Opportunity for an Epidemiological Observatory in Primary Care

Background: In recent years, Europe has experienced a significant increase in pertussis cases. One reason behind this rise is the decline in diphtheria-tetanus-pertussis (dTap) booster coverage among adults. Currently, Italy lacks a reliable monitoring system to track pertussis infections and vaccine coverage among adults. We therefore evaluated the reliability of a primary care framework to respond to this need. Methods: Using an Italian primary care database for individuals aged 15 or above, we determined the pertussis infection notification rate and dTap vaccine/booster coverage for the timeframe of 2009-2022. Results: In the overall population, we obtained a lifetime occurrence rate of pertussis infections of 7.52 per 10,000 individuals. The annual incidence rates of pertussis infections ranged from 0.008 to 0.001 per 10,000 person-years between 2009 and 2022. A rising trend in dTap vaccine coverage rate (ranging from 8.72 to 16.54 vaccines per 10,000 individuals) was observed during the same period. Notably, those aged 65 or older, smokers, and/or individuals with immunodeficiencies were more likely to receive the dTap vaccine compared to the general population. Conclusions: Given the organization of the Italian public health system, this primary care network might act as a reliable epidemiological monitoring system to keep track of pertussis infections and dTap vaccine coverage in adults. Pertussis cases were underreported, and there was a low uptake of vaccines and boosters. Therefore, it is crucial to closely monitor pertussis notifications and dTap administrations and develop intervention strategies at the national level to enhance vaccine-related prevention.

Development and validation of a diagnostic prediction model for children with pertussis

To develop and validate a diagnostic prediction model based on blood parameters for predicting the pertussis in children. A retrospective study of 477 children with suspected pertussis at Zigong First People's Hospital was performed between January 2020 and December 2021. The patients were randomly divided into training cohort and validation cohort. Stepwise regression and R software was performed to develop and validate the model. Stepwise regression analysis showed that white blood cell (WBC), hematocrit (HCT), lymphocyte (LYMPH), C-reactive protein (CRP) and platelet distribution width to mean platelet volume ratio (PDW-MPV-R) were found to be independent factors associated with pertussis. The model containing WBC, CRP and PDW-MPV-R had the best performance. The area under curve (ROC, 0.77 for the training cohort and 0.80 for the validation cohort) of the model indicated satisfactory discriminative ability. The sensitivity and specificity of the model were 72.1% and 72.6% in training cohort and 74% and 72.1%, respectively, in validation cohort. Based on the ROC analysis, calibration plots, and decision curve analysis, we concluded that the model exhibited excellent performance. A model based on blood parameters is sufficiently accurate to predict the probability of pertussis in children, and may provide some reference for clinical decisions.

High purity and recovery of native filamentous hemagglutinin (FHA) from Bordetella pertussis using affinity chromatography

Filamentous hemagglutinin (FHA) is a critical adhesion molecule produced by Bordetella pertussis (BP), the causative agent of highly contagious respiratory infection known as whooping cough. FHA plays a pivotal role in the pathogenesis of whooping cough and is a key component of acellular pertussis vaccines (aPV). However, conventional purification methods for FHA often involve labor-intensive processes and result in low purity and recovery rates. Therefore, this study explores the use of monoclonal and polyclonal antibodies as specific tools to achieve highly pure and efficient FHA purification. To generate FHA-specific antibodies, polyclonal antibodies were produced by immunizing sheep and monoclonal antibodies (MAbs) were generated by immunizing mice with recombinant and native FHA. The MAbs were selected based on affinity, isotypes, and specificity, which were assessed through ELISA and Western blot assays. Two immunoaffinity columns, one monoclonal and one polyclonal, were prepared for FHA antigen purification. The purity and recovery rates of these purifications were determined using ELISA, SDS-PAGE, and immunoblotting. Furthermore, the MAbs were employed to develop an ELISA assay for FHA antigen concentration determination. The study's findings revealed that immunoaffinity column-based purification of FHA resulted in a highly pure antigen with recovery rates of approximately 57% ± 6.5% and 59% ± 7.9% for monoclonal and polyclonal columns, respectively. Additionally, the developed ELISA exhibited appropriate reactivity for determining FHA antigen concentration. This research demonstrates that affinity chromatography is a viable and advantageous method for purifying FHA, offering superior purity and recovery rates compared to traditional techniques. This approach provides a practical alternative for FHA purification in the context of aPV development.

Effects of Early Administration of Macrolides on Whooping Cough in Adolescents and Adults: A Single-center Retrospective Cohort Study

Objective This study aimed to elucidate the effects of early macrolide administration on genetically confirmed pertussis-induced cough in adolescents and adults. Methods This single-center, retrospective cohort study examined the effects of the early administration of macrolides and antitussive agents on cough secondary to pertussis. We divided the patients into two groups based on the median duration from the beginning of the cough to the initiation of macrolide administration: early macrolide administration group (EMAG) and non-early macrolide administration group (NEMAG). The clinical improvement of cough was defined as maintaining a cough awareness score of ≤3 points for 3 consecutive days. Patients The medical records of 40 patients diagnosed with pertussis (≥12 years old) who were able to maintain a cough diary and received no other antibiotics aside from macrolides were included in the study. A diagnosis of pertussis was made using the loop-mediated isothermal amplification (LAMP) test. Results The EMAG (24 patients) showed a significantly shorter total cough period than the NEMAG [16 patients; 20.0 (95% confidence interval (CI), 16-28) vs. 30.5 (95% CI, 27-40) days; log-rank test, p=0.002]. There was no significant difference in the post-administration cough periods between the EMAG and NEMAG [11.0 (95% CI, 7-19) vs. 13.0 (95% CI, 5-23) days; log-rank test, p=0.232]. Antitussive agents did not affect the cough. Conclusion The early administration of macrolides, but not antitussive agents, is effective for treating pertussis. Therefore, macrolides should be administered as soon as possible for this disease.

Health seeking behavior and associated factors among individuals with cough in Yiwu, China: a population-based study

Background

Previous studies have shown that a certain proportion of the population did not seek medical treatment after coughing, and understanding the potential reasons is crucial for disease prevention and control.

Method

A population-based study was conducted with the probability proportional to population size sampling in Yiwu, Zhejiang, China. A total of 5855 individuals aged ≥15 years lived in Yiwu for more than 6 months were included. All participants completed a laptop-based questionnaire to collect detailed information by a face-to-face interview. Characteristics of individuals were described by categories of health seeking behavior using frequency and percentage. Univariate and multivariate logistic regression analyses were performed to estimate the associations of social-demographic and cough characteristics with health seeking behavior.

Results

19.3% (1129/5855) of participants had a cough in the past month, 40% (452/1129) had sought medical treatment. Of these, 26.5% (120/452) chose hospitals at county level or above. Individuals aged ≥65 years old (OR = 2.25, 95% CI: 1.23, 4.12), female (OR = 1.57, 95% CI: 1.21, 2.06), living in rural areas (OR = 1.30, 95% CI: 1.003, 1.69), persistent cough for 3–8 weeks (OR = 2.91, 95% CI: 1.72, 4.92) and with more accompanying symptoms (P _trend < 0.001) were more likely to seek medical treatment, but those coughed for > 8 weeks were not (p > 0.5). Female (OR = 0.33, 95% CI: 0.21, 0.54) and people living in rural areas (OR = 0.57, 95% CI: 0.36, 0.92) were less likely to choose hospitals at county level or above while the higher educated were more likely to (OR = 3.29, 95% CI: 1.35, 8.02). Those who coughed for more than 2 weeks were more likely to choose hospitals at or above the county level. But the number of accompanying symptoms does not show any significant relationship with the choice of medical facility.

Conclusion

The present study found that age, sex, living areas and features of cough were associated with health seeking behavior. It is worth noting that those who coughed for too long (e.g. > 8 weeks) were less likely to seek medical treatment. Targeted measures should be developed based on the key factors found in this study to guide persons to seek medical treatment more scientifically.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11250-5.

Epidemiology of pertussis among adolescents, adults, and older adults in selected countries of Latin American: a systematic review

We aimed to describe the impact of pertussis on adolescents, adults, and older adults over 2007–2018 in selected Latin American countries by reviewing the literature. We searched the Medline, Embase, Scopus, LILACS, Scielo, Google Scholar, CAPES Journals Web-portal, and Cochrane databases for observational epidemiological studies, clinical trials, and systematic reviews of primary studies. Data were extracted and analyzed for all individuals aged ≥10 years. Of 6,891 studies identified only 25 were eligible. Studies were conducted in Brazil (14), Argentina (4), Colombia (4), Mexico (2) and Chile (1). Epidemiological data among target population were limited. No studies clearly assessed the status of asymptomatic or oligosymptomatic B. pertussis carriers in these age groups. Among all pertussis cases identified, the percentage of patients ≥10 years-old ranged between 2.1% and 66.7% depending on country and sample characteristics. The definition of cases, diagnostic methods, and age groups were not consistent across studies.

A data driven clinical algorithm for differential diagnosis of pertussis and other respiratory infections in infants

Background

Clinical criteria for pertussis diagnosis and clinical case definitions for surveillance are based on a cough lasting two or more weeks. As several pertussis cases seek care earlier, a clinical tool independent of cough duration may support earlier recognition. We developed a data-driven algorithm aimed at predicting a laboratory confirmed pertussis.

Methods

We enrolled children <12 months of age presenting with apnoea, paroxistic cough, whooping, or post-tussive vomiting, irrespective of the duration of cough. Patients underwent a RT-PCR test for pertussis and other viruses. Through a logistic regression model, we identified symptoms associated with laboratory confirmed pertussis. We then developed a predictive decision tree through Quinlan's C4.5 algorithm to predict laboratory confirmed pertussis.

Results

We enrolled 543 children, of which 160 had a positive RT-PCR for pertussis. A suspicion of pertussis by a physician (aOR 5.44) or a blood count showing leukocytosis and lymphocytosis (aOR 4.48) were highly predictive of lab confirmed pertussis. An algorithm including a suspicion of pertussis by a physician, whooping, cyanosis and absence of fever was accurate (79.9%) and specific (94.0%) and had high positive and negative predictive values (PPV 76.3% NPV 80.7%).

Conclusions

An algorithm based on clinical symptoms, not including the duration of cough, is accurate and has high predictive values for lab confirmed pertussis. Such a tool may be useful in low resource settings where lab confirmation is unavailable, to guide differential diagnosis and clinical decisions. Algorithms may also be useful to improve surveillance for pertussis and anticipating classification of cases.

Diagnostic limitations of clinical case definitions of pertussis in infants and children with severe lower respiratory tract infection

INTRODUCTION

Diagnosis of pertussis is challenging especially in infants. Most low and middle-income countries (LMIC) lack resources for laboratory confirmation, relying largely on clinical diagnosis alone for both case management and surveillance. This necessitates robust clinical case definitions.

OBJECTIVES

This study assesses the accuracy of clinical case definitions with and without lymphocytosis in diagnosing pertussis in children with severe lower respiratory tract infection (LRTI) in a LMIC setting.

METHODS

Children hospitalized with severe LRTI in a South African hospital were prospectively enrolled and evaluated for pertussis using PCR on respiratory samples. Clinical signs and differential white cell counts were recorded. Sensitivity and specificity of pertussis clinical diagnosis using WHO and Global Pertussis Initiative (GPI) criteria; and with addition of lymphocytosis were assessed with PCR as the reference standard.

RESULTS

458 children <10 years were enrolled. Bordetella pertussis infection was confirmed in 32 (7.0%). For WHO criteria, sensitivity was 78.1% (95% CI 60.7-89.2%) and specificity 15.5% (95% CI 12.4-19.3%); for GPI sensitivity was 34.4% (95% CI 20.1-52.1) and specificity 64.8% (95% CI 60.1-69.2%). Area under the curve (AUC) on receiver operating character (ROC) analysis was 0.58 (95% CI 0.46-0.70 for WHO criteria, and 0.72 (95% CI 0.56-0.88) for GPI with highest likelihood ratios of 5.33 and 4.42 respectively. Diagnostic accuracy was highest between five and seven days of symptoms for both criteria. Lymphocytosis had sensitivity of 31.3% (95% CI 17.5-49.3%) and specificity of 70.7% (95% CI 66.1-74.8%) and showed a marginal impact on improving clinical criteria.

CONCLUSION

Clinical criteria lack accuracy for diagnosis and surveillance of pertussis. Non-outbreak settings should consider shorter durations in clinical criteria. New recommendations still fall short of what is required for a viable clinical screening test which means the need to improve access to laboratory diagnostic support remains crucial.

Spatio-temporal analysis of Pertussis using geographic information system among Iranian population during 2012-2018

Background: In spite of existing vaccination programs in many countries, outbreaks of pertussis are still reported. In Iran, the suspected and confirmed cases of pertussis are reported annually. Due to the lack of similar studies, the purpose of the current study was to determine the Spatio-temporal distribution of Pertussis using Geographic Information System (GIS) to identify high-risk areas in Iran during 2012-2018.

Methods: In the current cross-sectional study, registered data in the department of vaccine-preventable diseases in the Iranian ministry of health were used. To assess the temporal trend, the Cochran–Armitage test was used. To show the spatial distribution and to identify hotspot areas, Choropleth map and Getis-Ord Gi statistics were used. All analyses performed by Arc.map10.5, Stata 15 and Excel 2010.

Results: The incidence of suspect pertussis cases had an increasing trend but did not have a linear trend (p=0.06). Most of the cases happened in under 1 year infants (62.66%). The incidence of reported cases in northern areas was higher than in the Southern areas. The Zanjan had the most reported cases during the understudied period with a median of 7.63 reported cases per 100,000. The clustering of infection and hotspots were identified in northern areas of Iran including Qazvin, Qom, Markazi, and Hamadan.

Conclusion: Our results showed that the cumulative incidence of reported cases is increasing. The northern provinces had the highest incidence of Pertussis. Therefore, the causes of this spatio-temporal pattern of pertussis should be determined. Also, supervision on vaccination programs in high-risk areas is recommended.

Clinical Findings and Management of Pertussis

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

Evaluating the role of cough duration in the pertussis case definition among Michigan cases, 2000-2010

Impressive reductions in pertussis have been achieved in the U.S. during the 20th century through childhood vaccination. Over the past two decades, increasing pertussis incidence has highlighted the need for accurate and timely reporting of cases to improve prevention and control efforts. We assessed components of the pertussis case definition, comparing use of clinical characteristics and laboratory results and their effects on internal validity, including an examination of the 2014 infant case definition. All reported pertussis cases in Michigan during 2000–2010 with data on cough length (N = 3310) were analyzed using multivariate statistics to internally validate reported cases, and calculate odds of meeting the clinical case definition, including a cough of at least 14 days. Cough duration of reported cases averaged 32 days and was longer with greater time interval between cough onset and initial presentation to a physician. Only about half of reported cases had positive laboratory results. Among cases seeking medical evaluation prior to meeting the cough duration required to fulfill the clinical case definition, the presence of positive lab results doubled the odds that the cough duration was not met compared to cases without a positive lab test. Clinical characteristics of pertussis are frequently ignored in applying the case classification. Relying solely on laboratory confirmation and disregarding clinical characteristics results in undiagnosed pertussis cases among those who are vaccinated, among adults, and among anyone who delays seeking care. This may prevent use of appropriate prevention and prophylaxis in contacts.

•

Increasing incidence of pertussis in the U.S. makes accurate diagnosis and reporting of cases essential to control efforts.

•

Many pertussis cases with positive laboratory tests sought medical evaluation prior to meeting the cough duration criterion.

•

Clinical characteristics of pertussis are frequently ignored by public health and medical professionals in classifying cases.

•

Laboratory confirmation without accompanying clinical characteristics may result in mis-diagnosis of pertussis.

Clinically Diagnosing Pertussis-associated Cough in Adults and Children: CHEST Guideline and Expert Panel Report

BACKGROUND

The decision to treat a suspected case of pertussis with antibiotics is usually based on a clinical diagnosis rather than waiting for laboratory confirmation. The current guideline focuses on making the clinical diagnosis of pertussis-associated cough in adults and children.

METHODS

The American College of Chest Physicians (CHEST) methodologic guidelines and the Grading of Recommendations, Assessment, Development, and Evaluation framework were used. The Expert Cough Panel based their recommendations on findings from a systematic review that was recently published on the topic; final grading was reached by consensus according to Delphi methodology. The systematic review was carried out to answer the Key Clinical Question: In patients presenting with cough, how can we most accurately diagnose from clinical features alone those who have pertussis-associated cough as opposed to other causes of cough?

RESULTS

In adults, after pre-specified meta-analysis exclusions, pooled estimates of sensitivity and specificity were generated for only 4 clinical features: paroxysmal cough, post-tussive vomiting, inspiratory whooping, and absence of fever. Both paroxysmal cough and absence of fever had high sensitivity (93.2% [95% CI, 83.2-97.4] and 81.8% [95% CI, 72.2-88.7], respectively) and low specificity (20.6% [95% CI, 14.7-28.1] and 18.8% [95% CI, 8.1-37.9]). Inspiratory whooping and posttussive vomiting had a low sensitivity (32.5% [95% CI, 24.5-41.6] and 29.8% [95% CI, 18.0-45.2]) but high specificity (77.7% [95% CI, 73.1-81.7] and 79.5% [95% CI, 69.4-86.9]). In children, after pre-specified meta-analysis exclusions, pooled estimates of sensitivity and specificity were generated for only 1 clinical feature in children (0-18 years): posttussive vomiting. Posttussive vomiting in children was only moderately sensitive (60.0% [95% CI, 40.3-77.0]) and specific (66.0% [95% CI, 52.5-77.3]).

CONCLUSIONS

In adults with acute (< 3 weeks) or subacute (3-8 weeks) cough, 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 with acute (< 4 weeks) cough, posttussive vomiting is suggestive of pertussis but is much less helpful as a clinical diagnostic test. Guideline suggestions are made based upon these findings and conclusions.

Managing patients with chronic cough: challenges and solutions

Chronic cough is a common complaint and a frequent cause of medical consultation. Its management can be difficult. We present here an overview of the current guidelines for the management of chronic cough. Different steps are detailed, including the initial research of an obvious etiology and alert signs that should lead to further investigation of underlying condition. The diagnosis of the most frequent causes: asthma, non-asthmatic eosinophilic bronchitis, gastroesophageal reflux disease and upper airway cough syndrome should be considered, assessed and treated accordingly. Recent advances have been made in the comprehension of refractory chronic cough pathophysiology as well as its pharmacologic and non-pharmacologic treatment, especially speech pathology therapy.