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

Pertussis infection in critically ill infants: meta-analysis and validation of a mortality score

BACKGROUND

Despite widespread vaccination programs, pertussis continues circulating within populations and remains a life-threatening infection in infants. While several mortality risk factors have been described, a comprehensive synthesis is lacking. We conducted a meta-analysis of studies investigating mortality risk factors in Pertussis infections and validated those factors in a large cohort.

METHODS

Observational studies published in English were systematically searched in PubMed, EMBASE, and LiSSa databases from 01/2000 to 06/2024. The search yielded 816 unique citations. The primary outcome was mortality before discharge from the Pediatric Intensive Care Unit (PICU). Two independent reviewers assessed the risk of bias and extracted data. A REML-random effect model was used to calculate pooled prevalence and conduct the analysis. The identified risk factors were subsequently evaluated in a monocentric cohort of patients admitted to a tertiary hospital's PICU for severe pertussis between January 1996 and December 2020. Data analysis was conducted between June and August 2024.

RESULTS

Seventeen studies, including 2,725 patients, met the inclusion criteria. The pooled prevalence of mechanical ventilation, continuous renal replacement therapy, and Extracorporeal Membrane Oxygenation support were 55% (95% CI: 40-70; I2 = 98), 15% (95% CI: 3-27; I2 = 95), and 8% (95% CI: 3-12; I2 = 93), respectively. The pooled mortality incidence was 19% (95% CI:12-26; I2 = 96). Identified mortality risk factors included elevated heart rate, presence of pulmonary hypertension, presence of seizures, and elevated white blood cell (WBC) count. Validation in an 83-patient cohort (median age: 45 days, IQR: 30-55) revealed a mortality rate of 12%. Risk factors identified in the meta-analysis were significantly associated with non-survival in the cohort. A mortality prediction score was developed incorporating age < 30 days, heart rate > 200/min, and WBC > 30 G/l, achieving an area under the curve of 0.92 (95% CI: 0.86-0.99).

CONCLUSION

This meta-analysis identified a simple yet effective score to assess the severity of pertussis infection in infants admitted to PICU. Accurate risk stratification may enable timely treatment of critically ill patients, potentially improving outcomes.

TRIAL REGISTRATION

The study protocol was registered on PROSPERO: CRD42024582057.

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).

Pertussis clinical profile shift, severity, prediction in a tertiary hospital: A comparative study before, during, and after COVID-19 in Southern China

OBJECTIVE

To analyze the epidemiological characteristics, clinical manifestations, antimicrobial resistance and develop a predictive model for severe pertussis spanning five years - before, during, and after the COVID-19 pandemic - in Shenzhen children's hospital in southern China, aiming to provide insights into the pandemic impact and control measures on the pertussis disease profile.

METHODS

Demographic, clinical, vaccination, and laboratory data were collected for patients who tested positive for pertussis by polymerase chain reaction and/or culture from January 1, 2019, to March 30, 2024. Analysis included changes in demographic and clinical features, indicators of severe cases, and resistance patterns over the study period.

RESULTS

During this period, 3963 patients were diagnosed, with 79 severe (PICU admitted) cases; 1433 isolates underwent antimicrobial susceptibility testing. In late 2023, pertussis cases began to increase. From 2019 to 2024, the proportion of cases among 4-6 year olds rose from 4.9 % to 28.6 %, and among 7-11 year olds from 0.7 % to 21.2 %. Macrolide resistance surged from 46.5 % in 2019 to 97.3 % in 2024, with 80 % of resistant hospitalized cases initially treated with macrolides. Clinical severity and co-infection increased post-pandemic, with a larger number of cases necessitating antibiotic changes and enhanced supportive care. Vaccination protected against severe disease. Indicators such as white blood cell count, lymphocyte to neutrophil ratio, platelet count, cyanosis and pneumonia predicted disease severity.

CONCLUSIONS

Post-pandemic, pertussis cases shifted from infants to school-aged children, with increased clinical severity and high macrolide resistance. Urgent measures are needed to optimize vaccination schedules and develop management strategies addressing and changing epidemiological patterns.

[Application of exchange transfusion in neonates with severe pertussis and hyperleukocytosis]

OBJECTIVES

To investigate the efficacy and safety of exchange transfusion in neonates with severe pertussis.

METHODS

A retrospective analysis was performed for the medical data of five neonates with severe pertussis who underwent exchange transfusion in the Department of Neonatology, Hunan Children's Hospital, from August 2019 to March 2024. The clinical characteristics of the patients were summarized, and the efficacy and adverse reactions of exchange transfusion were analyzed.

RESULTS

All five neonates had the symptoms of hypoxemia, recurrent apnea, and heart failure and required invasive mechanical ventilation. Two cases of pulmonary hypertension were observed, one of which was complicated by decompensated shock. Before exchange transfusion, the five children had a median leukocyte count of 82.60×109/L, a median absolute lymphocyte count of 28.20×109/L, and a median absolute neutrophil count of 43.10×109/L, and reexamination at 4 hours after exchange transfusion showed that these values decreased to 28.40×109/L, 7.60×109/L, and 15.40×109/L, respectively. The four children who underwent exchange transfusion in the early stage of cardiopulmonary failure showed varying degrees of improvement in oxygenation and a reduction in the partial pressure of carbon dioxide, and they were discharged after improvement; the one child who underwent exchange transfusion in the late stage of cardiopulmonary failure ultimately died. No child experienced severe adverse reactions related to exchange transfusion.

CONCLUSIONS

For neonates with severe pertussis, initiating exchange transfusion in the early stages of cardiopulmonary failure can effectively reduce leukocyte levels, potentially improve survival rates, and is relatively safe.

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.

Whooping Cough Cases Increase in Central Italy after COVID-19 Pandemic

Pertussis continues to be a highly contagious respiratory infection, especially in children, with cyclical peaks of disease spread every three to five years. Here, we report relevant cases of B. pertussis infection between August 2023 and January 2024, and compare them with B. pertussis prevalence in pediatric patients admitted to the Reference Italian Pediatric Hospital, located in Rome, from January 2015 to July 2023. A total of 5464 tests for B. pertussis were performed during the study period, and 6.9% were positive. At the time of the COVID-19 pandemic, there was a sharp decrease in the presence of B. pertussis, which reappeared only in August 2023, recording five new cases. All five children presented with paroxysmal cough 5 to 10 days before admission. Four patients had other mild respiratory symptoms and moderate B. pertussis DNA levels (Ct mean: 26). Only one child, with very high B. pertussis DNA levels (Ct: 9), presented with severe respiratory failure. The patients with mild/moderate infection achieved clinical recovery while the patient with the severe manifestation died of cardiac arrest. These observations highlight the reemergence of pertussis even in vaccinated countries and its association with morbidity and mortality especially in young children. This emphasizes the importance of rapid diagnosis to immediately implement appropriate treatment and monitoring of immune status.

Association Between Real-time Polymerase Chain Reaction Cycle Threshold Value and Clinical Severity in Neonates and Infants Infected With Bordetella pertussis

BACKGROUND

Polymerase chain reaction (PCR) is highly sensitive and is thus the standard method for diagnosing pertussis. Real-time PCR is widely used because of its accuracy and the simplicity of the simultaneous cycle threshold (Ct) value, which represents the copy numbers of the target gene. Little is known of the association of Ct value with pertussis severity in neonates and infants.

METHODS

This study determined Ct values in neonates and infants diagnosed with pertussis by real-time PCR using nasopharyngeal samples at Vietnam National Children's Hospital in Hanoi in 2017 and 2019. The association of disease severity and clinical parameters were analyzed using univariate and multivariate analyses.

RESULTS

We evaluated 108 patients with pertussis [median age: 63 days, interquartile range (IQR): 41-92 days]. Only 6/108 (6%) received at least 1 dose of a pertussis-containing vaccine. Among them, 24 (22.2%) had severe disease requiring care in a pediatric intensive care unit, 16 (13.8%) required mechanical ventilation, and 3 (2.6%) died. The median Ct value was lower in patients with severe disease (19.0, IQR: 16.5-22.0, n = 24) than in those without severe disease (25.5, IQR: 20.0-30.0, n = 84) (P = 0.002). Logistic regression analyses demonstrated that PCR Ct value [odds ratio (OR): 1.783, 95% confidence interval (CI): 1.013-3.138, P = 0.045], age (OR: 3.118, 95% CI: 1.643-5.920, P = 0.001), and white blood cell counts (OR: 0.446, 95% CI: 0.261-0.763, P = 0.003) remained significantly associated with severe disease.

CONCLUSIONS

Real-time PCR Ct values for pertussis might be useful as a predictor of severe disease in neonates and infants.