Characteristics of Hospitalized Cases of Pertussis in Catalonia and Navarra, Two Regions in the North of Spain

Epidemiology, prevention and control of pertussis in Spain: New vaccination strategies for lifelong protection

Pertussis is a highly contagious, vaccine-preventable respiratory tract infection, with high morbidity and mortality and a particularly severe effect on newborns and infants under 2 months. The first pertussis vaccines were introduced in the 1940s. Since 1980, however, the incidence of cases has risen despite the extensive vaccination programmes and antibiotic adjuvant treatments available. Transition from the use of whole-cell vaccines to acellular vaccines and the antigenic modifications of Bordetella pertussis have contributed, among other factors, to a reduction in vaccine-acquired immunity and reemergence of the disease. Today, there are still unmet needs not covered by conventional prevention measures and existing antibiotic treatments. This review aims to update the available data, and to discuss which vaccine strategies might contribute to better disease control and prevention.

Effectiveness of maternal pertussis vaccination in protecting newborn: A matched case-control study

INTRODUCTION

The objective was to estimate the effectiveness of maternal pertussis vaccination in protecting infants aged < 2 months.

METHODS

We performed a case-control study. Laboratory-confirmed cases aged <8 weeks at disease onset were identified and 2-4 matched-controls born within ± 15 days of the case were included. Information was obtained from healthcare providers and maternal interviews. Odds ratios (OR) were calculated using multivariable conditional logistic regression. Vaccine effectiveness (VE) was estimated as (1 - OR) × 100%.

RESULTS

47 cases and 124 controls were studied. The mean age (in days) (39.8 ± 12.7 vs. 40.8 ± 13.2), weeks of gestation (38.8 vs. 39.1, p = 0.43) and mean birth weight (3.309 vs. 3.253 kg, p = 0.55) were comparable between cases and controls. Mothers of cases were less frequently vaccinated in the third trimester (59.6% vs. 83.9%, p <0.001). The VE of maternal vaccination in pregnancy was 88.0% (95%CI 53.8% -96.5%), and was slightly higher in those vaccinated before the 32nd week of gestation (88.5% vs 87.8%).

CONCLUSION

Pertussis vaccination in pregnancy is very effective in reducing pertussis in children aged < 2 months. Vaccination before and after the 32nd week of pregnancy are equally effective in reducing the risk of pertussis.

Epidemiology, prevention and control of pertussis in Spain: New vaccination strategies for lifelong protection

Pertussis is a highly contagious, vaccine-preventable respiratory tract infection, with high morbidity and mortality and a particularly severe effect on newborns and infants under 2 months. The first pertussis vaccines were introduced in the 1940s. Since 1980, however, the incidence of cases has risen despite the extensive vaccination programmes and antibiotic adjuvant treatments available. Transition from the use of whole-cell vaccines to acellular vaccines and the antigenic modifications of Bordetella pertussis have contributed, among other factors, to a reduction in vaccine-acquired immunity and reemergence of the disease. Today, there are still unmet needs not covered by conventional prevention measures and existing antibiotic treatments. This review aims to update the available data, and to discuss which vaccine strategies might contribute to better disease control and prevention.

Impact of Pertussis on the Italian population: Analysis of hospital discharge records in the period 2001-2014

OBJECTIVES

The study aimed to analyze and update the impact of pertussis on the Italian population by evaluating pertussis-related hospital admissions in the period 2001-2014.

DESIGN OR METHODS

Hospital Discharge Records (HDR) were provided by the National Archive of HDR data of the Ministry of Health. Only hospitalizations included in the primary diagnosis were evaluated. Significant trends over the considered years were assessed as average annual percent changes (AAPC) applying the Joinpoint model.

RESULTS

A total of 7,102 hospital admissions for pertussis (main diagnosis) were registered; the trend of hospitalizations progressively decreased from >1/100,000 inhabitants in the years 2001-2004 to 0.64/100,000 inhabitants in 2014. A great part of hospitalizations (63.6%) involved subjects <1 year of life; almost 20% of cases were registered in the age class 5-14 years. The Joinpoint analysis showed a statistically significant variation in some age classes.

CONCLUSIONS

Even if this study shows a decreasing trend in the number of pertussis-related hospitalizations, the impact of the disease in Italy in terms of hospital admissions continues to be relevant, especially in the <1 year age class. Pertussis therefore continues to be, in Italy as well as in other European countries, an important public health issue.

Paediatric hospitalizations due to whooping cough in Spain (1997-2017)

This epidemiological survey estimates the burden of whooping cough in infants up to 12 months old in Spain during a twenty-one-year period (1997-2017). The survey was conducted by reviewing data from the Spanish Surveillance System for Hospital Data. All hospitalizations due to whooping cough for infants, reported during the 1997-2017 period, were analysed. Codes were selected from the International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes 033.0-033.9. To explore the latest national outbreak and the implementation of vaccination in pregnant women, analyses were stratified to compare the following periods: 1997-2010, 2011-2015 and 2016-2017. A total of 13,352 hospital discharges for whooping cough in infants up to 12 months old were reported. A total of 6850 discharges in the period 1997-2010, 5271 in the period 2011-2015 and 1231 in 2016-2017 were identified. The annual hospitalization rate prior to 2011 was 131.02 cases per 100,000 infants; in 2011-2015, the rate was significantly higher (250.13 cases per 100,000 infants) and in 2016-2017 it decreased (157.69 cases per 100,000 infants). Most of the cases (n = 11,446) occurred in infants under 4 months of age, with hospitalization rates of 328.80, 670.81 and 385.84 cases per 100,000 infants up to 4 months of age in the periods 1997-2010, 2011-2015 and 2016-17, respectively. Thirty-four deaths occurred in the period 1997-2010, 36 in the period 2011-2015 and 4 in 2016-2017. All of the deaths occurred in infants under 4 months old. The case fatality rate did not vary significantly across the study periods. Whooping cough infections concentrate in infants up to 4 months of age in Spain. Public health measures such as vaccination of pregnant women, caregivers, health care professionals and relatives, especially young parents, could reduce the hospitalization burden during the current outbreak.

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.

Performance of the new clinical case definitions of pertussis in pertussis suspected infection and other diagnoses similar to pertussis

Background

In an effort to improve the pertussis diagnosis, the Global Pertussis Initiative (GPI) proposed an algorithm of the signs/symptoms of pertussis for three age groups: 0–3 months, 4 months to 9 years, and ≥10 years of age.

Methods

We evaluated the accuracy of the clinical case definitions for pertussis proposed by the GPI using laboratory-confirmed pertussis as a reference standard for four groups: clinically suspected pertussis without comorbidity; asthma exacerbation; allergic constitution, and other diagnoses (bronchitis, bronchiolitis, laryngitis, and tracheitis). We included only patients who fulfilled one or more criteria of clinical case definitions for the age groups (0–3 months, 4 months–9 years, and ≥10 years of age).

The data for this prospective epidemiological study were collected between 1^st January 2013–31^st December 2016 at the outpatients and inpatients health care settings in the South Bačka District of Autonomous Province of Vojvodina, Serbia. We evaluated accuracy of the certain sign and symptom combinations of GPI case definitions based on their sensitivity, specificity, and likelihood ratios.

Results

A total of 1043 participants were included, with 306 (29.3%) laboratory-confirmed pertussis cases. In patients aged 0–3 months, whoop and apnoea associated with laboratory confirmation of pertussis. In patients aged 4 months-9 years with a pertussis suspicion infection or with one of the other diagnoses, the highest accuracy was found for whoop combined with apnoea or post-tussive emesis. In patients aged 10 years and older, several different sign and symptom combinations were associated with an increased risk of pertussis among all enrolment diagnoses. There were fewer hospitalizations among the fully vaccinated children than in partly or unvaccinated children aged 4 months to 6 years (20.7% vs. 60.0%, p = 0.017).

Conclusions

The numerous sign and symptom combinations in the observed case definitions were good predictors for laboratory-confirmed pertussis among all enrolment diagnoses, therefore suggesting the necessity for increased awareness of possibility for pertussis in patients with certain pertussis-like medical conditions.

Real-Time Polymerase Chain Reaction-Based Detection of Bordetella pertussis in Mexican Infants and Their Contacts: A 3-Year Multicenter Study

OBJECTIVES

To evaluate the usefulness of real-time polymerase chain reaction (RT-PCR) as a diagnostic method for the detection of Bordetella pertussis in hospitalized patients aged <1 year with a clinical diagnosis of whooping cough, as well as to identify the role of household contacts as a source of infection.

STUDY DESIGN

This was a prospective, multicenter study of infants aged <1 year who were hospitalized with symptoms suggestive of whooping cough. Nasopharyngeal samples were obtained for culture and RT-PCR testing. The clinical and epidemiologic characteristics and outcomes were analyzed. B pertussis detection and symptoms in household contacts of patients diagnosed with pertussis were studied.

RESULTS

A total of 286 patients were included; of these, 67.1% had B pertussis and 4.5% had Bordetella spp. Complications occurred in 20% of patients, and the mortality rate was 6.7%. Of 434 contacts studied, 111 were mothers of study infants, representing the most frequently B pertussis-infected group and the main symptomatic contact.

CONCLUSION

The use of RT-PCR permits improved detection and diagnosis of pertussis and a better understanding of the epidemiology of sources of infection. The complications and mortality rate of pertussis continue to be high. Household contacts are confirmed as a frequent source of infection of B pertussis in young children.