Bordetella pertussis in children hospitalized with a respiratory infection: clinical characteristics and pathogen detection in household contacts

OBJECTIVE

Describe the prevalence of Bordetella pertussis via PCR in children under 5 years old hospitalized as probable cases of pertussis and report the most common clinical features among them.

RESULTS

A positive PCR result for B. pertussis was observed in 20.5% of our samples (18/88), one-third of them were from infants between 2 and 3 months old. The most common symptoms were paroxysms of coughing (88.9%), difficulty breathing (72.2%), cyanosis (77.8%) and fever (50%). The mother was the most common symptomatic carrier (27.8%), followed by uncles/aunts (22.2%) among children with pertussis.

Predictors of pertussis outbreak in urban and rural municipalities of Saskatchewan, Canada

OBJECTIVES

Increased numbers of pertussis cases in September 2015 led to the declaration of an outbreak in the Saskatoon Health Region (SHR). SHR (population approximately 350,000) is a geographic area in central Saskatchewan consisting of both urban and rural municipalities. The purpose of this study was to describe the epidemiology and identify possible predictors of the outbreak.

METHODS

Confirmed cases of pertussis in SHR from 2010 to 2015 were extracted from the integrated Public Health Information System (iPHIS) database. Univariate and bivariate analyses and a comparison of the two outbreaks were conducted. Poisson regression modelling was used to estimate incidence rate ratios (IRRs) of factors associated with pertussis infection.

OUTCOMES

Two outbreaks between 2010 and 2015. Factors associated with the 2015 outbreak were residence in rural areas (IRR = 18.67, 95% CI 11.82-29.49; 11.37, 95% CI 6.40-20.21; and 6.31, 95% CI 3.43-11.62) for Humboldt, Watrous, and Rosthern areas, respectively, compared to the City of Saskatoon, and among children 11-14 years of age (IRR = 3.11, 95% CI 1.67-5.79) compared to children under 5 years of age. Unvaccinated persons had increased risk (IRR = 1.60, 95% CI 1.07-2.38). Multiple interventions, including enhanced contact tracing, supplemental immunization clinics, and cocooning, were employed in the 2015 outbreak.

CONCLUSION

Pertussis is a cyclical disease with outbreaks occurring every 3 to 5 years. Teenagers have increased risk of disease compared to younger children, likely due to waning immunity. Rural residents had a higher incidence of disease, possibly due to clusters of conscientious objectors. Control efforts require recognition of waning immunity and unvaccinated susceptibles.

Trends and costs of pertussis hospitalizations in Portugal, 2000 to 2015: from 0 to 95 years old

BACKGROUND

Pertussis has caused several outbreaks and concern worldwide. Despite high vaccination coverage, people of all ages are still affected with significant morbidity and mortality. We aimed to analyse all pertussis hospitalizations in Portugal to help to delineate preventive policies.

METHODS

Data were collected from a Portuguese administrative database, which contains all registered hospitalizations in mainland Portugal. Cases were identified using the ICD-9-CM code 033.x (whooping cough) as principal or secondary diagnosis, with hospital discharges between 2000 and 2015. Data were analysed by age groups.

RESULTS

Of 2281 hospitalizations, 94% occurred in infants (<1 year). The mean and median ages were 20 and 2 months, respectively. A seasonal pattern was observed, with higher number of hospitalizations during the winter for infants, and during the summer for other age groups. Higher hospitalization rates were registered in the Southern regions. The mean and median lengths of hospital stay were 8 and 6 days, respectively. The main complications were acute respiratory failure and pneumonia. Invasive or non-invasive ventilation, or both, was required in 2.4, 1.8 and 0.6% of hospitalized cases, respectively. The overall inpatient case fatality rate was 0.7%; 0.8, 11.5 and 17.4% for the age groups 0-1 months, 18-64 years and ≥65 years, respectively. Total hospitalization costs were estimated to be 2,698,995€.

CONCLUSION

Our study emphasizes the need to adopt new preventive strategies mainly focused on infants, to reduce morbidity and costs of hospitalizations related to pertussis.

Challenges of interpreting epidemiologic surveillance pertussis data with changing diagnostic and immunization practices: the case of the state of São Paulo, Brazil

Background

A significant increase in pertussis incidence occurred in Brazil, from 2011 to 2014, despite high coverage of childhood immunization with whole-cell-pertussis (wP) containing vaccines. This study presents pertussis surveillance data from São Paulo state and discusses the challenges to interpret them considering pertussis cyclic epidemic behavior, the introduction of new diagnostic techniques and new vaccination strategies, and enhanced disease awareness during epidemics.

Methods

Observational study including pertussis cases reported to the Surveillance System in São Paulo state, from January 2001 to December 2015. Pertussis cases data were retrieved from the National Notifiable Diseases Information System (SINAN) website and from São Paulo state Epidemiological Surveillance Center (CVE/SP) database. Vaccination coverage and homogeneity data were collected from the Unified Health System Department of Informatics (DATASUS). We presented cases distribution by year, age group and diagnostic criteria and calculated pertussis incidence rates. The proportions of cases among different age groups were compared using chi-square test for trend.

Results

Infants less than 1 year of age were the most affected during the whole period, but the proportions of cases in this age group had a significant decreasing trend, with significant increase in the proportions of cases reported among older age groups (1–4, 5–10 and ≥20 years). Cases among infants aged less than 6 months represented ≥90% of all cases in children less than 1 year of age in all but 2 years (2012 and 2015). A non-significant decrease in the proportion of cases among infants aged < 2 months was observed in parallel to a significant increase in the proportion of cases in infants aged 6–11 months.

Conclusions

A pertussis outbreak has occurred in a state with universal use of wP vaccine. The disease cyclic behavior has probably had a major role in the increased incidence rates registered in São Paulo state, from 2011 to 2014, as well as in the decreased incidence in 2015. Maternal vaccination cannot explain the drop in the number of cases among all age groups, in 2015, as herd protection is not expected, but may have had an impact on the number of cases in infants aged < 2 months.

Core pertussis transmission groups in England and Wales: A tale of two eras

The recent resurgence of pertussis in England and Wales has been marked by infant deaths and rising cases in teens and adults. To understand which age cohorts are most responsible for these trends, we employed three separate statistical methods to analyze high-resolution pertussis reports from 1982 to 2012. The fine-grained nature of the time-series allowed us to describe the changes in age-specific incidence and contrast the transmission dynamics in the 1980s and during the resurgence era. Our results identified infants and school children younger than 10 years of age as a core group, prior to 2002: pertussis incidence in these populations was predictive of incidence in other age groups. After 2002, no core groups were identifiable. This conclusion is independent of methodology used. Because it is unlikely that the underlying contact patterns substantially changed over the study period, changes in predictability likely result from the introduction of more stringent diagnostics tests that may have inadvertently played a role in masking the relative contributions of core transmission groups.

Pertussis disease and transmission and host responses: insights from the baboon model of pertussis

Whooping cough is a highly contagious, acute respiratory disease, caused by the Gram-negative bacterium Bordetella pertussis (Bp). Despite the introduction and widespread use of vaccines starting in the 1950s pertussis cases continue to be reported, with a significant global impact. The role of specific virulence factors in disease and the immune mechanisms associated with protection following natural infection or vaccination are still not completely understood. The recently-developed baboon model of clinical pertussis provides a valuable tool for the study of pertussis. Baboons infected with B. pertussis exhibit all of the manifestations of human pertussis including paroxysmal coughing, mucus production, leukocytosis and transmission. The establishment of this model provides the opportunity to address unanswered questions about the natural progression of this disease and host responses to infection and vaccination in a very relevant model. In this review, we present an overview of our knowledge of pertussis along with recent advances resulting from use of the baboon model. Remaining questions and future research directions are discussed. We hope that the knowledge gained through use of the baboon model of pertussis and clinical studies will allow the development of more efficacious vaccines, conferring long lasting protection against disease and transmission.

Pertussis and Rotavirus Vaccines - Controversies and Solutions

Pertussis and rotavirus vaccines have been the subject of several controversies over the years. In this paper the authors discuss facts and myths behind these controversies and also suggest solutions to overcome some limitations of these vaccines. The whole-cell pertussis vaccine (wPV) came into disrepute due to the associated adverse reactions, resulting in its replacement by acellular pertussis vaccine (aPV) in industrialized nations in 1990s. Although wPV is known to have more side effects; but they are usually minor. Whole-cell pertussis containing vaccine is being used safely in the National Immunization programme in India from many years. Another controversy erupted during 2009-2010, when there were reports of resurgence of pertussis cases among adolescents and adults, from developed nations. Present literature review raises doubts about long term protection offered by aPV, when compared with wPV. In spite of prevailing controversy, acellular pertussis containing vaccines should be acceptable, if timely delivery of primary and booster doses is ensured; including vaccination of adolescents and pregnant women. Initial rotavirus vaccine was withdrawn from the market because of increased risk of intussusception. Although three new generation rotavirus vaccines are currently available for use in India, but doubts about their efficacy, long term protection and safety still exists. Present literature review found them to be safe and moderately efficacious because of reasonable good cross protection. Even a moderately efficacious vaccine like rotavirus vaccine could significantly improve the outcome if disease burden is high. Therefore, it is being included in National Immunization Programme of India.

Pertussis and parapertussis in children and adults with a persistent cough: an observational study

PURPOSE

We aimed to determine the prevalence, symptoms and course of pertussis and parapertussis among patients at any age with a cough of unknown aetiology that had lasted for ≥ 7 days and to assess the diagnostic value of the symptoms included in the World Health Organisations' (WHO) clinical case definition of pertussis.

METHODS

Patients were enrolled between the 23 April 2012 and 31 December 2014 at 25 general practitioner (GP) centres and three paediatric hospitals. Pertussis was confirmed by culture and/or polymerase chain reaction (PCR) and/or quantitative serology. Parapertussis was confirmed by culture and/or PCR.

RESULTS

Altogether, 549 patients were recruited. Of them, 22 (4.0%; 95% CI 2.5-6.0) had pertussis (predominately diagnosed by positive serology 17/22) and 7 (1.3%; 95% CI 0.5-2.6) had parapertussis. Patients with pertussis were more likely to have inspiratory whooping and posttussive emesis than those with a cough of another/unknown aetiology. However, the presence or absence of these two symptoms did not definitively confirm or exclude pertussis. The sensitivity and specificity of the WHO's clinical definition was 0.77 and 0.38, respectively.

CONCLUSIONS

The prevalence of pertussis and parapertussis among patients with a persistent cough of unknown aetiology in Estonia is low. As clinical symptoms alone cannot be used to distinguish pertussis, we recommend that laboratory testing for pertussis is performed in all patients with a persistent cough regardless of age.

Incidence of pertussis in subjects aged 50years and older in France in 2013-2014

OBJECTIVE

To assess the incidence of pertussis (whooping cough) in subjects aged 50years and older in France.

METHODS

Participating family physicians (FPs) using the patient record management software AxiSanté^® included patients aged 50years and older, who had signed an informed consent form, presenting with persistent cough for 7 to 21days. Bordetella genetic material was detected by polymerase chain reaction (PCR) on nasopharyngeal samples collected at the FP's discretion.

RESULTS

A total of 42 FPs included 129 patients from June 2013 to August 2014 (large cities: 38; medium-sized cities: 57; rural areas: 34); 106 samples were analyzed. Overall, 30 pertussis cases were diagnosed: 10 cases confirmed by PCR, 18 purely clinical cases, and two direct epidemiological cases. The crude incidence rate per 100,000 patients aged≥50years was 103.6 (95% CI: 69.9-47.9): 77.1 in large cities, 103.1 in medium-sized cities, and 143.9 in rural areas. The extrapolated incidence rate per 100,000 persons aged≥50years was 187.1 (95% CI: 126.2-67.1): 131.1 in large cities, 256.1 in medium-sized cities, and 242.2 in rural areas.

CONCLUSION

The population aged 50years and older can serve as a reservoir. Its role in Bordetella pertussis circulation should be taken into account for pertussis booster vaccination programs.

Prenatal Tdap immunization and risk of maternal and newborn adverse events

Many countries recommend combined tetanus toxoid, reduced diphtheria toxoid and acellular pertussis immunization (Tdap) during pregnancy to stimulate transplacental transmission of pertussis antibodies to newborns. The immune system can be altered during pregnancy, potentially resulting in differing immunization risks in pregnant women. The safety of widespread Tdap immunization during pregnancy needs to be established. Our objective was to assess whether prenatal Tdap immunization was associated with adverse birth outcomes, and to evaluate the effect of timing of Tdap administration on these outcomes. We identified pregnancies at delivery in a large insurance claims database (2010-2014). Tdap immunization was categorized as optimal prenatal (27+weeks), early prenatal (<27weeks), postpartum (≤7days post-delivery), or none. Medical claims were searched to identify maternal adverse immunization reactions (e.g. anaphylaxis, fever, Guillian-Barre syndrome [GBS]), adverse birth outcomes (e.g. preeclampsia/eclampsia, premature rupture or membranes, chorioamnionitis) and newborn outcomes (e.g. respiratory distress, pulmonary hypertension, neonatal jaundice). Women with optimal or early prenatal Tdap were compared to those not immunized in pregnancy, using propensity score-weighted log-binomial regression and Cox proportional hazards models to estimate risk ratios (RR) and hazard ratios (HR). We identified 1,079,034 deliveries and 677,075 linked newborns; 11.5% were immunized optimally and 2.3% immunized early. There were 1 case of post-immunization anaphylaxis, and 12 cases of maternal encephalopathy (all post- delivery); there were no cases of GBS. Optimally-timed immunization was associated with small increased relative risks of: chorioamnionitis [RR=1.11, (95% CI: 1.07-1.15), overall risk=2.8%], and postpartum hemorrhage [RR=1.23 (95% DI: 1.18-1.28), overall risk=2.4%]; however, these relative increases corresponded to low absolute risk increases. Tdap was not associated with increased risk of any adverse newborn outcome. Overall, prenatal Tdap immunization was not associated with newborn adverse events, but potential associations with chorioamnionitis consistent with one previous study and postpartum hemorrhage require further investigation.

Severe underestimation of pertussis related hospitalizations and deaths in the Netherlands: A capture-recapture analysis

OJECTIVE

Despite vaccination, pertussis has remained endemic, sometimes leading to severe disease. We aimed to quantify the completeness of reporting (CoR) of pertussis hospitalizations and deaths in the Netherlands.

STUDY DESIGN

CoR was estimated using capture-recapture analyses. Hospitalizations (2007-2014) from the National Registration Hospital Care (hospital data) were matched to the notifiable Infectious Disease case registry (notifications) providing (month and) year of birth, gender and postal code. Deaths (1996-2014) from Statistics Netherlands (death registry) were matched to notifications using gender, age, year of death and notification date. Cases <2years (y) and ≥2y were analysed separately. Chao's estimator estimated the total population, which was used to calculate CoR.

RESULTS

Using strict matching criteria, we found 461 matches among 876 (hospital data) and 757 (notifications) hospitalizations <2y. The population estimate of hospitalized infants was 1446, resulting in CoR between 52% and 61%. For hospitalizations ≥2y (246; hospital data and 264; notifications) 43 matches were found, with a population estimate of 1512 and CoR between 16.5% and 22%. Among thirteen (death registry) and eight (notifications) deaths <2y, seven cases overlapped. The population estimate was 16. CoR of the two sources was 50-81%. With two (death registry) and eight (notifications) deaths ≥2y without overlap, the population estimate was 26 and CoR 8-31%.

CONCLUSION

Results showed substantial underestimation of pertussis hospitalizations and deaths. This has to be taken into account in evaluation of current and future immunization programs.

Pertussis without apparent cough in a disabled girl with a tracheostomy

Pertussis is characterized by intense, prolonged coughing in children often followed by a distinctive whooping sound on inspiration. However, the clinical manifestations and natural course of pertussis in disabled children are largely unknown. We experienced a case of pertussis in a disabled girl who had previously undergone a tracheostomy and laryngotracheal separation. She presented with increased tracheal secretions and required hospitalization but did not develop a cough. Pertussis was suspected from the sputum Gram stain, which revealed numerous, short gram-negative rods that did not grow on chocolate agar. A nucleic acid amplification test was positive for Bordetella pertussis and the patient improved on azithromycin. Pertussis may present without its cardinal symptoms in disabled children.

Bordetella pertussis infections in travelers: data from the GeoSentinel global network

BACKGROUND

Pertussis is a highly contagious, vaccine-preventable respiratory infection that is endemic worldwide. There are limited data regarding the occurrence of pertussis in travelers. The objective of this study is to identify travel-related pertussis cases reported to the GeoSentinel Surveillance Network.

METHODS

This is a descriptive, retrospective analysis of GeoSentinel records from 25 travel/tropical medicine clinics in 16 countries. Frequencies of demographic and travel-related characteristics and symptoms of 74 cases of pertussis in travelers and new immigrants from 1999 to 2015 were analysed.

RESULTS

There were 74 probable and confirmed cases of pertussis in the GeoSentinel database; median age was 44 years, and 38 (51%) patients were female. Tourism was the most common reason for travel (41; 55%). Country of exposure was determined in 66 cases with travelers returning from India and China constituting the highest number of cases (10 cases each; 15% each). Seventy of 74 (95%) patients had respiratory symptoms, while fatigue and fever were reported by 21 (28%) and 20 (27%), respectively. Immunization status against pertussis was unknown. Most cases were reported after 2005 (69; 93%).

CONCLUSIONS

Our study describes 74 cases of pertussis acquired during travel and reported to the GeoSentinel Network. Pertussis should be considered in returned travelers who present with respiratory symptoms. Surveillance and detection of imported cases are important to prevent onward transmission in the community. The pre-travel consultation provides an opportunity to verify immunization status and provide routine vaccinations such as pertussis.

Evaluation of two vaccine education interventions to improve pertussis vaccination among pregnant African American women: A randomized controlled trial

BACKGROUND

Vaccination coverage with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine in pregnancy or immediately postpartum has been low. Limited data exist on rigorously evaluated interventions to increase maternal vaccination, including Tdap. Tailored messaging based on the Elaboration Likelihood Model (ELM) framework has been successful in improving uptake of some public health interventions. We evaluated the effect of two ELM-based vaccine educational interventions on Tdap vaccination among pregnant African American women, a group of women who tend to have lower vaccine uptake compared with other groups.

METHODS

We conducted a prospective randomized controlled trial to pilot test two interventions - an affective messaging video and a cognitive messaging iBook - among pregnant African American women recruited during routine prenatal care visits. We measured Tdap vaccination during the perinatal period (during pregnancy and immediately postpartum), reasons for non-vaccination, and intention to receive Tdap in the next pregnancy.

RESULTS

Among the enrolled women (n=106), 90% completed follow-up. Tdap vaccination in the perinatal period was 18% in the control group; 50% in the iBook group (Risk Ratio [vs. control group]: 2.83; 95% CI, 1.26-6.37), and 29% in the video group (RR: 1.65; 95% CI, 0.66-4.09). From baseline to follow-up, women's reported intention to receive Tdap during the next pregnancy improved in all three groups. Among unvaccinated women, the most common reason reported for non-vaccination was lack of a recommendation for Tdap by the woman's physician.

CONCLUSIONS

Education interventions that provide targeted information for pregnant women in an interactive manner may be useful to improve Tdap vaccination during the perinatal period. However, larger studies including multiple racial and ethnic groups are needed to evaluate robustness of our findings.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01740310.

Tetanus-diphtheria-acellular pertussis vaccination for adults: an update

Although tetanus and diphtheria have become rare in developed countries, pertussis is still endemic in some developed countries. These are vaccine-preventable diseases and vaccination for adults is important to prevent the outbreak of disease. Strategies for tetanus, diphtheria, and pertussis vaccines vary from country to country. Each country needs to monitor consistently epidemiology of the diseases and changes vaccination policies accordingly. Recent studies showed that tetanus–diphtheria–acellular pertussis vaccine for adults is effective and safe to prevent pertussis disease in infants. However, vaccine coverage still remains low than expected and seroprevalence of protective antibodies levels for tetanus, diphtheria, and pertussis decline with aging. The importance of tetanus–diphtheria–acellular pertussis vaccine administration should be emphasized for the protection of young adult and elderly people also, not limited to children.

[Outbreak of Whooping cough in 2016.Écija, Seville, Spain]

OBJECTIVE

Whooping cough is a global public health problem, is a highly contagious disease, and despite universal vaccination increased incidence is observed. The aim of this study was to describe the investigation of a population outbreak.

METHODS

A descriptive study of a population outbreak of whooping cough between February and June 2016 in Ecija (Seville). Case and outbreak definitions was taken of Whooping Cough Monitoring Protocol. Information was collected from Health History, Epidemiological Monitoring System and Laboratory. For statistical analysis used the free software R, for measuring quantitative variables were presented, median, standard deviation, minimum and maximum values and percentiles for qualitative variables frequency distribution.

RESULTS

91 suspected cases were identified, ruling 33. Of the remaining 58, 42 cases were confirmed and 16 probable cases. The cases have presented an average age of 10,24 years. 62,1% of cases occurred in women. The incidence during the duration of the outbreak was 148,51 cases/100.000 people globally, and 851,06 cases/100.000 people in under 14 years. All children under 18 years were successfully vaccinated in primary vaccination and only 2 children lacked the fifth dose. The average time between onset of symptoms and diagnosis was 24,86 days.

CONCLUSIONS

The establishment of monitoring and control measures have managed to limit and resolve the outbreak. It is recommended to enhance the information and coordination between the various levels of care (Primary care/Specialist) and professionals (Clinical/Epidemiology).

[Clinical, laboratorial and radiographic predictors of Bordetella pertussis infection]

OBJECTIVE

To identify clinical, laboratorial and radiographic predictors for Bordetella pertussis infection.

METHODS

This was a retrospective study, which analyzed medical records of all patients submitted to a molecular diagnosis (qPCR) for B. pertussis from September 2011 to January 2013. Clinical and laboratorial data were reviewed, including information about age, sex, signs/symptoms, length of hospitalization, blood cell counts, imaging findings, coinfection with other respiratory pathogens and clinical outcome.

RESULTS

222 cases were revised. Of these, 72.5% had proven pertussis, and 60.9% were under 1 year old. In patients aging up to six months, independent predictors for B. pertussis infection were cyanosis (OR 8.0, CI 95% 1.8-36.3; p=0.007) and lymphocyte count >10(4)/μL (OR 10.0, CI 95% 1.8-54.5; p=0.008). No independent predictors of B. pertussis infection could be determined for patients older than six months. Co-infection was found in 21.4% of patients, of which 72.7% were up to six months of age. Adenovirus was the most common agent (40.9%). In these patients, we were not able to identify any clinical features to detect patients presenting with a respiratory co-infection, even though longer hospital stay was observed in patients with co-infections (12 vs. 6 days; p=0.009).

CONCLUSIONS

Cyanosis and lymphocytosis are independent predictors for pertussis in children up to 6 months old.

Acellular pertussis vaccine efficacy: An updated systematic review and meta -analysis

Background: Recent studies indicate an increased incidence of pertussis disease in recent years. The aim of this study was to evaluate the efficacy of the acellular vaccine for children (as a replacement of current whole cell vaccine in the Expanded Program on Immunization) and for high-risk adults in Iran through updating current best available evidence. Methods: We performed a systematic literature review in relevant databases we focused on previously published systematic reviews to select those that address our questions. The AMSTAR (assessing the methodological quality of systematic reviews) tool was used for screening available reviews. Then search in databases was done until Feb 2014 to update the evidence. We pooled results using meta-analysis methods by Stata statistical package. Results: Eleven systematic review articles were included in the initial evaluation. In the end, two systematic reviews on acellular vaccine booster doses and the acellular vaccine in children were selected as the baseline evidence. In the update phase, new clinical trials were screened, and the results were updated. Overall pooled estimate of relative efficacy of acellular to whole cell was 0.68 (95% CI, 0.55-0.81) for children immunization Pooled estimates for the efficacy of acellular versus placebo were 0.70 (95% CI, 0.60-0.80). Overall pooled estimate of efficacy of booster dose of acellular was 0.87(95% CI, 0.85-0.88) compared to placebo. In addition pooled estimate of acellular vaccine efficacy based on response to antigen was 0.78(95% CI, 0.64-0.93) in highrisk group. Conclusion: The results show higher performance and safety of the acellular vaccine in the prevention of pertussis in children versus the whole cell vaccine. Moreover, the efficacy of the acellular vaccine in high-risk adult groups is acceptable. This study provides evidence in favor of the introduction of an acellular vaccine to the national program of immunization. Studies on cost effectiveness and aspects of policy analysis are recommended.

Epidemiology of pertussis in two Ibero-American countries with different vaccination policies: lessons derived from different surveillance systems

Background

Pertussis is a re-emerging disease worldwide despite its high vaccination coverage. European and Latin-American countries have used different surveillance and vaccination policies against pertussis. We compared the epidemiology of this disease in two Ibero-American countries with different vaccination and surveillance policies.

Methods

We compared the epidemiology of pertussis in Spain and the Dominican Republic (DR). We present a 10-year observational study of reported pertussis based on suspected and/or probable cases of pertussis identified by the national mandatory reporting system in both countries between 2005 and 2014. Both countries have a similar case definition for pertussis surveillance, although Spain applies laboratory testing, and uses real time PCR and/or culture for case confirmation while in DR only probable and/or suspected cases are reported. We analyzed incidence, hospitalization, case-fatality rates, mortality and vaccination coverage.

Results

The average annual incidence in children aged <1 year was 3.40/100,000 population in Spain and 12.15/100,000 in DR (p = 0.01). While the incidence in DR was generally higher than in Spain, in 2011 it was six times higher in Spain than in DR. The highest infant mortality in Spain was 0.017/100,000 in 2011, and the highest in DR was 0.08/100,000 in 2014 (p = 0.01). The proportion of hospitalized cases per year among children <1 year varied between 22.0% and 93.7% in Spain, and between 1.1% and 29.4% in DR (p = 0.0002), while mortality varied from 0 to 0.017 and 0 to 0.08 per 100,000 population in Spain and DR, respectively (p = 0.001). Vaccination coverage was 96.5% in Spain and 82.2% in DR (p = 0.001).

Conclusions

Pertussis is a public health problem in both countries. Surveillance, prevention and control measures should be improved, especially in DR. Current vaccination programs are not sufficient for preventing continued pertussis transmission, even in Spain which has high vaccination coverage.

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.

Assessing determinants of the intention to accept a pertussis cocooning vaccination: A survey among Dutch parents

INTRODUCTION

Pertussis cocooning is one of the strategies aiming to prevent the potential harm of pertussis in infants by vaccinating (among others) their parents. Several countries adopted this strategy, but uptake is a problem. Determinants of parental uptake are important in the design of an effective vaccination programme. Therefore, this study aims to assess parents' intention to accept a pertussis cocooning vaccination and its determinants.

METHODS

A 98 item questionnaire was developed based on a theoretical framework, assessing parents' intention to accept a pertussis cocooning vaccination and its personal and psychosocial determinants. In addition, beliefs underlying parents' attitude towards pertussis cocooning vaccination were assessed. Both logistic and linear regression analysis were used to assess univariate and multivariate associations amongst study variables.

RESULTS

Parents returned 282 questionnaires. The majority of the parents (78%) reported a positive intention to accept a pertussis cocooning vaccination. Attitude (OR 6.6, p<.001), anticipated negative affect in response to non acceptance (OR 1.65, p<.001), anticipated negative affect in response to acceptance (OR 0.55, p .040) and decisional uncertainty (OR 0.52, p .002) were significantly associated with intention. General vaccination beliefs (β 0.58, p<.001), moral norm (β 0.22, p<.001), perceived susceptibility of pertussis in children (β 0.10, p.004), and efficacy outcome expectations (β 0.15, p.011) were significant correlates of attitude towards pertussis cocooning vaccination.

CONCLUSION

The parental intention to accept a pertussis cocooning vaccination in this study is rather high. Targeting the identified determinants of parents' acceptance in a pertussis cocooning vaccination programme is crucial to secure that intention is translated into actual vaccination uptake.

A Bordetella pertussis proteoliposome induces protection in mice without affecting the immunogenicity of diphtheria and tetanus toxoids in a trivalent formulation

In this study, a formulation of Bordetella pertussis proteoliposome (PLBp), diphtheria, and tetanus toxoids and alum (DT-PLBp) was evaluated as a trivalent vaccine candidate in BALB/c mice. Vaccine-induced protection was estimated using the intranasal challenge for pertussis and enzyme-linked immunosorbent assay fvto assess serological responses for diphtheria or tetanus. Both, diphtheria-tetanus-whole cell pertussis (DTP) and diphtheria-tetanus vaccines (DT) were used as controls. Animals immunized with DT-PLBp, PLBp alone, and DTP showed total reduction of CFU in lungs 7 days after intranasal challenge. Likewise, formulations DT-PLBp, DTP, and DT elicited antibody levels ≥2 IU/mL against tetanus and diphtheria, considered protective when neutralization tests are used. Overall, results showed that combination of PLBp with tetanus and diphtheria toxoids did not affect the immunogenicity of each antigen alone.

Surveillance of pertussis: methods and implementation

INTRODUCTION

Pertussis or whooping cough is a respiratory disease caused by Bordetella pertussis or, to a lesser extent, by B. parapertussis. Vaccines against pertussis have been widely used for more than 50 years and have led to a significant reduction of morbidity and mortality. However, even in countries with a high vaccine coverage, the disease is still not well controlled. Surveillance is urgently needed.

AREAS COVERED

This review summarizes surveillance methods and gives examples that may be used when setting up a surveillance program or analyzing an outbreak. Expert commentary: Pertussis surveillance is urgently required in order to define the burden of disease, to adapt vaccine strategies according to the type of pertussis vaccine used and to follow the evolution of the bacteria.

Characterization of the immune response induced by pertussis OMVs-based vaccine

For the development of a third generation of pertussis vaccine that could improve the control of the disease, it was proposed that the immune responses induced by the classic whole cell vaccine (wP) or after infection should be used as a reference point. We have recently identified a vaccine candidate based on outer membrane vesicles (OMVs) derived from the disease etiologic agent that have been shown to be safe and protective in mice model of infection. Here we characterized OMVs-mediated immunity and the safety of our new candidate. We also deepen the knowledge of the induced humoral response contribution in pertussis protection. Regarding the safety of the OMVs based vaccine (TdapOMVsBp,) the in vitro whole blood human assay here performed, showed that the low toxicity of OMVs-based vaccine previously detected in mice could be extended to human samples. Stimulation of splenocytes from immunized mice evidenced the presence of IFN-γ and IL-17-producing cells, indicated that OMVs induces both Th1 and Th17 response. Interestingly TdapOMVsBp-raised antibodies such as those induced by wP and commercial acellular vaccines (aP) which contribute to induce protection against Bordetella pertussis infection. As occurs with wP-induced antibodies, the TdapOMVsBp-induced serum antibodies efficiently opsonized B. pertussis. All the data here obtained shows that OMVs based vaccine is able to induce Th1/Th17 and Th2 mixed profile with robust humoral response involved in protection, positioning this candidate among the different possibilities to constitute the third generation of anti-pertussis vaccines.