Prevalence and characterization of pertactin deficient Bordetella pertussis strains in Brazil, a whole-cell vaccine country

Many countries have reported antigenic divergence among circulating Bordetella pertussis strains, mainly in those countries which introduced the acellular pertussis (aP) vaccine. This phenomenon can be seen, for example, with the recent rise of pertactin (Prn)-deficient B. pertussis strains, one of the antigens included in aP vaccine formulas. The whole cell pertussis (wP) vaccine has been used in Brazil since 1977 for the primary pertussis, diphtheria and tetanus immunization series. In 2014, the aP vaccine was recommended for women during pregnancy to protect infants in the first months of life. Our objective was to determine the prevalence of Prn-deficiency in 511 isolates of B. pertussis collected in Brazil during 2010-2016. All isolates were characterized, through PFGE and serotyping, and screened for the loss of Prn by ELISA. Prn-deficiency was confirmed by immunoblotting, and identification of the possible genetic markers was performed with PCR and Sanger sequencing. Results indicate that 110 PFGE profiles are currently circulating, with five profiles representing the majority, and the predominant serotype 3, has been gradually replaced by serotype 2 and serotype 2,3. ELISA screening and immunoblotting identified three Prn-deficient isolates. Genotypic characterization by PCR and sequencing indicated that one isolate had a promoter mutation in prn, while the other two did not have an obvious genetic explanation for their deficiency. While the lack of Prn was identified in a few isolates, this study did not detect a relevant occurrence of Prn-deficiency, until 2016, confirming previous observations that Prn-deficiency is likely aP vaccine-driven.

Impact of vaccinating pregnant women against pertussis on hospitalizations of children under one year of age in a tertiary hospital in Catalonia

INTRODUCTION

The recommendation for pertussis vaccination in pregnancy was established in Catalonia in February 2014. The objective of this study was to compare the hospitalization rate for pertussis in children under one year of age before and after the implementation of the vaccination program.

METHODS

Observational and retrospective study of patients under one year of age admitted to hospital with a diagnosis of pertussis. The hospitalization rate of patients under one year of age of the period prior to the vaccination program (2008-2013) was compared with the period with vaccination program (2014-2019) in the total of children under one year of age and in 2subgroups: children under 3 months and between 3-11 months.

RESULTS

Hospitalization rate was significantly lower in the period with vaccination program in children under one year of age and specifically in children under 3 months (2.43 vs. 4.72 per 1,000 person-years and 6.47 vs. 13.11 per 1,000 person-years, respectively). The rate ratios were: 0.51 (95% CI 0.36-0.73) for children under one year of age; 0.49 (95% CI 0.32-0.75) for those younger than 3 months and 0.56 (95% CI 0.30-1.03) for those with 3-11 months. No statistically significant differences were observed in the clinical severity between both periods.

CONCLUSION

The introduction of the pertussis vaccination program in pregnancy was associated with a global lower hospitalization rate for pertussis in children under one year of age and specifically in those under 3 months of age.

Pertussis vaccine effectiveness and duration of protection - A systematic review and meta-analysis

A comprehensive review of observational pertussis vaccine effectiveness (VE) studies is needed to update gaps from previous reviews. We conducted a systematic review of VE and duration of protection studies for the whole-cell (wP) and acellular (aP) pertussis vaccines and conducted a formal meta-analysis using random effects models. Evidence continues to suggest that receipt of any pertussis vaccine confers protection in the short-term against disease although this protection wanes rapidly for aP vaccine. We detected significant heterogeneity in pooled estimates due, in part, to factors such as bias and confounding which may be mitigated by study design. Our review of possible sources of heterogeneity may help interpretation of other VE studies and aid design decisions in future pertussis VE research.

Bordetella pertussis in School-Age Children, Adolescents, and Adults: A Systematic Review of Epidemiology, Burden, and Mortality in Asia

Cyclic epidemics of pertussis (whooping cough) have been observed globally over the past twenty years despite high infant vaccine coverage. The resurgence of pertussis in high-income countries is partly due to waning vaccine immunity in older children and adults, as well as better surveillance and diagnostics. Moreover, in adolescents and adults, pertussis symptoms are mild and similar to common cough syndromes, meaning that it is under-diagnosed in older populations. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in Asia. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible due to the mix of methodologies used. The results showed that in East Asia, including Japan, South Korea, China, and Taiwan, pertussis is circulating in older children and adults. Diphtheria-tetanus-pertussis (DTP4) coverage is high in East Asia, yet outbreaks observed in Japan and South Korea suggest that vaccine-acquired immunity had waned in adolescents and adults. Several school outbreaks in China show that pertussis is circulating in young children, with continued circulation in adolescents and adults. There was a lack of information from Southeast/South Asian countries, although pan-Asian serosurveys showed that recent pertussis infection was common in adolescents and in adults with persistent cough. To conclude, the circulation of pertussis in Asian countries with high DTP4 coverage supports the expansion of routine vaccination to include booster doses for children at school entry and adolescents. However, surveillance is weak or absent in many countries, meaning that the true burden of pertussis, particularly among older populations, is unknown.

Bordetella pertussis in School-Age Children, Adolescents, and Adults: A Systematic Review of Epidemiology, Burden, and Mortality in the Middle East

Despite modern diphtheria-tetanus-pertussis (DTP) vaccines and high vaccine coverage, a resurgence of pertussis (whooping cough) has been observed globally. In North America and Europe, high vaccine coverage in children has led to a shift in the age-specific peak incidence of infection away from infants and towards older children and adolescents. However, much less is known about the prevalence of pertussis in older children and adults in the Middle East. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in the Middle East. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible because of the mix of methodologies used. The results showed that surveillance data are weak or missing in most Middle Eastern countries, and among 24 epidemiological studies identified, most were from Iran (14), Israel (4), and Turkey (3), with single studies from the United Arab Emirates and Iraq. Despite various surveillance periods, clinical definitions, and antibody cut-off values used across the studies, the reported seroprevalence of pertussis antibodies suggested that adolescents and adults are commonly exposed to pertussis in the community and that vaccine-acquired immunity from childhood wanes. Few countries in the Middle East include a diphtheria-tetanus-acellular pertussis (Tdap) booster for adolescents on the national schedule. Israel was the only country with epidemiological data in a population that received Tdap, and the study showed that after the introduction of the adolescent booster dose, there was decrease in pertussis among children aged 5–14 years. To conclude, results from the Middle East suggest that in common with other regions, pertussis is widely circulating and that it might be shifting towards older age groups.

Construction and evaluation of a pertactin-deficient live attenuated pertussis vaccine candidate BPZE1 derivative

Pertussis, mainly caused by Bordetella pertussis, is a severe respiratory disease that can be fatal, especially in young infants. Vaccines, massively implemented since the middle of the last century, have substantially reduced the pertussis incidence, but have not been able to fully control the disease. One of the shortcomings of current pertussis vaccines is their inability to prevent infection by and transmission of B. pertussis, in contrast to immunity following natural infection. We have developed the live attenuated nasal vaccine BPZE1 and have shown that it prevents both disease and B. pertussis infection in preclinical models. This vaccine is now in clinical development. However, the initial clinical studies have suggested that vaccine take is hampered by pre-existing antibodies to pertactin. Here, we have constructed a pertactin-deficient BPZE1 derivative called BPZE1P in order to overcome this limitation. BPZE1P colonized the murine respiratory tract as efficiently as BPZE1 and induced antibodies at levels similar to those elicited by BPZE1. In the presence of pre-existing antibodies induced by acellular pertussis vaccination, BPZE1P colonized the mouse respiratory tract more efficiently than BPZE1. Both vaccines protected equally well the murine lungs and noses from challenge with laboratory and clinical strains of B. pertussis, including pertactin-deficient strains, against which current acellular pertussis vaccines are less efficient. BPZE1P may thus be an interesting alternative to BPZE1 to overcome vaccine take limitations due to pre-existing antibodies to pertactin.

Bordetella pertussis in School-Age Children, Adolescents, and Adults: A Systematic Review of Epidemiology, Burden, and Mortality in Africa

The Global Pertussis Initiative recommends diphtheria–tetanus–pertussis (DTP3) vaccination of infants aged < 1 year for all African countries, and recommends the vaccination of pregnant women as a primary prevention strategy. However, the role of older children and adults in the transmission of pertussis in Africa is not clear. A systematic search of MEDLINE, EMBASE, and BIOSIS was undertaken to identify studies published between 1 January 1990 and 17 June 2019, with information on pertussis epidemiology, burden of illness, and mortality in school-aged children, adolescents, and adults in Africa. Studies identified for inclusion were reviewed narratively because a statistical comparison was not possible because of the mix of methodologies used.

Studies from North Africa (Morocco, Tunisia, and Algeria) reported that although DTP4 vaccine coverage is high, severe pertussis-related complications persist in young children, vaccine-acquired immunity wanes in adolescents, and household contacts are important transmitters of infection. A serosurvey in Gambia showed that 6% of the general population had pertussis antibody levels suggesting recent infection, and studies from Senegal showed that pertussis infection was endemic despite high DTP3 coverage. During a pertussis outbreak in Ethiopia, the case fatality rate was 3.7% overall, and 6.3% among children aged 5–9 years. In a case-surveillance study in South Africa, the incidence of pertussis among hospitalized children was 526/100,000, and infection rates were higher in HIV-exposed and -infected children compared with uninfected children. In conclusion, the highest burden of pertussis in Africa is among infants, and surveillance is lacking in many African countries meaning that the burden of pertussis among infants and infection rates among older children and adults are not well reported, and likely underestimated.

Clinical characteristics and molecular detection of Bordetella pertussis in hospitalized children with a clinical diagnosis of whooping cough in Peru

Background and Objectives

Pertussis is an infectious disease caused by the Gram-negative bacterium Bordetella pertussis. In Peru, actual public health programs indicate that vaccination against B. pertussis must be mandatory and generalized, besides all detected cases must be reported. The objective of this study was to determine the prevalence of B. pertussis among children under five years of age with a presumptive diagnosis of whopping cough in Cajamarca, a region located in northern Peru.

Materials and Methods

The population of this cross-sectional study were children under 5 years old hospitalized as presumptive cases of pertussis during December 2017 to December 2018. The nasopharyngeal samples were analyzed by real-time PCR for the detection of B. pertussis.

Results

B. pertussis was identified as PCR + in 42.3% of our sample (33/78). The clinical presentation that was observed most frequently includes paroxysmal coughing (97%), difficulty breathing (69.7%), cyanosis (72.7%) and post-tussive emesis (60.6%). Additionally, pneumonia was the most observed complication (33.3%). Four of the patients with PCR+ for B. pertussis presented only lymphocytosis, five only leukocytosis, two patients with decreased leukocytosis and lymphocytes and only one patient with leukopenia and relative lymphocytosis. There was a percentage of 84.8% of unvaccinated children in the PCR+ group. Finally, the mother was the most frequent symptom carrier (18.2%).

Conclusion

In conclusion, in the studied population there is a high rate of PCR+ cases for B. pertussis. Laboratory values may show leukopenia or lymphopenia in patients with pertussis. It is necessary to use appropriate laboratory diagnostic tests in all infants with respiratory symptoms for B. pertussis. Since, the clinical diagnosis overestimates the diagnosis of pertussis.

An observational study of antibody responses to a primary or subsequent pertussis booster vaccination in Australian healthcare workers

Adult pertussis vaccination is increasingly recommended to control pertussis in the community. However, there is little data on the duration and kinetics of immunity to pertussis boosters in adults. We compared IgG responses to vaccination with a tetanus, low-dose diphtheria, low-dose acellular pertussis (Tdap) booster at 1 week, 1 month and 1 year post-vaccination in whole-cell (wP)-primed Australian paediatric healthcare workers who had received an adult Tdap booster 5-12 years previously, to those who received their first Tdap booster. Tdap vaccination was well tolerated in both groups. Previously boosted adults had significantly higher pre-vaccination IgG concentrations for all vaccine-antigens, and more were seropositive for pertussis toxin (PT)-specific IgG (≥ 5 IU/mL) (69.5%; 95% confidence interval (CI) 59.5-79.5) than adults in the naïve group (45.2%; 95% CI 32.8-57.5). Tdap vaccination significantly increased IgG responses 1 month post-vaccination in both groups. This increase was more rapid in previously boosted than in naïve adults, with geometric mean fold-increases in PT-IgG at 1 week post vaccination of 3.6 (95% CI 2.9-4.3) and 2.6 (95% CI 2.2-3.2), respectively. Antibody waning between 1 month and 1 year post-vaccination was similar between groups for IgG specific to PT and filamentous haemagglutinin (FHA), but was faster for IgG against pertactin (PRN) in the naïve group (GMC ratio 0.36; 95% CI 0.31-0.42) than the previously boosted group (GMC ratio 0.45; 95% CI 0.39-0.50). At baseline, all but one adult had protective IgG titres against tetanus toxin (TT) (≥ 0.1 IU/mL), and 75.6% in the previously boosted and 61.3% in the naïve group had protective IgG titres against diphtheria toxoid (DT) of ≥ 0.1 IU/mL. This study shows that pertussis immune memory is maintained up to 12 years after Tdap vaccination in wP-primed Australian adults. There was no evidence that pertussis immune responses waned faster after a booster dose. These findings support current recommendations of repeating Tdap booster vaccination in paediatric healthcare workers at least every 10 years. Clinical trials registry: ACTRN12615001262594.

The data used to build the models: Pertussis morbidity and mortality burden considering various Brazilian data sources

BACKGROUND

Pertussis is associated with significant disease burden in children worldwide. In addition to its cyclical nature, resurgences of pertussis cases, hospitalizations and deaths have been reported by many countries. We describe the dynamics of pertussis in Brazil, a middle-income country that has experienced a resurgence and that provides good quality data to allow building a dynamic transmission disease model.

METHODS

We conducted a descriptive analysis of pertussis burden considering data from the national disease surveillance system, national hospitalization information system and national mortality registry. Study period was 2000-2016. Absolute numbers and rates per 100,000 inhabitants over time, by age sub-groups and geographical regions are presented.

RESULTS

From 2000 to 2016, a total of 37,299 reported pertussis cases, 25,240 hospitalizations, and 601 deaths due to pertussis were reported. Although the outcomes - pertussis cases, hospitalizations, and deaths - come from independent information systems, our results document low disease burden with periodic increases every 3-4 years during the years 2000-2010, followed by a sharp increase which peaked in 2014. In both periods, disease burden is concentrated in young children, while its more serious outcomes - hospitalizations and deaths, are concentrated in infants. Pre-outbreak and outbreak disease burden as well as timing of peak during the outbreak period vary by states and within geographical regions, representing valuable resources of data for modelling purposes.

CONCLUSION

Consistent disease burden patterns were observed over time in Brazil using a variety of data sources. Given the scarcity of good epidemiological data on pertussis available from low- and middle-income countries, our reported data provide valuable information for the assessment of the public health impact and cost-effectiveness modelling studies of newer strategies to prevent and control pertussis. These data were used to build and calibrate a national dynamic transmission model, which was used to evaluate the cost-effectiveness of maternal immunization. Clinical Trial registry name and registration number: Not applicable.

The traditional use of southern African medicinal plants for the treatment of bacterial respiratory diseases: A review of the ethnobotany and scientific evaluations

ETHNOPHARMACOLOGICAL RELEVANCE

Multiple plant species were used traditionally in southern Africa to treat bacterial respiratory diseases. This review summarises this usage and highlights plant species that are yet to be verified for these activities.

AIM OF THE STUDY

This manuscript reviews the traditional usage of southern African plant species to treat bacterial respiratory diseases with the aim of highlighting gaps in the literature and focusing future studies.

MATERIALS AND METHODS

An extensive review of ethnobotanical books, reviews and primary scientific studies was undertaken to identify southern African plants which are used in traditional southern African medicine to treat bacterial respiratory diseases. We also searched for southern African plants whose inhibitory activity against bacterial respiratory pathogens has been conmfirmed, to highlight gaps in the literature and focus future studies.

RESULTS

One hundred and eighty-seven southern African plant species are recorded as traditional therapies for bacterial respiratory infections. Scientific evaluations of 178 plant species were recorded, although only 42 of these were selected for screening on the basis of their ethnobotanical uses. Therefore, the potential of 146 species used teraditionally to treat bacterial respiratory diseases are yet to be verified.

CONCLUSIONS

The inhibitory properties of southern African medicinal plants against bacterial respiratory pathogens is relatively poorly explored and the antibacterial activity of most plant species remains to be verified.

Bordetella pertussis, a reemerging pathogen in pediatric respiratory infections. A study in Quito, Ecuador

Bordetella pertussis is the causative agent of pertussis, which mainly affects unvaccinated children, while Bordetella parapertussis causes a disease presenting clinical characteristics that are indistinguishable from whooping cough. Despite high vaccination coverage, pertussis remains a public health concern worldwide, with approximately 140000 cases reported annually. Here we determined the prevalence of B. pertussis and B. parapertussis infection among infants under one year of age by polymerase chain reaction (PCR); our aim being to identify whether the data obtained relates to the relevant sociodemographic and clinical data. The study included 86 samples of nasopharyngeal swabs from infants aged between 0-12 months, who were reported as probable cases of whooping cough by the health centers around the Ecuadorian highlands, from August 2016 to July 2017. The nasopharyngeal swabs were cultured and microbiological and molecular analyses were performed. B. pertussis was identified by PCR in 41% of the samples (30/86), more than half of which corresponded to infants aged between 0-3 months. Moreover, a statistically significant correlation (p<0.05) between the identification of bacteria in culture and the catarrhal stage of the disease was observed. The results obtained from the study highlighted the need for an active national surveillance of pertussis, in particular for laboratory testing, to provide a highly sensitive and more specific diagnosis of Bordetella infection.

Seasonal Bordetella pertussis pattern in the period from 2008 to 2018 in Germany

BACKGROUND

After the introduction of a vaccine against B. pertussis the seasonal pattern with the highest number of infections in the spring to summer months changed. Recent studies from around the world suggest that B. pertussis infections again follow a seasonal pattern with increased incidence in summer.The aim of this study was to investigate whether respiratory infections caused by B. pertussis in the period from January 2008 to December 2018 also seasonally spread in Germany and if so, when the B. pertussis activity peaked.

METHODS

We tested 19,031 samples, mainly from Southern Germany, collected in the period from January 2008 to December 2018 using a Multiplex PCR assay. We assessed the number and proportion of samples positive for B. pertussis, stratified by patient's age and month. The seasonal distribution was investigated by plotting the average proportion of positive samples for each month.

RESULTS

We observed a B. pertussis seasonality with the highest number of positive samples in the months from June until September. In contrast, testing of samples for B. pertussis was requested most frequently in the period from October until March. The proportion of positive samples increased earlier in adolescents (age 10 to 19) than in other age groups.

CONCLUSIONS

We found a seasonality of B. pertussis infections in Germany, which differs from the time when most samples are sent in for testing of B. pertussis. Our study suggests that clinicians should be more aware of B. pertussis infections in the months from June until September to prevent further transmission to vulnerable family members.

Neurologic alterations in an HIV adult patient with pertussis: a case report

Background

Pertussis is a highly contagious disease of public health interest caused by the bacterium Bordetella pertussis. Although its incidence has decreased substantially after the introduction of a vaccination, the burden of the disease remains high. Although the paroxysmal phase is highly disabling, complications are uncommon and more prevalent in children than in adults. The most frequent neurological complication is encephalopathy, but seizures, paresis, paraplegia, ataxias, aphasias, and decerebration postures have also been described. The complication of decerebration postures has not been previously reported in adults.

Case presentation

We present a video case of an adult HIV patient with severe coughing paroxysms, post-tussive emesis and syncope, whose workup confirmed the diagnosis of a B. pertussis respiratory infection. During hospitalization, he had fluctuant encephalopathy and post-tussive decerebration postures following paroxysms. He was treated with antibiotic therapy and finally sent home without residual neurological deficits.

Conclusion

This case illustrates the biological plausibility of neurologic complications of pertussis in adults, which, albeit rare, can cause important morbidities. Future research should explore whether there are differences in the clinical presentation, risk factors and pathophysiology of the disease among adults or interventions aimed at preventing or treating pertussis encephalopathy.

Urgent Bordetella PCR in infants under 3 months, a useful tool in the Pediatric Emergency Department

INTRODUCTION

Whooping cough in patients aged under 3 months has higher rates of morbimortality. Hospitalization and treatment with azithromycin is generally recommended. Many patients with cough without other signs of alarm, are admitted and started antibiotic therapy until a result of Bordetella-PCR is available. This technique, when performed urgently, can provide the diagnosis in a few hours. The objective of this study is to determine if its generalisation in the Emergency Department allows to improve patient management.

METHODS

Retrospective cohort study of patients aged under 3 months who underwent Bordetella-PCR testing from upper respiratory tract secretions since March 2011 to December 2017. From December 2015 the test was performed urgently.

RESULTS

One hundred and fifty-eight PCR were performed, 16 (10%) were positive for B. pertussis. Negative results (142; 90%) were divided in 2 cohorts: conventional-PCR, with 74 cases, and urgent-PCR, with 68 cases. The 2 groups were homogeneous in terms of clinical and analytical characteristics. In the urgent-PCR group there was 18% reduction in chest X-rays performed (P=.008). There were 33 (48.5%) patients admitted in the urgent-PCR group, compared to 49 (66.2%) in the conventional-PCR (P=.042). Antibiotic treatment was initiated in 32% of the patients in the urgent-PCR group compared to 67% in the conventional-PCR group (P=.000047), without observing any significant increase in the number of visits to the Emergency Department or worse clinical performance.

CONCLUSIONS

The introduction of urgent PCR in the Emergency Department is a useful tool in the management of infants under 3 months of age with suspected pertussis, since it can avoid unnecessary admissions, diagnostic tests and antibiotic treatments.

Comparative genomics of whole-cell pertussis vaccine strains from India

BACKGROUND

Despite high vaccination coverage using acellular (ACV) and whole-cell pertussis (WCV) vaccines, the resurgence of pertussis is observed globally. Genetic divergence in circulating strains of Bordetella pertussis has been reported as one of the contributing factors for the resurgence of the disease. Our current knowledge of B. pertussis genetic evolution in circulating strains is mostly based on studies conducted in countries using ACVs targeting only a few antigens used in the production of ACVs. To better understand the adaptation to vaccine-induced selection pressure, it will be essential to study B. pertussis populations in developing countries which are using WCVs. India is a significant user and global supplier of WCVs. We report here comparative genome analyses of vaccine and clinical isolates reported from India. Whole-genome sequences obtained from vaccine strains: WCV (J445, J446, J447 and J448), ACV (BP165) were compared with Tohama-I reference strain and recently reported clinical isolates from India (BPD1, BPD2). Core genome-based phylogenetic analysis was also performed using 166 isolates reported from countries using ACV.

RESULTS

Whole-genome analysis of vaccine and clinical isolates reported from India revealed high genetic similarity and conserved genome among strains. Phylogenetic analysis showed that clinical and vaccine strains share genetic closeness with reference strain Tohama-I. The allelic profile of vaccine strains (J445:ptxP1/ptxA2/prn1/fim2-1/fim3-1; J446: ptxP2/ptxA4/prn7/fim2-2/fim3-1; J447 and J448: ptxP1/ptxA1/ prn1/fim2-1/fim3-1), which matched entirely with clinical isolates (BPD1:ptxP1/ptxA1/prn1/fim2-1 and BPD2: ptxP1/ptxA1/prn1/fim2-1) reported from India. Multi-locus sequence typing (MLST) demonstrated the presence of dominant sequence types ST2 and primitive ST1 in vaccine strains which will allow better coverage against circulating strains of B. pertussis.

CONCLUSIONS

The study provides a detailed characterization of vaccine and clinical strains reported from India, which will further facilitate epidemiological studies on genetic shifts in countries which are using WCVs in their immunization programs.

Factors Affecting the Implementation Process of Pertussis [Tdap] Immunization in Pregnant Women in an Italian Region: A Qualitative Study

Whooping cough (pertussis) represents one of the most prevalent vaccine-preventable diseases in Western countries, capable of causing disease in infants, with a high risk of severe complications. To protect new-borns from pertussis, many countries have introduced the acellular pertussis adult vaccine in combination with tetanus and diphtheria toxoids for women in the third trimester of pregnancy. Thanks to the approval of the new National Immunization Prevention Plan 2017-2019: Italy is among those countries. The Italian health-care system is a regionally based National Health Service, therefore, regions organize and implement new vaccination strategy on their own. This study focuses on Tuscany's experience in implementing the maternal pertussis vaccination. The present study had a qualitative design: we obtained information about the implementation process through interviews with relevant stakeholders involved in the planning or implementation of vaccination programme at different levels. We noticed heterogeneous implementation's status between Tuscan Health Care Departments. The most frequently reported barriers influencing the success of the implementation process of this prevention strategy included: lack of accountability, lack of enabling instruments, financial constraints, logistics barriers, training deficiencies, attitudes of health care workers, and lack of communication experts. The implementation of new vaccination programs is complex and challenging. Often the importance of education and information activities targeting health professionals are underestimated and underfunded. These elements would need to be carefully considered and adequate provisions should be made to address them when designing and implementing effective vaccine interventions.

High healthcare resource utilisation due to pertussis in Australian adults aged 65 years and over

BACKGROUND

In the context of co-morbid illness and increasing age, data on excess morbidity from pertussis in older adults is crucial for immunisation policy but has been largely limited to case-series.

METHODS

We designed a matched case-control study nested within a population-based cohort of 267,153 adults aged ≥45 years in New South Wales, Australia (The 45 and Up Study cohort). Excess hospital bed days, emergency department (ED) admissions, general practitioner (GP) visits, and prescriptions were estimated using negative binomial regression models. An additional self-controlled analysis was also conducted to validate the main models, and to evaluate results for those with either asthma or a body mass index (BMI)≥30 compared to those without these risk factors.

RESULTS

Based on 524 pairs of PCR-confirmed pertussis cases and matched controls, we estimated an excess healthcare utilisation per case of 2.5 prescriptions (95% CI: 0.2-4.7), of which 1.1 (95% CI: 0.5-2.2) were antibiotics, 2.3 GP visits (95% CI: 2.0-2.6), and 0.1 ED admissions (95% CI: 0.1-0.2). Compared to those 45-64 years, cases ≥65 years had a significantly greater excess for all prescriptions (1.1 vs 4.7/case), antibiotic prescriptions (0.1 vs 2.2/case), and ED admissions (0.1 vs 0.2/case), but no significant excess of respiratory-related hospital bed days. An additional self-controlled analysis confirmed that cases with either asthma or BMI≥30 had higher overall healthcare utilisation but this was not associated with pertussis infection.

CONCLUSION

We found a substantial excess outpatient healthcare burden among adults aged 65 years and over with PCR-confirmed pertussis, supporting further evaluation of preventive measures.

Pertussis Vaccines and Vaccination Strategies. An Ever-Challenging Health Problem

Vaccines and vaccination against pertussis (whooping cough) have had one of the longest and most complex history, with alternating splendour and public disbelief, enthusiasm and concerns, overall resulting in changes in composition and replacement of vaccines, and associated vaccination strategies, including use of different vaccines in different countries, with no apparent equals for other bacterial vaccines. Of this both frustrating and exciting venue no end has been reached. In this note, I am shortly recapitulating the history of pertussis vaccines, from the inactivated, whole-cell vaccine to the acellular ones, with their merits and limitations, particularly concerning the debated issue of waning immunity, and a glimpse on a new vaccine proposal. Some reflections on the complexity and apparent peculiarity of this field are also made to the final scope of discussing aspects of the evolving strategies of disease control in a high-income country.

Timeliness and equity of infant pertussis vaccination in wales: Analysis of the three dose primary course

Infants aged under one year are at the highest risk of severe complications or death from pertussis infection. Prompt vaccination with a three dose course at two, three and four months of age decreases the amount of time they are vulnerable following waning of maternal antibodies. In Wales, uptake of all three doses of the primary course of pertussis containing vaccine is high. However, timeliness and equity at a population level have not been previously reported. This analysis included 163,733 children born from 1st January 2013 to 31st December 2017. In this cohort 87.9% received the first dose of a pertussis containing vaccine by 12 weeks of age, 87.1% had received all three doses by 24 weeks of age, and 96.3% received three doses by 52 weeks of age. Differences in uptake between those living in the most deprived and least deprived quintiles of Lower Super Output Area (LSOA) were smaller than differences in timeliness, but statistically significant. In 2017 the difference in timely uptake between those living in the most and least deprived quintiles was 4%, 5% and 7% for doses one, two and three respectively. There was a difference of 10% in the proportion of infants receiving all three primary vaccinations on time between the most and least deprived quintile of LSOAs. Consideration is needed on interventions that will help improve timeliness such as enhanced follow up of defaulters, electronic communication between primary care data systems, enhanced health visitor intervention and opportunistic vaccination in those who fail to attend scheduled vaccination appointments. There is also the need for routine monitoring of timeliness and further research into what influences delayed vaccination.

Population dynamics and antigenic drift of Bordetella pertussis following whole cell vaccine replacement, Barcelona, Spain, 1986-2015

Among the factors associated with the resurgence of whooping cough, special emphasis has been given to pathogen adaptation after the introduction of the acellular vaccine (ACV). To assess the impact of the vaccine transition strategy from whole-cell vaccine (WCV) to ACV on population dynamics of Bordetella pertussis in Barcelona (Spain), we studied 339 isolates collected from 1986 to 2015 by PFGE and multi-locus variable-number tandem repeat analysis (MLVA). Additionally, allelic variants for the pertussis toxin and its promoter, pertactin, type 3 fimbriae and fimbrial serotyping were assessed to determine its antigenic drift. A shift was observed in the B. pertussis population as well as in its antigenic profile concurrently with the introduction of ACV in Barcelona. Four out of the five most prevalent PFGE profiles were replaced by new profiles following the ACV introduction. MLVA type 27 was the dominant genotype, and its frequency increased from 25% to 79.3% after WCV replacement. Antigen typing demonstrated the emergence of prn2, ptxP3, fim3-2 and a shift from the fimbriae 3 to the fimbriae 2 serotypes after the ACV introduction. Our findings support the presence of population and antigenic dynamic changes in B. pertussis likely driven by the introduction of ACV.

Safety of Maternal Immunization Against Pertussis: A Systematic Review

The WHO recommends vaccination of all children against pertussis. However, newborn infants remain vulnerable to infection. Pertussis vaccination during pregnancy has been introduced in several countries to protect newborns via transplacental transfer of maternal pertussis antibodies to the infant. We reviewed the impact of maternal pertussis vaccination on the health of pregnant women, the developing fetus, and health of the newborn. We searched PubMed/MEDLINE, EMBASE, Scopus (Elsevier), Cochrane Database of Systematic Reviews, ProQuest, and Science Direct to identify studies that assessed the safety of maternal pertussis vaccination. Twenty-seven English language publications published between January 1995 and December 2018 were included in this review. Pregnant women receiving pertussis vaccines did not have increased rates of systemic or local reactions. There were no safety concerns with repeat vaccination with other tetanus-containing vaccines or their concomitant administration with influenza vaccines. Maternal pertussis vaccination did not adversely affect pregnancy, birth or neonatal outcomes. This review confirms the safety of maternal pertussis vaccination during pregnancy. FUNDING: Sanofi Pasteur. Plain language summary available for this article.

Impact of the adolescent pertussis booster dose on the incidence of pertussis in British Columbia and Quebec, Canada

Impact of an adolescent tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine program was assessed in the provinces of British Columbia and Quebec, Canada. In both provinces, the Tdap booster has been in place since 2004, targeting Grade 9 students (14-15-years-of-age). Incidence rate ratios (IRRs) standardizing notification rates among teens 15-19-years-old to infants <1-year-old decreased following introduction of the Tdap program and were significantly halved during the 2009-2012 post-Tdap versus 2000-2003 pre-Tdap period. This program impact, however, is tempered by the observation that pertussis incidence among 15-19-year-olds was already lower than any other pediatric age group, following gradual decline from pre-teen rates even before the Tdap program. The risk of hospitalization among adolescents 15-19-years-old was also low throughout at <1/100,000. Furthermore, IRRs increased in 2013-2017 when an increasing proportion of 15-19-year-olds were primed with acellular pertussis vaccine only, suggesting short-lived Tdap booster-dose effectiveness that warrants further monitoring.

Cost-effectiveness analysis of universal adult immunization with tetanus-diphtheria-acellular pertussis vaccine (Tdap) versus current practice in Brazil

BACKGROUND

A pertussis outbreak occurred in Brazil from 2011 to 2014, despite high coverage of whole-cell pertussis containing vaccines in early childhood. Infants were the most affected. This study aimed to evaluate the cost-effectiveness of introducing universal adult vaccination with Tdap into the National Immunization Program in Brazil.

METHODS

Economic evaluation using a dynamic model to compare two strategies: (1) universal vaccination with single dose of Tdap at 20 years of age and (2) current practice (only pregnant women pertussis vaccination). The health system perspective was adopted. Temporal horizon was 10 years. Discount rate of 5% was applied to costs and benefits. Vaccine effectiveness (VE) was obtained from a population-based observational study. Epidemiological, resource utilization and cost estimates were obtained from the Brazilian Health Information Systems. The primary outcome was cost per life year saved (LYS), based on life expectancy at birth in Brazil in 2015. Univariate and multivariate sensitivity analysis were performed.

RESULTS

Adult vaccination with VE of 82.6% and coverage of 40%, at price of US$7.01 per dose, and assuming herd protection would avoid 167 infant deaths by pertussis, saving 12,325 years of life and costing a total of US$105495891.61, from the health system perspective. The universal immunization would result in ICER of US$8459.13. The results were highly sensitive to disease incidence.

CONCLUSIONS

The results suggest that universal adult vaccination with Tdap would not be a cost-effective intervention for preventing pertussis cases and deaths in infants in Brazil.

The health and economic burden of pertussis in Canada: A microsimulation study

BACKGROUND

Despite excellent vaccine coverage, pertussis persists in Canada, with high incidence during recent outbreaks and non-negligible incidence in non-outbreak years. While Canadian pertussis incidence is well-characterized, the full health and economic impact of pertussis have not been examined in Canada. We estimated age-specific life years (LYs) and quality-adjusted life years (QALYs) lost, and costs due to pertussis in Ontario, Canada, using a model-based approach.

METHODS

We developed a microsimulation model to simulate pertussis natural history. Daily probabilities of pertussis complications, hospitalizations, and disease sequelae as well as utilities and costs for health states were literature-derived. A healthcare payer perspective was used with a lifetime time horizon. Model outcomes were compared to those from a model with no pertussis health states. Probabilistic sensitivity analyses were used to generate distributions for estimates. Economic burden was estimated by multiplying case cost estimates by annual age-specific incidence.

RESULTS

Overall, LYs lost per pertussis case was low, with negligible LYs lost in those aged >4 years. Infants (<6 months) had the greatest mean QALY loss per case (0.58), while adults lost only 0.05 QALYs per case. Infants experienced the greatest mean cost per case of $22,768 (95% CI: 21,144-23,406). Case costs generally declined with age, but increased in seniors (aged 65+) with mean cost of $1920 (95% CI: 1800-2033). Based on historic age-specific incidence, pertussis costs the Ontario healthcare system approximately $7.6-$21.5 M annually. In total economic cost estimates with QALYs valued at 1xGDP (3xGDP) per capita, the net impact of pertussis in Ontario was estimated at $21.7-$66.5 M annually ($50.0-$156.3 M). For all of Canada, total economic costs were estimated at $79.6-$241.3 M ($187.5-$580.5 M) annually.

CONCLUSION

The health and economic consequences of pertussis persistence are substantial and highlight the need for improved control strategies.