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.

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.

Ellipsometric-based novel DNA biosensor for label-free, real-time detection of Bordetella parapertussis

Pertussis (or whooping cough) is a contagious disease mainly affecting infants and children and predominantly caused by Bordetella pertussis followed by Bordetella parapertussis. B. parapertussis causes a milder cough but usually symptomatically appears like B. pertussis infection. Thus the epidemiology of illness caused by B. parapertussis is not well understood. In this study, a sensitive and specific method for the rapid diagnosis of B. parapertussis is presented. The covalent immobilization of thiol-terminated DNA oligonucleotides (ss DNA SAM) on a silicon surface by disulfide bond formation is investigated with atomic force microscopy (AFM) and ellipsometry. The measurements indicated an average layer thickness of 5 ± 0.84 nm for 2 μg/μl concentration and 24 h incubation time. This thickness changed to 8.4 ± 0.92 nm for the same concentration (2 μg/μl) by altering the incubation time to 48 h. Ellipsometric data recorded before and after hybridization of B. parapertussis revealed an increase in mean grain area from 91 nm2 to 227 nm2 and a change in the refractive index from 1.489 to 1.648 for 2 μg/μl B. parapertussis, respectively. This change in the refractive index was used to evaluate the amount of adsorbed molecules and their density. The results showed that the density of adsorbed molecules increased from 0.2 to 0.97 g/cm3 after B. parapertussis attachment, respectively. To confirm the hybridization of B. parapertussis to ss DNA SAM, the ds DNA SAM was denatured and the ss DNA SAM surface was reproduced with an average height variation of 6.42 ± 0.75 nm. This showed the stability of the DNA film that can be tuned by varying the concentration and incubation time, thus providing a robust method for the label-free detection of B. parapertussis other than routinely used PCR detection.

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

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

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

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

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

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

Pertussis diagnostic practices of general practitioners in the Netherlands: A survey study

Background: Pertussis testing is most important when transmission to vulnerable groups is likely. Patients with signs and symptoms suggestive of pertussis are prevalent in primary care, yet general practitioners' (GPs) reasons (not) to test for pertussis are largely unknown.Objectives: To evaluate GP-reported diagnostic practices for pertussis, reasons for (not) testing and intentions towards testing among GPs.Methods: A total of 594 Dutch GPs were invited by email to participate in a survey study including a questionnaire reflecting on their pertussis diagnostic practices, reasons for (not) testing and the intention to test for pertussis in the year of 2013. Intention to test was measured as the likelihood to test for eight clinical vignettes.Results: In total, 122 GPs (21%) completed the online questionnaire. Most GPs reported having diagnosed at least one pertussis case (84%) in the previous year. Of all GPs, 14% did not perform any pertussis tests in the last year. The most reported reason for testing was to confirm the clinical pertussis diagnosis (70%); the most reported reason for not testing was that the diagnostic test result does not influence treatment (70%). Overall, judging from the clinical vignettes, GPs reported being more likely to perform diagnostic testing based on symptoms than based on vulnerable groups at risk.Conclusion: In contrast to national guidelines, our results suggest that GPs report to test for pertussis mainly based on clinical symptoms rather than based on protecting vulnerable groups at risk.

Pertussis detection in children with cough of any duration

Background

The diagnosis of pertussis in clinical practice continues to be a challenge worldwide as the symptoms are variable. We aimed to determine the prevalence of pertussis in Chinese children irrespective of cough duration and explore the clinical characteristics of children with pertussis with different cough durations.

Methods

This was a prospective study of children 1 month to 11 years of age with different cough durations in one large Chinese hospital. Bilateral deep posterior nasopharyngeal swabs and venepuncture for full blood count, CRP and serology and sputum were obtained when possible for investigation. E-test strips were used for testing the susceptibility of the B.pertussis isolates against erythromycin, azithromycin, sulphamethoxazole/trimethoprim, levofloxacin, amoxicillin and doxycycline. Demographic, clinical and laboratory information on culture and antimicrobial susceptibility testing was collected from children, and analyzed using SAS v.10 (SAS Institute Inc., USA).

Results

After exclusions we analyzed 312 children. Ninety-seven (31.1%) children had laboratory evidence of pertussis. When grouped by cough duration, few characteristics were significant between children with and without pertussis. Of the 36 isolates, 72.2% (26/36)could not be inhibited by erythromycin and azithromycin at all. The MIC50 and MIC90 to amoxicillin were 0.75 mg/L and 1 mg/L respectively, sensitive to amoxicillin by the EUCAST points.

Conclusions

The “one-size-fits-all” clinical pertussis case definition is no longer optimal to recognize this disease. A large comprehensive study of children with all types of cough is required to make substantial inroads into increasing both the sensitivity and specificity in pertussis diagnosis, which will have a beneficial impact on public health. Amoxicillin maybe an alternative for children with marolide-resistant B.pertussis infection; however, local sensitivities are required to inform clinical practice.

Proteomics of Bordetella pertussis whole-cell and acellular vaccines

OBJECTIVES

Bordetella pertussis is the etiological agent of whooping cough, a bacterial infection of especially children, which may be fatal without treatment. In frame of studies to investigate putative effects of vaccination on host-pathogen interaction and clonal distribution of strains, in addition to Corynebacterium diphtheriae and Clostridium tetani toxoid vaccines, also whole-cell and acellular pertussis vaccines were analyzed by mass spectrometry.

DATA DESCRIPTION

LC-MS/MS spectra were generated and analyzed using B. pertussis genome data and proteins present in whole-cell and acellular pertussis vaccines were identified. Subcellular localization of proteins and presence of signal peptides was determined bioinformatically.

Disparities in Tdap Vaccination and Vaccine Information Needs Among Pregnant Women in the United States

Objectives The Advisory Committee on Immunization Practices (ACIP) and the American College of Obstetricians and Gynecologists (ACOG) recommend that pregnant women receive the Tdap vaccine during every pregnancy. The objectives of this paper are to evaluate disparities in Tdap vaccination among pregnant women in the U.S., and to assess whether race/ethnicity and other characteristics are associated with factors that inform pregnant women's decisions about Tdap vaccination. Methods We conducted a nationwide cross-sectional web-based survey of pregnant women in the U.S. during June-July 2014. The primary outcome was self-reported vaccination status with Tdap during pregnancy, categorized as vaccinated, unvaccinated with intent to be vaccinated during the current pregnancy, and unvaccinated with no intent to be vaccinated during the current pregnancy. Secondary outcomes included factors that influenced women's decisions about vaccination and information needs. We used multivariable logistic regression models to estimate odds ratios for associations between race/ethnicity and the outcomes. Results Among pregnant women who completed the survey, 41% (95% CI 36-45%) reported that they had received Tdap during the current pregnancy. Among those women in the third trimester at the time of survey, 52% (95% CI 43-60%) had received Tdap during the current pregnancy. Hispanic women had higher Tdap vaccination than white women and black women (53%, p < 0.05, compared with 38 and 36%, respectively). In logistic regression models adjusting for maternal age, geographic region, education, and income, Hispanic women were more likely to have been vaccinated with Tdap compared with white women (aOR 2.29, 95% CI 1.20-4.37). Higher income and residing in the western U.S. were also independently associated with Tdap vaccination during pregnancy. Twenty-six percent of surveyed women had not been vaccinated with Tdap yet but intended to receive the vaccine during the current pregnancy; this proportion did not differ significantly by race/ethnicity. The most common factor that influenced women to get vaccinated was a health care provider (HCP) recommendation. The most common reason for not getting vaccinated was a concern about safety of the vaccine. Conclusions This study found that some disparities exist in Tdap vaccination among pregnant women in the U.S., and HCPs have an important role in providing information and recommendations about the maternal Tdap recommendation to pregnant women so they can make informed vaccination decisions.

[Clinical analysis of 309 hospitalized children with pertussis-associated pneumonia]

Objective: To investigate the clinical characteristics of pertussis-associated pneumonia and analyze it's risk factors. Methods: Clinical data were taken from Shenzhen Children's Hospital with Bordetella pertussis infection and confirmed by culture or real-time polymerase chain reaction (PCR) of nasopharyngeal secretion from October 2013 to December 2015. Patients were divided into two groups, those with radiologically confirmed pneumonia in the course of their disease and those with not. Clinical data were retrospectively analyzed and compared. T test, Rank sum test or chi square test were used for comparison between groups. Risk factors were analyzed by unconditional Logistic regression analysis. Results: A total of 501 children hospitalized with Bordetella pertussis infection were included. Among them, 309 patients were diagnosed with pneumonia. The median age was 3 (2, 6) months. Symptoms were paroxysmal cough (n=252, 81.6%), tachypnea (n=69, 22.3%), and cyanosis (n=105, 34.0%). The time from onset of cough to radiologically confirmed pneumonia was between 1 and 66 days with a median of 9 (5.5, 15.0) days. The most common pathogen of coinfection was respiratory syncytial virus (RSV)(20 cases). Macrolides were used in 306 cases for (8.2±3.6) days. All cases showed significant improvement. There were more male children (62.1% (192/309) vs. 50.3% (95/189) , χ(2)=6.768, P=0.009), and more instances of comorbidities (13.3% (41/309) vs.5.8% (11/189) , χ(2)=6.957, P=0.008) in the pneumonia group than in the other. The age was younger (3 (2,6) vs.4 (2,6) months, Z=32.91, P=0.000) in pneumonia group than in the other. Male sex, younger age, and underlying disease were independent risk factors for pertussis-associated pneumonia (OR=1.648, 1.486, 2.695, P=0.008, 0.036, 0.005). Conclusions: Pneumonia, as a complication of pertussis, is very easy to see in hospitalized children. The duration of hospitalization is extensive. It is more likely to happen in children who are male, young, and having underlying diseases. Pneumonia is easy to occur in the first 2 weeks of the course of disease.

[Clinical analysis of children with pertussis and significance of respiratory virus detection in the combined diagnosis]

Objective: To analyze the clinical data of children with pertussis and explore the necessity of respiratory virus detection in the combined diagnosis so as to improve the clinician's understanding and standardize the diagnosis and treatment of pertussis in children. Method: Clinical data and laboratory examination of 195 suspected pertussis children between Jan. 2015 and Dec. 2016 in Children's Hospital Affiliated to Capital Institute of Pediatric were analyzed retrospectively. Result: The nasopharyngeal secretions were collected from 195 suspected pertussis children, PCR was employed to detect the nucleic acid of Bordetella pertussis. Meanwhile, 172 of 195 cases were screened for antigens of 7 common respiratory viruses by direct immunofluorescence (DIF) (respiratory syncytial virus(RSV), adenovirus(ADV), influenza virus A and B, parainfluenza viruses type Ⅰ-Ⅲ). (1) Eighty cases were positive in pertussis nucleic acid detection (positive rate was 41.0%), 47 males and 33 females, age ranged from one month to ten years, all of them had paroxysmal cough (100.0%), 50 cases with spasmodic cough (62.5%), 9 cases with vomiting after cough(11.2%), 22 cases with cyanosis after cough(27.5%), 13 cases with roaring after cough(16.2%), 4 cases with dyspnea(5.0%), 18 cases were diagnosed as pneumonia by chest radiography(22.5%) and 1 case was diagnosed as pertussis encephalopathy(1.2%); (2) 172 cases of respiratory virus DIF detection were completed and 69 of them were positive(positive rate was 40.1%), including 32 cases positive for RSV(18.6%), 29 cases for PIVⅢ(16.8%); (3) In 80 confirmed pertussis children, 66 cases of respiratory virus DIF detection were completed and 9 were positive(9/66, 13.6%), including 7 cases positive for PIVⅢ. The clinical manifestations were cyanosis after cough(6 cases), dyspnea(2 cases) and pneumonia were diagnosed by chest radiography in 3 cases, the clinical symptoms of these children were more prominent than children with general pertussis; (4) Patients were divided into three groups according to the pathogens: 57 cases in single pertussis group, 32 cases in RSV infection group, 22 cases in single PIVⅢ infection group.The cases of spasmodic cough in Pertussis group was 35 (61.4%), RSV infection group was 7(21.9%), single PIVⅢ infection group was 8(36.4%), compared with the other two groups, the incidence of spasmodic cough were higher in Pertussis group (χ(2) =12.850, 4.013, P<0.05). The cases of roaring in Pertussis group was 11 (19.3%), RSV infection group was 1(3.1%), single PIVⅢ infection group was 0, and the incidence were higher in Pertussis group (χ(2)=4.596, 4.932, P<0.05). The cases of dyspnea in Pertussis group was 2 (3.5%), RSV infection group was 11(34.4%), single PIVⅢ infection group was 0, and the incidence was higher in RSV infection group (χ(2)=15.654, 9.487, P<0.01). Conclusion: Pertussis is common in children, especially in unvaccinated or incompletely vaccinated infants. The typical clinical manifestation is paroxysmal spasmodic cough; complicated with PIVⅢ infection is a risk factor for sever pertussis. Early detecting of Bordetella by PCR is helpful for the diagnosis of pertussis, RSV and PIVⅢ are the main pathogen for Pertussis-like syndrome. The detection of respiratory virus is helpful for differential diagnosis and medication guidance.

Prenatal vaccination of mothers and hepatitis B vaccination of their infants

Tetanus, diphtheria, and acellular pertussis (Tdap) vaccination and influenza vaccination are recommended during pregnancy primarily to prevent influenza and pertussis in mothers and their infants. This study examines associations between prenatal Tdap vaccination and influenza vaccination of mothers and hepatitis B vaccination of their infants. A retrospective cohort study was conducted using data from electronic medical records from 15,468 deliveries to 14,925 mothers occurring April 2, 2014-December 3, 2016 at a university hospital in Texas. Hepatitis B vaccine receipt in the first 3 days of life was dichotomized. Margins post-estimation commands in Stata SE 15.1 were used to obtain predicted probabilities and risk differences after estimating odds ratios in logistic regression with robust variance estimates. Adjusted models included maternal age, race/ethnicity, Medicaid use, year of delivery, parity, and gravidity. Infants of mothers who received prenatal influenza vaccination in the 2014-2015 and 2015-2016 influenza seasons were more likely than those of mothers who did not to receive a hepatitis B vaccine in their first 3 days of life (adjusted risk difference (RD) 2.8%, 95% confidence interval (CI) 1.5-4.1% and RD 2.2%, 95% CI 0.9-3.5%, respectively). Hepatitis B vaccination was also higher among infants of Tdap-eligible mothers who received prenatal Tdap vaccination during pregnancy compared to those of mothers who did not (adjusted RD 9.1%, 95% CI 7.6-10.5%). Overall, prenatal vaccination was significantly associated with uptake of infant hepatitis B vaccine.

[Compliance with adult measles and pertussis vaccination recommendations : Analysis of data from the national monitoring system KV-Impfsurveillance]

The Standing Committee on Vaccination recommends adult measles and pertussis vaccination. The measles vaccine has been recommended since 2010 to adults born after 1970 with less than two doses in childhood, and an acellular pertussis vaccine (ap) since 2009 to be administered to all adults, with the next recommended decennial tetanus (T) and diphtheria (d) booster as a Tdap combination vaccine.We aim to determine the annual uptake of the measles vaccine (vaccination incidence) and its proportion in pediatric and gynecological practices as interdisciplinary services (2009-2016). We further aim to calculate the 10-year ap vaccination coverage and missed vaccination opportunities as the proportion vaccinated with Td only among all Td and Tdap vaccinees (2007-2016).Within the national vaccination monitoring system KV-Impfsurveillance of the Robert Koch Institute and all Associations of Statutory Health Insurance Physicians, all persons receiving the relevant vaccinations were identified in nationwide statutory health insurance claims and related to the numbers of insured persons.The measles vaccination incidence in 2009 was 0.4%, increasing to ≥1.0% annually since 2013. It was higher in western than eastern federal states and higher among women than men. Of all measles vaccinations, 6.8% were given by pediatricians. Men received 2.6% of their vaccinations by gynecologists. The ap vaccination coverage was 32.4%. The proportion of exclusively Td vaccinated adults fell from 84% (2007) to 24% (from 2013 onwards).Since their recommendation, the KV-Impfsurveillance system shows increased uptake of measles and pertussis vaccines with regional and sex differences and is thus instrumental in their evaluation. Analyses of interdisciplinary vaccinations and missed vaccination opportunities provide insight into the potential for increasing uptake.

Does the economic recession influence the incidence of pertussis in a cosmopolitan European city?

Background

In the last few years, pertussis has re-emerged worldwide. The aim of this article is to study how the incidence of the disease has evolved in Barcelona city over a 16-year period, and determine which factors are associated with the evolution of the disease. We discuss the causes of the observed changes considering different possibilities such as vaccination coverage, vaccine effectiveness, increased surveillance or the effect of the current economic recession.

Methods

We performed a cross-sectional, observational, population-based descriptive study using data for the 2000–2015 period from the notifiable diseases register maintained by Barcelona Public Health Agency. We used Poisson regression to compute adjusted odds ratios (aOR) and their corresponding 95% confidence intervals (CI).

Results

A total of 1791 cases were registered. The incidence of the disease increased throughout the city from 2011 onwards. While children under 1 year of age had the highest-incidence and were the most at risk (aOR = 27.18, CI:23.51–31.44), we found that the age of affected children was higher in the last years. Incidence proportion (PRR) was lower among foreign-born children than native children (PRR = 0.43 CI:0.32–0.58). In the whole-cell vaccine period (2000–2004), the percentage of cases under 1 year of age who received the vaccine was lower than in 2005–2015 when the acellular vaccine was used (p = 0.01), suggesting a lower efficacy of the acellular vaccine. However, vaccination coverage in children under 6 years remained high (~ 90%), and there were no significant year-to-year variations (p = 0.757). Moreover, there did not appear to be any significant restrictions in medical care. According to the index of disposable household income (DHI), pertussis incidence increased from 2011 onwards in all neighbourhoods and remained higher in those with lower DHI.

Conclusions

The noteworthy increase in pertussis incidence does not seem to be due to the economic recession, but to other factors here described.

Rapid and Accurate Diagnosis of the Respiratory Disease Pertussis on a Point-of-Care Biochip

BACKGROUND

Pertussis is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis (B. pertussis). The infection is difficult to diagnose especially in underserved or resource-limited areas. We developed a low-cost and instrument-free diagnostic method for rapid and accurate detection of B. pertussis on a point-of-care (POC) testing device.

METHODS

We developed a paper/polymer hybrid microfluidic biochip integrated with loop-mediated isothermal amplification (LAMP) method for the rapid and accurate detection of B. pertussis. This microfluidic approach was validated by testing 100 de-identified remnant clinical nasopharyngeal swabs and aspirates, which were confirmed to be either positive or negative for B. pertussis by a validated real-time PCR assay at the Children's Hospital Los Angeles.

FINDINGS

The instrument-free detection results could be successfully read by the naked eye within 45 min with a limit of detection (LOD) of 5 DNA copies per well. Our optimized bacterial lysis protocol allowed the direct testing of clinical samples without any complicated sample processing/preparation (i.e. DNA extraction) or the use of any equipment (e.g. centrifuges). The validation of the microfluidic approach was accomplished by testing 100 clinical samples. High sensitivity (100%) and specificity (96%) with respect to real-time PCR were achieved.

INTERPRETATION

This microfluidic biochip shows great potential for point-of-care disease diagnosis in various venues including schools and physician's offices, especially in low-resource settings in developing nations.

FUNDING

NIH/NIAID under award number R21AI107415, NIH RCMI Pilot Grant, the Philadelphia Foundation, the Medical Center of the Americas Foundation.

Enzyme-linked immunosorbent assay for detecting anti-pertussis toxin antibody in mouse

Purpose

Although the DTaP and Tdap vaccines used to prevent pertussis have been used for a long time, there is no standard method for measuring pertussis antigens. Therefore, this preliminary study was conducted to develop an enzyme-linked immunosorbent assay method using an animal model for measuring antibodies against pertussis toxin, the most important pertussis pathogenic antigen, in the sera of vaccinated mice.

Materials and Methods

Bordetella pertussis Tohama phase I was cultured for 24–30 hours, and then pertussis toxin was purified from the culture medium by chromatography. Purified pertussis toxin was diluted in phosphate-buffered saline-coating buffer, and 100 µL of diluted pertussis toxin was added to each well and reacted at room temperature for 4 hours. Positive serum was diluted to 1/1,250–1/80,000 and negative serum was diluted to 1/50 to determine the coating concentration with the optimal signal/noise ratio. Optimal test conditions were confirmed from the dilution factors of the secondary antibody and streptavidin horseradish peroxidase (SA-HRP).

Results

Optimal conditions were as follows: 4 µg/mL for coating antigen; 1/40,000 for secondary antibody; and 1/1,000 for the SA-HRP dilution factor. Comparison of the sera obtained from mice treated with a developing vaccine and commercial vaccine with National Institute for Biological Standard and Control standard serum under the established conditions showed the following results: 1,300.62, 534.94, and 34.85, respectively.

Conclusion

The method developed in this study is suitable for measuring anti-pertussis toxin antibodies and may be applicable for clinical sample analysis or indirect diagnosis of pertussis.

Immunogenicity and protective potential of Bordetella pertussis biofilm and its associated antigens in a murine model

The resurgence of whooping cough reflects novel genetic variants of Bordetella pertussis and inadequate protection conferred by current acellular vaccines (aP). Biofilm is a source of novel vaccine candidates, including membrane protein assembly factor (BamB) and lipopolysaccharide assembly protein (LptD). Responses of BALB/c mice to candidate vaccines included IFN-γ and IL-17a production by spleen and lymph node cells, and serum IgG1 and IgG2a reactive with whole bacteria or aP. Protection was determined using bacterial cultured from lungs of vaccinated mice challenged with virulent B. pertussis. Mice vaccinated with biofilm produced efficient IFN-γ responses and more IL-17a and IgG2a than mice vaccinated with planktonic cells, aP or adjuvant alone. Vaccination with aP produced abundant IgG1 with little IgG2a. Mice vaccinated with aP plus BamB and LptD retained lower bacterial loads than mice vaccinated with aP alone. Whooping cough vaccines formulated with biofilm antigens, including BamB and LptD, may have clinical value.

Acute exacerbation of idiopathic pulmonary fibrosis induced by pertussis: the first case report

BACKGROUND

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is a severe condition with limited treatment strategies. Although respiratory infection is a major cause of AE-IPF, no reports have indicated pertussis infection as a cause. Here we report two cases of pertussis infection-induced AE-IPF.

CASE PRESENTATION

Both patients presented with a chief complaint of acute respiratory distress and were previously diagnosed with idiopathic pulmonary fibrosis (IPF). Neither patient had received any pertussis vaccination since adolescence. Both patients were diagnosed with AE-IPF accompanying acute pertussis infection based on chest computed tomography and serum pertussis toxin antibody > 100 EU/mL. Both patients were treated with macrolide antibiotics and systemic corticosteroids. Both patients were able to be discharged and return home.

CONCLUSIONS

The presence of pertussis infection in AE-IPF can present a diagnostic challenge, as coughing accompanying pertussis may be difficult to distinguish from IPF-associated coughing. Pertussis infection should be assayed in AE-IPF patients. Since pertussis can be prevented with vaccination and is expected to be affected by antibiotics, consideration of pertussis infection as a causative virulent factor of AE-IPF may be important for management of subjects with IPF.

A systematic review of adult tetanus-diphtheria-acellular (Tdap) coverage among healthcare workers

During the last decades pertussis incidence raised globally. Several vaccination strategies targeting adults to reduce pertussis among young infants have been proposed, including vaccination of healthcare workers (HCWs). The aim of this study was to analyse, by performing a systematic review of literature, published papers that evaluated Tdap coverage among HCWs, variables associated with vaccine uptake and efforts implemented to raise vaccination rates. We searched the MedLine, Embase, SCOPUS, LILACS, Web of Science and Cochrane for full-text studies that evaluated Tdap coverage in HCW. Two independent reviewers screened the articles and extracted the data.Twenty-eight studies published from 2009 to 2018 were reviewed. Most studies were conducted in the USA. Initial Tdap coverage varied from 6.1% to 63.9%. USA and France are the only two countries with studies evaluating Tdap coverage within HCWs using national data. In the USA, Tdap coverage in HCWs raised from 6.1% to 45.1% from 2007 to 2015. In the analysis of French national data, a Tdap coverage of 63.9% was observed. Five studies used interventions to raise Tdap coverage in HCWs. Two intervention studies implemented mandatory vaccination and three used educational strategies. All of them achieved coverages over 86%. Only eleven studies analysed the association of Tdap vaccination with variables of interest. Previous immunization with other vaccines recommended for HCWs (like influenza, hepatitis B and MMR) was positively associated with Tdap uptake in four studies. In conclusion, overall Tdap coverage among HCWs is low, but seems to increase over the years after the vaccine introduction and with implementation of interventions to increase coverage.

How Genomics Is Changing What We Know About the Evolution and Genome of Bordetella pertussis

The evolution of Bordetella pertussis from a common ancestor similar to Bordetella bronchiseptica has occurred through large-scale gene loss, inactivation and rearrangements, largely driven by the spread of insertion sequence element repeats throughout the genome. B. pertussis is widely considered to be monomorphic, and recent evolution of the B. pertussis genome appears to, at least in part, be driven by vaccine-based selection. Given the recent global resurgence of whooping cough despite the wide-spread use of vaccination, a more thorough understanding of B. pertussis genomics could be highly informative. In this chapter we discuss the evolution of B. pertussis, including how vaccination is changing the circulating B. pertussis population at the gene-level, and how new sequencing technologies are revealing previously unknown levels of inter- and intra-strain variation at the genome-level.

Pertussis: The Whooping Cough

Bordetella pertussis can cause serious and potentially fatal complications, especially in very young infants. Early diagnosis and treatment of pertussis with a macrolide antibiotic, such as azithromycin, before the paroxysmal stage of disease can help mitigate complications and reduce the spread of this highly contagious disease.

Clinical-epidemiological study of Bordetella pertussis infection in the Gran Canaria island in the period, 2008-2016

OBJECTIVE

Describe the epidemiological and clinical pattern of Bordetella pertussis infection (whooping cough) among hospitalised infants less than one year-old in a paediatric hospital in Gran Canaria.

PATIENTS AND METHODS

A retrospective review of the patient hospital records was performed, and recording only those with a microbiological diagnosis of pertussis infection detected using polymerase chain reaction, from January 2008 to December 2016.

RESULTS

A total of 110 patients were identified, of which 105 (95.4%) were less than 6 months old, and 59.1% were males. The annual incidence of hospital admissions was estimated between 13.7 and 425.0 cases per 100 000 infants <12 months old, with 2 peaks in 2011 and 2015. Household members were the main potential sources of infection. Main clinical features were pertussis cough associated with signs of catarrh, cyanosis, and lymphocytosis. Complications occurred in 15.4% of the patients (mainly pneumonia), but the outcome was favourable in all the cases. A lower age and non-vaccination were associated with an increased risk of developing complications (p < .05). Viral co-infection occurred in 31.6% of infants diagnosed with pertussis.

CONCLUSIONS

The incidence of pertussis has increased in the last years in Gran Canaria, with a lower development of complications and mortality rates compared with the previous period. Lower age and non-vaccination status are considered risk factors for developing complications. Vaccination in pregnant women will probably lead to a decline in the incidence in the future, especially in infants younger than 6 months.

[Clinical-epidemiological study of Bordetella pertussis infection in the Gran Canaria island in the period, 2008-2016]

OBJECTIVE

Describe the epidemiological and clinical pattern of Bordetella pertussis infection (whooping cough) among hospitalised infants less than one year-old in a paediatric hospital in Gran Canaria.

PATIENTS AND METHODS

A retrospective review of the patient hospital records was performed, and recording only those with a microbiological diagnosis of pertussis infection detected using polymerase chain reaction, from January 2008 to December 2016.

RESULTS

A total of 110 patients were identified, of which 105 (95.4%) were less than 6 months-old, and 59.1% were males. The annual incidence of hospital admissions was estimated between 13.7 to 425.0 cases per 100,000 infants <12 months old, with 2peaks in 2011 and 2015. Household members were the main potential sources of infection. Main clinical features were pertussis cough associated with signs of catarrh, cyanosis, and lymphocytosis. Complications occurred in 15.4% of the patients (mainly pneumonia), but the outcome was favourable in all the cases. A lower age and non-vaccination were associated with an increased risk of developing complications (P<.05). Viral co-infection occurred in 31.6% of infants diagnosed with pertussis.

CONCLUSIONS

The incidence of pertussis has increased in the last years in Gran Canaria, with a lower development of complications and mortality rates compared with the previous period. Lower age and non-vaccination status are considered risk factors for developing complications. Vaccination in pregnant women will probably lead to a decline in the incidence in the future, especially in infants younger than 6 months.

Effect of maternal immunization against pertussis in Medellin and the metropolitan area, Colombia, 2016-2017

BACKGROUND

In 2013, pertussis immunization (Tdap) for pregnant women was implemented in Colombia to protect newborns in response to increased pertussis incidence.

OBJECTIVE

To assess the effect of Tdap maternal immunization on the concentration of mother/umbilical cord antibodies and the occurrence of pertussis in infants during their first six months of life.

METHODS

A cohort study in eight randomly selected hospitals in Medellin and metropolitan area of Antioquia, Colombia was conducted in 2015-2016. IgG PT antibody levels in paired maternal and umbilical cord sera were measured from 805 mothers immunized recruited during labor and 200 mothers recruited during the prenatal care before immunization and followed until delivery. Antibodies were analyzed by commercial ELISA kits. 896 infants were followed to detect acute respiratory infections and paroxysms of coughing, inspiratory whoop, apnea, cyanosis or post-tussive vomiting. For laboratory confirmation, B. pertussis- specific real time PCR was performed.

RESULTS

We observed a high prevalence of titers >100 IU/mL (mother: 18.40% [95% CI 16-21%]; umbilical cord: 23.1% [95% CI 19.2-27.4%]), positive correlation of umbilical cord and maternal antibodies, higher antibody concentration in vaccinated than in non-vaccinated mothers and significant difference in antibody levels before and after vaccination (Wilcoxon test p = 0.000). The trans placental transport ratio was higher if the mother was vaccinated between 26 and 30 weeks of pregnancy and maximum eight weeks before delivery. Two cases of pertussis were confirmed in infants (incidence of 1.99 per 1000).

CONCLUSION

The expected effect of Tdap maternal vaccination against pertussis was observed.