The burden of pertussis in older adults: what is the role of vaccination? A systematic literature review

Pertussis Vaccination for Adults: An Updated Guide for Clinicians

Pertussis, or whooping cough, is a highly contagious respiratory infection caused by the Gram-negative bacterium Bordetella pertussis. Although traditionally associated with children, pertussis is increasingly prevalent among adults, particularly those with comorbidities or weakened immune systems, where it can lead to severe complications. Diagnosing pertussis in adults can be challenging due to its nonspecific symptoms, underreporting, and the limited sensitivity of available diagnostic tests. While treatment with macrolides is generally effective, it may not significantly alter the clinical course of the disease, and growing concerns about macrolide resistance are emerging. Vaccination remains the cornerstone of prevention, offering proven immunogenicity, efficacy, and safety. However, vaccination uptake remains low, partly due to limited patient awareness and insufficient prioritization by healthcare professionals. This review aims to provide clinicians with critical insights into pertussis epidemiology, vaccination strategies, and the latest guideline recommendations, empowering them to engage in meaningful discussions with adult patients and advocate for increased vaccination to combat this often-overlooked infection.

Understanding the impact of adult pertussis and current approaches to vaccination: A narrative review and expert panel recommendations

Pertussis has several notable consequences, causing economic burden, increased strain on healthcare facilities, and reductions in quality of life. Recent years have seen a trend toward an increase in pertussis cases affecting older children and adults. To boost immunity, and protect vulnerable populations, an enduring approach to vaccination has been proposed, but gaps remain in the evidence surrounding adult vaccination that are needed to inform such a policy. Gaps include: the true incidence of pertussis and its complications in adults; regional variations in disease recognition and reporting; and incidence of severe disease, hospitalizations, and deaths in older adults. Better data on the efficacy/effectiveness of pertussis vaccination in adults, duration of protection, and factors leading to poor vaccine uptake are needed. Addressing the critical evidence gaps will help highlight important areas of unmet need and justify the importance of adult pertussis vaccination to healthcare professionals, policymakers, and payers.

Public health management of pertussis in adults: Practical challenges and future strategies

A panel of 24 international experts met in July 2022 to discuss challenges associated with pertussis detection, monitoring, and vaccination in adults; conclusions from this meeting are presented. There has been a shift in the epidemiology of pertussis toward older children and adults. This shift has been attributed to the waning of infection- or vaccine-induced immunity, newer detection techniques causing detection bias, and possibly the replacement of whole-cell pertussis with acellular vaccines in high-income countries, which may lead to immunity waning more quickly. The burden of adult pertussis is still likely under-ascertained due to widespread under-recognition by healthcare professionals (HCPs), under-diagnosis, and under-reporting in this age group. Non-standardized testing guidance and varied case definitions have contributed to under-reporting. Key barriers to HCP engagement with the tetanus, diphtheria, and pertussis (Tdap) vaccine include low awareness, lack of time/funding, and lack of motivation due to low prioritization of Tdap.

Pertussis epidemiology in adults: Retrospective analysis of pertussis incidence and association with comorbidities among adult populations in Aotearoa New Zealand, using national administrative datasets

BACKGROUND

In New Zealand, approximately half reported pertussis cases are adult. Studies indicate underestimated pertussis burden in this population and probable reservoir for childhood pertussis. Pertussis is linked to chronic obstructive pulmonary disease (COPD) development and increased risk with pre-existing COPD. While acellular pertussis vaccines are available for adults, data on pertussis disease burden in adults and association with COPD remain limited.

AIM

To estimate pertussis incidence in New Zealand adult health service user (HSU) population aged ≥ 18 between 2008-2019 and inform adult pertussis vaccination strategies by assessing disease burden and risk factors in different adult populations.

METHODS

Retrospective observational cohort study using an HSU cohort, formed by linking administrative health data using unique National Health Index identifier. For primary analysis, annual incidence rates were calculated using pertussis hospitalisations and notifications. In secondary analysis, Cox proportional hazards survival analyses explored association between pertussis in adults and chronic comorbidities.

RESULTS

The cohort had 2,907,258 participants in 2008 and grew to 3,513,327 by 2019, with 11,139 pertussis cases reported. Highest annual incidence rate of 84.77 per 100,000 PYRS in 2012, notably affecting females, those aged 30-49 years, and European or Māori ethnicity. Adjusting for sociodemographic variables found no significant risk of prior pertussis notification leading to comorbidity diagnosis (Adjusted-HR: 0.972). However, individuals with prior comorbidity diagnosis had 16 % greater risk of receiving pertussis notification or diagnosis (Adjusted-HR: 1.162).

CONCLUSIONS

Study found significant pertussis burden among the HSU adult cohort and highlighted higher risk of pertussis for those with recent comorbidity diagnoses. Vaccination for pertussis should be recommended for individuals with comorbidities to reduce infection risk and disease severity. GPs must have capability to test for pertussis, given it is notifiable disease with implications for individuals, their families, and broader population. High-quality disease surveillance is crucial for informing policy decisions.

Pertussis Notification Rate and Tdpa Vaccine/Booster Coverage in Adults: An Opportunity for an Epidemiological Observatory in Primary Care

Background: In recent years, Europe has experienced a significant increase in pertussis cases. One reason behind this rise is the decline in diphtheria-tetanus-pertussis (dTap) booster coverage among adults. Currently, Italy lacks a reliable monitoring system to track pertussis infections and vaccine coverage among adults. We therefore evaluated the reliability of a primary care framework to respond to this need. Methods: Using an Italian primary care database for individuals aged 15 or above, we determined the pertussis infection notification rate and dTap vaccine/booster coverage for the timeframe of 2009-2022. Results: In the overall population, we obtained a lifetime occurrence rate of pertussis infections of 7.52 per 10,000 individuals. The annual incidence rates of pertussis infections ranged from 0.008 to 0.001 per 10,000 person-years between 2009 and 2022. A rising trend in dTap vaccine coverage rate (ranging from 8.72 to 16.54 vaccines per 10,000 individuals) was observed during the same period. Notably, those aged 65 or older, smokers, and/or individuals with immunodeficiencies were more likely to receive the dTap vaccine compared to the general population. Conclusions: Given the organization of the Italian public health system, this primary care network might act as a reliable epidemiological monitoring system to keep track of pertussis infections and dTap vaccine coverage in adults. Pertussis cases were underreported, and there was a low uptake of vaccines and boosters. Therefore, it is crucial to closely monitor pertussis notifications and dTap administrations and develop intervention strategies at the national level to enhance vaccine-related prevention.

Epidemiology of Pertussis and Pertussis-Related Complications in Adults: A German Claims Data Analysis

INTRODUCTION

Pertussis is a highly contagious respiratory infection. It affects people of all ages, yet evidence of the impact of pertussis in adults with underlying conditions (UCs) is scarce. This study investigated the incidence and complication rate of pertussis in adult patients with and without UC.

METHODS

A retrospective analysis was conducted using routinely collected German claims data between 2015 and 2019. Patients with and without different pneumological, cardiovascular, endocrinological, musculoskeletal, and psychological UCs were matched for incidence estimation. Logistic regression models were used to estimate the risk of pertussis depending on the presence of UCs. Negative binomial models were used to assess complication rates in patients with pertussis and with and without UC.

RESULTS

In total, 4383 patients were diagnosed with pertussis during the study period. Patients with any UC had an increased risk for pertussis compared to matched patients without UC (odds ratio [OR] 1.72; 95% confidence interval [CI]1.60-1.84, p < 0.0001). Underlying asthma had the highest risk of pertussis (OR 2.70; 95% CI 2.50-2.91, p < 0.0001), followed by chronic obstructive pulmonary disease (OR 2.35; 95% CI 2.10-2.60, p < 0.0001) and depression (OR 2.08; 95% CI 1.95-2.22, p < 0.0001). Severe complications occurred in 10.8% of the pertussis cohort (13.4% with UC vs. 9.5% without UC). The UC-attributable effect on the risk of severe pertussis-related complications was significantly increased for any UC (incidence rate ratio [IRR] 1.29, 95% CI 1.19-1.39). The severe complication risk was also increased for patients aged 60+ (IRR 1.59, 95% CI 1.46-1.72).

CONCLUSION

This study shows that adults with certain UCs have an increased risk for pertussis and are more likely to have complications. These results provide further evidence that pertussis is a relevant and impactful infectious disease in adults with and without certain UC, indicating that these patients need to be considered when developing vaccination recommendations to avoid pertussis and its associated complications. A graphical abstract is available with this article.

Population-Based Study of Pertussis Incidence and Risk Factors among Persons >50 Years of Age, Australia

Despite vaccination programs, pertussis has been poorly controlled, especially among older adults in Australia. This longitudinal, retrospective, observational study aimed to estimate the incidence and risk factors of pertussis among persons ≥50 years of age in Australia in the primary care setting, including those with underlying chronic obstructive pulmonary disease (COPD) or asthma. We used the IQVIA general practitioner electronic medical record database to identify patients ≥50 years of age with a clinical diagnosis of pertussis during 2015-2019. Pertussis incidence rates ranged from 57.6 to 91.4 per 100,000 persons and were higher among women and highest in those 50-64 years of age. Patients with COPD or asthma had higher incidence rates and an increased risk for pertussis compared with the overall population ≥50 years of age. Our findings suggest that persons ≥50 years of age in Australia with COPD or asthma have a higher incidence of and risk for pertussis diagnosis.

Adaptive immune response to bordetella pertussis during vaccination and infection: emerging perspectives and unanswered questions

INTRODUCTION

Whooping cough, also known as pertussis, remains a significant challenge as a vaccine-preventable disease worldwide. Since the switch from the whole-cell Pertussis (wP) vaccine to the acellular Pertussis vaccine (aP), cases of whooping cough have increased in countries using the aP vaccine. Understanding the immune system's response to pertussis vaccines and infection is crucial for improving current vaccine efficacy.

AREAS COVERED

This review of the literature using PubMed records offers an overview of the qualitative differences in antibody and T cell responses to B. pertussis (BP) in vaccination and infection, and their potential association with decreased efficacy of the aP vaccine in preventing infection and subclinical colonization. We further discuss how asymptomatic infections and carriage are widespread among vaccinated human populations, and explore methodologies that can be employed for their detection, to better understand their impact on adaptive immune responses and identify key features necessary for protection against the disease.

EXPERT OPINION

An underappreciated human BP reservoir, stemming from the decreased capacity of the aP vaccine to prevent subclinical infection, offers an alternative explanation for the increased incidence of clinical disease and recurrent outbreaks.

Development of an algorithm for finding pertussis episodes in a population-based electronic health record database

While tetanus-diphtheria-acellular pertussis (Tdap) vaccines for adolescents and adults were licensed in 2005 and immunization strategies proposed, the burden of pertussis in this population remains under-recognized mainly due to atypical disease presentation, undermining efforts to optimize protection through vaccination. We developed a machine learning algorithm to identify undiagnosed/misdiagnosed pertussis episodes in patients diagnosed with acute respiratory disease (ARD) using signs, diseases and symptoms from clinician notes and demographic information within electronic health-care records (Optum Humedica repository [2007-2019]). We used two patient cohorts aged ≥11 years to develop the model: a positive pertussis cohort (4,515 episodes in 4,316 patients) and a negative pertussis (ARD) cohort (4,573,445 episodes and patients), defined using ICD 9/10 codes. To improve contrast between positive pertussis and negative pertussis (ARD) episodes, only episodes with ≥7 symptoms were selected. LightGBM was used as the machine learning model for pertussis episode identification. Model validity was determined using laboratory-confirmed pertussis positive and negative cohorts. Model explainability was obtained using the Shapley additive explanations method. The predictive performance was as follows: area under the precision-recall curve, 0.24 (SD, 7 × 10^-3); recall, 0.72 (SD, 4 × 10^-3); precision, 0.012 (SD, 1 × 10^-3); and specificity, 0.94 (SD, 7 × 10^-3). The model applied to laboratory-confirmed positive and negative pertussis episodes had a specificity of 0.846. Predictive probability for pertussis increased with presence of whooping cough, whoop, and post-tussive vomiting in clinician notes, but decreased with gastrointestinal bleeding, sepsis, pulmonary symptoms, and fever. In conclusion, machine learning can help identify pertussis episodes among those diagnosed with ARD.

Estimating the pertussis burden in adolescents and adults in the United States between 2007 and 2019

We developed a machine learning algorithm to identify undiagnosed pertussis episodes in adolescent and adult patients with reported acute respiratory disease (ARD) using clinician notes in an electronic healthcare record (EHR) database. Here, we utilized the algorithm to better estimate the overall pertussis incidence within the Optum Humedica clinical repository from 1 January 2007 through 31 December 2019. The incidence of diagnosed pertussis episodes was 1-5 per 100,000 annually, consistent with data registered by the US Centers for Disease Control and Prevention (CDC) over the same time period. Among 18,573,496 ARD episodes assessed, 1,053,946 were identified (i.e. algorithm-identified) as likely undiagnosed pertussis episodes. Accounting for these undiagnosed pertussis episodes increased the estimated pertussis incidence by 110-fold on average (34-474 per 100,000 annually). Risk factors for pertussis episodes (diagnosed and algorithm-identified) included asthma (Odds ratio [OR] 2.14; 2.12-2.16), immunodeficiency (OR 1.85; 1.78-1.91), chronic obstructive pulmonary disease (OR 1.63; 1.61-1.65), obesity (OR 1.44; 1.43-1.45), Crohn's disease (OR 1.39; 1.33-1.45), diabetes type 1 (OR 1.21; 1.17-1.24) and type 2 (OR 1.12; 1.1-1.13). Of note, all these risk factors, except Crohn's disease, increased the likelihood of severe pertussis. In conclusion, the incidence of pertussis in the adolescent and adult population in the USA is likely substantial, but considerably under-recognized, highlighting the need for improved clinical awareness of the disease and for improved control strategies in this population. These results will help better inform public health vaccination and booster programs, particularly in those with underlying comorbidities.

Cost of illness due to pertussis in adults ≥50 years of age in the United Kingdom

BACKGROUND

Pertussis is an endemic respiratory tract infection caused by Bordetella pertussis that may affect all individuals from infants to older adults. Pertussis incidence in adults is often underreported and in various countries, including the United Kingdom (UK), there are evidence gaps on pertussis-associated economic burden in the older adult population. We aimed to quantify the economic burden of pertussis in adults aged ≥50 years in the UK.

METHODS

A cost-of-illness study was conducted to estimate the cost of pertussis from a societal perspective. We utilized a sum diagnosis cost approach in which costs related to infection with pertussis were included. Medical, patient, and indirect costs were calculated individually and combined to calculate total costs. A framework was developed to assess costs for consecutive age groups from 50-54 years of age to ≥85 years of age. Sensitivity and scenario analyses were used to assess analysis uncertainty.

RESULTS

The base-case analysis estimated the total annual economic burden of pertussis to be approximately £238 million (M). This comprised approximately £159 M in indirect costs, £66 M in medical costs, and £13 M in patient costs. Costs for the age group 55-59 years had the highest impact on the economic burden, with approximately £79 M in total annual costs. Visits to general practitioners and nurses were the largest contributors to medical costs (∼£37 M) followed by inpatient visits (∼£21 M). Transportation costs (∼£10 M) were the major patient costs. Productivity loss (∼£71 M) and leisure time loss (∼£72 M) had comparable contributions to annual indirect costs. Sensitivity and scenario analyses suggested that incidence rates, indirect costs, and underreporting estimates had the highest impact on outcomes.

CONCLUSION

Total cost of pertussis in the UK among adults ≥50 years of age is substantial and highest for adults 55-59 years of age. Indirect costs were the main contributors to the economic burden.

The Present and Future Aspects of Life-Long Pertussis Prevention: Narrative Review with Regional Perspectives for Türkiye

Pertussis, caused by Bordetella pertussis, remains one of the most widespread, contagious, and vaccine-preventable diseases. It results in notable morbidity and mortality as well as severe medical, social, and economic burden. Despite high global vaccine coverage, pertussis continues to be a significant epidemiologic problem, with outbreak episodes every few years just as in the pre-vaccination era. In Türkiye, there is a lack of comprehensive data on the current burden of pertussis in different age and risk groups, leading to underdiagnosis and underreporting of the disease, especially in adults who are often not considered at risk. Available data from Türkiye also reveal inadequate levels of protective antibodies in preterm newborns, emphasizing the need for additional preventive measures. Authors stated that improving physician awareness of pertussis symptoms in patients with prolonged cough, increasing access to routine pertussis tests, and conducting surveillance studies would aid in accurate diagnosis and reporting in Türkiye. As the Turkish Ministry of Health Antenatal Care Management Guide suggests routine second and third pregnancy check-up visits at weeks 18-24 and 28-32 correspondingly, this period can be considered the ideal vaccination time for Türkiye. Introducing a booster dose of Tdap at around 10 years of age or during national military service would reduce transmission and protect susceptible individuals. Identifying individuals at high risk of severe pertussis and prioritizing them for a booster dose is also crucial in Türkiye. Enhancing surveillance systems, increasing healthcare professionals' awareness through training, and organizing catch-up visits for missed vaccinations during the COVID-19 pandemic are mentioned as additional strategies to improve pertussis prevention in Türkiye. This review focuses on the global and regional burden of pertussis and obstacles to effective prevention and evaluates existing strategies to achieve lifelong pertussis prevention. Literature and current strategies were also discussed from a Turkish national standpoint.

T cell reactivity to Bordetella pertussis is highly diverse regardless of childhood vaccination

The incidence of whooping cough due to Bordetella pertussis (BP) infections has increased recently. It is believed that the shift from whole-cell pertussis (wP) vaccines to acellular pertussis (aP) vaccines may be contributing to this rise. While T cells are key in controlling and preventing disease, nearly all knowledge relates to antigens in aP vaccines. A whole-genome mapping of human BP-specific CD4+ T cell responses was performed in healthy vaccinated adults and revealed unexpected broad reactivity to hundreds of antigens. The overall pattern and magnitude of T cell responses to aP and non-aP vaccine antigens are similar regardless of childhood vaccination, suggesting that asymptomatic infections drive the pattern of T cell reactivity in adults. Lastly, lack of Th1/Th2 polarization to non-aP vaccine antigens suggests these antigens have the potential to counteract aP vaccination Th2 bias. These findings enhance our insights into human T cell responses to BP and identify potential targets for next-generation pertussis vaccines.

Bordetella pertussis and outer membrane vesicles

Bordetella pertussis is the causative agent of a respiratory infection called pertussis (whooping cough) that can be fatal in newborns and infants. The pathogen produces a variety of antigenic compounds which alone or simultaneously can damage various host cells. Despite the availability of pertussis vaccines and high vaccination coverage around the world, a resurgence of the disease has been observed in many countries. Reasons for the increase in pertussis cases may include increased awareness, improved diagnostic techniques, low vaccine efficacy, especially acellular vaccines, and waning immunity. Many efforts have been made to develop more effective strategies to fight against B. pertussis and one of the strategies is the use of outer membrane vesicles (OMVs) in vaccine formulations. OMVs are attracting great interest as vaccine platforms since they can carry immunogenic structures such as toxins and LPS. Many studies have been carried out with OMVs from different B. pertussis strains and they revealed promising results in the animal challenge and human preclinical model. However, the composition of OMVs differs in terms of isolation and purification methods, strains, culture, and stress conditions. Although the vesicles from B. pertussis represent an attractive pertussis vaccine candidate, further studies are needed to advance clinical research for next-generation pertussis vaccines. This review summarizes general information about pertussis, the history of vaccines against the disease, and the immune response to these vaccines, with a focus on OMVs. We discuss progress in developing an OMV-based pertussis vaccine platform and highlight successful applications as well as potential challenges and gaps.

The Prevalence of COVID-19 Vaccine Hesitancy Among the Black Asian Ethnic Minority in New South Wales, Australia

INTRODUCTION

Vaccination provides a cost-effective approach to controlling the COVID-19 pandemic. The success of vaccination depends on global preparedness and acceptance of the new vaccines, and this is threatened by vaccine hesitancy worldwide. This study aimed to measure the prevalence of COVID-19 vaccine hesitancy, attitudes, and contributing factors in the Black Asian Ethnic Minority (BAME) of New South Wales (NSW), Australia.  Aim: This study aimed to measure the prevalence of COVID-19 vaccine hesitancy and identify contributing factors leading to vaccine hesitancy in the Black Asian and Ethnic Minority (BAME) in NSW.

METHOD

A cross-sectional study was conducted among the BAME community in NSW; over 12 weeks, from January 3^rd, 2022, to March 28^th, 2022. The study used the pre-existing previously known 5Cs model (confidence, constraints, complacency, calculation, and collective responsibility) to assess reasons for hesitancy. The questionnaire was distributed in English using social media platforms: Facebook and WhatsApp.

RESULTS

The study received 101 respondents over 18 years from all states in Australia from BAME communities, males and females, with different educational levels, employment sectors, marital statuses, co-existing chronic medical conditions, previous COVID-19 infection status, and COVID-19 vaccine received. Of these, 56 respondents were from NSW. Our findings revealed a high prevalence of COVID-19 vaccine hesitancy among the BAME community in NSW, with 72.8% of respondents demonstrating hesitancy/reluctance due to various attitudes identified by the 5Cs model. Despite this high hesitancy, 98.2% of the participants had received at least one to three vaccine doses.

CONCLUSION

 Even in populations with high vaccine uptake, it is still essential to address vaccine hesitancy and provide ongoing education about the importance of vaccination, particularly as new variants of COVID-19 continue to emerge and the need for booster shots may arise. This can help ensure continued protection against the virus and prevent future outbreaks.

Maternal vaccination against pertussis as part of the national immunization program: a qualitative evaluation among obstetric care providers one year after the implementation in December 2019

BACKGROUND

Immunization of pregnant women with a tetanus-diphtheria-and-acellular-pertussis (Tdap) vaccine is an effective and safe way to protect infants from pertussis before their primary vaccinations. Vaccine uptake among pregnant women is influenced by their care providers' attitudes toward maternal vaccination. This qualitative study aimed to evaluate the implementation of the maternal Tdap vaccination under the National Immunization Program of the Netherlands from the perspective of obstetric care providers.

METHODS

In this qualitative and explorative study, we conducted in-depth interviews by telephone with obstetric care providers who were selected from a pool of respondents (convenience sampling) to a questionnaire in a previous study. The interviews were based on a semi-structured interview guide that covered three aspects of the implementation strategy: providers' overall experience with the implementation of maternal Tdap vaccination in the Netherlands; implementation logistics and counseling, and pregnant women referrals to municipal Youth Healthcare Centers. The interviews were recorded, pseudonymized and transcribed verbatim. Transcripts were analyzed according to the Thematic Analysis approach by two researchers independently in two phases of iterative coding, categorizing, reviewing and redefining until ultimately, emergent themes regarding maternal Tdap vaccination implementation were identified.

RESULTS

Interviews with 11 midwives and 5 OB-GYN physicians yielded 5 major themes regarding the Tdap vaccination implementation strategy: challenges throughout the implementation process, views on maternal Tdap vaccination, general versus tailored counseling, provider responsibilities in vaccine promotion, and impact of materials for information delivery. Participants indicated that to improve provider attitudes toward Tdap vaccination, its implementation requires clear and transparent information about what is entailed, i.e., what is expected from obstetric care providers, how they can obtain information, and when their actions must be initiated. Participants demanded involvement throughout the implementation planning process. They preferred tailored communication with pregnant women over a generalized approach.

CONCLUSION

This study emphasized the importance of involving all relevant healthcare professionals in planning the implementation of maternal Tdap vaccination. Possible barriers perceived by these professionals should be taken into account in order to improve their attitudes toward vaccination, thus to increase uptake among pregnant women.

Genome-wide characterization of T cell responses to Bordetella pertussis reveals broad reactivity and similar polarization irrespective of childhood vaccination profiles

The incidence of whooping cough (pertussis), the respiratory disease caused by Bordetella pertussis (BP) has increased in recent years, and it is suspected that the switch from whole-cell pertussis (wP) to acellular pertussis (aP) vaccines may be a contributing factor to the rise in morbidity. While a growing body of evidence indicates that T cells play a role in the control and prevention of symptomatic disease, nearly all data on human BP-specific T cells is related to the four antigens contained in the aP vaccines, and data detailing T cell responses to additional non-aP antigens, are lacking. Here, we derived a full-genome map of human BP-specific CD4+ T cell responses using a high-throughput ex vivo Activation Induced Marker (AIM) assay, to screen a peptide library spanning over 3000 different BP ORFs. First, our data show that BP specific-CD4+ T cells are associated with a large and previously unrecognized breadth of responses, including hundreds of targets. Notably, fifteen distinct non-aP vaccine antigens were associated with reactivity comparable to that of the aP vaccine antigens. Second, the overall pattern and magnitude of CD4+ T cell reactivity to aP and non-aP vaccine antigens was similar regardless of aP vs wP childhood vaccination history, suggesting that the profile of T cell reactivity in adults is not driven by vaccination, but rather is likely driven by subsequent asymptomatic or sub-clinical infections. Finally, while aP vaccine responses were Th1/Th2 polarized as a function of childhood vaccination, CD4+ T cell responses to non-aP BP antigens vaccine responses were not, suggesting that these antigens could be used to avoid the Th2 bias associated with aP vaccination. Overall, these findings enhance our understanding of human T cell responses against BP and suggest potential targets for designing next-generation pertussis vaccines.

Burden of Pertussis in Adults Aged 50 Years and Older: A Retrospective Database Study in England

INTRODUCTION

Pertussis, a highly infectious respiratory disease caused by Bordetella pertussis, affects people of all ages. Older adults are particularly susceptible to its severe outcomes and complications.

METHODS

In this retrospective cohort study, the incidence rate of pertussis among individuals aged ≥ 50 years was assessed during 2009-2018 using Clinical Practice Research Datalink and Hospital Episode Statistics databases, United Kingdom. Health care resource utilisation (HCRU) and direct medical costs (DMCs) were compared between patients with a pertussis diagnosis and propensity score-matched controls (matched on demographic and clinical variables).

RESULTS

Among 5,222,860 individuals, 1638 had a pertussis diagnosis (incidence rate: 5.8 per 100,000 person-years; 95% confidence interval 5.5-6.0). Baseline (- 18 to - 6 months) HCRU and DMC were similar among 1480 pertussis patients and 1480 matched controls. However, there were increases in HCRU in the pertussis vs. matched cohort around the pertussis diagnosis (from months - 6 to - 1 to 5-11). The most notable increases (pertussis vs. controls) were in the rates of general practitioner (GP)/nurse visits (4.7-fold), clinical assessments (4.1-fold), and accident and emergency visits (3.0-fold) during the month before diagnosis and GP/nurse visits during the 2 months after diagnosis (2.5-fold) (all p < 0.001). DMCs were significantly higher in the pertussis cohort (p < 0.001). Total excess DMC in the pertussis cohort during months - 1 to + 11 was £318 per patient.

CONCLUSION

A pertussis diagnosis among adults aged ≥ 50 years resulted in significant increases in HCRU and DMC across several months around diagnosis. These results highlight the need for increased awareness of pertussis infection among adults aged ≥ 50 years and suggest that pertussis booster doses among this population should be considered.

Vaccination against Community-Acquired Pneumonia in Spanish Adults: Practical Recommendations by the NeumoExperts Prevention Group

In the adult population, community-acquired pneumonia (CAP) is a serious disease that is responsible for high morbidity and mortality rates, being frequently associated with multidrug resistant pathogens. The aim of this review is to update a practical immunization prevention guideline for CAP in Spain caused by prevalent respiratory pathogens, based on the available scientific evidence through extensive bibliographic review and expert opinion. The emergence of COVID-19 as an additional etiological cause of CAP, together with the rapid changes in the availability of vaccines and recommendations against SARS-CoV-2, justifies the need for an update. In addition, new conjugate vaccines of broader spectrum against pneumococcus, existing vaccines targeting influenza and pertussis or upcoming vaccines against respiratory syncytial virus (RSV) will be very useful prophylactic tools to diminish the burden of CAP and all of its derived complications. In this manuscript, we provide practical recommendations for adult vaccination against the pathogens mentioned above, including their contribution against antibiotic resistance. This guide is intended for the individual perspective of protection and not for vaccination policies, as we do not pretend to interfere with the official recommendations of any country. The use of vaccines is a realistic approach to fight these infections and ameliorate the impact of antimicrobial resistance. All of the recently available scientific evidence included in this review gives support to the indications established in this practical guide to reinforce the dissemination and implementation of these recommendations in routine clinical practice.

Safety and immunogenicity of an indigenously developed tetanus toxoid, diphtheria toxoid, and acellular pertussis vaccine (Tdap) in adults, adolescents, and children in India

BACKGROUND

This study assessed safety and immunogenicity of Serum Institute of India Pvt Ltd (SIIPL)'s tetanus toxoid (TT), diphtheria toxoid (DT), and acellular pertussis booster vaccine (Tdap).

RESEARCH DESIGN AND METHODS

In this Phase II/III, multicenter, randomized, active-controlled, open-label study, 1500 healthy individuals, aged 4-65 years, were randomized to receive a single dose of SIIPL Tdap or comparator Tdap vaccine (Boostrix®; GlaxoSmithKlines, India). Adverse events (AEs) during initial 30 minutes, 7-day, 30-day post-vaccination were assessed. Blood samples were taken before and 30 days post-vaccination for immunogenicity assessment.

RESULTS

No significant differences in incidence of local and systemic solicited AEs were observed between the two groups; no vaccine-related serious AEs were reported. SIIPL Tdap was non-inferior to comparator Tdap in achieving booster responses to TT and DT in 75.2% and 70.8% of the participants, respectively, and to pertussis toxoid (PT), pertactin (PRN), and filamentous hemagglutinin (FHA) in 94.3%, 92.6%, and 95.0% of the participants, respectively. Anti-PT, anti-PRN, and anti-FHA antibody geometric mean titers in both the groups, were significantly higher post-vaccination compared to pre-vaccination.

CONCLUSIONS

Booster vaccination with SIIPL Tdap was non-inferior to comparator Tdap with respect to immunogenicity against tetanus, diphtheria, and pertussis and was well tolerated.

Development of carbohydrate based next-generation anti-pertussis vaccines

Pertussis is a highly contagious respiratory disease caused by the Gram-negative bacterial pathogen, Bordetella pertussis. Despite high global vaccination rates, pertussis is resurging worldwide. Here we discuss the development of current pertussis vaccines and their limitations, which highlight the need for new vaccines that can protect against the disease and prevent development of the carrier state, thereby reducing transmission. The lipo-oligosaccharide of Bp is an attractive antigen for vaccine development as the anti-glycan antibodies could have bactericidal activities. The structure of the lipo-oligosaccharide has been determined and its immunological properties analyzed. Strategies enabling the expression, isolation, and bioconjugation have been presented. However, obtaining the saccharide on a large scale with high purity remains one of the main obstacles. Chemical synthesis provides a complementary approach to accessing the carbohydrate epitopes in a pure and structurally well-defined form. The first total synthesis of the non-reducing end pertussis pentasaccharide is discussed. The conjugate of the synthetic glycan with a powerful immunogenic carrier, bacteriophage Qβ, results in high levels and long-lasting anti-glycan IgG antibodies, paving the way for the development of a new generation of anti-pertussis vaccines with high bactericidal activities and biocompatibilities.

Vaccination coverage in Italian children and antimicrobial resistance: an ecological analysis

BACKGROUND

Although a general consensus that vaccines could be a complementary strategy against antimicrobial resistance (AMR), there is still the need for studies investigating the relationship between childhood vaccination coverage and AMR proportions in the overall population.

METHODS

We performed an ecological analysis of available Italian data (vaccination coverages, AMR proportions, number of isolates tested, and antibiotic use) to evaluate the relationships between vaccination coverages in children and AMR proportions in the last 2 decades.

RESULTS

After adjusting for covariates, we showed that AMR proportions decreased with increasing vaccination coverages, especially for some combinations of vaccines, pathogens, and antimicrobials. Vaccination coverages for pertussis, diphtheria, and tetanus were inversely related to proportions of E. coli resistant to fluoroquinolones and third generation cephalosporins, K. pneumoniae resistant to carbapenems and third generation cephalosporins, and P. aeruginosa resistant to piperacillin and tazobactam. Polio vaccination coverage was inversely related to proportions of E. coli and K. pneumoniae resistant to third generation cephalosporins.

CONCLUSIONS

These results, however, should be interpreted cautiously due to the ecological nature of our analysis. For this reason, further studies designed ad hoc should be encouraged to measure the impact of increasing childhood vaccination coverage on AMR.

Descriptive Overview of Pertussis Epidemiology Among Older Adults in Europe During 2010–2020

Introduction

Following the introduction of pertussis vaccination during infancy, the age-related demographics of pertussis epidemiology have changed.

Methods

To better understand the pertussis burden (defined here as number of cases and/or incidence rate [IR]) among older adults (OA; at least 50 years of age) in Europe, we collected data on the reported number of cases and IR in this population in Denmark, England and Scotland, Finland, Germany, the Netherlands, Norway and Sweden from 2010 to 2020. Additionally, we collected contextual epidemiological information on surveillance systems, case definitions, laboratory diagnostics and vaccination approaches.

Results

We observed large heterogeneity in the burden among OA between countries: annual IRs ranged from 0.4 (England, 2010) to 54.5 (Norway, 2011) per 100,000 population; 9% (Denmark, 2010) to 45% (England, 2017) of all reported cases occurred in OA. No clear impact of changes in contextual epidemiological information or common trends between countries could be observed, highlighting the need for standardised pertussis surveillance programmes across Europe. The epidemiological trends observed in OA were similar to those observed in 0–4-year-olds.

Conclusion

This analysis showed that B. pertussis continues to circulate among OA in Europe, suggesting that current vaccination strategies are insufficient to decrease the disease burden in all age groups. This may indicate that improved monitoring of pertussis in OA and booster vaccination throughout adulthood are necessary to control the total pertussis burden.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-022-00668-y.

Whooping cough is an infectious, vaccine-preventable disease that is primarily serious in unvaccinated infants but can also affect adults (at least 50 years old). While vaccination is well established in children, many countries do not routinely vaccinate older adults. Moreover, whooping cough infections in older adults can be difficult to identify for healthcare professionals because of the atypical and mild nature of symptoms. Consequently, the extent of whooping cough occurrence in this population is underestimated. To better understand the extent of disease occurrence, we studied whooping cough infections in Denmark, England and Scotland, Finland, Germany, the Netherlands, Norway and Sweden from 2010 to 2020. Our study was based on the number of laboratory-confirmed cases reported to relevant institutions. We also assessed whether we could identify links between disease occurrence among older adults and contextual epidemiological information, such as disease monitoring systems, methods used for laboratory confirmation, vaccination schedules and vaccination coverage rates. Our study confirmed that whooping cough affects older adults and disease occurrence follows similar trends to those in 0- to 4-year-old children. Because the contextual epidemiological information differed over time and between countries, we could not establish links with disease occurrence in older adults. These data may provide further evidence to authorities that whooping cough among older adults would be better controlled and its burden more accurately estimated with a reinforced comprehensive approach around vaccination and monitoring. Because adults can also infect children who are not yet fully vaccinated, such an approach might help further control the disease in children.

Direct Medical Costs of Four Vaccine-Preventable Infectious Diseases in Older Adults in Spain

OBJECTIVE

Protection against vaccine-preventable diseases is especially relevant in older adults due to age-related decline in immunity (immunosenescence). However, adult vaccination remains a challenge with overall low coverage rates, which has an impact on both the patients who have these diseases and the health care system in terms of resource use and costs derived. This study aimed to estimate the direct economic impact of herpes zoster, pneumococcal disease, influenza and pertussis in Spanish adults 45 years and older.

METHODS

Data from 2015 were extracted from two Spanish public databases: the Minimum Basic Data Set for Hospitalisations and the Clinical Database of Primary Care. Codes from the International Classification of Diseases and the International Classification of Primary Care were used to identify and classify the diseases analysed. The variables extracted and calculated were hospitalisation (cases, percentage, length of stay, costs, mortality), primary care (cases, percentage, costs) and referrals (cases, percentage, costs). Results were presented for the age groups 45-64 years, 65-74 years, > 74 years and all ages.

RESULTS

In adults 45 years and older, total costs amounted to €134.1 million in 2015 (i.e. 63.9% of the total direct costs for all age groups): 44.4% due to pneumococcal disease, 39.5% due to influenza, 16.0% due to herpes zoster and 0.1% due to pertussis. Hospitalisations represented 58.1% (€77.9 million) of the total costs, with 15,910 admissions, 144,752 days of hospitalisation and 1170 deaths. Primary care registered 566,556 visits with a cost of €35.0 million, and 269,186 referrals with a cost of €21.1 million.

CONCLUSION

The direct economic burden of herpes zoster, pneumococcal disease, influenza and pertussis in adults 45 years and older was high in Spain, and may be underestimated as it only considered medical assistance and not other applicable direct or indirect costs. Increasing vaccination rates in adults may potentially reduce the economic burden derived from these diseases, although future cost-effectiveness analysis including other disease-related costs, vaccination costs and vaccination effectiveness would be needed.

Vaccination and modern management of chronic obstructive pulmonary disease - a narrative review

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) carries a tremendous societal and individual burden, posing significant challenges for public health systems worldwide due to its high morbidity and mortality. Due to aging and multimorbidity but also in the wake of important progress in deciphering the heterogeneous disease endotypes, an individualized approach to the prevention and management of COPD is necessary.

AREAS COVERED

This article tackles relevant immunization strategies that are available or still under development with a focus on the latest evidence but also controversies around different regional immunization approaches. Further, we present the crossover between chronic lung inflammation and lung microbiome disturbance as well as its role in delineating COPD endotypes. Moreover, the article attempts to underline endotype-specific treatment approaches. Lastly, we highlight non-pharmacologic prevention and management programs in view of the challenges and opportunities of the COVID-19 era.

EXPERT OPINION

Despite the remaining challenges, personalized medicine has the potential to offer tailored approaches to prevention and therapy and promises to improve the care of patients living with COPD.

Memory B Cell Activation Induced by Pertussis Booster Vaccination in Four Age Groups of Three Countries

Background

Immunogenicity of acellular pertussis (aP) vaccines is conventionally assessed by measuring antibody responses but antibody concentrations wane quickly after vaccination. Memory B cells, however, are critical in sustaining long-term protection and therefore may be an important factor when assessing pertussis immunity after vaccination.

Aim

We studied pertussis specific memory B cell (re)activation induced by an aP booster vaccination in four different age groups within three countries.

Materials and methods

From a phase IV longitudinal interventional study, 268 participants across Finland, the Netherlands and the United Kingdom were included and received a 3-component pertussis booster vaccine: children (7-10y, n=53), adolescents (11-15y, n=66), young adults (20-34y, n=74), and older adults (60-70y, n=75). Memory B cells at baseline, day 28, and 1 year post-vaccination were measured by a pertussis toxin (Ptx), filamentous haemagglutinin (FHA), and pertactin (Prn) specific ELISpot assay. Antibody results measured previously were available for comparison. Furthermore, study participants were distributed into groups based on their baseline memory B cell frequencies, vaccine responses were monitored between these groups.

Results

Geometric mean (GM) memory B cell frequencies for pertussis antigens at baseline were low. At 28 days post-vaccination, these frequencies increased within each age group and were still elevated one year post-booster compared to baseline. Highest frequencies at day 28 were found within adolescents (GM: 5, 21, and 13, for Ptx, FHA and Prn, respectively) and lowest within older adults (GM: 2, 9, and 3, respectively). Moderate to strong correlations between memory B cell frequencies at day 28 and antibody concentrations at day 28 and 1 year were observed for Prn. Memory B cell frequencies &gt; 1 per 100,000 PBMCs at baseline were associated with significantly higher memory responses after 28 days and 1 year.

Conclusions

An aP booster vaccine (re)activated memory B cells in all age groups. Still elevated memory B cell frequencies after one year indicates enhanced immunological memory. However, antigen specific memory B cell activation seems weaker in older adults, which might reflect immunosenescence. Furthermore, the presence of circulating memory B cells at baseline positively affects memory B cell responses. This study was registered at www.clinicaltrialsregister.eu: No. 2016-003678-42.

Long-Term Immunogenicity upon Pertussis Booster Vaccination in Young Adults and Children in Relation to Priming Vaccinations in Infancy

Booster vaccinations for pertussis are advised in many countries during childhood or adulthood. In a phase IV longitudinal interventional study, we assessed long-term immunity following an extra pertussis booster vaccination in children and adults. Children (9 years of age) were primed in infancy with either the Dutch whole cell pertussis (wP) vaccine (n = 49) or acellular pertussis (aP) vaccines (n = 59), and all children received a preschool aP booster. Adults (25–29 years, n = 86) were wP-primed in infancy and did not receive a preschool booster. All were followed-up for approximately 6 years. After the additional booster, antibody responses to pertussis were more heterogeneous but generally higher in adults compared with children, and additional modelling showed that antibody concentrations remained higher for at least a decade. Serologic parameters indicative of recent pertussis infection were more often found in aP-primed children (12%) compared with wP-primed individuals (2%) (p = 0.052). This suggests that the aP booster vaccination in aP-primed children offers less long-term protection against pertussis infection and consequently against transmission. Together, these data show that aP priming in combination with aP boosting may not be sufficient to prevent circulation and transmission, while wP-primed adults may benefit from enhanced long-lasting immunity.

Facilitating the planning and evaluation of narrative intervention reviews: Systematic Transparency Assessment in Intervention Reviews (STAIR)

Narrative reviews offer a flexible way to report intervention results and comprise the majority of reviews published in top medical journals. However variations in their transparency pose evaluation challenges, compromising their value and potentially resulting in research wastage. Calls have been made to reduce the number of narrative reviews published. Others argue narrative reviews provide an important platform and should even be placed on an equal footing to systematic reviews. We believe narrative intervention reviews can provide a vital perspective when transparent, and thus support Systematic Transparency Assessment in Intervention Reviews (STAIR). This research evaluates the transparency of 172 health-related narrative and literature reviews (K = 172), by assessing how they communicate information about the interventions they review. Eight points supporting transparency, relating to sample sizes, traceability, article numbers, and references, were assessed. Half of the reviews reported on at least four of the eight points, but 24% reported on none. Only 56% of the reviews clearly communicated full references. The STAIR* (Sample sizes, Traceability, Article numbers, Intervention numbers, References*) checklist comprises five sections, and nine points. It is proposed as a convenient tool to address STAIR and complement existing review guidelines to assist authors in planning, reviewers in evaluating, and scholars in utilising narrative reviews. The objectives of STAIR* are to: 1) encourage narrative review transparency and readability, 2) facilitate the incorporation of narrative reviews results into other research; and 3) enrich narrative review methodology with a checklist to guide, and evaluate, intervention reviews.

Reduced Bordetella pertussis-specific CD4+ T-Cell Responses at Older Age

Pertussis, a human-specific respiratory infectious disease caused by the Gram-negative bacterium Bordetella pertussis (Bp), remains endemic with epidemic years despite high vaccination coverage. Whereas pertussis vaccines and natural infection with Bp confer immune protection, the duration of protection varies and is not lifelong. Recent evidence indicates a considerable underestimation of the pertussis burden among older adults. Whereas the impact of increasing age on Bp-specific humoral immunity has been demonstrated, little is known on immunosenescence of CD4⁺ T-cell responses in the context of Bp. Here, we aimed to address whether increasing age impacts responsiveness of the Bp-specific CD4⁺ T-cells in the memory pool following a clinically symptomatic pertussis infection in whole cell vaccine-primed pediatric and adult cases. Cytokine and proliferative responses and phenotypical profiles of CD4⁺ T cells specific for Bp antigens at an early and late convalescent timepoint were compared. Responses of various Th cytokines, including IFNγ, were significantly lower in older adults at early and late timepoints post diagnosis. In addition, we found lower frequencies of Bp-specific proliferated CD4⁺ T cells in older adults, in the absence of differences in replication profile. Phenotyping of Bp-specific CD4⁺ T cells suggested reduced expression of activation markers rather than increased expression of co-inhibitory markers. Altogether, our findings show that the magnitude and functionality of the Bp-specific memory CD4⁺ T-cell pool decrease at older age. Declined CD4⁺ T-cell responsiveness to Bp is suggested to contribute to the burden of pertussis in older adults.

Age and Primary Vaccination Background Influence the Plasma Cell Response to Pertussis Booster Vaccination

Pertussis is a vaccine-preventable disease caused by the bacterium Bordetella pertussis. Over the past years, the incidence and mortality of pertussis increased significantly. A possible cause is the switch from whole-cell to acellular pertussis vaccines, although other factors may also contribute. Here, we applied high-dimensional flow cytometry to investigate changes in B cells in individuals of different ages and distinct priming backgrounds upon administration of an acellular pertussis booster vaccine. Participants were divided over four age cohorts. We compared longitudinal kinetics within each cohort and between the different cohorts. Changes in the B-cell compartment were correlated to numbers of vaccine-specific B- and plasma cells and serum Ig levels. Expansion and maturation of plasma cells 7 days postvaccination was the most prominent cellular change in all age groups and was most pronounced for more mature IgG1+ plasma cells. Plasma cell responses were stronger in individuals primed with whole-cell vaccine than in individuals primed with acellular vaccine. Moreover, IgG1+ and IgA1+ plasma cell expansion correlated with FHA-, Prn-, or PT- specific serum IgG or IgA levels. Our study indicates plasma cells as a potential early cellular marker of an immune response and contributes to understanding differences in immune responses between age groups and primary vaccination backgrounds.

Burden of Pertussis in Individuals with a Diagnosis of Asthma: A Retrospective Database Study in England

Purpose

The impact of pertussis in individuals with asthma is not fully understood. We estimated the incidence, health care resource utilization (HCRU), and direct medical costs (DMC) of pertussis in patients with asthma.

Patients and Methods

In this retrospective cohort study, the incidence rate of pertussis (identified using diagnostic codes) among individuals aged ≥50 years with an asthma diagnosis was assessed during 2009–2018 using Clinical Practice Research Datalink and Hospital Episode Statistics databases. HCRU and DMC were compared – between patients with diagnoses of asthma and pertussis (asthma+/pertussis+) and propensity score-matched patients with a diagnosis of asthma without pertussis (asthma+/pertussis–) – in the months around the pertussis diagnosis (–6 to +11).

Results

Among 687,105 individuals, 346 had a reported pertussis event (incidence rate: 9.6/100,000 person-years of follow-up; 95% confidence interval: 8.6–10.7). HCRU and DMC were assessed among 314 asthma+/pertussis+ patients and 1256 matched asthma+/pertussis– controls. Baseline HCRU was similar in both cohorts, but increases were observed in the asthma+/pertussis+ cohort from –6 to –1 month before to 2–5 months after diagnosis. Rates of accident and emergency visits, general practitioner (GP)/nurse visits, and GP prescriptions were 4.3-, 3.1-, and 1.3-fold, respectively, in the asthma+/pertussis+ vs asthma+/pertussis– cohorts during the month before diagnosis; GP/nurse visit rates were 2.0- and 1.2-fold during 0–2 and 2–5 months after diagnosis, respectively (all p<0.001). DMC was 1.9- and 1.6-fold during the month before and 2 months from diagnosis, respectively, in the asthma+/pertussis+ vs asthma+/pertussis– cohorts (both p<0.001). During months –1 to +11, DMC in the asthma+/pertussis+ cohort was £370 higher than in the asthma+/pertussis– controls.

Conclusion

A pertussis diagnosis among adults aged ≥50 years with asthma resulted in significant increases in HCRU and DMC across several months around diagnosis, suggesting lengthy diagnosis times and highlighting the need for prevention strategies.

Improving vaccination rates in older adults and at-risk groups: focus on pertussis

Despite the implementation of effective paediatric vaccination programmes, pertussis remains a global health problem. Disease epidemiology has changed over time, shifting towards the adolescent and adult populations. In adults, the true burden of pertussis is greatly underestimated and pertussis vaccine coverage rates are suboptimal, including individuals with chronic conditions. Here, we report the outcomes of a virtual international scientific workshop to assess the evidence on the burden of pertussis in older adults and identify potential solutions to improve uptake of pertussis vaccines. In adults, pertussis is underdiagnosed in part due to atypical or milder clinical presentation and the lack of testing and case confirmation. However, contemporary epidemiological data denoted an increase in the burden of pertussis among adolescents and adults. This might be related to a variety of reasons including the waning of immunity over time, the lack of booster vaccination, and the improved diagnostic methods that led to increased recognition of the disease in adults. Pertussis sequelae can be severe in older adults, particularly those with existing chronic medical conditions, and the vulnerability of these groups is further enhanced by low pertussis vaccine coverage. Possible measures to increase vaccine uptake include strengthening and harmonisation of immunisation guidelines, healthcare professionals taking a more active role in recommending pertussis vaccination, involvement of vaccination centres and pharmacies in the vaccination process, and improving knowledge of pertussis burden and vaccine efficacy among the general population.

Vaccination in pregnancy against pertussis and seasonal influenza: key learnings and components from high-performing vaccine programmes in three countries: the United Kingdom, the United States and Spain

BACKGROUND

Pertussis and seasonal influenza are responsible for significant maternal, neonatal, and infant morbidity and mortality, but vaccine coverage rates (VCR) for both pertussis (administered as a tetanus, diphtheria, acellular pertussis [Tdap] vaccination) and seasonal influenza in pregnancy remain generally low. Only a small number of countries, including Spain, the United Kingdom (UK), and the United States (US), have high Tdap and seasonal influenza VCRs in pregnancy. The purpose of this study was to identify the key factors that contributed to the high VCRs observed in these countries.

METHODS

The experience from both Tdap and seasonal influenza vaccination programmes during pregnancy were documented in Spain, the UK, and the US using a three-step approach. A literature review yielded 157 publications, and a further 117 documents were selected through desk research. A published five-pillar VCR framework for influenza was amended to evaluate the specific contributing factors leading to high Tdap and seasonal influenza VCRs among pregnant women.

RESULTS

The analysis identified components that contributed to higher VCR in pregnant women across three different healthcare systems in Spain, UK, and US. The combination of several key interventions in each country led to a rapid increase in VCR that reached near-optimal levels (i.e. 75% for seasonal influenza) within a few years. As well as inclusion in national immunisation programme and vaccine reimbursement, key components that were identified included the mobilisation of health authorities, prenatal care Healthcare Professionals (HCP) and scientific societies, the inclusion of vaccination in antenatal medical guidance, the provision of educational material to HCPs, and a strong disease awareness driven by recent pertussis outbreaks in each country.

CONCLUSIONS

Although there is no simple, universal solution to improving sub-optimal VCRs, the list of components identified in this study from three countries with high-performing Tdap and seasonal influenza vaccination programmes provides a basis for public health and medical stakeholders in other countries to define strategies to successfully implement national vaccination programmes for pregnant women.

More than 10 years after introduction of an acellular pertussis vaccine in infancy: a cross-sectional serosurvey of pertussis in the Netherlands

Background

Pertussis is a respiratory disease and still endemic despite high vaccination coverage. In the Dutch national immunisation programme (NIP) whole cell pertussis (wP) priming vaccines for infants were replaced by acellular pertussis (aP) priming vaccines in 2005. Serosurveillance gives the opportunity to objectively monitor effects of changes in the NIP on infection prevalence and vaccine response in the population over time.

Methods

For this population-based cross-sectional serosurvey a representative sample of Dutch residents (0-89 years) was drawn in 2016/2017. Primary outcome was the percentage of participants with pertussis toxin specific antibody concentrations ≥ 100 IU/ml as an indicator of recent infection, and to identify groups possibly more vulnerable to pertussis infection. Percentages were compared with previous results from 2006/2007.

Findings

In total 7621 persons were included in the analysis. An increase in recent infections from 3•5% to 5•9% was found in the population from 7 years and older (n=6013) in 2016/2017 compared with 2006/2007. Most noteworthy increase was seen in 12-18-year-olds who were wP primed and aP boosted.

Interpretation

Infection prevalence is still increasing in the Netherlands inducing a risk of pertussis disease in vulnerable (age) groups. Delaying the preschool booster might prolong the period of protection during primary school and thereby possibly protect younger siblings. Extra boosters might be considered for risk populations like older adults and people with (pulmonary) co-morbidities, since they have higher chances of complications and hospitalisation.

An unedited Dutch translation of the abstract is available in Supplementary text 1: Nederlandse samenvatting.

Funding

The Dutch Ministry of Health, Welfare, and Sport.

The need for pertussis vaccination among older adults and high-risk groups: a perspective from advanced economies of the Asia Pacific region

INTRODUCTION

Influenza and pneumococcal vaccines are the most regularly prescribed vaccines amongst adults <65 years of age. Pertussis booster vaccines (available as combined diphtheria-tetanus-acellular pertussis, Tdap) uptake is relatively low in many countries in the Asia-Pacific region. Increasing Tdap vaccination is a strategy that may aid healthy aging.Areas Covered: Epidemiology data, including notification reports from 6 advanced economies in Asia (Australia, Hong Kong, New Zealand, Singapore, South Korea, and Taiwan) were reviewed to assess the pertussis disease burden and identify high-risk groups. Existing Tdap vaccination recommendations were reviewed. Current vaccination practices were discussed to benchmark and identify barriers and success factors for Tdap booster vaccination in older adults.Expert Opinion: The available evidence supports Tdap vaccination at an individual level for the prevention of pertussis, along with tetanus and diphtheria in those aged 65+ years, together with influenza and pneumococcal vaccination. Data gaps need to be filled to support the development of national/supranational recommendations for pertussis booster vaccination. Groups at higher risk of pertussis infection and its complications, including those with chronic obstructive pulmonary disease and asthma, could be considered as priority groups. Increasing disease awareness and establishing adult vaccination registries could improve vaccine coverage and promote healthy aging.

Survey among Italian experts on existing vaccines' role in limiting antibiotic resistance

Antimicrobial resistance (AMR) is a major public health problem threatening to reverse the progress made against infectious diseases. The rapid increase of AMR exposes Italian hospitals at increased risk of untreatable infections. Vaccinations can potentially limit AMR by reducing the number of infected cases in need of antibiotics. We conducted a survey among Italian vaccine experts to record their opinion regarding the role of vaccinations against antibiotic resistance (ABR). Among 80 invited experts, 51 answered all questions. Most respondents were experts in hygiene and preventive medicine (56.9%) and aged >50 years (72.6%). ABR was a priority concern in the daily professional activity of 82.4% of respondents. Overall, 47.1% of respondents believed that all vaccinations included in the vaccination calendar played a role against ABR: 92.2% for pertussis vaccination followed by 88.2%, 74.5%, and 70.6% for meningococcus, measles, and varicella vaccinations, respectively. Almost all respondents agreed that the role of vaccinations against ABR should be clearly expressed in the national vaccination guidelines (96.1%) and Scientific Societies should take an explicit position on the issue (92.2%). These results show that Italian experts have recognized the vaccinations' potential role in limiting ABR and guidelines from the appropriate scientific and governmental authorities are needed.

Recommendations of the Italian society for infectious and tropical diseases (SIMIT) for adult vaccinations

Vaccination prevents 2-3 million deaths worldwide every year. Nevertheless, vaccine-preventable diseases (VPDs) still cause a considerable number of deaths especially in subjects belonging to "risk groups." These are represented by older adults, immunocompromised individuals and all subjects with underlying chronic medical conditions (cardiovascular, pulmonary, renal and liver chronic diseases, diabetes, immunodeficiency disorders). They have a weaker immune system and, if infected, are more likely to develop severe complications of their condition or of the preventable-infectious disease. This document summarizes the recommendations for vaccination of the main Global Institutional Organizations and analyses the risks of comorbidities associated with infectious disease and the benefits of vaccination for each specific group. The document provides a clear, practical and authoritative guide to adult vaccination.

Manifesto on the Value of Adult Immunization: "We Know, We Intend, We Advocate"

Immunization through vaccination is a milestone achievement that has made a tremendous contribution to public health. Historically, immunization programs aimed firstly to protect children, who were disproportionally affected by infectious diseases. However, vaccine-preventable diseases can have significant impacts on adult mortality, health, and quality of life. Despite this, adult vaccinations have historically been overlooked in favor of other health priorities, because their benefits to society were not well recognized. As the general population is aging, the issue of vaccination in older adults is gaining importance. In high-income countries, recommendations for the routine vaccination of older adults have been gradually introduced. The Italian National Immunization Plan is considered to be among the most advanced adult vaccination plans in Europe. However, available data indicate there is low adherence to vaccination recommendations in Italy. The COVID-19 pandemic has exposed the damage that can be caused by an infectious disease, especially among adults and individuals with comorbidities. The aim of this “Manifesto”, therefore, is to provide an overview of the existing evidence on the value of adult vaccination, in the Italian context, with a call to action to healthcare providers and health authorities.

Circulation of Bordetella pertussis in the Caribbean Netherlands: a population-based seroepidemiological study

OBJECTIVES

Pertussis is a respiratory infectious disease caused by Bordetella pertussis. In the Caribbean Netherlands (CN), comprising the islands Bonaire, St Eustatius, and Saba, registration of cases is mandatory for disease surveillance. However, insufficient laboratory facilities hamper case confirmation, and circulation persists. The aim of this seroepidemiological study was to gain insight into B. pertussis circulation in CN, and to investigate what factors contribute to the risk of infection.

METHODS

Blood samples and questionnaires were collected for 1829 participants aged 0-90 years. Concentrations of B. pertussis toxin-specific IgG antibodies (anti-Pt) were determined using a bead-based immunoassay to indicate infections within the previous 12 months (based on anti-Pt ≥ 50 IU/mL) in participants without detectable vaccine-induced humoral immunity. Risk factors for recent infection were analyzed using logistic regression models.

RESULTS

An estimated 8.2% (95% CI 6.6-10.1) of CN residents aged ≥ 9 years were found to have been recently infected by B. pertussis. Risk factors for a recent infection were age 12-29 years (13.8-14.6%) and Dutch Caribbean or Surinamese origin (10.7%).

CONCLUSIONS

B. pertussis infections occur frequently among CN residents aged ≥ 9 years, although few clinical pertussis cases are reported. Transmission to vulnerable individuals seems likely and should be taken into account in optimizing vaccination programs.

[Vaccination against community acquired pneumonia in adults. Update 2021 of the position paper by Neumoexpertos en Prevención Group]

Community-acquired pneumonia (CAP) continues to be an important cause of morbidity and mortality in adults. The aim of this study is to update the practical prevention guide for CAP through vaccination in Spain developed in 2016 and updated in 2018, based on available vaccines and evidence through bibliographic review and expert opinion. The arrival of COVID-19 as a new cause of CAP and the recent availability of safe and effective vaccines constitutes the most significant change. Vaccines against pneumococcus, influenza, pertussis and COVID-19 can help to reduce the burden of disease from CAP and its associated complications. The available evidence supports the priority indications established in this guide, and it would be advisable to try to achieve a widespread dissemination and implementation of these recommendations in routine clinical practice.

Pertussis in Individuals with Co-morbidities: A Systematic Review

Pertussis is a highly contagious disease of the respiratory tract caused by Bordetella pertussis. Although the burden of pertussis is highest in children, available data suggests that pertussis in the elderly and those with underlying chronic conditions or illnesses can result in significant morbidity, mortality and costs. We undertook a comprehensive review to assess the association between pertussis and chronic conditions/illnesses. A search was undertaken on 17 June 2019 across EMBASE, Medline and BIOSIS. Citations were limited to those in English, in humans and published since 1 January 1990. There were 1179 papers identified with an additional 70 identified through a review of the reference lists. Of these, 34 met the inclusion criteria. Papers included were categorised in groups, those which reported: associations between prior pertussis and subsequent chronic conditions or illnesses; a link between chronic conditions/illnesses and subsequent risk of pertussis; and those which reported on the effect of the chronic conditions/illnesses on pertussis complications or exacerbations. Pertussis appears to increase the likelihood of developing some chronic conditions/illnesses, but also appears to decrease the likelihood of developing some haematological cancers. There were several chronic conditions/illnesses where the study results were mixed, and several studies that found no association with previous pertussis. There were also studies which showed that having some comorbid health condition(s) might increase the risk of developing pertussis. Three studies showed pertussis can lead to increased exacerbations of chronic conditions/illnesses and associated hospitalisations, although one study showed it reduced the effects of chronic bronchitis. Previous pertussis appears to contribute to the increased likelihood of developing some respiratory conditions like asthma, and conversely those with asthma or COPD are at increased risk of severe pertussis requiring further intervention. Further research is required to confirm or disprove these associations, and to characterise the pathophysiological mechanisms behind the potential associations with pertussis.

Estimating pertussis incidence in general practice using a large Australian primary care database

BACKGROUND

While pertussis is notifiable in most countries, notifications typically underestimate the true pertussis burden. We explored the incidence of pertussis in general practice in Australia.

METHODS

Using MedicineInsight, a large longitudinal electronic medical record database of general practice (primary care) encounters which includes >1.5 million patients, we first defined a cohort of active patients and then used free-text search algorithms to identify patients with pertussis-related encounters. We defined and identified pertussis-related encounters in four patient categories: pertussis-associated (category 1), potential pertussis (category 2), epidemiologically-linked pertussis (category 3), and symptoms consistent with pertussis (category 4). Incident pertussis-related encounter rates per 100,000 active patients were calculated from Jan 2008 to Aug 2015.

RESULTS

Estimated mean annual pertussis incidence increased as definitions were expanded, from 94.3 (category 1 patients only) to 148.8 (categories 1+2+3 patients combined) per 100,000 active patients per year. Monthly time-series corresponding to the first three categories were highly correlated (Pearson's r > 90% for each pair), but each was poorly correlated with category 4. For categories 1+2+3, the highest incidence was among 0-4 and 5-9 year olds. Incidence was 30% higher in females than males (i.e. 184.5 vs 139.8 per 100,00 active patients for categories 1-3 patients combined). Pertussis-associated incidence (category 1) was similar to national pertussis notification rates. Categories 2 and 3 added 25% and 33%, respectively, on average relative to category 1 incidence. The estimated incidence from categories 1+2+3 together were on average 64% higher than national pertussis notification rates.

CONCLUSION

We provide comprehensive estimates of pertussis-related incidence in general practice (primary care), well in excess of notified pertussis incidence in Australia. This highlights the utility of MedicineInsight data in providing a greater understanding of the burden of medically-attended pertussis infections.

Epidemiology of pertussis among adolescents, adults, and older adults in selected countries of Latin American: a systematic review

We aimed to describe the impact of pertussis on adolescents, adults, and older adults over 2007–2018 in selected Latin American countries by reviewing the literature. We searched the Medline, Embase, Scopus, LILACS, Scielo, Google Scholar, CAPES Journals Web-portal, and Cochrane databases for observational epidemiological studies, clinical trials, and systematic reviews of primary studies. Data were extracted and analyzed for all individuals aged ≥10 years. Of 6,891 studies identified only 25 were eligible. Studies were conducted in Brazil (14), Argentina (4), Colombia (4), Mexico (2) and Chile (1). Epidemiological data among target population were limited. No studies clearly assessed the status of asymptomatic or oligosymptomatic B. pertussis carriers in these age groups. Among all pertussis cases identified, the percentage of patients ≥10 years-old ranged between 2.1% and 66.7% depending on country and sample characteristics. The definition of cases, diagnostic methods, and age groups were not consistent across studies.

Seroprevalence of Bordetella pertussis Infection in Patients With Chronic Obstructive Pulmonary Disease in England: Analysis of the AERIS Cohort

Pertussis is underdiagnosed and underreported in adults and patients with underlying conditions. Patients with chronic obstructive pulmonary disease (COPD) may be at increased risk of severe pertussis. Understanding the true prevalence of pertussis infections in such patients is important. We therefore evaluated the seroprevalence of anti-pertussis toxin (PT) antibodies in a cohort of 40-85-year-old patients diagnosed with moderate, severe or very severe COPD enrolled (between June 2011 and June 2012) in the prospective, observational "Acute Exacerbation and Respiratory InfectionS in COPD" (AERIS; NCT01360398) study, conducted in England. Serum anti-PT antibodies were measured in 104 patients using an enzyme-linked immunosorbent assay on samples collected 12 months (M12) and 24 months (M24) after enrollment. Overall, 14/104 (13.5%) patients had anti-PT concentrations ≥50 IU/mL at M12 or M24, indicative of exposure to Bordetella pertussis during the preceding 2-3 years. Of these, 6/104 (5.8%) had anti-PT ≥70 IU/mL, of whom 3/104 (2.9%) had anti-PT ≥120 IU/mL, indicative of exposure within 12 and 6 months, respectively. These results show a high circulation of B. pertussis in 40-85-year-old patients with moderate, severe or very severe COPD in England between 2012 and 2014, and call for enhanced immunization to prevent pertussis infections in such patients.

Burden of Pertussis in COPD: A Retrospective Database Study in England

Chronic obstructive pulmonary disease (COPD) may increase the risk and severity of pertussis infection. Health care resource utilization (HCRU) and direct medical costs (DMC) of treating pertussis among patients with COPD are unknown. Reported incidence of pertussis among individuals aged ≥ 50 years with COPD was assessed in Clinical Practice Research Datalink and Hospital Episode Statistics databases during 2009-2018 using a retrospective cohort design. HCRU and DMC from the National Health Service perspective were compared between patients with COPD and pertussis and propensity score-matched patients with COPD without pertussis. Seventy-eight new pertussis events were identified among 387 086 patients with COPD aged ≥ 50 years (incidence rate: 4.73; 95% confidence interval 3.74-5.91 per 100 000 person-years). HCRU and DMC were assessed among 67 patients with COPD and pertussis and 267 matched controls. During the month before the pertussis diagnosis, the rates of general practitioner (GP)/nurse visits (4289 vs. 1774 per 100 patient-years) and accident and emergency visits (182 vs. 18 per 100 patient-years) were higher in the pertussis cohort; GP/nurse visits (2935 vs. 1705 per 100 patient-years) were also higher during the following 2 months (all p < 0.001). During the month before the pertussis diagnosis, annualized per-patient total DMC were £2012 higher in the pertussis cohort (£3729 vs. £1717; p < 0.001); during the following 2 months, they were £2407 higher (£5498 vs. £3091; p < 0.001). In conclusion, a pertussis episode among individuals with COPD resulted in significant increases in HCRU and DMC around the pertussis event.

Responses to an acellular pertussis booster vaccination in children, adolescents, and young and older adults: A collaborative study in Finland, the Netherlands, and the United Kingdom

Background

Pertussis can lead to serious disease and even death in infants. Older adults are more vulnerable to complications as well. In high-income countries, acellular pertussis vaccines are used for priming vaccination. In the administration of booster vaccinations to different age groups and target populations there is a substantial between-country variation. We investigated the effect of age on the response to acellular pertussis booster vaccination in three European countries.

Methods

This phase IV longitudinal intervention study performed in Finland, the Netherlands and the United Kingdom between October 2017 and January 2019 compared the vaccine responses between healthy participants of four age groups: children (7–10y), adolescents (11–15y), young adults (20–34y), and older adults (60–70y). All participants received a three-component acellular pertussis vaccine. Serum IgG and IgA antibody concentrations to pertussis antigens at day 0, 28, and 1 year were measured with a multiplex immunoassay, using pertussis toxin concentrations at day 28 as primary outcome. This trial is registered with ClinicalTrialsRegister.eu (2016–003,678–42).

Findings

Children (n = 109), adolescents (n = 121), young adults (n = 74), and older adults (n = 75) showed high IgG antibody concentrations to pertussis toxin at day 28 with GMCs of 147 (95% CI 120–181), 161 (95% CI 132–196), 103 (95% CI 80–133), and 121 IU/ml (95% CI 94–155), respectively. A significant increase in GMCs for vaccine antigens in all age groups by 28 days was found which had decreased by 1 year. Differences in patterns of IgG GMCs at 28 days and 1 year post-vaccination did not have a consistent relationship to age. In contrast, IgA antibodies for all antigens increased with age at all timepoints.

Interpretation

Acellular pertussis booster vaccination induces significant serum IgG responses to pertussis antigens across the age range which are not uniformly less in older adults. Acellular boosters could be considered for older adults to reduce the health and economic burden of pertussis.

Perceptions of vaccine preventable diseases in Australian healthcare: focus on pertussis

Adult vaccination in Australia is suboptimal. For instance, as few as one in nine people have received a pertussis vaccine in adolescence or adulthood, despite increasing disease burden and evidence of a positive correlation between older age and hospitalization rates. The objectives of this study were to describe general practitioners' (GPs) and adult consumers' knowledge and attitudes toward adult vaccination, with an emphasis on pertussis. Australian GPs and consumers were recruited in two nationally representative online surveys repeated annually between 2014 and 2018. Vaccination discussions occurred in a minority of adult/GP encounters. Pertussis was among the five most frequently identified vaccine preventable diseases but was unlikely to be proactively discussed with adults not in contact with young children. Among consumers, only one in three recalled ever receiving a pertussis vaccination. GPs are a strong predictor of adults receiving a pertussis vaccine. Possible factors contributing to low uptake are misconceptions around pertussis disease, vaccination requirements and lack of GP recommendation for adult vaccination. GPs have a key role to play in increasing adult vaccination coverage with their recommendation.