Severe Pertussis Infections in the United States, 2011-2015

Differences in Pertussis Incidence by Race and Ethnicity in the United States, 2010-2017

Background

An increased pertussis burden has been demonstrated among Hispanic or Latino and American Indian or Alaska Native (AI/AN) infants. However, data on potential disparities among other age and racial groups are limited.

Methods

We analyzed pertussis cases reported through Enhanced Pertussis Surveillance from 2010 to 2017. Pertussis and severe pertussis incidence were calculated by race (White, Black or African American, AI/AN, and Asian or Pacific Islanders), ethnicity (Hispanic or Latino and non-Hispanic or non-Latino), and age.

Results

Compared with White persons, overall incidence was lower among Black or African American (incidence rate ratio [IRR], .57; 95% confidence interval [CI], .53-.61), AI/AN (IRR, 0.65; 95% CI, .58-.72), and Asian or Pacific Islander persons (IRR, 0.39; 95% CI, .35-.43). Overall incidence of pertussis was higher (1.5-fold; 95% CI, 1.37-1.60) among Hispanic or Latino compared with non-Hispanic or non-Latino adults, potentially related to household size or lower pertussis vaccine uptake among adult Hispanic or Latino cases. Severe pertussis incidence was similar among Black or African American and AI/AN persons compared with White persons. Among infants, severe pertussis incidence was 1.4-fold higher (95% CI, 1.03-1.82) among Black or African American infants than among White infants, and 2.1-fold higher (95% CI, 1.67-2.57) among Hispanic or Latino infants than non-Hispanic or non-Latino infants.

Conclusions

The contrast between lower reported incidence but similar or higher severe pertussis incidence among Black or African American and AI/AN persons compared with White persons warrants further investigation and may reflect underdiagnosis or underreporting of mild disease.

Influenza and Tetanus, Diphtheria, and Acellular Pertussis Vaccination Coverage During Pregnancy: Pregnancy Risk Assessment Monitoring System, 2020

OBJECTIVES

Estimates of vaccination coverage during pregnancy and identification of disparities in vaccination coverage can inform vaccination campaigns and programs. We reported the prevalence of being offered or told to get the influenza vaccine by a health care provider (hereinafter, provider); influenza vaccination coverage during the 12 months before delivery; and tetanus, diphtheria, and acellular pertussis (Tdap) vaccination coverage during pregnancy among women with a recent live birth in the United States.

METHODS

We analyzed 2020 data from the Pregnancy Risk Assessment Monitoring System from 42 US jurisdictions (n = 41 673). We estimated the overall prevalence of being offered or told to get the influenza vaccine by a provider and influenza vaccination coverage during the 12 months before delivery. We estimated Tdap vaccination coverage during pregnancy from 21 jurisdictions with available data (n = 22 020) by jurisdiction and select characteristics.

RESULTS

In 2020, 84.9% of women reported being offered or told to get the influenza vaccine, and 60.9% received it, ranging from 35.0% in Puerto Rico to 79.7% in Massachusetts. Influenza vaccination coverage was lower among women who were not offered or told to get the influenza vaccine (21.4%) than among women who were offered or told to get the vaccine (68.1%). Overall, 72.7% of women received the Tdap vaccine, ranging from 52.8% in Mississippi to 86.7% in New Hampshire. Influenza and Tdap vaccination coverage varied by all characteristics examined.

CONCLUSIONS

These results can inform vaccination programs and strategies to address disparities in vaccination coverage during pregnancy and may inform vaccination efforts for other infectious diseases among pregnant women.

Maternal pertussis immunization and the blunting of routine vaccine effectiveness: a meta-analysis and modeling study

A key goal of pertussis control is to protect infants too young to be vaccinated, the age group most vulnerable to this highly contagious respiratory infection. In the last decade, maternal immunization has been deployed in many countries, successfully reducing pertussis in this age group. Because of immunological blunting, however, this strategy may erode the effectiveness of primary vaccination at later ages. Here, we systematically reviewed the literature on the relative risk (RR) of pertussis after primary immunization of infants born to vaccinated vs. unvaccinated mothers. The four studies identified had ≤6 years of follow-up and large statistical uncertainty (meta-analysis weighted mean RR: 0.71, 95% CI: 0.38-1.32). To interpret this evidence, we designed a new mathematical model with explicit blunting mechanisms and evaluated maternal immunization's short- and long-term impact on pertussis transmission dynamics. We show that transient dynamics can mask blunting for at least a decade after rolling out maternal immunization. Hence, the current epidemiological evidence may be insufficient to rule out modest reductions in the effectiveness of primary vaccination. Irrespective of this potential collateral cost, we predict that maternal immunization will remain effective at protecting unvaccinated newborns, supporting current public health recommendations.

Immunogenicity and safety of reduced-antigen tetanus, diphtheria and acellular pertussis vaccination in adults treated for obstructive airway diseases

Patients with obstructive airway diseases (OAD), like chronic obstructive pulmonary disease (COPD) and asthma, may be at increased risk of pertussis infection. Pertussis may also trigger COPD and asthma exacerbations. Vaccination against pertussis could help protect OAD patients from the additional burden of pertussis, but there may be hesitancy related to vaccine safety and immunogenicity in such patients. We performed a meta-analysis on 5 clinical trials in adults receiving reduced-antigen tetanus-diphtheria-acellular pertussis vaccine (Tdap, Boostrix, GSK), from which we selected participants on active OAD treatment. We compared immunogenicity and reactogenicity outcomes of the meta-analysis with data from the overall populations of Tdap-vaccinated adults from 6 Tdap trials (including the 5 in the meta-analysis). The meta-analysis comprised 222 adults on active standard OAD treatment. One month post-Tdap, 89.0% and 97.2% of these adults, respectively, achieved seroprotective anti-diphtheria and anti-tetanus antibody concentrations; 78.3%-96.1% showed booster responses across the 3 pertussis antigens. These rates were consistent with those in the comparator population. The most frequently reported solicited local and systemic adverse events within 4 days post-Tdap were injection site pain (47.7%) and fatigue (19.3%), with low rates of grade 3 intensity (0.9% and 2.8%). This was consistent with Tdap reactogenicity in the comparator population. Evaluation of unsolicited and serious adverse events within 1 month post-Tdap did not identify safety concerns. In conclusion, Tdap was immunogenic and well tolerated in adults under active standard OAD treatment, with immunogenicity and safety profiles consistent with those in a comparator population representing the general adult population.

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.

Increased Burden of Pertussis Among Adolescents and Adults With Asthma or COPD in the United States, 2007 to 2019

BACKGROUND

Individuals with chronic respiratory illnesses may be at higher risk of pertussis infection and severe pertussis than those without.

RESEARCH QUESTION

What is the incidence of pertussis and pertussis complications in cohorts with preexisting asthma or COPD vs age- and sex-matched control patients from the general population in the United States?

STUDY DESIGN AND METHODS

This observational, retrospective study included individuals aged ≥ 10 years from an administrative health claims system between 2007 and 2019. Individuals with preexisting asthma or COPD were matched with control patients from the general population. The incidence of pertussis infections and pertussis-related complications were assessed overall and by age. The incidence of asthma or COPD exacerbations was also assessed before and after diagnosis of pertussis.

RESULTS

In the general population, incidence per 100,000 person-years of pertussis infection ranged from 5.33 in 2007 to 13.04 in 2012, with highest (all years) in those aged 10 to 17 years. The risk of pertussis was higher for the asthma (rate ratio, 3.57; 95% CI, 3.25-3.92) and COPD cohorts (rate ratio, 1.83; 95% CI, 1.57-2.12) than the general population. Those with asthma or COPD had a 4.12-fold (95% CI, 3.16-5.38) and 2.82-fold (95% CI, 2.14-3.27) increased risk of pertussis with complications than the general population, respectively. Exacerbations were most frequent 30 days before pertussis diagnosis (incidence rate [IR], 25%) in the asthma cohort and 30 days before (IR, 26%) and after (IR, 22%) pertussis diagnosis, remaining elevated for 180 days after diagnosis, in the COPD cohort.

INTERPRETATION

Among these insured individuals, asthma or COPD increased the risk for pertussis disease and complications vs the general population. COPD and asthma exacerbations were observed most frequently within 30 days of receiving a pertussis diagnosis and remained elevated, suggesting a long-term effect of pertussis in the COPD cohort.

Incidence and Healthcare Burden of Pertussis among Older Adults with and without Pre-Existing Chronic Obstructive Pulmonary Disease or Asthma in South Korea

A retrospective cohort study was conducted to examine trends in the incidence and burden of pertussis among adults ≥50 years in South Korea, with/without pre-existing chronic obstructive pulmonary disease (COPD) or asthma. The nationwide Health Insurance Review and Assessment Service (HIRA) database was used to identify patients ≥50 years diagnosed with pertussis (2009-2018). Mean annual incidence of pertussis per 100 000 persons and overall mean incidence rate ratios (IRR) were calculated for patients with pre-existing COPD or asthma versus those with neither. Incremental healthcare costs (all-cause and pertussis-related) and healthcare utilisation (number of outpatient visits, emergency room visits, and number and length of hospitalisations) up to 12 months after, compared to 3 months before pertussis diagnosis, were also measured for each group (matched on sex, age, and Charlson Comorbidity Index). Of 1011 pertussis cases, 175 had asthma, 96 had COPD (not mutually exclusive), and 796 had neither. Overall mean pertussis incidence was 2.5, 3.4, and 0.5 for adults with pre-existing COPD, asthma, and those with neither. IRR (95% confidence interval) of pertussis for adults with pre-existing COPD and asthma was 4.9 (4.0-‍6.1) and 6.7 (5.7-7.9). Both COPD-pertussis and asthma-pertussis groups had higher mean incremental all-cause costs and length of hospitalisations than the general-pertussis group 3 months following pertussis diagnosis. In conclusion, individuals ≥50 years in South Korea with pre-existing COPD or asthma were at an increased risk of being diagnosed with pertussis and had higher healthcare resource utilisation than those without these conditions.

Pertussis immunisation strategies to optimise infant pertussis control: A narrative systematic review

OBJECTIVE

Countries routinely offering acellular pertussis vaccine, where long-term protection is not sustained, have the challenge of selecting an optimal schedule to minimise disease among young infants. We conducted a narrative systematic review and synthesis of information to evaluate different pertussis immunisation strategies at controlling pertussis disease, hospitalisation, deaths, and vaccine effectiveness among young infants.

METHODS

We conducted a review of the literature on studies about the primary, booster, and/or maternal vaccination series and synthesised findings narratively. Countries offering the first three doses of vaccine within six-months of life and a booster on or before the second year or life were defined as accelerated primary and booster schedules, respectively. Countries offering primary and booster doses later were defined as extended primary and booster schedules. All search results were screened, and articles reviewed and reconciled, by two authors. The Risk of Bias in Non-randomised Studies of Intervention tool was used to evaluate the risk of bias.

FINDINGS

A total of 98 studies were included in the analyses and the following recurring themes were described: timing of vaccination, vaccine coverage, waning immunity/vaccine effectiveness, direct and indirect effectiveness, switching from an accelerated to extended schedule, impact of changes in testing. The risk of bias was generally low to moderate for most studies.

CONCLUSION

Comparing schedules is challenging and there was insufficient evidence to that one schedule was superior to another. Countries must select a schedule that maintains high vaccine coverage and reduced the risk of delaying the delivery vaccines to protect infants.

Effectiveness of maternal immunisation with a three-component acellular pertussis vaccine at preventing pertussis in infants in the United States: Post-hoc analysis of a case-control study using Bayesian dynamic borrowing

BACKGROUND

Immunisation during pregnancy with a tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine can protect infants against pertussis between birth and paediatric vaccination. We aimed to estimate the vaccine effectiveness (VE) of third-trimester pregnancy immunisation with the three-component acellular pertussis (Td3ap) vaccine at preventing pertussis in infants <2 months in the United States (US), to support a label update.

METHODS

We performed a post-hoc sub-analysis of a case-control study conducted in six US Emerging Infections Program Network states between 2011 and 2014. Our analysis included only cases and controls whose mothers were either vaccinated with Td3ap or did not receive any Tdap vaccine. The association between Td3ap maternal immunisation and pertussis in infants was assessed for US data using a frequentist method with conditional logistic regression. A robustified analysis was conducted using Bayesian dynamic borrowing of non-US data, considering a mixing-weighted prior of 90% for historical non-US VE data, and of 10% for a vague prior. VE was estimated as (1-odds ratio) × 100%. Sensitivity analyses accounting for the impact of each non-US study, different mixing weights and missing/ambiguous data were performed.

RESULTS

We included 108 cases and 183 controls. Based on US data, the estimated VE of third-trimester maternal immunisation with Td3ap at preventing pertussis in infants <2 months was 78.0% (95% confidence interval: -38.0; 96.5). VE estimated by Bayesian dynamic borrowing of non-US data (with a 90% weight for historical data) was 83.4% (95% credible interval: 55.7; 92.5); sensitivity analyses produced similar VE estimates.

CONCLUSIONS

Effectiveness of third-trimester pregnancy immunisation with Td3ap at preventing infant pertussis in the US is very likely to be ≥ 50% and is most likely ∼ 80%. Bayesian dynamic borrowing of non-US VE data allowed overcoming the limited power (due to small sample size) of a brand-specific sub-analysis by considering additional evidence.

Tetanus, diphtheria, and acellular pertussis vaccine coverage in adults with chronic respiratory conditions

BACKGROUND

Pertussis is a highly contagious respiratory disease, and those with chronic respiratory illnesses may be at higher risk of infection and severe pertussis. Acellular pertussis-containing vaccines (Tdap) are recommended in the United States for those with risk factors, such as asthma and chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To determine Tdap vaccination rates among people with asthma or COPD compared with matched controls with type 2 diabetes and the general population.

METHODS

This observational database study identified adults with asthma or COPD, and their matched controls, from a large US administrative health claims system between January 2008 and December 2014. Vaccination with Tdap was identified using current procedural terminology and national drug codes, and vaccination rates per 1000 patient-years and adjusted rate ratios (RR) were calculated using a generalized linear model with a Poisson distribution and 95% confidence intervals (CI).

RESULTS

Vaccination rates were low overall; however, they were slightly higher in asthma than the general population cohort, with vaccination incidence RRs of 1.12 (95% CI, 1.08-1.17), 1.09 (95% CI, 1.06-1.11), and 1.11 (95% CI, 1.07-1.16) in those aged 18 to 44, 45 to 64, and 65 years and older, respectively. However, Tdap vaccination rates were lower in the COPD than in the general population cohort, with vaccination incidence RRs of 0.72 (95% CI, 0.60-0.86), 0.87 (95% CI, 0.83-0.91), and 0.94 (95% CI, 0.92-0.96), respectively.

CONCLUSION

Pertussis vaccination rates were suboptimal among adults in general and adults with asthma or COPD. Work is needed to boost Tdap vaccination uptake among people with chronic respiratory conditions.

Impact of national recommendations for routine pertussis vaccination during pregnancy on infant pertussis in Ontario, Canada: a population-based time-series study

BACKGROUND

In February 2018, Canada's National Advisory Committee on Immunization (NACI) recommended antenatal tetanus-diphtheria-acellular pertussis (Tdap) immunization in every pregnancy regardless of previous Tdap immunization history. We examined the impact of the NACI recommendation on rates of infant pertussis in Ontario, Canada.

METHODS

We conducted a population-based time-series study of all live births in Ontario between August 1, 2011 and February 28, 2020. We used interventional autoregressive integrated moving average models to examine the impact of the NACI recommendation on monthly rates of pertussis among infants ≤ 3 months of age.

RESULTS

We observed 675 incident cases of pertussis among 1,368,024 infants 3 months of age or less between August 2011 and February 2020. The average monthly percent change in infant pertussis during the period up to and including publication of the NACI guidance and the period following publication were 0.0% (95% CI: -0.4-0.3%) and - 0.8% (95% CI -2.3% to -0.1%), respectively. Following interventional ARIMA modelling, publication of the NACI guidance was not associated with a statistically significant decrease in the monthly pertussis incidence trend (-0.67 cases per 100,000 infants; p = 0.73).

CONCLUSION

Publication of national recommendations for antenatal Tdap immunization in every pregnancy did not significantly reduce infant pertussis rates. This may reflect the persistently low rate of antenatal vaccination following publication of the recommendations. Expanding the scope of practice of allied health care providers to include antenatal Tdap immunization and patient education regarding antenatal pertussis immunization should be considered to further optimize uptake of vaccination.

Immune response to pertussis vaccine in COPD patients

Exacerbation triggered by respiratory infection is an important cause of morbidity and mortality in chronic obstructive pulmonary disease (COPD) patients. Strategies aiming to preventing infection may have significant public health impact. Our previous study demonstrated decreased immunological response to seasonal flu vaccination in COPD patients, questioning the efficiency of other vaccines in this group of patients. We performed a prospective, monocenter, longitudinal study that evaluated the humoral and cellular responses upon pertussis vaccination. We included 13 patients with stable COPD and 8 healthy volunteers. No difference in circulating B and T cell subsets at baseline was noted. Both groups presented similar levels of TFH, plasmablasts and pertussis specific antibodies induction after vaccination. Moreover, monitoring T cell immunity after ex-vivo peptide stimulation revealed equivalent induction of functional and specific CD4+ T cells (IFNγ, TNFα and IL-2-expressing T cells) in both groups. Our results highlight the immunological efficiency of pertussis vaccination in this particularly vulnerable population and challenge the concept that COPD patients are less responsive to all immunization strategies. Healthcare providers should stress the necessity of decennial Tdap booster vaccination in COPD patients.

Review of Vaccination Recommendations in Guidelines for Non-Communicable Diseases with Highest Global Disease Burden among Adults 75 Years Old and Above

This scientific review paper explores international and country-specific healthcare guidelines for non-communicable diseases with the highest burden among individuals aged 75 years and above. The study aims to identify the best vaccination practices and standardize healthcare practices to improve vaccination adherence in this vulnerable population. Given that older people are more prone to infectious illnesses and have higher rates of morbidity and mortality, vaccinations are essential for disease prevention. Despite the proven efficacy of vaccinations, adherence has plateaued in recent years, partly due to a lack of accessibility, public education, and variability in disease-specific guidelines. This paper highlights the need for a more robust and standardized international vaccination model to improve quality of life and reduce disability-adjusted life years among the elderly. The findings of this study call for further research to review the guidelines as more implementations are put in place, including non-English guidelines.

Surveillance Systems for Monitoring Vaccination Coverage with Vaccines Recommended for Pregnant Women, United States

Pregnant women* and their infants are at increased risk for serious influenza, pertussis, and COVID-19-related complications, including preterm birth, low-birth weight, and maternal and fetal death. The advisory committee on immunization practices recommends pregnant women receive tetanus-toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during pregnancy, and influenza and COVID-19 vaccines before or during pregnancy. Vaccination coverage estimates and factors associated with maternal vaccination are measured by various surveillance systems. The objective of this report is to provide a detailed overview of the following surveillance systems that can be used to assess coverage of vaccines recommended for pregnant women: Internet panel survey, National Health Interview Survey, National Immunization Survey-Adult COVID Module, Behavioral Risk Factor Surveillance System, Pregnancy Risk Assessment Monitoring System, Vaccine Safety Datalink, and MarketScan. Influenza, Tdap, and COVID-19 vaccination coverage estimates vary by data source, and select estimates are presented. Each surveillance system differs in the population of pregnant women, time period, geographic area for which estimates can be obtained, how vaccination status is determined, and data collected regarding vaccine-related knowledge, attitudes, behaviors, and barriers. Thus, multiple systems are useful for a more complete understanding of maternal vaccination. Ongoing surveillance from the various systems to obtain vaccination coverage and information regarding disparities and barriers related to vaccination are needed to guide program and policy improvements.

Risk Factors of Pertussis Among Older Adults in South Korea: A Nationwide Health Data-Based Case-Control Study

INTRODUCTION

To better understand the conditions associated with pertussis diagnosis among older adults in South Korea, a matched case-control study was conducted of individuals ≥ 50 years diagnosed with pertussis between 2009 and 2018.

METHODS

Pertussis cases were identified using the nationwide Health Insurance Review and Assessment service (HIRA) database. Each case was then matched to up to 10 controls identified using the National Health Insurance Service-National Sample Cohort (NHIS-NSC) by age, sex, and geographic region at index date. In the 12 months and 30 days prior to index date, the presence of clinical characteristics previously reported to be related to pertussis and pertussis-like conditions were assessed, respectively. A conditional multivariate logistic regression model was then used to calculate odds ratios (ORs) of pertussis diagnosis, adjusted for each of the characteristics.

RESULTS

Pertussis cases (n = 1004) generally demonstrated a higher prevalence of comorbidities compared to controls (n = 9710). Pre-existing asthma and chronic obstructive pulmonary disease (COPD) within 12 months of index date were associated with a two-fold increased risk of pertussis with adjusted ORs (95% confidence interval) of 2.08 (1.68-2.58) and 2.32 (1.59-3.39), respectively. Gastroesophageal reflux disease [GERD; 2.67 (2.23-3.19)], cancer [1.68 (1.23-2.31)], cardiovascular disease [1.62 (1.31-2.00)], renal disease [1.56 (1.12-2.16)], autoimmune disease [1.50 (1.25-1.79)], and hyperlipidemia [1.43 (1.16-1.77)] were also associated with pertussis diagnosis. Finally, acute respiratory events within 30 days prior to index date, such as pneumonia, acute bronchitis, and upper respiratory tract infection (URTI), were highly associated with increased odds of pertussis diagnosis [adjusted ORs of 8.28 (5.10-13.44), 4.86 (3.84-6.14), and 2.90 (2.30-3.67), respectively].

CONCLUSIONS

This study's findings complement and expand upon previous studies on the adult pertussis population, generating real-world data to describe underlying clinical characteristics of those diagnosed with pertussis in South Korea.

Evaluation of Whole-Cell and Acellular Pertussis Vaccines in the Context of Long-Term Herd Immunity

After the pertussis vaccine had been introduced in the 1940s and was shown to be very successful in reducing the morbidity and mortality associated with the disease, the possibility of improving both vaccine composition and vaccination schedules has become the subject of continuous interest. As a result, we are witnessing a considerable heterogeneity in pertussis vaccination policies, which remains beyond universal consensus. Many pertussis-related deaths still occur in low- and middle-income countries; however, these deaths are attributable to gaps in vaccination coverage and limited access to healthcare in these countries, rather than to the poor efficacy of the first generation of pertussis vaccine consisting in inactivated and detoxified whole cell pathogen (wP). In many, particularly high-income countries, a switch was made in the 1990s to the use of acellular pertussis (aP) vaccine, to reduce the rate of post-vaccination adverse events and thereby achieve a higher percentage of children vaccinated. However the epidemiological data collected over the past few decades, even in those high-income countries, show an increase in pertussis prevalence and morbidity rates, triggering a wide-ranging debate on the causes of pertussis resurgence and the effectiveness of current pertussis prevention strategies, as well as on the efficacy of available pertussis vaccines and immunization schedules. The current article presents a systematic review of scientific reports on the evaluation of the use of whole-cell and acellular pertussis vaccines, in the context of long-term immunity and vaccines efficacy.

Review of scientific evidence to support recommendations of the full-dose DTaP-IPV vaccination in pre-school age children in Italy

INTRODUCTION

Two vaccine formulations are available to prevent diphtheria, tetanus, pertussis, and poliomyelitis: the pediatric full-dose (DTaP-IPV) and the reduced dose formulation (dTap-IPV). Different immunization schedules are internationally recommended for the pre-school booster dose.

AREAS COVERED

International and Italian recommendations, scientific evidence on immunogenicity and safety of DTaP/dTap vaccines to support the full dose as a pre-school booster and Italian vaccination coverage (VC) up to adolescence.

EXPERT OPINION

The WHO recommends a '3+1' schedule with DTaP vaccine for primary immunization, followed by a pre-school booster with DTaP or dTap vaccine. In Italy, a '2+1' schedule, with no booster in the second year, and a pre-school booster dose are recommended with DTPa-IPV vaccines. Studies showed a non-inferior immunogenicity in dTap vaccinees in pre-school age; nevertheless, the antibody titers were usually greater in children vaccinated with DTaP, while lower frequencies of adverse events were recorded in children receiving dTap. Italian VCs for pre-school and adolescent boosters have not been satisfactory, which further reduced during the COVID-19 period. In Italy, the pre-school booster offers the last chance to receive a full dose of DTaP vaccine, thus, representing the most suitable intervention to provide lasting protection in children.

A Cross-Sectional Study Revealing the Emergence of Erythromycin-Resistant Bordetella pertussis Carrying ptxP3 Alleles in China

Background

Previous limited studies have identified that Bordetella pertussis (B. pertussis) isolates circulating in China possess distinct molecular features and high rates of erythromycin-resistance (ER). Their evolution and potential impact on the prevention and control of global pertussis are worthy of attention.

Methods

The present cross-sectional study involved 311 non-duplicate and unrelated B. pertussis strains isolated from Chinese children from 2017 to 2019. Their antimicrobial susceptibilities were assessed using both E-test strips and Kirby-Bauer (KB) disk diffusion methods. Seven virulence-related genes (ptxA, ptxC, ptxP, prn, fim2, fim3, and tcfA2) and the A2047G mutation in the 23S rRNA gene were detected by PCR. Based on the susceptibilities and genotypes, 50 isolates were selected for multi-locus variable-number tandem-repeat analysis (MLVA) typing and whole-genome sequencing.

Results

A total of 311 B. pertussis strains were isolated from children with a median age of 4 months (interquartile range: 2–9 months). Strains carrying the ptxP1 allele were more frequent (84.9%, 264/311), were always ER (except for one strain), and were mainly related to ptxA1/ptxC1/prn1 alleles (99.6%, 263/264). The remaining 47 (15.1%) strains carried the ptxP3 allele, mainly harboring the ptxA1/ptxC2/prn2 alleles (93.6%, 44/47), and were sensitive to erythromycin (except for two strains). The two ER-ptxP3 isolates were first identified in China, belonged to MT27 and MT28 according to MLVA, and were classified into sub-lineage IVd by phylogenetic analysis of their genome sequences. This sub-lineage also includes many strains carrying the ptxP3 allele spreading in developed countries. For each tested antimicrobial, the susceptibilities judged by KB disks were consistent with those determined by E-test strips.

Conclusion

The present results reveal that B. pertussis strains with the ptxP1-ER profile still dominate in China, and a few strains carrying the ptxP3 allele have acquired the A2047G mutation in the 23S rRNA gene and the ER phenotype. The surveillance of the drug susceptibility of B. pertussis is necessary for all countries, and the KB disk method can be adopted as a screening test.

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.

Pertussis Disease and Antenatal Vaccine Effectiveness in Australian Children

BACKGROUND

Population-level studies of severe pertussis extending beyond infancy are sparse, and none in the context of antenatal vaccination. We compared hospitalized pertussis cases from birth to 15 years of age before and after introduction of antenatal immunization.

METHODS

Active surveillance of laboratory-confirmed pertussis hospitalizations in a national network of pediatric hospitals in Australia January 2012 to June 2019. Impact of maternal vaccination was assessed by vaccine effectiveness (VE) in cases and test-negative controls with <2 months of age and by before-after comparison of age distribution of cases. Among cases eligible for one or more vaccine doses, we examined proportions age-appropriately immunized and with comorbidities by age group.

RESULTS

Among 419 eligible cases, the proportion <2 months of age significantly decreased from 33.1% in 2012 to 2014 compared with 19.6% in 2016 to 2019 when mothers of only 4 of 17 (23.5%) cases <2 months of age had received antenatal vaccination. VE was estimated to be 84.3% (95% CI, 26.1-96.7). Across all years (2012-2019), of 55 cases 4-11 months of age, 21 (38%) had ≥2 vaccine doses, whereas among 155 cases ≥12 months of age, 122 (85.2%) had ≥3 vaccine doses. Prevalence of comorbidities (primarily cardiorespiratory) increased from 5 (2.1%) <6 months of age to 36 (24.2%) ≥12 months of age (P < 0.001), with 6/16 (38%) cases ≥12 months of age who required intensive care having comorbidities.

CONCLUSIONS

Below the age of 12 months, prevention of severe pertussis will be maximized by high maternal antenatal vaccine uptake and timeliness of infant vaccine doses. Despite full immunization, we found children ≥12 months of age accounted for 27% of hospitalizations <15 years, with 24% having comorbities, suggesting new vaccine strategies, such as additional doses or more immunogenic vaccines, require evaluation.

Presence of Cytomegalovirus Infection Is Associated With an Unfavorable Outcome in Immunocompetent Infants With Pertussis

Background

We aimed to examine cytomegalovirus (CMV) infection in immunocompetent infants with pertussis, based on polymerase chain reaction in plasma and broncho alveolar lavage (BAL), and to assess the clinical characteristics and outcomes for these patients.

Methods

We performed a prospective observational cohort study of consecutive infants with pertussis in Children’s Hospital of Soochow University between Jan 2017 and Jan 2020. We report the burden of CMV PCR in plasma and BAL within this patient group, and evaluate associations between CMV infection and pertussis in these hospitalized infants.

Results

During the study period, 1,867 infants <1 years were evaluated for pertussis, 190 infants were diagnosed as pertussis. For the 190 pertussis patients, 38 (20.0%) patients had positive CMV PCR in plasma. CMV PCR in plasma had high sensitivity and specificity for CMV PCR in BAL (81.3% and 94.4%, respectively). Children with positive CMV PCR in plasma were 3.67 times more likely to present with severe disease (OR 3.67; CI 1.61-8.36). Comparisons of duration of hospital stay curves using the log-rank test statistic demonstrated that the relative risk of longer hospital stay of positive CMV PCR relative to negative CMV was 1.51 (95% CI: 1.05 to 2.14, P = 0.01).

Conclusions

Our study reported a high prevalence of CMV reactivation in immunocompetent infants with lower respiratory tract infection. The presence of CMV in plasma may be associated with an unfavorable outcome in infants with pertussis.

Association of Maternal Tdap Recommendations With Pertussis Hospitalizations of Young Infants

BACKGROUND

It is well established that young infants have the highest risk of severe pertussis, which often results in hospitalization. Since the 2012 recommendation of administering tetanus toxoid, diphtheria toxoid, and acellular pertussis (Tdap) vaccine for every pregnancy, evaluation of pertussis hospitalizations among young infants in the United States has been limited.

METHODS

In this ecological study, we used the Kids' Inpatient Database, the largest all-payer pediatric inpatient database in the United States, to study pertussis hospitalizations among infants <1 month of age from 2000 to 2016.

RESULTS

The overall rate of pertussis hospitalizations before the Tdap vaccination recommendation was 5.06 per 100 000 infants (95% confidence interval, 4.36-5.76) and 2.15 per 100 000 infants (95% confidence interval, 1.49-2.81) afterward.

CONCLUSIONS

This study supports maternal vaccination against pertussis as an important strategy in protecting young infants, and continued evaluation is needed to assess the long-term trends in hospitalization.

Seroprevalence Study of Pertussis in Adults at Childbearing Age and Young Infants Reveals the Necessity of Booster Immunizations in Adults in China

In China, the vaccination strategy against pertussis is started from 3 months of age, with no booster dose used after the booster given at two years. Despite a high vaccination coverage, pertussis has been increasingly reported since the last decade. This study evaluates the prevalence of serum anti-pertussis toxin (PT) IgG antibodies in adults at childbearing age and infants before the age of primary immunization in Beijing, China. A total of 1175 serum samples randomly selected from individuals who attended an annual health examination at the Sixth Medical Center of the PLA General Hospital, Beijing, in 2019, was included. The geometric mean concentration (GMC) and median concentration of anti-PT IgG antibodies among adults aged 20–39 years were 3.81 IU/mL and 3.24 IU/mL, and the corresponding concentrations were 1.72 IU/mL and 1.43 IU/mL among infants under 3 months of age. The seroprevalence of PT IgG antibodies ≥ 40 IU/mL in adults and infants was 2.0% (15/735) and 1.1% (5/440). In total, 65.99% (485/735) of adults and 83.41% (367/440) of infants had non-detectable pertussis-specific antibodies (<5 IU/mL). Our results showed that the majority of adults at a reproductive age and young infants are vulnerable to pertussis, suggesting that booster vaccinations in adults should be considered in this country.

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.

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.

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.

Exploring the nasopharyngeal microbiota composition in infants with whooping cough: A test-negative case-control study

Purpose

The purpose of this study was to characterize the nasopharyngeal microbiota of infants with possible and confirmed pertussis compared to healthy controls.

Methods

This prospective study included all infants <1 year with microbiologically confirmed diagnosis of pertussis attended at a University Hospital over a 12-month period. For each confirmed case, up to 2 consecutive patients within the same age range and meeting the clinical case definition of pertussis but testing PCR-negative were included as possible cases. A third group of asymptomatic infants (healthy controls) were also included. Nasopharyngeal microbiota was characterized by sequencing the V3-V4 region of the 16S rRNA gene. Common respiratory DNA/RNA viral co-infection was tested by multiplex PCR.

Results

Twelve confirmed cases, 21 possible cases and 9 healthy controls were included. Confirmed whooping cough was primarily driven by detection of Bordetella with no other major changes on nasopharyngeal microbiota. Possible cases had limited abundance or absence of Bordetella and a distinctive microbiota with lower bacterial richness and diversity and higher rates of viral co-infection than both confirmed cases and healthy controls. Bordetella reads determined by 16S rRNA gene sequencing were found in all 12 confirmed cases (100%), 3 out of the 21 possible cases (14.3%) but in any healthy control.

Conclusion

This study supports the usefulness of 16S rRNA gene sequencing for improved sensitivity on pertussis diagnosis compared to real-time PCR and to understand other microbial changes occurring in the nasopharynx in children <1 year old with suspected whooping cough compared to healthy controls.

Strategies to increase uptake of maternal pertussis vaccination

INTRODUCTION

Pertussis is a highly contagious respiratory disease that results in disproportionate morbidity and mortality in infants who have yet to receive the primary diphtheria-tetanus-pertussis vaccine series. In the preceding decades numerous countries began to pursue either prenatal vaccination of pregnant women or postpartum vaccination of caregivers to protect infants. Despite proven benefit, maternal uptake of pertussis vaccine continues to remain suboptimal.

AREAS COVERED

Many studies have been conducted to address the suboptimal uptake of maternal pertussis vaccination. This systematic review was undertaken to systematically identify those studies, highlight the most successful strategies and find the knowledge gaps that need to be filled over the coming years to improve vaccine uptake. Twenty-five studies were identified from six different databases.

EXPERT OPINION

Five different interventions were shown to be successful in promoting uptake of pertussis vaccination: (1) standing orders, (2) opt-in orders, (3) provider education, (4) on-site vaccination and (5) interactive patient education. Three major knowledge gaps were also identified that need to be filled over the coming years: (1) lack of studies in low- and middle-income countries, (2) lack of studies targeting midwives and/or home birth and (3) lack of studies on the process of vaccine communication.

Structure and Immunogenicity of the Bordetella pertussis LOS-Derived Oligosaccharides in the Endosomal-Like Pre-Processing Mice Model

Glycoproteins are processed endosomally prior to presentation to T cells and subsequent induction of specific antibodies. The sugar part of glycoconjugate may be degraded while the type of the process depends on the features of the particular structure. The generated carbohydrate epitopes may differ from native structures and influence immunogenicity of the antigens. We have devised a model of endosomal-like pre-processing of Bordetella pertussis 186 oligosaccharides (OSs) to verify how it affects the immunogenicity of their conjugates. The glycoconjugates of structurally defined forms of the dodecasaccharide OS were synthesized and their immunogenicity was assessed using immunochemical methods. The structural features of the oligosaccharides and their sensitivity to deamination were analyzed by NMR spectroscopy. The distal trisaccharide-comprising pentasaccharide conjugated to a protein was the most effective in inducing immune response against the B. pertussis 186 LOS and the immune response to the complete OS conjugates was significantly lower. This could be explained by the loss of the distal trisaccharide during the in-cell deamination process suggesting that the native structure is not optimal for a vaccine antigen. Consequently, our research has shown that designing of new glycoconjugate vaccines requires the antigen structures to be verified in context of possible endosomal reactions beforehand.

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.

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.

Analysis of clinical characteristics of severe pertussis in infants and children: a retrospective study

BACKGROUND

The incidence of pertussis shows an increasing trend in recent years, but some clinicians often lack sufficient understanding of the clinical characteristics and risk factors for severe pertussis, and more effective measures should be taken to reduce the incidence and mortality of pertussis in young infants METHODS: A retrospective study was conducted, and 184 infants and children with pertussis who had been hospitalized in the Department of Pediatrics of Beijing Ditan Hospital affiliated with Capital Medical University from January 2016 to December 2017 were included. Clinical data of the patients were collected and the clinical characteristics were statistically analyzed RESULTS: Among the 184 patients, 41.85% were infants < 3 months of age, and 65.22% of the total patients were not vaccinated against pertussis. There were 22 critically ill children, among whom 4 died, and compared with mild cases, they had a higher proportion of children younger than 3 months of age and infants not vaccinated against pertussis (63.64% vs. 38.89% and 100% vs. 60.49%, respectively); a higher proportion of children with severe pneumonia (100% vs. 0%); higher leukocyte count(× 109/L , 35.80 ± 20.53 vs 19.41 ± 8.59); and a higher proportion of children with severe hyperleukocytosis (18.18% vs. 0%, respectively) (P<0.05) CONCLUSIONS: 1. Infants aged <3 months not vaccinated for pertussis appear more likely to become infected and have more severe disease. 2. Severe pneumonia and hyperleukocytosis are the main mechanisms underlying severe pertussis.

Seroprevalence of Antibodies against Diphtheria, Tetanus and Pertussis in Adult At-Risk Patients

Patients with chronic diseases are at increased risk of complications following infection. It remains, however, unknown to what extend they are protected against vaccine-preventable diseases. We assessed seroprevalence of antibodies against diphtheria, tetanus and pertussis to evaluate whether current vaccination programs in Belgium are adequate. Antibody titers were assessed with a bead-based multiplex assay in serum of 1052 adults with chronic diseases. We included patients with diabetes mellitus type 1 (DM1) (n = 172), DM2 (n = 77), chronic kidney disease (n = 130), chronic obstructive pulmonary disease (COPD) (n = 170), heart failure (n = 77), HIV (n = 196) and solid organ transplant (SOT) recipients (n = 230). Factors associated with seroprevalence were analysed with multiple logistic regression. We found seroprotective titers in 29% for diphtheria (≥0.1 IU/mL), in 83% for tetanus (≥0.1 IU/mL) and 22% had antibodies against pertussis (≥5 IU/mL). Seroprotection rates were higher (p < 0.001) when vaccinated within the last ten years. Furthermore, diphtheria seroprotection decreased with age (p < 0.001). Tetanus seroprotection was less reached in women (p < 0.001) and older age groups (p < 0.001). For pertussis, women had more often a titer suggestive of a recent infection or vaccination (≥100 IU/mL, p < 0.01). We conclude that except for tetanus, the vast majority of at-risk patients remains susceptible to vaccine-preventable diseases such as diphtheria and pertussis.

[Immunisation schedule of the Pediatric Spanish Association: 2021 recommendations]

The CAV-AEP annually publishes the immunisation schedule considered optimal for all children and adolescent resident in Spain, taking into account the available evidence. The 2+1 schedule is recommended (2, 4, and 11 months) with hexavalent vaccines (DTPa-VPI-Hib-HB) and with 13-valent pneumococcal conjugate.A 6-year booster is recommended, preferably with DTPa (if available), with a dose of polio for those who received 2+1 schemes, as well as vaccination with Tdpa in adolescents and in each pregnancy, preferably between 27 and 32 weeks. Rotavirus vaccine should be systematic for all infants. Meningococcal B vaccine, with a 2+1 schedule, should be included in routine calendar. In addition to the inclusion of the conjugated tetravalent meningococcal vaccine (MenACWY) at 12 years of age with catch up to 18 years, inclusive, the CAV recommends this vaccine to be also included at 12 months of age, replacing MenC. Likewise, it is recommended in those over 6 weeks of age with risk factors or who travel to countries with a high incidence of these serogroups. Two-dose schedules for triple viral (12 months and 3-4 years) and varicella (15 months and 3-4 years) will be used. The second dose could be applied as a tetraviral vaccine. Universal systematic vaccination against HPV is recommended, regardless of gender, preferably at 12 years, and greater effort should be made to improve coverage. The 9 genotype extends coverage for both genders.

Approach to the Patient with Cough

Cough is a common presenting symptom for patients in a primary care setting. Chronic cough is defined as a cough lasting for more than 8 weeks. The most common causes of chronic cough are upper airway cough syndrome, asthma, and gastroesophageal reflux disease. Detailed history and physical examination are critical in identifying potential etiologies of cough. When there is no prevailing diagnosis, step-wise empiric trial of medication is a strategic and cost-effective approach. Certain features of chronic cough should provoke an expedited and invasive diagnostic strategy. Effectively treating patients with chronic cough has a high impact on quality of life.

Pertussis in high-risk groups: an overview of the past quarter-century

Infectious diseases can impact chronic medical conditions. However, it is currently not clear how pertussis correlates with preexisting or underlying disorders. We reviewed literature from the last 25 years to describe the burden and impact of pertussis infection in specific risk groups in individuals aged ≥11 years.

Our literature search returned 543 hits, of which 18 were eligible for this review. Adolescents and adults with underlying conditions, such as asthma, chronic obstructive pulmonary disease (COPD), or obesity are potentially at increased risk of pertussis infection. Immunodeficiency and smoking have also been associated with worsened pertussis symptoms and an increased pertussis-related hospitalization rate. In patients with pertussis and preexisting asthma or COPD, symptoms were worsened, and health-care costs were consequently increased.

Further efforts are needed to close the knowledge gap and to understand the burden of pertussis in at-risk adolescent and adult populations to help inform vaccination strategies and recommendations.

Clinical Findings and Management of Pertussis

Pertussis is an endemic highly infectious vaccine-preventable disease. The disease is a major cause of childhood morbidity and mortality. In the most recent years, the re-emergence of pertussis occurred, and many efforts were done to identify the possible causes. Certainly, more effective laboratory methods have a role in making the diagnosis easier. However, sub-optimal efficacy of available vaccines as well as their limited duration of protection could explain the resurgence of the disease. Many forms and clinical features of the disease, ranging from the most classical to atypical and very nuanced forms, have been reported. There are many aspects that influence the clinical features of the pathology, such as a previous immunization or infection, patient's age, gender and antibiotic treatment. A prompt suspect and a rapid diagnosis of pertussis is fundamental for an appropriate clinical management and for preventing pertussis complications, especially in children. However, under a clinical point of view, pertussis is often difficult to be diagnosed. A prompt treatment may decrease the duration and severity of cough; the cornerstone drugs are the macrolides. Although prompt diagnosis and effective therapy are important for pertussis control, only with a broad vaccination coverage will be possible to reduce circulation of Bordetella pertussis.

The unmet need for pertussis prevention in patients with chronic obstructive pulmonary disease in the Italian context

Despite high rates of vaccination, pertussis resurgence has been reported worldwide in recent years, including in Italy, especially in older adults.Chronic obstructive pulmonary disease (COPD) is a respiratory disease associated with progressive inflammation of the respiratory tract. Regional population studies have shown the prevalence of COPD in Italy to be approximately 15% with an age-dependent increase in proportion of COPD cases.Emerging data shows that individuals with COPD are at high risk of contracting pertussis. Furthermore, those who develop pertussis could experience exacerbation of their pre-existent COPD and further susceptibility to other infections.Immunization programs in Italy currently recommend a decennial reduced-antigen-content diphtheria-tetanus-acellular pertussis booster vaccine dose for adults. Active measures to encourage booster vaccination, especially for high-risk adults such as those with COPD, could positively impact pertussis morbidity and the associated healthcare burden.

Bordetella pertussis in a four-time kidney transplant recipient: A call for immunization programs at transplant centers

Pertussis, or whooping cough, is a highly contagious respiratory illness caused most frequently by Bordetella pertussis. Clinical presentation ranges in severity, but life-threatening illness disproportionately affects children and immunocompromised individuals. Acellular vaccines for pertussis have been available for decades, and they are recommended throughout the lifespan. A patient who had received a kidney transplant presented with respiratory distress and dry cough as manifestations of co-infection with B pertussis and Bordetella parapertussis/bronchiseptica. The goal of this case report was to highlight the importance of immunization programs at transplant centers, which are in the unique position to care for patients both with end-stage organ disease and in the post-transplant setting.

A Pertussis Outer Membrane Vesicle-Based Vaccine Induces Lung-Resident Memory CD4 T Cells and Protection Against Bordetella pertussis, Including Pertactin Deficient Strains

Pertussis is a respiratory infectious disease that has been resurged during the last decades. The change from the traditional multi-antigen whole-cell pertussis (wP) vaccines to acellular pertussis (aP) vaccines that consist of a few antigens formulated with alum, appears to be a key factor in the resurgence of pertussis in many countries. Though current aP vaccines have helped to reduce the morbidity and mortality associated with pertussis, they do not provide durable immunity or adequate protection against the disease caused by the current circulating strains of Bordetella pertussis, which have evolved in the face of the selection pressure induced by the vaccines. Based on the hypothesis that a new vaccine containing multiple antigens could overcome deficiencies in the current aP vaccines, we have designed and characterized a vaccine candidate based on outer membrane vesicle (OMVs). Here we show that the OMVs vaccine, but not an aP vaccine, protected mice against lung infection with a circulating pertactin (PRN)-deficient isolate. Using isogenic bacteria that in principle only differ in PRN expression, we found that deficiency in PRN appears to be largely responsible for the failure of the aP vaccine to protect against this circulating clinical isolates. Regarding the durability of induced immunity, we have already reported that the OMV vaccine is able to induce long-lasting immune responses that effectively prevent infection with B. pertussis. Consistent with this, here we found that CD4 T cells with a tissue-resident memory (T_RM) cell phenotype (CD44⁺CD62L^lowCD69⁺ and/or CD103⁺) accumulated in the lungs of mice 14 days after immunization with 2 doses of the OMVs vaccine. CD4 T_RM cells, which have previously been shown to play a critical role sustained protective immunity against B. pertussis, were also detected in mice immunized with wP vaccine, but not in the animals immunized with a commercial aP vaccine. The CD4 T_RM cells secreted IFN-γ and IL-17 and were significantly expanded through local proliferation following respiratory challenge of mice with B. pertussis. Our findings that the OMVs vaccine induce respiratory CD4 T_RM cells may explain the ability of this vaccine to induce long-term protection and is therefore an ideal candidate for a third generation vaccine against B. pertussis.