Pneumococcal Vaccine for Adults Aged ≥19 Years: Recommendations of the Advisory Committee on Immunization Practices, United States, 2023

Vaccination strategies for solid organ transplant candidates and recipients: insights and recommendations

INTRODUCTION

Vaccines save lives. They are integral to reducing the morbidity and mortality of vaccine-preventable infections in solid organ transplant recipients. Pre-transplant vaccination provides a unique opportunity for administration of live, viral vaccines, and enhanced vaccine efficacy, compared to the post-transplant period with decreased vaccine response due to immunosuppression.

AREAS COVERED

We discuss a general approach to pre- and post-transplant vaccination in solid organ transplant candidates and recipients. We then review guideline statements and recent literature related to individual vaccines, including the recently developed respiratory syncytial virus vaccine. Travel and occupation-related vaccines are also discussed.

EXPERT OPINION

The challenge of vaccination for immunocompromised patients expands as the prevalence of immunocompromised adults rises, and immunocompromised patients are frequently excluded from vaccine trials. In an age of vaccine hesitancy and reemerging vaccine-preventable infections, well-powered, prospective studies are needed to evaluate the clinical effectiveness of vaccines in solid organ transplant candidates and recipients.

Global distribution and characteristics of pneumococcal serotypes in adults

The introduction of pneumococcal conjugate vaccines (PCVs) into pediatric national immunization programs (NIP) has significantly reduced invasive pneumococcal diseases and pneumococcal pneumonia caused by PCV serotypes in adults due to herd immunity. However, diseases caused by PCV13 serotypes persist, mainly serotype 3, known for its severity. With the reduction in PCV13 serotypes, diseases caused by non-PCV13 serotypes increased. Residual and emerging serotypes vary regionally; serotype 8 in Europe and South Africa, and serotype 4 in the US and Canada. PCV20 and PCV21 were recently developed, which can prevent residual and emerging pneumococcal diseases where herd immunity is well-established. In countries that have not introduced PCV into pediatric NIP, the pneumococcal disease burden due to PCV serotypes is still marked. Given that serotype distribution varies by region and evolves over time, this review aimed to discuss serotype distribution and disease severity in adults across countries to support future pneumococcal vaccine strategies.

Death from S. pneumoniae in HbSC Disease: Was Expanded Pneumococcal Vaccination Too Late?

Despite proven efficacy, only 70% of eligible individuals in the U.S. are vaccinated against Streptococcus pneumoniae. This is especially concerning for patients with sickle cell disease (SCD), as they are susceptible to invasive pneumococcal disease owing to functional asplenia. Early and complete vaccination is crucial in preventing pneumococcal sepsis and its complications, including the rare but often fatal fat embolism syndrome. Here, we report a case of an adolescent male with Hemoglobin SC (HbSC) disease who presented to our pediatric emergency department (ED) with abdominal and back pain. Notably he had received all vaccinations according to published guidelines, however had not yet received the expanded pneumococcal vaccine. He was in his usual state of health the previous day. He arrived to the ED mildly febrile, tachypneic, and tachycardic with altered mental status. His condition rapidly deteriorated into acute respiratory failure, coagulopathy, and multiorgan dysfunction syndrome. Unfortunately, he succumbed following multiple cardiac arrests less than 12 hours into his illness course. This case highlights to pediatric and adolescent providers that invasive pneumococcal disease remains a significant risk for vaccinated, adolescent patients, even with mild SCD genotypes. Moreover, it underscores the critical importance of early, complete pneumococcal vaccination in SCD patients. The newer expanded pneumococcal vaccines could enhance protection for this vulnerable population.

Optimal Timing of Vaccination: A Narrative Review of Integrating Strategies for COVID-19, Influenza, and Respiratory Syncytial Virus

Lower respiratory tract infections caused by SARS-CoV-2, influenza, and respiratory syncytial virus (RSV) cause a significant disease burden globally, despite the availability of effective vaccines. Certain populations, such as older adults (≥ 60 years) and individuals of all ages with particular comorbidities, are at increased risk for severe outcomes, including hospitalization and death. National administration schedules for available vaccines against respiratory viruses are not unified, and not all current guidelines are clear and directive, concerning the optimal timing of vaccination. Herein, we formulate an evidence-based position regarding the optimal timing of COVID-19, influenza, and RSV vaccination for older adults and individuals with chronic comorbidities, based on a synthesis of the literature and current guidelines. Vaccination impact and timing were found to be influenced by vaccinee risk factors, including age and comorbidities, and waning vaccine effectiveness and seasonal pathogen burden. Because COVID-19, influenza, and RSV display unique seasonal patterns within and between regions, local epidemiological surveillance of each virus is crucial for determining optimal vaccination timing and guidelines. To maximize the benefits of these respiratory virus vaccines, the timing of peak vaccine effectiveness and period of greatest risk for severe outcomes should be aligned. Thus, COVID-19, influenza, and other recommended vaccines given ahead of the start of the respiratory virus season (or other regionally appropriate time) and co-administered at a single, routine visit represent the optimal approach to protecting at-risk populations. More data will be required to establish the clinical benefit of additional RSV vaccine doses and whether these may be integrated within a seasonal schedule. Coordinated policy decisions that align with strain selection for new and annually reformulated vaccines would enable the timely raising of public health awareness, ultimately leading to enhanced vaccine uptake. Implementation strategies will require engagement of healthcare providers and strong, evidence-based public health recommendations for integrated vaccine schedules.

Assessing the Impact of Vaccination Status on Meningitis Risk Post Cochlear Implantation

OBJECTIVE

To better understand the protective benefit of pneumococcal vaccines on rates of meningitis after cochlear implantation.

STUDY DESIGN

Retrospective large database review.

SETTING

Several studies have shown that cochlear implantation increases the incidence of bacterial meningitis, mostly due to pneumococcal meningitis. However, there are no studies that have demonstrated that pneumococcal vaccination is associated with a decreased risk of meningitis among cochlear implant recipients.

METHODS

TriNetX, an electronic medical record database, was queried for incidence of meningitis after cochlear implantation, with and without pneumococcal vaccination.

RESULTS

There are a total of 35,434 patients in the TriNetX database who have received a cochlear implant. Of these patients, 9803 patients (27.7%) had coding sufficient to assess their immunization status and were included in our study. Of the patients in our study, 9264 patients (93.7%) had evidence of receiving a PCV immunization, while 539 (5.5%) were found to be under vaccinated. A total of 258 patients in our study had an episode of meningitis after cochlear implantation, translating to an overall rate of 2.6%. The vaccinated group demonstrated a significantly lower incidence of meningitis (2.5%, n = 236) compared to the under-vaccinated group (4.1%, n = 22) (relative risk: 1.60; confidence interval (1.0441, 2.4586); P < .0310).

CONCLUSION

Our study provides evidence that pneumococcal vaccination is associated with a significantly lower rate of bacterial meningitis after cochlear implantation. Meningitis is a potentially life-threatening complication. Better adherence to pneumococcal vaccination guidelines pre- and post-CI is critical to reducing the feared risk of bacterial meningitis after cochlear implantation.

Evaluation of Inborn Errors of Immunity Among Patients with Opportunistic Pulmonary Infection

This review of immunocompromised host pneumonia as the result of inborn errors of immunity (IEI) is organized by opportunistic pulmonary pathogen. The authors identify patients who warrant an evaluation for an IEI based on their clinical presentation. Their recommendations are guided by the immune defect(s) associated with each opportunistic pulmonary infection. Physicians without expertise in immunology may begin an evaluation for IEI using the guidance provided here. Comprehensive evaluation by an immunologist may also be warranted in many instances.

Pulmonary Immunocompromise in Chronic and High-dose Steroid Therapy

Glucocorticoid (GC) use is often the mainstay of treatment in many pulmonary, autoimmune, allergic, and oncologic diseases, along with organ transplantation. Short-term and long-term GC use is estimated to be around 1% to 2% worldwide. It has been associated with significant infectious complications such as streptococcus and influenza, mycobacterial infections, and opportunistic infections, specifically Pneumocystis pneumonia, invasive fungal infections, and strongyloidiasis. It is important to use minimal effective dose for the shortest duration to minimize complications. This review summarizes the prevalence of steroid prescriptions, mechanisms, manifestations, and mitigation strategies of pulmonary immunocompromise in patients on chronic and high-dose steroid therapies.

Functional testing of humoral immunity in the Prevnar 20 era

Humoral immune disorders such as common variable immunodeficiency and specific antibody deficiency are prevalent in clinical practice and require accurate functional testing of humoral immunity for diagnosis and to guide treatment approach. Traditionally, the 23-valent pneumococcal polysaccharide vaccine (PPSV23) has been used to assess polysaccharide antibody responses by measuring pre- and post-vaccination pneumococcal titers. However, the recent introduction of pneumococcal conjugate vaccines (PCVs), such as PCV13, PCV15, and PCV20, into the childhood and adult vaccine schedules has significantly reduced the number of unique serotypes available for testing and in turn has complicated the evaluation process. We retrospectively analyzed serotype-specific antibody responses in patients aged 2 to 65 years who received PPSV23 at the University of Virginia Health System to compare diagnostic outcomes using all 23 serotypes vs the limited number of unique serotypes not included in previous PCVs-11 serotypes for PCV13 recipients and 4 for PCV20 recipients. Our findings reveal that although previous PCVs mean that there is a reduced number of serotypes available for interpretation, PPSV23 testing maintains diagnostic accuracy between 81% and 84%. Despite limitations, the use of PPSV23 remains a valuable tool for identifying patients with clinically significant humoral immune deficiencies. In the future, alternative diagnostic approaches such as Salmonella typhi polysaccharide vaccine response and opsonophagocytosis assays may become more frequently used as part of the evaluation of humoral immune disorders.

Musculoskeletal diseases, infections and vaccines: state of the art, research perspectives and educational needs

Musculoskeletal disorders are a significant public health burden concern, projected to increase in the coming decades, and will substantially contribute to the rising prevalence of functional impairment, frailty and disability in a growing global population. Since persons with musculoskeletal disorders tend to have immune dysfunction, inflammation or be taking immunosuppressive medication, prevention of vaccine-preventable diseases (VPDs) in this group is particularly important. The European Interdisciplinary Council for Aging (EICA) and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) jointly convened a 2-day in-person and virtual meeting on 26-27 September 2023, to review the state of the evidence on the link between musculoskeletal diseases, infections and vaccines. We present here the Executive Summary of the proceedings of this meeting. We review the importance of physical activity in preventing or mitigating both musculoskeletal diseases and risk of infection. We summarize current knowledge of the impact of common VPDs on the development and progression of musculoskeletal diseases, and the role of selected vaccines in preventing onset and worsening of frailty and disability in these individuals. This report summarizes the evidence presented at the two-day meeting, highlighting the need to raise awareness among scientists, healthcare professionals, decision-makers, civil society and the general public about the long-term sequelae of VPDs, with focus on the health status of older patients with musculoskeletal diseases.

Gut IgA functionally interacts with systemic IgG to enhance antipneumococcal vaccine responses

The gut microbiota enhances systemic immunoglobulin G (IgG) responses to vaccines, but it is unknown whether this effect involves IgA, which coats intestinal microbes. That IgA may amplify postimmune IgG production is suggested by the impaired IgG response to pneumococcal vaccines in some IgA-deficient patients. Here, we found that antipneumococcal but not total IgG production was impaired in mice with IgA deficiency. The positive effect of gut IgA on antipneumococcal IgG responses started very early in life and could implicate gut bacteria, as these responses were attenuated in germ-free mice recolonized with gut microbes from IgA-deficient donors. IgA could exert this effect by constraining the systemic translocation of gut antigens, which was associated with chronic immune activation, including T cell overexpression of programmed cell death protein 1 (PD-1). This inhibitory receptor may attenuate antipneumococcal IgG production by causing B cell hyporesponsiveness, which improved upon anti-PD-1 treatment. Thus, gut IgA functionally interacts with systemic IgG to enhance antipneumococcal vaccine responses.

Impact of invasive and noninvasive pneumococcal diseases on adult populations: risk factors and vaccination status

BACKGROUND

Streptococcus pneumoniae infections continue to pose significant health risks, particularly in adults with underlying conditions. This study assesses both demographic and clinical profiles of adult patients with invasive and non-invasive pneumococcal diseases, focusing on their vaccination status and outcomes.

METHODS

We retrospectively analyzed clinical data from 217 adults diagnosed with pneumococcal infections at Eskişehir Osmangazi University Faculty of Medicine, a tertiary-care university hospital in Eskişehir, Türkiye, from January 2016 to November 2023. Cases meeting specific clinical and microbiological criteria were included. Logistic regression was utilized to identify key predictors of mortality.

RESULTS

Of the 217 patients initially screened, 155 were included in the final analysis, comprising 75 cases of invasive and 80 cases of non-invasive disease. Notably, among those recommended for pneumococcal vaccination, only 20.6% were vaccinated, and strikingly, only 9% were vaccinated before infection. Significant correlations were observed between mortality and various factors, including age, comorbidities, bacteremia, invasive disease, and intensive care unit admissions. Mortality occurred in 39 (25.2%) of the patients, with notably higher risks among those with comorbidities and requiring intensive care.

CONCLUSION

Pneumococcal infections continue to impose a significant health burden, particularly among older adults and those with pre-existing conditions. Our findings highlight the critical role of comorbidities and intensive care unit admissions in affecting patient outcomes, stressing the importance of timely interventions and enhanced health strategies to improve vaccination rates and overall outcomes in high-risk populations.

Adult vaccinations against respiratory infections

INTRODUCTION

Lower respiratory infections have a huge impact on global health, especially in older individuals, immunocompromised people, and those with chronic comorbidities. The COVID-19 pandemic highlights the importance of vaccination. However, there are lower rates of vaccination in the adult population that are commonly due to a missed opportunity to vaccinate. Vaccination offers the best strategy to prevent hospitalization, complications, and death caused by lower respiratory infections.

AREAS COVERED

In this review, the authors provide an overview of the vaccines for lower respiratory infections in the adult population. The review highlights the available data about the impact of vaccines on preventing respiratory infections, focusing on the pneumococcal vaccine, influenza vaccine, COVID-19 vaccines, and respiratory syncytial virus (RSV) vaccines. The authors discuss the currently available scientific evidence on the role of vaccines against respiratory infections. Finally, the authors review the current recommendations for vaccines in the adult population.

EXPERT OPINION

Scientific evidence on the effectiveness of vaccines against respiratory infections is important. An efficient implementation of adult immunization strategies will provide an opportunity to decrease the global burden of lower respiratory infections. Recognizing the existing vaccines and their recommendations for the adult population is essential to achieve a high vaccination rate in the population.

Vaccination against Respiratory Infections in the Immunosenescent Older Adult Population: Challenges and Opportunities

Respiratory infections are associated with a huge burden of disease every year and disproportionately affect older adults, namely those aged 65 years and older. Older adults are at increased risk of infections compared with their younger counterparts, and once infected, have a higher risk of experiencing severe disease course, complications, and long-term sequelae. Therefore, vaccination is clearly a key strategy to prevent infection and its attendant negative consequences. We review here the burden of common respiratory diseases in older adults, namely influenza, pneumococcal disease, and respiratory syncytial virus. We then review some of the challenges facing immunization of older adults, namely immunosenescence, inflammaging, and low vaccine uptake. Next, potential opportunities for overcoming these challenges are reviewed, including the use of higher antigen doses and/or adjuvants in vaccine formulations for older adults, and the potential of multiomics analyses to improve development, performance, and implementation of vaccines.

IFN-I promotes T-cell-independent immunity and RBC autoantibodies via modulation of B-1 cell subsets in murine SCD

ABSTRACT

The pathophysiology of sickle cell disease (SCD) is characterized by hemolytic anemia and vaso-occlusion, although its impact on the adaptive immune responses remains incompletely understood. To comprehensibly profile the humoral immune responses, we immunized SCD mice with T-cell-independent (TI) and T-cell-dependent (TD) antigens (Ags). Our study showed that SCD mice have significantly enhanced type 2 TI (TI-2) immune responses in a manner dependent on the level of type I interferons (IFN-I), while maintaining similar or decreased TD immune responses depending on the route of Ag administration. Consistent with the enhanced TI-2 immune responses in SCD mice, the frequencies of B-1b cells (B-1 cells in humans), a major cell type responding to TI-2 Ags, were significantly increased in both the peritoneal cavity and spleens of SCD mice and in the blood of patients with SCD. In support of expanded B-1 cells, elevated levels of anti-red blood cell (anti-RBC) autoantibodies were detected in both SCD mice and patients. Both the levels of TI-2 immune responses and anti-RBC autoantibodies were significantly reduced after IFN-I receptor (IFNAR) antibody blockades and in IFNAR1-deficient SCD mice. Moreover, the alterations of B-1 cell subsets were reversed in IFNAR1-deficient SCD mice, uncovering a critical role for IFN-I in the enhanced TI-2 immune responses and the increased production of anti-RBC autoantibodies by modulating the innate B-1 cell subsets in SCD. Overall, our study provides experimental evidence that the modulation of B-1 cells and IFN-I can regulate TI immune responses and the levels of anti-RBC autoantibodies in SCD.

Pneumonia Vaccines: Indications for Use and Current Safety Data in Pregnancy

Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, and invasive pneumococcal disease among adults in the United States, with higher rates of disease occurring among individuals with chronic medical and immunocompromising conditions. Pregnant individuals, especially those with comorbid conditions, are also at increased risk of infection due to S. pneumoniae due to physiological and immunologic changes in pregnancy. Vaccination against pneumococcus is recommended for adults living with HIV aged 19 to 49, congenital or acquired immunodeficiency, asplenia, chronic renal failure, sickle cell disease, alcohol abuse, cerebrospinal fluid leaks, congestive heart failure and cardiomyopathies, chronic lung disease, chronic liver disease, and diabetes mellitus. During pregnancy, the American College of Obstetricians and Gynecologists (ACOG) recommends vaccination against S. pneumoniae for individuals meeting the criteria for immunization outside of pregnancy. Pneumococcal vaccine uptake has been low. There are no data available for vaccine uptake in pregnancy, but we suspect it is lower than nonpregnant populations. Low uptake of immunization rates in pregnancy is likely multifactorial and includes general vaccine hesitancy among pregnant individuals, cost, access to care, and supply shortages. While data in support of pneumococcal vaccines during pregnancy are limited, sufficient evidence exists to support the safety and efficacy of vaccination in the antepartum period. Pregnancy provides an opportunity to continuously engage individuals in care, allowing obstetricians and gynecologists to establish rapport, work to reduce vaccine hesitancy, and to provide pneumococcal immunization to those who are eligible. Medical indications for pneumococcal vaccination will increasingly apply to pregnant persons as the population acquires comorbidities and there is a need for improved education among obstetricians on the topic of antenatal pneumococcal vaccination. KEY POINTS: · Pregnant persons are at risk of S. pneumoniae.. · Adult pneumococcal vaccine uptake has been low.. · Obstetricians and gynecologists can benefit from education on pneumococcal vaccines.. · Encourage pneumococcal vaccines for eligible pregnant people..

Expanded Recommendations for Use of Pneumococcal Conjugate Vaccines Among Adults Aged ≥50 Years: Recommendations of the Advisory Committee on Immunization Practices - United States, 2024

Before October 2024, the Advisory Committee on Immunization Practices (ACIP) recommended use of a pneumococcal conjugate vaccine (PCV) for all adults aged ≥65 years, as well as for those aged 19-64 years with risk conditions for pneumococcal disease who have not received a PCV or whose vaccination history is unknown. Options included either 20-valent PCV (PCV20; Prevnar20; Wyeth Pharmaceuticals) or 21-valent PCV (PCV21; CAPVAXIVE; Merck Sharp & Dohme) alone or 15-valent PCV (PCV15; VAXNEUVANCE; Merck Sharp & Dohme) in series with 23-valent pneumococcal polysaccharide vaccine (PPSV23; Pneumovax23; Merck Sharp & Dohme). There are additional recommendations for use of PCV20 or PCV21 for adults who started their pneumococcal vaccination series with 13-valent PCV (PCV13; Prevnar13; Wyeth Pharmaceuticals). The ACIP Pneumococcal Vaccines Work Group employed the Evidence to Recommendations framework to guide its deliberations on expanding the age-based PCV recommendation to include adults aged 50-64 years. On October 23, 2024, ACIP recommended a single dose of PCV for all PCV-naïve adults aged ≥50 years. Recommendations for PCVs among adults aged 19-49 years with risk conditions and PCV13-vaccinated adults have not changed from previous recommendations. This report summarizes evidence considered for these recommendations and provides updated clinical guidance for use of PCV.

Influence of Aging and Immune Alterations on Susceptibility to Pneumococcal Pneumonia in the Elderly

Pneumonia is a common respiratory infection affecting individuals of all ages, with a significantly higher incidence among the elderly. As the aging population grows, pneumonia is expected to become an increasingly critical health concern. In non-institutionalized elderly individuals, the annual incidence ranges from 25 to 44 per 1000, approximately four times higher than in those under 65. Streptococcus pneumoniae, a Gram-positive diplococcus, is the leading cause of pneumonia-related deaths in older adults. Management of S. pneumoniae infections in the elderly is challenging due to impaired antibody responses to polysaccharides and surface proteins, compounded by rising antibiotic resistance. The underlying mechanisms for increased susceptibility remain unclear, but age-related changes in the immune system, particularly in dendritic cells and T cells, are implicated. This review explores how aging-related immune alterations contribute to the heightened vulnerability of the elderly to S. pneumoniae infections.

Disparities in Vaccination Amongst Socially Vulnerable Patients with Inflammatory Bowel Disease

INTRODUCTION

Social determinants of health (SDOH) have a known impact on disparities in vaccination. Despite an increased risk for infection in patients with inflammatory bowel disease (IBD), SDOH and vaccination in this population have not been studied. Using census tract-level data from the Centers for Disease Control's social vulnerability index (SVI), we aimed to understand the relationship between SDOH and adherence to guideline-recommended vaccinations in patients with IBD.

METHODS

A single-center retrospective cohort of patients with IBD was used to geocode patient addresses to their individual census tract and corresponding SVI and subthemes (Socioeconomic Status, Household Composition, Minority Status, and Housing/Transportation). We used separate multivariable logistic regressions to examine the relationship between SVI and vaccination against influenza, COVID-19, pneumococcal pneumonia, and herpes zoster.

RESULTS

A total of 7,036 patients were included. Rates of vaccination varied across vaccine-types: influenza (57%), COVID-19 (65%), pneumococcal pneumonia (58%), and herpes zoster (11%). High social vulnerability was associated with lower odds of vaccination against influenza (OR 0.47, p < 0.001), COVID-19 (OR 0.54, p < 0.001), pneumonia (OR 0.73, p = 0.012), and herpes zoster (OR 0.39, p < 0.001). Within the SVI subthemes, Socioeconomic Status, Household Composition, and Minority Status were important factors associated with differences in vaccine uptake.

CONCLUSION

Higher social vulnerability was associated with lower rates of vaccination across all vaccine types. Identifying these disparities in vaccination for socially vulnerable patients with IBD is the first step to reducing preventable infections and ensuring all patients receive high quality, equitable care.

Infection prevention in the immunocompromised traveler due to conditions other than transplantation: a review

This narrative review explores the risks related to infection in immunocompromised travelers due to conditions other than transplantation, and evaluates the evidence behind current prophylactic strategies, including immunizations, antimicrobials, and non-pharmacological interventions, to prevent various infection and how the current evidence applies to this special patient population, from the perspective of a US-based traveler.

Brazilian Society of Otology task force - cochlear implant ‒ recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the indications and complications of Cochlear Implant (CI) surgery in adults and children.

METHODS

Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on cochlear implantation were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 2 parts: (1) Evaluation of candidate patients and indications for CI surgery; (2) CI surgery - techniques and complications.

CONCLUSIONS

CI is a safe device for auditory rehabilitation of patients with severe-to-profound hearing loss. In recent years, indications for unilateral hearing loss and vestibular schwannoma have been expanded, with encouraging results. However, for a successful surgery, commitment of family members and patients in the hearing rehabilitation process is essential.

Streptococcus pneumoniae Serotype Distribution Among US Adults Hospitalized With Community-Acquired Pneumonia, 2019-2020

Background

Serotype-specific urinary antigen detection (UAD) assay results can be used to estimate the serotype contribution among adults with pneumococcal community-acquired pneumonia (CAP) and to guide recommendations regarding higher-valency pneumococcal conjugate vaccines (PCVs).

Methods

Adults aged ≥18 years hospitalized with radiographic evidence of CAP were prospectively enrolled in 4 US cities from November 2019 to December 2020, overlapping the coronavirus disease 2019 (COVID-19) pandemic. Data were collected by patient interview and medical chart review. Streptococcus pneumoniae was isolated from standard-of-care respiratory samples and blood; urine collected per-protocol was tested by S pneumoniae BinaxNOW and UAD assays. The proportions of adults with radiologically confirmed CAP (RAD+ CAP) testing positive for S pneumoniae and for serotypes contained in PCV13, PCV15, and PCV20 were calculated.

Results

Among 3098 adults enrolled, 2105 (67.9%) had RAD+ CAP. Of these, 44.3% were ≥65 years of age, and most had a chronic medical condition (46.0%) or were immunocompromised (38.5%). Streptococcus pneumoniae was detected by any method in 214 (10.2%) RAD+ CAP participants, including 63 (3.0%) with serotypes covered by PCV13, 81 (3.9%) by PCV15, and 119 (5.7%) by PCV20. Streptococcus pneumoniae and PCV serotype positivity were higher before the pandemic (November 2019-April 2020) compared to during the COVID-19 pandemic (May 2020-December 2020).

Conclusions

Our study demonstrated that despite the COVID-19 pandemic, PCV serotype pneumococcus continued to cause an important proportion of adult CAP in the US. These data are useful for informing PCV recommendations and for establishing an epidemiologic baseline to assess the impact of such recommendations.

Pneumococcal vaccines for prevention of adult pneumonia

Streptococcus pneumoniae, pneumococcus, is one of most important bacterial pathogens in adult community-acquired pneumonia. Although it can cause a variety of illness including invasive diseases (IPD), pneumonia has a greater impact than IPD from the perspective of health economics. 23 valent pneumococcal polysaccharide vaccine (PPSV23) and 13 valent pneumococcal conjugate vaccine (PCV13) have been recommended for people ≥65 years old until recently based on evidence in preventing IPD and pneumonia. Because the introduction and dissemination of PCVs for infants and its effects on herd immunity have led 'serotype replacement' in adult IPD and pneumococcal pneumonia since the 2000s, serotypes targeted by vaccines have sifted accordingly. With the availability of PCV21 this year, in addition to PCV15 and PCV20, vaccine prevention strategies for adult pneumococcal pneumonia need to be reconsidered. In this narrative review, we discuss current and future challenges regarding pneumococcal vaccines to prevent adult pneumococcal pneumonia.

Strategies for pneumococcal vaccination in older adults in the coming era

Pneumonia, predominantly caused by Streptococcus pneumoniae, remains a leading cause of global mortality. The 23-valent Pneumococcal polysaccharide vaccine (PPSV23) and conjugate vaccines (PCVs) are vital measures to fight against it. This paper discussed the changes in pneumococcal vaccination strategies, particularly for older adults, as vaccine effectiveness and epidemiological patterns shift. While PPSV23 maintains effectiveness against invasive pneumococcal disease (IPD), its effectiveness against pneumococcal pneumonia is declining. Conversely, PCV13 consistently demonstrates effectiveness against both IPD and pneumonia. Consequently, the US Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices recommends using PCVs, notably PCV20 and PCV15, over PPSV23. Japanese studies indicate a change in the efficacy/effectiveness of PPSV23 following PCV introduction in children, likely owing to serotype replacement and herd immunity. Additionally, recent data reveals a plateau in the reduction of PCV13 and PPSV23-covered serotypes, posing a challenge to current strategies. This paper indicates a paradigm shift in pneumonia management, acknowledging its chronic nature and potential to exacerbate other diseases. The future of pneumococcal vaccination lies in broader serotype coverage through PCVs, adapting to serotype changes driven by childhood vaccination programs. Furthermore, continuous research and vaccine development are crucial in this evolving field.

Sex-based difference in immune responses and efficacy of the pneumococcal conjugate vaccine

Vaccine-mediated protection and susceptibility to Streptococcus pneumoniae (pneumococcus) infections are influenced by biological sex. The incidence of invasive pneumococcal disease remains higher in males compared to females even after the introduction of the pneumococcal conjugate vaccine. However, sex-based differences in the immune response to this conjugate vaccine remain unexplored. To investigate those differences, we vaccinated adult male and female mice with pneumococcal conjugate vaccine and assessed cellular and humoral immune responses. Compared to females, male mice displayed lower levels of T follicular helper cells, germinal center B cells, and plasmablasts, which are all required for antibody production following vaccination. This was linked to lower IgG and IgM levels against pneumococci and lower isotype switching to IgG3 in vaccinated males. Due to lower antibody levels, sera of vaccinated male mice had lower efficacy in several anti-pneumococcal functions, including neutralization of bacterial binding to pulmonary epithelial cells as well as direct cytotoxicity against S. pneumoniae. Importantly, while the vaccine was highly protective in females, vaccinated males succumbed to infection more readily and were more susceptible to both lung-localized infection and systemic spread following S. pneumoniae challenge. These findings identify sex-based differences in immune responses to pneumococcal conjugate vaccine that can inform future vaccine strategies.

Pneumococcal disease burden in high-risk older adults: Exploring impact of comorbidities, long-term care facilities, antibiotic resistance, and immunization policies through a narrative literature review

This study aims to provide a comprehensive review of literature on pneumococcal disease burden in high-risk older adults aged ≥65 with focus on impact of comorbidities, long-term care facilities (LTCFs), antibiotic resistance, and vaccination policies across various countries. Research showed that the disease burden and the prevalence of antibiotic-resistant pneumococci was higher in the elderly, particularly those residing in LTCFs, and with comorbidities. These individuals are at high risk of infection with antibiotic-resistant serotypes 10A, 11A, and 15B. The vaccination strategies and national guidelines for pneumococcal vaccines in the elderly vary across countries. Some countries focus on single-dose strategies, while others recommend sequential vaccinations with varying intervals. Although vaccination policies are well-established for the elderly, they are not as well-established for high-risk elderly groups, and this review underscores the need for more tailored vaccination strategies for these groups.

Vaccination After Haematopoietic Stem Cell Transplant: A Review of the Literature and Proposed Vaccination Protocol

Background/Objectives: Haematopoietic stem cell transplantation (HCT) induces profound immunosuppression, significantly increasing susceptibility to severe infections. This review examines vaccinations' necessity, timing, and efficacy post-HCT to reduce infection-related morbidity and mortality. It aims to provide a structured protocol aligned with international and national recommendations. Methods: A systematic review of current guidelines and studies was conducted to assess vaccination strategies in HCT recipients. The analysis included the timing of vaccine administration, factors influencing efficacy, and contraindications. Recommendations for pre- and post-transplant vaccination schedules were synthesised, specifically for graft-versus-host disease (GVHD), immunosuppressive therapy, and hypogammaglobulinemia. Results: Vaccination is essential as specific immunity is often lost after HCT. Inactivated vaccines are recommended to commence three months post-transplant, including influenza, COVID-19, and pneumococcal vaccines. Live attenuated vaccines remain contraindicated for at least two years post-transplant and in patients with ongoing GVHD or immunosuppressive therapy. Factors such as GVHD and immunosuppressive treatments significantly impact vaccine timing and efficacy. The review also underscores the importance of pre-transplant vaccinations and ensuring that patients' close contacts are adequately immunised to reduce transmission risks. Conclusions: Implementing a structured vaccination protocol post-HCT is critical to improving patient outcomes. Timely and effective vaccination strategies can mitigate infection risks while addressing individual patient factors such as GVHD and immunosuppression. This review highlights the need for tailored vaccination approaches to optimize immune reconstitution in HCT recipients.

PNEUMOCOCCAL SEROTYPE DISTRIBUTION AND COVERAGE OF EXISTING AND PIPELINE PNEUMOCOCCAL VACCINES

Background

Streptococcus pneumoniae (pneumococcus) causes invasive pneumococcal disease (IPD) and non-invasive acute respiratory infections (ARIs). Three pneumococcal conjugate vaccines (PCVs) are recommended in the United States with additional products in clinical trials. We aimed to estimate 1) proportions of IPD cases and pneumococcal ARIs caused by serotypes targeted by existing and pipeline PCVs and 2) annual U.S. pneumococcal burdens potentially preventable by PCVs.

Methods

We estimated serotype distribution and proportions of non-invasive pneumococcal ARIs (AOM [children only], sinusitis, non-bacteremic pneumonia) and IPD attributable to serotypes targeted by each PCV using Markov chain Monte Carlo approaches incorporating data from studies of serotype distribution in ARIs and Active Bacterial Core Surveillance (ABCs) data. We then estimated annual numbers of outpatient-managed pneumococcal ARIs, non-bacteremic pneumococcal pneumonia hospitalizations, and IPD cases potentially preventable by PCVs in the United States by multiplying pneumococcal disease incidence rates by PCV-targeted proportions of disease and vaccine effectiveness estimates.

Results

In children, PCV15, PCV20, PCV24, PCV25, and PCV31 serotypes account for 16% (95% confidence interval: 15-17%), 31% (30-32%), 34% (32-35%), 43% (42-44%), and 68% (67-69%) of pneumococcal acute otitis media cases, respectively. In adults, PCV15, PCV20, PCV21, PCV24, PCV25, and PCV31 serotypes account for 43% (38-47%), 52% (47-57%), 69% (64-73%), 65% (61-70%), 62% (57-67%), and 87% (83-90%) of pneumococcal non-bacteremic pneumonia cases. For IPD, 42-85% of pediatric and 42-94% of adult cases were due to PCV-targeted serotypes. PCV-preventable burdens encompassed 270 thousand-3.3 million outpatient-managed ARIs, 2-17 thousand non-bacteremic pneumonia hospitalizations, and 3-14 thousand IPD cases in the United States annually.

Conclusions

Across pneumococcal conditions, coverage and preventable burdens were lowest for PCV15 and highest for PCV31, with PCV21 also targeting sizeable burdens of adult disease. Serotype distribution across syndromes may inform vaccine formulations and policy.

Cost-Effectiveness of the Pneumococcal Vaccine in the Adult Population: A Systematic Review

Objectives: Pneumococcal disease (PD), caused by S. pneumoniae, is a serious global health issue, primarily for adults over 65, due to its high mortality and morbidity rates. Recently, broader-serotype vaccines have been introduced to cope with tremendous hospital costs and decreasing quality of life. Our study aims to systematically review the cost-effectiveness of current PCVs (pneumococcal conjugate vaccines) and PPVs (pneumococcal polysaccharide vaccine) from 2018 to April 2024. Methods: Articles were identified through PubMed, Embase, and Cochrane. Key outcomes include an improved incremental cost-effectiveness ratio (ICER) and quality-adjusted life-years (QALY), with the article's quality assessed via the Consolidated Health Economic Evaluation Reporting Standards 2022 (CHEERS 2022). In total, 23 studies were included, with 22 studies of high quality and 1 of moderate quality. Results: These articles showed that PCV20 was the most cost-effective option compared with other vaccines, including PPV23, PCV13, PCV15, and PCV15/PPV23, for both young and older adults, regardless of risk factors. PCV20, when used alone, saved greater costs than PCV20, followed by PPV23. Conclusions: For countries applying lower-valency vaccines, switching to PCV20 as a single regimen would be the most beneficial for averting pneumococcal cases and reducing costs in adults aged 18-64 and over 65.

Association Between Introduction of the 23-valent Pneumococcal Polysaccharide Vaccine (PPSV23) and Pneumonia Incidence and Mortality Among General Older Population in Japan: A Community-Based Study

BackgroundWith global aging, especially in Asia, preventing pneumonia among seniors is vital. The necessity of introducing pneumococcal vaccines among the elderly has been highlighted but there is a paucity of community-based real-world evidence on their effect. Sera Town in Hiroshima Prefecture, a super-aged community, launched a distinctive pneumococcal vaccination support project for elderly residents and conducted a 5-year follow-up survey. This study evaluates the effectiveness of this vaccination initiative.MethodsFrom October 2010 to March 2015, Sera Town recruited elderly residents for PPSV23 vaccination with partial cost subsidies. Participants were surveyed annually for five years post-vaccination to assess pneumonia incidence, calculated on a person-years basis. Using vital statistics from 2000 to 2016, we quantified changes in mortality rates associated with the vaccination support project through interrupted time series analysis.ResultsOf approximately 7,900 residents aged 65 and older, 3,422 (43%) participated in the project (median age: 84 years; range: 70-114 years; 56.7% female). Over 14,559 person-years of observation, 295 participants developed pneumonia. The post-vaccination incidence rate was 20.3 per 1,000 person-years (95% CI: 18.0-22.7). Interrupted time series analysis indicated a 25% reduction in Sera Town's pneumonia mortality rate post-project, reversing an annual increase of 0.23 per 1,000 population pre-project to an annual decrease of 0.04 per 1,000 population post-project.ConclusionThis study provided real-world evidence on the association with PPSV23 vaccination on the general elderly through a community-based study. The results may be particularly useful for regions where PPSV23 serotypes are prevalent, offering insights for areas facing aging challenges.

Invasive pneumococcal disease in adults after the introduction of pneumococcal vaccination: a retrospective study in the metropolitan area of Zagreb, Croatia (2010-2022)

Introduction

Invasive pneumococcal disease (IPD) is a severe form of illness caused by Streptococcus pneumoniae with high morbidity and mortality rate in the general population, particularly in children <5 years of age, adults ≥65 years of age and the immunocompromised. As known, pneumococcal vaccination lowers the risk of IPD so the aim of this study was to investigate whether the introduction of pneumococcal vaccination has influenced the incidence and mortality of IPD in adults in Croatia.

Materials and methods

A retrospective study was conducted among adult patients (aged ≥18 years) hospitalized due to IPD in the metropolitan area of Zagreb from 1st January 2010 to 31st December 2022. Number of vaccine doses distributed were obtained from the healthcare system.

Results

During the study period, 389 patients were hospitalized, of whom 214 (55.5%) were male. The annual incidence of IPD ranged from 0.6 to 4.1/100,000 population. A total of 185 (47.6%) patients were ≥ 65 years of age and 309 (79.4%) were ≥ 50 years of age. In 331 (85.1%) of the patients, at least one risk factor was identified, with age ≥ 65 years being the most common. Bacteremic pneumonia was the most frequent clinical presentation of IPD (66.3%). Indication for vaccination had 249 patients (64%) but only 11 patients (4.4%) were vaccinated. Also, 64 patients (16.5%) died. Serotype was determined in 233 (59.9%) of the isolates, with serotype 3 being the most frequent (49, 21%), followed by serotype 14 (38, 16.3%) and 19A (15, 6.4%). A total of 180 isolates (77.3%) were included in the 13-valent conjugate vaccine, 208 (89.3%) in the 20-valent conjugate vaccine and 212 (91%) in the 23-valent pneumococcal polysaccharide vaccine.

Discussion

The introduction of pneumococcal vaccination has led to a significant decrease in the incidence and mortality of IPD in adults. To further reduce morbidity and mortality from IPD, it is necessary to increase vaccine coverage in adults, particularly in individuals with risk factors. It may be beneficial to lower the recommended vaccination age from ≥65 to ≥50 years as the substantial difference in the incidence rates of IPD between these age groups was noticed.

The TLR7/8 agonist INI-4001 enhances the immunogenicity of a Powassan virus-like-particle vaccine

Powassan virus (POWV) is a pathogenic tick-borne flavivirus that causes fatal neuroinvasive disease in humans. There are currently no approved therapies or vaccines for POWV infection. Here, we develop a POW virus-like-particle (POW-VLP) based vaccine adjuvanted with the novel synthetic Toll-like receptor 7/8 agonist INI-4001. We demonstrate that INI-4001 outperforms both alum and the Toll-like receptor 4 agonist INI-2002 in enhancing the immunogenicity of a dose-sparing POW-VLP vaccine in mice. INI-4001 increases the magnitude and breadth of the antibody response as measured by whole-virus ELISA, induces neutralizing antibodies measured by FRNT, reduces viral burden in the brain of infected mice measured by RT qPCR, and confers 100% protection from lethal challenge with both lineages of POWV. We show that the antibody response induced by INI-4001 is more durable than standard alum, and 80% of mice remain protected from lethal challenge 9-months post-vaccination. Lastly, we show that the protection elicited by INI-4001 adjuvanted POW-VLP vaccine is unaffected by either CD4+ or CD8+ T cell depletion and can be passively transferred to unvaccinated mice indicating that protection is mediated through humoral immunity. This study highlights the utility of novel synthetic adjuvants in VLP-based vaccines.

Cost-Effectiveness Analysis of the Use of V116, a 21-Valent Pneumococcal Conjugate Vaccine, in Vaccine-Naïve Adults Aged ≥ 65 Years in the United States

INTRODUCTION

Given the recent approval and recommendation of V116, a 21-valent pneumococcal conjugate vaccine (PCV), in the United States (US), we evaluated the cost-effectiveness of using V116 versus the 20-valent PCV (PCV20) or the 15-valent PCV (PCV15) in series with the 23-valent pneumococcal polysaccharide vaccine (PPSV23) among adults aged ≥ 65 years in the US who had never received a PCV previously.

METHODS

A static multi-cohort state-transition Markov model was developed to estimate the lifetime incremental clinical and economic impact of V116 vs. PCV20 or PCV15 + PPSV23 from the societal perspective. All model inputs were based on published literature and publicly available databases and/or reports. Model outcomes included undiscounted clinical cases: invasive pneumococcal disease (IPD), inpatient and outpatient non-bacteremic pneumococcal pneumonia (NBPP), post-meningitis sequelae (PMS), deaths from IPD and inpatient NBPP, discounted quality-adjusted life years (QALYs) as well as the discounted total cost (in 2023 USD), which consisted of vaccine acquisition and administration costs, direct and indirect costs associated with the disease, and travel costs for vaccination. The final summary measure was the incremental cost-effectiveness ratio (ICER), reported as $/QALY gained. Three percent was used for the annual discounting rate.

RESULTS

Based on the inputs and assumptions used, the results indicated that the V116 strategy prevented 27,766 and 32,387 disease cases/deaths and saved $239 million and $1.8 billion in total costs when compared to the PCV20 and PCV15 + PPSV23 strategies, respectively, in vaccine-naïve adults aged ≥ 65 years. The estimated ICERs were cost saving in both regimens (i.e., V116 vs. PCV20 or vs. PCV15 + PPSV23). The scenario analysis and deterministic and probabilistic sensitivity analyses also demonstrated the robustness of the qualitative results.

CONCLUSIONS

These results demonstrated that using V116 in adults aged ≥ 65 years in the US can prevent a substantial number of PD cases and deaths while remaining highly favorable economically over a wide range of inputs and scenarios.

Prevalence, Clinical Severity, and Serotype Distribution of Pneumococcal Pneumonia Among Adults Hospitalized With Community-Acquired Pneumonia in Tennessee and Georgia, 2018-2022

INTRODUCTION

Understanding the pneumococcal serotypes causing community-acquired pneumonia (CAP) is essential for evaluating the impact of pneumococcal vaccines.

METHODS

We conducted a prospective surveillance study of adults aged ≥18 years hospitalized with CAP at 3 hospitals in Tennessee and Georgia between 1 September 2018 and 31 October 2022. We assessed for pneumococcal etiology with cultures, the BinaxNOW urinary antigen detection test, and serotype-specific urinary antigen detection assays that detect 30 pneumococcal serotypes contained in the investigational pneumococcal conjugate vaccine V116, as well as licensed vaccines PCV15 and PCV20 (except serotype 15B). The distribution of pneumococcal serotypes was calculated based on serotype-specific urinary antigen detection results.

RESULTS

Among 2917 hospitalized adults enrolled with CAP, 352 (12.1%) patients had Streptococcus pneumoniae detected, including 51 (1.7%) patients with invasive pneumococcal pneumonia. The 8 most commonly detected serotypes were: 3, 22F, 19A, 35B, 9N, 19F, 23A, and 11A. Among 2917 adults with CAP, 272 (9.3%) had a serotype detected that is contained in V116, compared to 196 (6.7%) patients with a serotype contained in PCV20 (P < .001), and 168 (5.8%) patients with a serotype contained in PCV15 (P < .001). A serotype contained in V116 but not PCV15 or PCV20 was detected in 120 (4.1%) patients, representing 38.0% of serotype detections.

CONCLUSIONS

Approximately 12% of adults hospitalized with CAP had S. pneumoniae detected, and approximately one-third of the detected pneumococcal serotypes were not contained in PCV15 or PCV20. Development of new pneumococcal vaccines with expanded serotype coverage has the potential to prevent a substantial burden of disease.

Celiac disease: Guideline update overview

ABSTRACT

The American College of Gastroenterology revised its recommendations for diagnosing and managing celiac disease in its updated 2023 clinical guideline. Celiac disease is an autoimmune disorder causing malabsorption following exposure to gluten. A wide range of both gastrointestinal and nongastrointestinal signs and symptoms can occur. This article provides an overview of the diagnosis and management of celiac disease, aiding the NP in developing a greater awareness of the condition both to diagnose it and to refer patients as needed to gastroenterology for evaluation.

Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae isolates cultured from Japanese adult patients with community-acquired pneumonia in Goto City, Japan

Streptococcus pneumoniae is an important cause of community-acquired pneumonia (CAP) in Japan. Here, we report the serotype distribution and antimicrobial susceptibility of cultured pneumococcal isolates from Japanese adults aged ≥18 years with CAP. This was a prospective, population-based, active surveillance study conducted in Goto City, Japan from December 2015 to November 2020. Pneumococcal isolates from sterile sites (blood and pleural fluid) and non-sterile sites (sputum and bronchoalveolar lavage) were cultured as part of the standard of care. S. pneumoniae were serotyped using the Quellung reaction. Antimicrobial susceptibility was tested using microdilution and interpreted according to the Clinical and Laboratory Standards Institute criteria. Isolates resistant to erythromycin were phenotyped using the triple-risk test and genotyped by polymerase chain reaction. A total of 156 pneumococcal isolates were collected (138 from sputum, 15 from blood, and 3 from bronchoalveolar lavage) from 1992 patients. Of these, 142 were non-duplicate isolates from unique patients and were included in the analyses. Serotypes contained within the 13-valent pneumococcal conjugate vaccine (PCV13) (including 6C), PCV15 (including 6C), and PCV20 (including 6C and 15C) were detected in 39 (27%), 45 (32%), and 80 (56%) of 142 isolates, respectively. The most common serotypes were 35B (12%), 11A (11%), and 3 (11%). Multidrug resistance (MDR) was detected in 96/142 (68%) isolates. Of the 96 MDR isolates, 31, 32, and 59% were PCV13, PCV15, and PCV20 serotypes, respectively; the most common MDR serotypes were 35B (16%), 6C, 10A, and 15A (9% each), and 3 and 11A (8% each). A total of 119 isolates were resistant to macrolides; 41 (35%) had an M phenotype, 53 (45%) had an iMcLS phenotype, and 25 (21%) had a cMLS phenotype. In conclusion, pneumococcal serotypes 35B, 11A and 3 were most frequently associated with pneumonia and antimicrobial resistance was common among pneumococcal isolates from adults with CAP in Goto City, Japan. Implementing higher-valency PCVs May help reduce vaccine-type CAP among Japanese adults.

Use of 21-Valent Pneumococcal Conjugate Vaccine Among U.S. Adults: Recommendations of the Advisory Committee on Immunization Practices - United States, 2024

On June 17, 2024, the Food and Drug Administration approved 21-valent pneumococcal conjugate vaccine (PCV) (PCV21; CAPVAXIVE; Merck Sharp & Dohme, LLC) for adults aged ≥18 years. PCV21 does not contain certain serotypes that are included in other licensed pneumococcal vaccines but adds eight new serotypes. The Advisory Committee on Immunization Practices (ACIP) recommends use of a PCV for all adults aged ≥65 years, as well as adults aged 19-64 years with certain risk conditions for pneumococcal disease if they have not received a PCV or whose vaccination history is unknown. Previously, options included either 20-valent PCV (PCV20; Prevnar20; Wyeth Pharmaceuticals, Inc.) alone or a 15-valent PCV (PCV15; VAXNEUVANCE; Merck Sharp & Dohme, LLC) in series with 23-valent pneumococcal polysaccharide vaccine (PPSV23; Pneumovax23; Merck Sharp & Dohme, LLC). Additional recommendations for use of PCV20 exist for adults who started their pneumococcal vaccination series with 13-valent PCV (PCV13; Prevnar13; Wyeth Pharmaceuticals, Inc.). The ACIP Pneumococcal Vaccines Work Group employed the Evidence to Recommendations framework to guide its deliberations on PCV21 vaccination among U.S. adults. On June 27, 2024, ACIP recommended a single dose of PCV21 as an option for adults aged ≥19 years for whom PCV is currently recommended. Indications for PCV have not changed from previous recommendations. This report summarizes evidence considered for these recommendations and provides clinical guidance for use of PCV21.

Protective Effects of 23-Valent Pneumococcal Polysaccharide Vaccination Against Mortality: The VENUS Study

This retrospective matched cohort study investigated the protective effects of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) against pneumonia mortality and all-cause mortality in Japanese adults aged ≥65 years. We analyzed claims data, vaccination records, and death certificate records between October 2016 and December 2019 from 55 509 PPSV23-vaccinated individuals and 55 509 unvaccinated individuals. Cox proportional hazards analyses were performed to calculate the adjusted hazard ratios (HRs) of PPSV23 vaccination for mortality. The results showed that PPSV23 vaccination was significantly associated with a reduction in all-cause mortality (adjusted HR, 0.52; P < .001) but not pneumonia mortality (adjusted HR, 0.70; P = .374).

Infectious Disease Prophylaxis During and After Immunosuppressive Therapy

Immune-mediated renal diseases are a diverse group of disorders caused by antibody, complement, or cell-mediated autosensitization. Although these diseases predispose to infection on their own, a growing array of traditional and newer, more targeted immunosuppressant medications are used to treat these diseases. By understanding their mechanisms of action and the infections associated with suppression of each arm of the immune system, nephrologists can better anticipate these risks and effectively prevent and recognize opportunistic infections. Focusing specifically on nonkidney transplant recipients, this review discusses the infections that can be associated with each of the commonly used immunosuppressants by nephrologists and suggest interventions to prevent infectious complications in patients with immune-mediated renal disease.

Evaluating patient immunocompetence through antibody response to pneumococcal polysaccharide vaccine using a newly developed 23 serotype multiplexed assay

Assessing T-cell independent antibody response to polysaccharide vaccines is crucial for diagnosing humoral immune deficiencies. However, immunocompetence criteria based on S. pneumoniae vaccination remain unclear. We evaluated IgG antibody vaccine response in healthy individuals to establish interpretive criteria. Pre- and 4-week post-vaccination sera were collected from 79 adults. Antibody concentrations to PNEUMOVAX 23 serotypes were measured using a multiplexed platform. Immunocompetence was determined by fold increase in post-vaccination response, percentage of serotypes achieving 4- or 2-fold antibody ratio, and post-vaccination concentration ≥ 1.3 μg/mL. Immunogenicity varied widely across the 23 serotypes (26.6% to 94.9% for ≥4-fold increase, 51.9% to 98.7% for ≥2-fold increase). Immunocompetence based on historic criteria of ≥4-fold increase in antibody ratio to ≥70% of serotypes was low (72.2%), but increased to 98.7% with criteria of at least a 2-fold increase and/or post-vaccination concentration ≥ 1.3 μg/mL. Current criteria for assessing immunocompetence may be overly stringent and require updating.

Commentary on: Cost-effectiveness of pneumococcal vaccination and of programs to increase its uptake in U.S. older adults

See related articles by Wateska et al.

Deciphering structural variation upon biotinylation of biotin carboxyl carrier protein domain in Streptococcus pneumoniae

Streptococcus pneumoniae is a leading cause of community-acquired pneumonia and is responsible for acute invasive and non-invasive infections. Fight against pneumococcus is currently hampered by insufficient vaccine coverage and rising antimicrobial resistance, making the research necessary on novel drug targets. High-throughput mutagenesis has shown that acetyl-CoA carboxylase (ACC) is an essential enzyme in S. pneumoniae which converts acetyl-CoA to malonyl-CoA, a key step in fatty acid biosynthesis. ACC has four subunits; Biotin carboxyl carrier protein (BCCP), Biotin carboxylase (BC), Carboxyl transferase subunit α and β. Biotinylation of S. pneumoniae BCCP (SpBCCP) is required for the activation of ACC complex. In this study, we have biophysically characterized the apo- and holo- biotinylating domain SpBCCP80. We have performed 2D and 3D NMR experiments to analyze the changes in amino acid residues upon biotinylation of SpBCCP80. Further, we used NMR backbone chemical shift assignment data for bioinformatical analyses to determine the secondary and tertiary structure of proteins. We observed major changes in AMKVM motif and thumb region of SpBCCP80 upon biotinylation. Overall, this work provides structural insight into the apo- to holo- conversion of SpBCCP80 which can be further used as a drug target against S. pneumoniae.

International circumpolar surveillance: update on the interlaboratory quality control program for Streptococcus pneumoniae, 2009 to 2020

The International Circumpolar Surveillance (ICS) program is a population-based surveillance network for invasive bacterial diseases throughout Arctic countries and territories. The ICS quality control program for Streptococcus pneumoniae serotyping and antimicrobial susceptibility testing has been ongoing since 1999. Current participating laboratories include the Provincial Laboratory for Public Health in Edmonton, Alberta; Laboratoire de santé publique du Québec in Sainte-Anne-de-Bellevue, Québec; the Centers for Disease Control's Arctic Investigations Program in Anchorage, Alaska; the Neisseria and Streptococcus Reference Laboratory at Statens Serum Institut in Copenhagen, Denmark; the Department of Clinical Microbiology, Landspitali in Reykjavik, Iceland; and Public Health Agency of Canada's National Microbiology Laboratory in Winnipeg, Manitoba. From 2009 to 2020, 140 isolates of S. pneumoniae were distributed among the six laboratories as part of the quality control program. Overall serotype concordance was 96.9%, with 99.3% concordance to pool level. All participating laboratories had individual concordance rates >92% for serotype and >97% for pool. Overall concordance by modal minimum inhibitory concentration (MIC) for testing done by broth microdilution or Etest was 99.1%, and >98% for all antimicrobials tested. Categorical concordance was >98% by both CLSI and EUCAST criteria. For two laboratories performing disc diffusion, rates of concordance by modal MIC were >97% for most antimicrobials, except chloramphenicol (>93%) and trimethoprim/sulfamethoxazole (>88%). Data collected from 12 years of the ICS quality control program for S. pneumoniae demonstrate excellent (≥95%) overall concordance for serotype and antimicrobial susceptibility testing results across six laboratories.

IMPORTANCE

Arctic populations experience several social and physical challenges that lead to the increased spread and incidence of invasive diseases. The International Circumpolar Surveillance (ICS) program was developed to monitor five invasive bacterial diseases in Arctic countries and territories. Each ICS organism has a corresponding interlaboratory quality control (QC) program for laboratory-based typing, to ensure the technical precision and accuracy of reference testing services for these regions, and identify and correct potential problems. Here, we describe the results of the ICS Streptococcus pneumoniae QC program, from 2009 to 2020. Excellent overall concordance was achieved for serotype and antimicrobial susceptibility testing results across six laboratories. Ongoing participation in these QC programs ensures the continuation of quality surveillance systems within Arctic populations that experience health disparities.

Diabetes Mellitus and Pneumococcal Pneumonia

Currently, there are more than 500 million people suffering from diabetes around the world. People aged 65 years or older are the most affected by this disease, and it is estimated that approximately 96% of diabetes cases worldwide are type 2 diabetes. People with diabetes mellitus are at an increased risk of infections such as pneumonia, due to a series of factors that may contribute to immune dysfunction, including hyperglycemia, inhibition of neutrophil chemotaxis, impaired cytokine production, phagocytic cell dysfunction, altered T cell-mediated immune responses and the co-existence of chronic comorbidities. Rates of infection, hospitalization and mortality in diabetic patients are reported to be higher than in the general population. Research into the risk of infectious diseases such as pneumonia in these patients is very important because it will help improve their management and treatment.

Invasive Pneumococcal Disease and Potential Impact of Pneumococcal Conjugate Vaccines Among Adults, Including Persons Experiencing Homelessness-Alaska, 2011-2020

BACKGROUND

Adults aged ≥65 years, adults with certain underlying medical conditions, and persons experiencing homelessness are at increased risk for invasive pneumococcal disease (IPD). Two new pneumococcal conjugate vaccines, 15-valent pneumococcal conjugate vaccine (PCV15) and 20-valent pneumococcal conjugate vaccine (PCV20), were recently approved for use in US adults. We describe the epidemiology of IPD among Alaska adults and estimate the proportion of IPD cases potentially preventable by new vaccines.

METHODS

We used statewide, laboratory-based surveillance data to calculate and compare IPD incidence rates and 95% confidence intervals (CIs) among Alaska adults aged ≥18 years during 2011-2020 and estimate the proportion of IPD cases that were caused by serotypes in PCV15 and PCV20.

RESULTS

During 2011-2020, 1164 IPD cases were reported among Alaska adults for an average annual incidence of 21.3 cases per 100 000 adults per year (95% CI, 20.1-22.5). Incidence increased significantly during the study period (P < .01). IPD incidence among Alaska Native adults was 4.7 times higher than among non-Alaska Native adults (95% CI, 4.2-5.2). Among adults experiencing homelessness in Anchorage, IPD incidence was 72 times higher than in the general adult population (95% CI, 59-89). Overall, 1032 (89%) Alaska adults with IPD had an indication for pneumococcal vaccine according to updated vaccination guidelines; 456 (39%) and 700 (60%) cases were caused by serotypes in PCV15 and PCV20, respectively.

CONCLUSIONS

Use of PCV15 and PCV20 could substantially reduce IPD among adults in Alaska, including Alaska Native adults and adults experiencing homelessness.