Incidence and Risk Factors for Invasive Pneumococcal Disease and Community-acquired Pneumonia in Human Immunodeficiency Virus-Infected Individuals in a High-income Setting

Critical illness due to infection in people living with HIV

People living with HIV comprise a substantial number of the patients admitted to intensive care. This number varies according to geography, but all areas of the world are affected. In lower-income and middle-income countries, the majority of intensive care unit (ICU) admissions relate to infections, whereas in high-income countries, they often involve HIV-associated non-communicable diseases diagnoses. Management of infections potentially resulting in admission to the ICU in people living with HIV include sepsis, respiratory infections, COVID-19, cytomegalovirus infection, and CNS infections, both opportunistic and non-opportunistic. It is crucial to know which antiretroviral therapy (ART) is appropriate, when is the correct time to administer it, and to be aware of any safety concerns and potential drug interactions with ART. Although ART is necessary for controlling HIV infections, it can also cause difficulties relevant to the ICU such as immune reconstitution inflammatory syndrome, and issues associated with ART administration in patients with gastrointestinal dysfunction on mechanical ventilation. Managing infection in people with HIV in the ICU is complex, requiring collaboration from a multidisciplinary team knowledgeable in both the management of the specific infection and the use of ART. This team should include intensivists, infectious disease specialists, pharmacists, and microbiologists to ensure optimal outcomes for patients.

Recent changes to adult national immunization programs for pneumococcal vaccination in Europe and how they impact coverage: A systematic review of published and grey literature

Despite widespread use of pneumococcal vaccines throughout Europe, the burden of pneumococcal disease (PD) in adults is considerable. To mitigate this burden, National Immunization Technical Advisory Groups (NITAGs) and Health Technology Assessment (HTA) agencies assess the value of different vaccine schedules for protecting against PD. The aim of this review was to assess the evidence and rationales used by NITAGs/HTA agencies, when considering recent changes to National Immunization Programs (NIPs) for adults, and how identified changes affected vaccine coverage rates (VCRs). A systematic review was conducted of published literature from PubMed® and Embase®, and gray literature from HTA/NITAG websites from the last 5 y, covering 31 European countries. Evidence related to NIP recommendations, epidemiology (invasive PD, pneumonia), health economic assessments and VCRs were collected and synthesized. Eighty-four records providing data for 26 countries were identified. Of these, eight described explicit changes to NIPs for adults in seven countries. Despite data gaps, some trends were observed; first, there appears to be a convergence of NIP recommendations in many countries toward sequential vaccination, with a pneumococcal conjugate vaccine (PCV), followed by pneumococcal polysaccharide vaccine 23. Second, reducing economic or healthcare burden were common rationales for implementing changes. Third, most health economic analyses assessing higher-valency PCVs for adults found its inclusion in NIPs cost-effective. Finally, higher coverage rates were seen in most cases where countries had expanded their NIPs to cover at-risk populations. The findings can encourage agencies to improve surveillance systems and work to reach the NIP's target populations more effectively.

Predictors of serological non-response to the 13-valent pneumococcal conjugate vaccine followed by the 23-valent polysaccharide vaccine among adults living with HIV

BACKGROUND

People living with HIV (PLWH) have higher incidence of pneumococcal disease compared to people without HIV. Immunization with pneumococcal vaccines is recommended, but serological non-response to pneumococcal vaccination is common for largely unknown reasons.

METHODS

PLWH on antiretroviral treatment and no prior pneumococcal vaccination received the 13-valent pneumococcal conjugate vaccine (PCV13) followed 60 days later by the 23-valent polysaccharide vaccine (PPV23). Serological response was evaluated 30 days post-PPV23 by antibodies against 12 serotypes covered by both PCV13 and PPV23. Seroprotection was defined as a ≥2-fold rise to a level above 1.3 µg/ml in geometric mean concentration (GMC) across all serotypes. Associations with non-responsiveness were evaluated by logistic regression.

RESULTS

Fifty-two virologically suppressed PLWH (median age of 50 years (IQR 44-55) and median CD4 count of 634 cells/mm3 (IQR 507-792)) were included. Forty-six percent (95 % CI 32-61, n = 24) achieved seroprotection. Serotypes 14, 18C and 19F had the highest, and serotypes 3, 4 and 6B the lowest GMCs. Pre-vaccination GMC levels less than 100 ng/ml were associated with increased odds of non-responsiveness compared to levels above 100 ng/ml (adjusted OR 8.7, 95 % CI 1.2-63.6, p = 0.0438).

CONCLUSION

Less than half of our study population achieved anti-pneumococcal seroprotective levels following PCV13 and PPV23 immunization. Low pre-vaccination GMC levels were associated with non-response. Further research is required to optimize vaccination strategies that achieve higher seroprotection in this high-risk group.

Immunocompromised Host Pneumonia: Definitions and Diagnostic Criteria: An Official American Thoracic Society Workshop Report

Pneumonia imposes a significant clinical burden on people with immunocompromising conditions. Millions of individuals live with compromised immunity because of cytotoxic cancer treatments, biological therapies, organ transplants, inherited and acquired immunodeficiencies, and other immune disorders. Despite broad awareness among clinicians that these patients are at increased risk for developing infectious pneumonia, immunocompromised people are often excluded from pneumonia clinical guidelines and treatment trials. The absence of a widely accepted definition for immunocompromised host pneumonia is a significant knowledge gap that hampers consistent clinical care and research for infectious pneumonia in these vulnerable populations. To address this gap, the American Thoracic Society convened a workshop whose participants had expertise in pulmonary disease, infectious diseases, immunology, genetics, and laboratory medicine, with the goal of defining the entity of immunocompromised host pneumonia and its diagnostic criteria.

Facilitating access to pneumococcal vaccine for people living with HIV: an experience report

OBJECTIVE

The article describes a strategy to facilitate access to pneumococcal conjugate vaccine 13 (PCV-13) for people living with HIV/AIDS (PLHIV) during the COVID-19 pandemic.

METHOD

report on the experience regarding the organization of a care service for PLHIV in the city of São Paulo to facilitate access to PCV-13 in the framework of the 2020 influenza vaccination campaign during the COVID-19 pandemic.

RESULTS

through the integration between a PLHIV care service and an Immunization Center (CRIE in Portuguese), it was possible to offer PCV-13 to PLHIV at the point of care, reducing physical barriers to access to immunization. Thus, of the 1,906 PLHIV who passed through the service during the period March 23-July 31, 2020, 84.4% (1,609) received the influenza vaccine, PCV-13 or both. Of the 1609 vaccinated, 50.6% (814) were eligible and received PCV-13.

CONCLUSION

offering the vaccine at the point of care and orienting PLHIV on the importance of vaccination as a disease prevention strategy, identifying those eligible to receive it, was an important action carried out by the institution together with the nursing team, as a strategy to facilitate access to vaccination.

Asplenia and spleen hypofunction

Asplenia (the congenital or acquired absence of the spleen) and hyposplenism (defective spleen function) are common causes of morbidity and mortality. The spleen is a secondary lymphoid organ that is responsible for the regulation of immune responses and blood filtration. Hence, asplenia or hyposplenism increases susceptibility to severe and invasive infections, especially those sustained by encapsulated bacteria (namely, Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae type b). Asplenia is predominantly due to splenectomy for either traumatic events or oncohaematological conditions. Hyposplenism can be caused by several conditions, including haematological, infectious, autoimmune and gastrointestinal disorders. Anatomical disruption of the spleen and depletion of immune cells, especially IgM memory B cells, seem to be predominantly responsible for the clinical manifestations. Early recognition of hyposplenism and proper management of asplenia are warranted to prevent overwhelming post-splenectomy infections through vaccination and antibiotic prophylaxis. Although recommendations are available, the implementation of vaccination strategies, including more effective and immunogenic vaccines, is needed. Additionally, screening programmes for early detection of hyposplenism in high-risk patients and improvement of patient education are warranted.

The remarkable history of pneumococcal vaccination: an ongoing challenge

Although it varies with age and geographical distribution, the global burden of infection with Streptococcus pneumoniae (pneumococcus) remains considerable. The elderly, and younger adults with comorbid conditions, are at particularly high risk of pneumococcal infection, and this risk will increase as the population ages. Vaccination should be the backbone of our current strategies to deal with this infection.

Main body: This manuscript reviews the history of the development of pneumococcal vaccines, and the impact of different vaccines and vaccination strategies over the past 111 years. It documents the early years of vaccine development in the gold mines of South Africa, when vaccination with killed pneumococci was shown to be effective, even before the recognition that different pneumococci were antigenically distinct. The development of type-specific vaccines, still with whole killed pneumococci, showed a high degree of efficacy. The identification of the importance of the pneumococcal capsule heralded the era of vaccination with capsular polysaccharides, although with the advent of penicillin, interest in pneumococcal vaccine development waned. The efforts of Austrian and his colleagues, who documented that despite penicillin therapy, patients still died from pneumococcal infection in the first 96 h, ultimately led to the licensing first of a 14-valent pneumococcal polysaccharide in 1977 followed by the 23-valent pneumococcal polysaccharide in 1983. The principal problem with these, as with other polysaccharide vaccines, was that that they failed to immunize infants and toddlers, who were at highest risk for pneumococcal disease. This was overcome by chemical linking or conjugation of the polysaccharide molecules to an immunogenic carrier protein. Thus began the era of pneumococcal conjugate vaccine (PCV), starting with PCV7, progressing to PCV10 and PCV13, and, most recently, PCV15 and PCV20. However, these vaccines remain serotype specific, posing the challenge of new serotypes replacing vaccine types. Current research addresses serotype-independent vaccines which, so far, has been a challenging and elusive endeavor.

Conclusion: While there has been enormous progress in the development of pneumococcal vaccines during the past century, attempts to develop a vaccine that will retain its efficacy for most pneumococcal serotypes are ongoing.

Improved induced innate immune response after cART initiation in people with HIV

Introduction

Impairment of the innate immune function may contribute to the increased risk of bacterial and viral infections in people with HIV (PWH). In this study we aimed to investigate the induced innate immune responses in PWH prior to and after initiation of combinational antiretroviral therapy (cART). Furthermore, we aimed to investigate if the induced innate immune responses before initiation of cART were associated with CD4+ T-cell recovery one year after initiating cART.

Material and method

The induced innate immune response was assessed by the TruCulture^® whole blood technique in 32 PWH before cART initiation and after 1, 6 and 12 months. To mimic bacterial and viral infections we used a panel of three stimuli (lipopolysaccharide (LPS), resiquimod (R848), and polyinosinic:polycytidylic acid (Poly I:C)) to stimulate the extracellular Toll-like receptor (TLR) 4 and the intracellular TLR7/8 and TLR3, respectively. The following cytokine responses were analyzed by Luminex 200: Tumor Necrosis Factor (TNF)-α, Interleukin (IL)-1b, IL-6, IL-8, IL-10, IL-12p40, IL17A, Interferon (IFN)-α, and IFN-γ.

Results

At baseline PWH with nadir CD4+ T-cell count <350 cell/µL had lower levels of LPS-, R848-, and Poly I:C-induced IL-6 and IFN-γ, LPS- and R848-induced TNF-α and IL-12, LPS induced IL-1b, and R848-induced IL-10 than PWH with nadir CD4+ T-cell count >350 cells/µL. The majority (>50%) had induced cytokine concentrations below the reference intervals at baseline which was most pronounced for the LPS- and Poly I:C-induced responses. The induced responses in the whole population improved after 12 months of cART, and more PWH had induced cytokine concentrations within the reference intervals after 12 months. However, the majority of PWH still had LPS-induced INF-α, INF-γ and Poly I:C-induced TNF-α and IL-6 below the reference interval. The induced innate immune responses before cART initiation were not associated with the CD4+ T-cell recovery after 12 months of cART.

Conclusion

The innate immune response was impaired in PWH, with a more pronounced impairment in PWH with low nadir CD4+ T-cell count. Initiation of cART improved the innate immune response, but compared to the reference intervals, some impairment remained in PWH without viral replication.

COVID-19 Outcomes and Risk Factors Among People Living with HIV

Purpose of Review

In this review, we examine the intersection of the HIV and COVID-19 epidemics with focus on COVID-19-related health outcomes and risk factors for SARS-CoV-2 among people living with HIV (PLWH).

Recent Findings

Evidence to date do not suggest a higher incidence of SARS-CoV-2 infection among PLWH compared to the general population, although—once exposed—PLWH are at greater risk of severe COVID-19 outcomes. Key risk factors for severe COVID-19 include non-HIV comorbidities known to be associated with severe disease, as well as HIV-specific risk factors such as low CD4 + T-cell count, unsuppressed viral load, and tuberculosis co-infection. The disproportionate impact of the SARS-CoV-2 pandemic among Black, Latinx, and Native American/Alaskan Native PLWH could worsen pre-existing disparities in health outcomes among PLWH. Data on SARS-CoV-2 vaccine protection among PLWH needs additional study, although some studies suggest decreased humoral responses among those with low CD4 + T-cell counts, while there is a signal of increased vaccine breakthrough rates among PLWH in two large observational cohorts. Data on post-acute sequelae of SARS-CoV-2 (PASC) among PLWH is also limited.

Summary

PLWH do not have a higher susceptibility to SARS-CoV-2, but once exposed, they are at higher risk of severe COVID-19 outcomes. Additional resources will need to be dedicated to the development of interventions to improve health outcomes and address disparities among PLWH impacted by the COVID-19 pandemic.

Immunogenicity of the 13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide in people living with HIV on combination antiretroviral therapy

BACKGROUND

People living with HIV (PLWH) are at increased risk of pneumococcal infections compared with the general population. The objective of this study was to investigate the immunogenicity of the combined pneumococcal vaccination schedule in PLWH.

METHODS

In this prospective cohort study, adult PLWH on antiretroviral therapy and HIV negative controls received the 13-valent pneumococcal conjugate vaccine (PCV13) at baseline followed by the 23-valent polysaccharide vaccine (PPSV23) at month 2. Serotype-specific IgG levels of 24 vaccine serotypes were measured (months 0, 2, 4, 6, 12). The primary outcome was seroprotection at month 4, defined as the proportion of patients with a post-immunization IgG concentration of ≥1.3 µg/mL for ≥70% (17/24) of vaccine serotypes.

FINDINGS

Samples of 120 patients were analysed. Seroprotection at month 4 was 49% (39/80) for PLWH and 82% (28/34) in controls. At month 12, seroprotection had decreased to 23% (18/79) and 63% (22/35), respectively. Nadir CD4 counts ≥ 200 cells/mm³, preserved kidney function and co-administration of the diphtheria-tetanus-polio (DTP) vaccine were associated with better seroprotection among PLWH. IgG levels of both PLWH and controls (all 24 vaccine serotypes) were significantly higher compared with baseline at all timepoints.

INTERPRETATION

Although IgG levels of all 24 vaccine serotypes increased significantly in both PLWH and controls, only a minority of PLWH achieved seroprotection after PCV13 followed by PPSV23. In addition, protective immunity waned rapidly. Further research into alternative vaccinations strategies for PLWH is needed, such as vaccination schedules with higher-valent pneumococcal vaccines. The DTP vaccine may augment pneumococcal vaccination responses.

Incidence and Predictors of Community-Acquired Pneumonia in Patients With Hematological Cancers Between 2016 and 2019

Background

Patients with hematological cancers (HC) are at high risk of infections, in particular community-acquired pneumonia (CAP). Recent data on incidence and predictors of CAP among patients with HC are scarce.

Methods

We performed a cohort study (2016–2019) in 2 hospitals in the Netherlands among adults with HC to calculate incidence rates (IRs) of CAP. In addition, we performed a nested case-control study to identify predictors of CAP.

Results

We identified 275 CAP cases during 6264 patient-years of follow-up. The IR of CAP was 4390/100 000 patient-years of follow-up. Compared with the general population, IR ratios ranged from 5.4 to 55.3 for the different HCs. The case fatality and intensive care unit (ICU) admission rates were 5.5% and 9.8%, respectively. Predictors for CAP in patients with HC were male sex, anemia, lymphocytopenia, chronic kidney disease, cardiovascular disease, autologous and allogeneic stem cell transplantation, treatment with immunosuppressive medication for graft-vs-host disease, treatment with rituximab in the past year, and treatment with immunomodulators (lenalidomide, thalidomide, pomalidomide and/or methotrexate) in the past month. Independent predictors of a severe disease course (death or ICU admission) included neutropenia (odds ratio, 4.14 [95% confidence interval, 1.63–10.2]), pneumococcal pneumonia (10.24 [3.48–30.1]), chronic obstructive pulmonary disease (6.90 [2.07–23.0]), and the use of antibacterial prophylaxis (2.53 [1.05–6.08]).

Conclusions

The burden of CAP in patients with HC is high, with significant morbidity and mortality rates. Therefore, vaccination against respiratory pathogens early in the disease course is recommended, in particular before starting certain immunosuppressive therapies.

Facilitando o acesso à vacina pneumocócica para pessoas vivendo com HIV: relato de experiência

RESUMO Descrever uma estratégia para facilitar o acesso à vacina conjugada pneumocócica 13-valente (PCV-13) para pessoas vivendo com HIV (PVHIV), durante a pandemia de COVID-19. Método: relato de experiência sobre a organização de um serviço de atendimento para PVHIV na cidade de São Paulo, para facilitar o acesso à PCV-13 no decorrer da campanha de vacinação de influenza de 2020, durante a pandemia de COVID-19. Resultados: por meio da integração entre um serviço de atendimento para PVHIV e um Centro de Imunizações (CRIE) foi possível oferecer a PCV-13 para as PVHIV em seu local de atendimento, diminuindo barreiras físicas de acesso à imunização. Dessa forma, das 1906 PVHIV que passaram pelo serviço durante o período de 23 de março a 31 de julho de 2020, 84,4% (1609) receberam a vacina influenza, PCV-13 ou ambas. Dos 1609 vacinados, 50,6% (814) foram elegíveis e receberam a PCV-13. Conclusão: oferecer a vacina em seu local de tratamento e orientar as PVHIV sobre a importância da vacinação como estratégia de prevenção de doenças, identificando os elegíveis a recebê-las, foi uma importante ação realizada pela instituição em conjunto com a equipe de enfermagem, como estratégia de facilitar o acesso à vacinação.

Recent Topics of Pneumococcal Vaccination: Indication of Pneumococcal Vaccine for Individuals at a Risk of Pneumococcal Disease in Adults

Pneumococcal disease is one of the most common and severe vaccine-preventable diseases (VPDs). Despite the advances in antimicrobial treatment, pneumococcal disease still remains a global burden and exhibits a high mortality rate among people of all ages worldwide. The immunization program of the pneumococcal conjugate vaccine (PCV) in children has decreased pneumococcal disease incidence in several countries. However, there are several problems regarding the pneumococcal vaccine, such as indications for immunocompetent persons with underlying medical conditions with a risk of pneumococcal disease, the balance of utility and cost, i.e., cost-effectiveness, vaccine coverage rate, serotype replacement, and adverse events. Especially for individuals aged 19-64 at risk of pneumococcal disease, physicians and vaccine providers should make a rational decision whether the patients should be vaccinated or not, since there is insufficient evidence supporting it. We describe this review regarding topics and problems regarding pneumococcal vaccination from the clinician's point of view.

Understanding the Host in the Management of Pneumonia. An Official American Thoracic Society Workshop Report

Pneumonia causes a significant burden of disease worldwide. Although all populations are at risk of pneumonia, those at extremes of age and those with immunosuppressive disorders, underlying respiratory disease, and critical illness are particularly vulnerable. Although clinical practice guidelines addressing the management and treatment of pneumonia exist, few of the supporting studies focus on the crucial contributions of the host in pneumonia pathogenesis and recovery. Such essential considerations include the host risk factors that lead to susceptibility to lung infections; biomarkers reflecting the host response and the means to pursue host-directed pneumonia therapy; systemic effects of pneumonia on the host; and long-term health outcomes after pneumonia. To address these gaps, the Pneumonia Working Group of the Assembly on Pulmonary Infection and Tuberculosis led a workshop held at the American Thoracic Society meeting in May 2018 with overarching objectives to foster attention, stimulate research, and promote funding for short-term and long-term investigations into the host contributions to pneumonia. The workshop involved participants from various disciplines with expertise in lung infection, pneumonia, sepsis, immunocompromised patients, translational biology, data science, genomics, systems biology, and clinical trials. This workshop report summarizes the presentations and discussions and important recommendations for future clinical pneumonia studies. These recommendations include establishing consensus disease and outcome definitions, improved phenotyping, development of clinical study networks, standardized data and biospecimen collection and protocols, and development of innovative trial designs.

Current and Past Immunodeficiency Are Associated With Higher Hospitalization Rates Among Persons on Virologically Suppressive Antiretroviral Therapy for up to 11 Years

BACKGROUND

Persons with human immunodeficiency virus (PWH) with persistently low CD4 counts despite efficacious antiretroviral therapy could have higher hospitalization risk.

METHODS

In 6 US and Canadian clinical cohorts, PWH with virologic suppression for ≥1 year in 2005-2015 were followed until virologic failure, loss to follow-up, death, or study end. Stratified by early (years 2-5) and long-term (years 6-11) suppression and lowest presuppression CD4 count <200 and ≥200 cells/µL, Poisson regression models estimated hospitalization incidence rate ratios (aIRRs) comparing patients by time-updated CD4 count category, adjusted for cohort, age, gender, calendar year, suppression duration, and lowest presuppression CD4 count.

RESULTS

The 6997 included patients (19 980 person-years) were 81% cisgender men and 40% white. Among patients with lowest presuppression CD4 count <200 cells/μL (44%), patients with current CD4 count 200-350 vs >500 cells/μL had aIRRs of 1.44 during early suppression (95% confidence interval [CI], 1.01-2.06), and 1.67 (95% CI, 1.03-2.72) during long-term suppression. Among patients with lowest presuppression CD4 count ≥200 (56%), patients with current CD4 351-500 vs >500 cells/μL had an aIRR of 1.22 (95% CI, .93-1.60) during early suppression and 2.09 (95% CI, 1.18-3.70) during long-term suppression.

CONCLUSIONS

Virologically suppressed patients with lower CD4 counts experienced higher hospitalization rates and could potentially benefit from targeted clinical management strategies.

Underutilised human immunodeficiency virus testing in the setting of invasive pneumococcal disease

People living with human immunodeficiency virus (HIV) are at increased risk of invasive pneumococcal disease (IPD). We assessed whether patients with invasive Streptococcus pneumoniae, in blood or cerebrospinal fluid, underwent HIV serology testing over a 5-year period. We found that only 39 inpatients out of 156 (25%) with IPD were tested for HIV and thus conclude that such testing is not being undertaken according to some guidelines in patients with IPD. Education and implementation strategies are required to increase testing.

Long-term mortality after tuberculosis treatment among persons living with HIV in Haiti

INTRODUCTION

Long-term mortality among TB survivors appears to be higher than control populations without TB in many settings. However, data are limited among persons with HIV (PWH). We assessed the association between cured TB and long-term mortality among persons with PWH in Haiti.

METHODS

A prospective cohort of PWH from the CIPRA HT-001 trial was followed from study enrolment (August 2005 to July 2008) to study closure (December 2018) to compare mortality between participants with and without TB. The index date for the survival analysis was defined as 240 days after TB diagnosis or randomization date. Time to death was described using Kaplan-Meier curves, and log-rank tests were used to compare time to death between the TB and no-TB cohorts. The association between TB and long-term mortality was estimated with multivariable Cox models.

RESULTS

Of the 816 participants in the CIPRA HT-001 trial, 77 were excluded for a history of TB prior to study enrolment and 31 were excluded due to death or attrition prior to the index date, leaving 574 in the no-TB and 134 in the TB cohort. Twenty-four (17.9%) participants in the TB and 48 (8.4%) in the no-TB cohort died during follow-up. Five and 10-year mortality rates were 14.2% and 17.9% respectively, in the TB cohort, and 6.1% and 8.4% in the no-TB cohort. In Kaplan-Meier analysis, participants in the TB cohort had a significantly shorter time to death (log-rank p < 0.001). In multivariable analysis, TB treatment was the only predictor of mortality (HR: 2.78; 95% CI: 1.61, 4.79). Sensitivity analyses, which included only baseline TB cases, an index date of two years after TB diagnosis, and study enrolment and case-control matching yielded results that were consistent with primary analyses.

CONCLUSIONS

PWH who are successfully treated for TB have higher long-term mortality than those who are never diagnosed with TB, even after accounting for acute TB-related mortality. A better understanding of the underlying mechanisms associated with TB sequelae is critically needed to guide specific interventions. Until then, more aggressive measures for health promotion and disease prevention are essential to improve long-term survival for PWH after TB treatment.

Pneumococcal Vaccination in Immunocompromised Hosts: An Update

Infections with the pathogen, Streptococcus pneumoniae, are a common cause of morbidity and mortality worldwide. It particularly affects those at the extremes of age and immunocompromised individuals. Preventing pneumococcal disease is paramount in at risk individuals, and pneumococcal vaccination should be offered. Here, we discuss the role of pneumococcal vaccination in specific groups of immunocompromised hosts.

Changes in Immune Activation During Pregnancy and the Postpartum Period in Treated HIV Infection

Background

Pregnant women with HIV (PWWH) have high postpartum morbidity and mortality from infections like tuberculosis. Immunologic changes during pregnancy and postpartum periods may contribute to these risks, particularly the immunoregulatory kynurenine pathway of tryptophan catabolism, which contributes to both HIV and tuberculosis pathogenesis and increases in the early postpartum period.

Methods

Women with HIV initiating antiretroviral therapy (ART) in the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort who were pregnant at enrollment or became pregnant during observation were studied (n = 54). Plasma kynurenine/tryptophan (KT) ratio, soluble CD14 (sCD14), sCD163, sCD27, interferon-inducible protein 10 (IP-10), D-dimer, interleukin-6, and intestinal fatty-acid binding protein levels were assessed through the first year of ART and at 3-month intervals throughout pregnancy and 1 year postpartum. Biomarker changes were assessed with linear mixed models adjusted for ART duration. Hemoglobin concentration changes were used to estimate pregnancy-related changes in plasma volume.

Results

The median pre-ART CD4 count was 134. D-dimer increased through the third trimester before returning to baseline postpartum, while most other biomarkers declined significantly during pregnancy, beyond what would be expected from pregnancy-associated plasma volume expansion. IP-10 and sCD14 remained suppressed for at least 12 months postpartum. KT ratio was the only biomarker that increased above prepregnancy baseline postpartum (mean + 30%; P < .001) and remained higher than baseline for ≥9 months (P ≤ .045 for all time points).

Conclusions

Several immune activation markers decline during pregnancy and remain suppressed postpartum, but the kynurenine pathway of tryptophan catabolism increases above baseline for ≥9 months postpartum. The mechanisms underlying postpartum kynurenine pathway activity are incompletely understood but may contribute to increased tuberculosis risk in this setting.

The Architecture of Circulating Immune Cells Is Dysregulated in People Living With HIV on Long Term Antiretroviral Treatment and Relates With Markers of the HIV-1 Reservoir, Cytomegalovirus, and Microbial Translocation

Long-term changes in the immune system of successfully treated people living with HIV (PLHIV) remain incompletely understood. In this study, we assessed 108 white blood cell (WBC) populations in a cohort of 211 PLHIV on stable antiretroviral therapy and in 56 HIV-uninfected controls using flow cytometry. We show that marked differences exist in T cell maturation and differentiation between PLHIV and HIV-uninfected controls: PLHIV had reduced percentages of CD4+ T cells and naïve T cells and increased percentages of CD8+ T cells, effector T cells, and T helper 17 (Th17) cells, together with increased Th17/regulatory T cell (Treg) ratios. PLHIV also exhibited altered B cell maturation with reduced percentages of memory B cells and increased numbers of plasmablasts. Determinants of the T and B cell composition in PLHIV included host factors (age, sex, and smoking), markers of the HIV reservoir, and CMV serostatus. Moreover, higher circulating Th17 percentages were associated with higher plasma concentrations of interleukin (IL) 6, soluble CD14, the gut homing chemokine CCL20, and intestinal fatty acid binding protein (IFABP). The changes in circulating lymphocytes translated into functional changes with reduced interferon (IFN)- γ responses of peripheral blood mononuclear cells to stimulation with Candida albicans and Mycobacterium tuberculosis. In conclusion, this comprehensive analysis confirms the importance of persistent abnormalities in the number and function of circulating immune cells in PLHIV on stable treatment.

Brief Report: Increased Cotinine Concentrations are Associated With Reduced Expression of Cathelicidin (LL-37) and NOD-2 in Alveolar Macrophages of PLWH Who Smoke

There is a strong link between cigarette smoking and pulmonary complications among people living with HIV. However, the effects of smoking on the local lung immune environment in this population remain unclear. Bronchoalveolar lavage and saliva were collected from HIV-infected smokers involved in a prospective study investigating alveolar macrophage expression of host defense molecules. Salivary cotinine concentrations were inversely related to expression of the immune cell receptor nucleotide-binding oligomerization domain-2 and the cathelicidin antimicrobial peptide LL-37. The negative correlation between salivary cotinine and LL-37 was particularly strong. Our study provides insight into how nicotine may adversely affect lung innate immunity in HIV.

Invasive pneumococcal disease among adults with hematological and solid organ malignancies: A population-based cohort study

OBJECTIVES

To determine the risk of invasive pneumococcal disease (IPD) in adult cancer patients stratified by type of underlying malignancy, age, and capsular serotype and to assess herd effects of childhood pneumococcal vaccination.

METHODS

All adult IPD cases reported to the Dutch pneumococcal surveillance system between 2004 and 2016 were included in this study. IPD incidence rates (IR) stratified by subtype of malignancy were calculated per 100 000 patient-years of follow-up. Incidence rate ratios (IRR) were calculated to compare IRs between groups.

RESULTS

A total of 7167 IPD cases were included, of which 1453 were in patients with malignancies. For patients with hematological malignancies (HM) and solid organ malignancies (SOM), IRs were 482/100 000 and 79/100 000, respectively, compared with 15/100 000 in controls. The highest incidence was observed among patients with multiple myeloma, non-Hodgkin lymphoma, chronic lymphocytic leukemia, pancreatic cancer, and lung cancer (3299/100 000, 2717/100 000, 538/100 000, 559/100 000, and 393/100 000, respectively), and in patients ≥50 years old. Among HM patients, the incidence of IPD declined significantly after the implementation of infant pneumococcal vaccination (IRR 0.65, 95% confidence interval 0.51-0.84); among SOM patients, the decline was not statistically significant (IRR 0.88, 95% confidence interval 0.72-1.07).

CONCLUSIONS

The IPD disease burden in cancer patients remains high. Large differences in IPD incidence between the different types of cancer demand tailored guidance regarding pneumococcal vaccination.

Immunogenicity of pneumococcal vaccination in HIV infected individuals: A systematic review and meta-analysis

BACKGROUND

The objective of this systematic review and meta-analysis was to summarise the literature regarding the immunogenicity of pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPSV) in adult people living with HIV (PLWH) in the era of advanced combination antiretroviral therapy (cART).

METHODS

The systematic review protocol was published online (PROSPERO ID: CRD 42020153137). We searched Medline (Ovid), EMBASE (Ovid), and the Global Health Library for publications from 2000 to June 11, 2020. We included all studies in adult PLWH that reported vaccine immunogenicity outcomes. The primary outcome was seroconversion rate (SCR) after PCV, PPSV and PCV/PPSV combined. For random-effects meta-analysis, we included studies defining SCR as a ≥ 2-fold increase in IgG from baseline, and reporting SCR for serotypes 6B, 14, or overall SCR, 1-3 months after vaccination.

FINDINGS

Our search identified 1597 unique studies, of which 115 were eligible for full-text assessment. Of these, 39 met the inclusion criteria (11 RCTs; 28 cohort studies). A high degree of heterogeneity was observed. Nineteen studies were included in the meta-analysis. Pooled overall SCRs were 42% (95% CI 30-56%), 44% (95% CI 33-55%) and 57% (95% CI 50-63%) for PLWH who received PPSV, PCV or a combination of PCV/PPSV, respectively. Compared to PPSV alone, a combination of PCV/PPSV yielded higher SCRs (OR 2.24 95% CI 1.41- 3.58), whereas we did not observe a significant difference in SCR between PCV and PPSV23 alone. There were no statistically significant differences in geometric mean post-vaccination antibody concentrations between vaccination schedules. Vaccination at higher CD4 cell counts improved immunogenicity in 8/21 studies, especially when PCV was administered. No studies assessed the long-term immunogenicity of PCV followed by PPSV23. Quality of evidence ranged from poor (n = 19) to good quality (n = 7). A limited number of pneumococcal serotypes was assessed in the majority of studies.

INTERPRETATION

We show that the recommended immunisation schedule consisting of a combination of PCV13/PPSV23, is immunogenic in PLWH in the era of advanced cART. However, the durability of this vaccination schedule remains unknown and must be addressed in future research. Vaccination with PCV should be delayed until immunological recovery (CD4>200) in recently diagnosed PLWH for optimal immunogenicity. The evidence gathered here supports wide implementation of the combination of PCV/PPSV23 for all PLWH. We recommend reassessment of this strategy once higher-valent PCVs become available.

FUNDING

HMGG is funded by a public research grant of ZonMw (project number 522004005).

Abnormal Levels of Some Biomarkers of Immune Activation Despite Very Early Treatment of Human Immunodeficiency Virus

BACKGROUND

Despite early antiretroviral therapy (ART), ART-suppressed people with human immunodeficiency virus (HIV) (PWH) remain at higher risk for infections and infection-related cancers than the general population. The immunologic pathways that remain abnormal in this setting, potentially contributing to these complications, are unclear.

METHODS

ART-suppressed PWH and HIV-negative controls, all cytomegalovirus seropositive and enriched for HIV risk factors, were sampled from an influenza vaccine responsiveness study. PWH were stratified by timing of ART initiation (within 6 months of infection [early ART] vs later) and nadir CD4+ T-cell count among later initiators. Between-group differences in kynurenine-tryptophan (KT) ratio, interferon-inducible protein 10, soluble CD14 and CD163, soluble tumor necrosis factor receptor 2, interleukin 6, and soluble urokinase plasminogen activator receptor were assessed after confounder adjustment.

RESULTS

Most participants (92%) were male, reflecting the demographics of early-ART initiators in San Francisco. Most biomarkers were higher among later-ART initiators. Participants in the early-ART group achieved near-normal soluble tumor necrosis factor receptor 2, interleukin 6, and soluble urokinase plasminogen activator receptor levels, but substantially higher KT ratio than those without HIV after confounder adjustment (P = .008). Soluble CD14, soluble CD163, and interferon-inducible protein 10 trended similarly.

CONCLUSIONS

While early-ART initiators restore near-normal levels of many inflammatory markers, the kynurenine pathway of tryptophan catabolism remains abnormally high. Because this pathway confers adaptive immune defects and predicts tuberculosis and cancer progression, this it may contribute to persistent risks of these complications in this setting.