Immunogenicity and safety of pneumococcal conjugate polysaccharide and free polysaccharide vaccines alone or combined in HIV-infected adults in Brazil

Invasive Pneumococcal Disease in People Living with HIV: A Retrospective Case-Control Study in Brazil

HIV-infected patients are at particular risk for invasive pneumococcal disease (IPD). We describe cases of IPD in people living with HIV/AIDS (PLWHA) and find associated risk factors for infection and death.

METHODS

A retrospective case-control study, nested in a cohort, including PLWHA with and without IPD, conducted in Brazil, 2005-2020. Controls were of the same gender/age and seen at the same time/place as cases.

RESULTS

We identified 55 episodes of IPD (cases) in 45 patients and 108 controls. The incidence of IPD was 964/100,000 person-years. A total of 42 of 55 (76.4%) IPD episodes presented with pneumonia and 11 (20%) with bacteremia without a focus and 38/45 (84.4%) were hospitalized. Blood cultures were positive in 54/55 (98.2%). Liver cirrhosis and COPD were the only factors associated with IPD in PLWHA in univariate analysis, although no associated factors were found in multivariate analysis. Penicillin resistance was found in 4/45 (8.9%). Regarding antiretroviral therapy (ART), 40/45 (88.9%) cases vs. 80/102 controls (74.1%) were in use (p = 0.07). Patients with HIV and IPD had a higher CD4 count of 267 cells/mm³ compared with the control group, in which it was 140 cells/mm³ (p = 0.027). Pneumococcal vaccination was documented in 19%. Alcoholism (p = 0.018), hepatic cirrhosis (p = 0.003), and lower nadir CD4 count (p = 0.033) were associated with the risk of death in patients with IPD. In-hospital mortality among PLWHA and IPD was 21.1%, and it was associated with thrombocytopenia and hypoalbuminemia, elevated band forms, creatinine, and aspartate aminotransferase (AST).

CONCLUSIONS

The incidence of IPD in PLWHA remained high despite ART. The vaccination rate was low. Liver cirrhosis was associated with IPD and death.

Single-Dose 13-Valent Conjugate Pneumococcal Vaccine in People Living With HIV – Immunological Response and Protection

Background

Patients living with HIV (PLHIV) are prone to invasive pneumococcal disease. The 13-valent conjugated pneumococcal vaccine (PCV13) is currently recommended for all PLHIV, followed in most guidelines by a 23-valent polysaccharide pneumococcal vaccine. Data are scarce concerning the immunological efficacy of PCV13 among PLHIV.

Objective

To assess the immunological response at one month, and the immunological protection at 1-, 6-, and 12 months in PLHIV with a CD4 cell count above 200 cells/µl after a single dose of PCV13, as measured by both ELISA and opsonophagocytic assay (OPA).

Methods

PLHIV with CD4 cell count >200 cells/µl were included. Specific IgG serum concentrations for eight serotypes by ELISA and seven serotypes by OPA were measured at baseline, 1-, 6-, and 12 months after the PCV13 vaccination. Global response was defined as a two-fold increase from baseline of specific IgG antibody levels (μg/ml) assayed by ELISA or as a four-fold increase in OPA titer from baseline, for at least five serotypes targeted by PCV13. Global protection was defined as an IgG-concentration ≥1 µg/ml by ELISA or as an opsonization titer ≥LLOQ by OPA for at least five tested serotypes targeted by PCV13. Factors associated with global response and global protection were assessed using logistic regression.

Results

Of the 38 PLHIV included, 57.9% and 63.2% were global responders, 92.1% and 78.9% were globally protected at one month, and 64.7% and 55.9% were still protected at 12 months, by ELISA and OPA respectively. A CD4/CD8 ratio of >0.8 was significantly associated with a better global response by OPA (OR=6.11, p=0.02), and a CD4 nadir <200 was significantly associated with a poorer global response by ELISA (OR=0.22, p=0.04). A CD4 cell count nadir <200 and age over 50 years were associated with poorer global protection by OPA at M1 (OR=0.18, p=0.04) and M12 (OR= 0.15, p=0.02), respectively. Plasma HIV RNA viral load <40 copies/ml was significantly associated with a better global protection at M1 by ELISA and OPA (OR=21.33, p=0.025 and OR=8.40, p=0.04)

Conclusion

Vaccination with PCV13 in these patients induced immunological response and protection at one month. At one year, more than half of patients were still immunologically protected.

Effects of Probiotic Mixture Supplementation on the Immune Response to the 13-Valent Pneumococcal Conjugate Vaccine in People Living with HIV

Background: In people living with HIV, combination antiretroviral therapy (cART) reduces the risk of death, but the persistent immune-deficient state predisposes them to pneumococcal infections. Current guidelines encourage administering pneumococcal vaccine Prevenar 13 to patients living with HIV. Since probiotic supplementation could act as adjuvants and improve vaccine immunogenicity by modulating gut microbiota, the present study aimed to assess whether the effect of a formulation containing a combination of specific probiotics (Vivomixx^®) could improve the immune response to 13-valent pneumococcal conjugate vaccine (PCV13) in adult people living with HIV. Methods: Thirty patients who were clinically stable and virologically suppressed, without opportunistic infections during this time and no ART changes in the 12 months before the study started were enrolled. Patients were divided into two groups: (1) received a placebo dose and (2) received Vivomixx^® (1800 billion CFU) for four weeks before and after the vaccination with a single dose of PCV13. Results: Vivomixx^® supplementation induced a better response to PCV13 immunization, as shown by greater change in anti-Pn CPS13 IgG and increase in salivary IgA, IL-10 and IL-8. Conclusions: Additional investigations will help to clearly and fully elucidate the optimal strains, doses, and timing of administration of probiotics to improve protection upon vaccination in immunocompromised individuals and the elderly.

Immunogenicity following revaccination or sequential vaccination with 23-valent pneumococcal polysaccharide vaccine (PPSV23) in older adults and those at increased risk of pneumococcal disease: a review of the literature

Introduction: Immunogenicity studies evaluating sequential administration of pneumococcal conjugate vaccine (PCV) followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) or revaccination with PPSV23 have raised concerns that PPSV23 may not elicit higher antibody levels than those measured following PCV or first PPSV23 dose.Areas covered: Recent literature was evaluated for evidence of blunted immune response (hyporesponsiveness), focusing on studies using adequate intervals between doses in accordance with vaccination recommendations. In eight of nine studies that evaluated revaccination with PPSV23 at an interval of ≥5 years after the previous dose, immunoglobulin G geometric mean concentrations and/or opsonophagocytic assay geometric mean titers for most serotypes increased from pre- to post-repeat vaccination and were comparable between repeat and primary vaccination groups post-vaccination. In seven studies in which PPSV23 was administered after PCVs (8 weeks to 1 year apart), responses to PPSV23 were comparable to those seen after initial PCV dose for shared vaccine serotypes. Studies in which PCVs were administered after PPSV23 were not evaluated.Expert opinion: Published data suggest immune responses following repeat vaccination with PPSV23, or sequential PCV/PPSV23 vaccination, are robust, without evidence of hyporesponsiveness. PPSV23 vaccination of at-risk adults is essential to ensure broad protection against all 23 vaccine serotypes.

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).

Vaccine strategies to reduce the burden of pneumococcal disease in HIV-infected adults in Africa

INTRODUCTION

Streptococcus pneumoniae is the leading cause of invasive bacterial disease, globally. Despite antiretroviral therapy, adults infected with human immunodeficiency virus (HIV) are also at high risk of pneumococcal carriage and disease. Pneumococcal conjugate vaccines (PCVs) provide effective protection against vaccine serotype (VT) carriage and disease in children, and have been introduced worldwide, including most HIV-affected low- and middle-income countries. Unlike high-income countries, the circulation of VT persists in the PCV era in some low-income countries and results in a continued high burden of pneumococcal disease in HIV-infected adults. Moreover, no routine vaccination that directly protects HIV-infected adults in such settings has been implemented.

AREAS COVERED

Nonsystematic review on the pneumococcal burden in HIV-infected adults and vaccine strategies to reduce this burden.

EXPERT OPINION

We propose and discuss the relative merit of changing the infant PCV program to use (1a) a two prime plus booster dose schedule, (1b) a two prime plus booster dose schedule with an additional booster dose at school entry, to directly vaccinate (2a) HIV-infected adults or vaccinating (2b) HIV-infected pregnant women for direct protection, with added indirect protection to the high-risk neonates. We identify key knowledge gaps for such an evaluation and propose strategies to overcome them.

Pneumococcal Vaccination Strategies Among HIV-infected Adult Patients: A Review of the Literature

BACKGROUND/AIM

Streptococcus pneumoniae is the leading cause of bacterial pneumonia and an important cause of invasive disease. Despite the antiretroviral therapies, adults infected with human immunodeficiency virus (HIV) are at particular risk for invasive pneumococcal disease (IPD). The purpose of this study was to report the efficacy of the strategies currently being used in pneumococcal vaccination for HIV-infected adults.

MATERIALS AND METHODS

A literature search was performed through electronic databases, for original articles in English, from years 2000 to 2019. Clinical trials controlled or randomized, and cohort studies were included.

RESULTS

While 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for immunocompromised patients, it has been reported that it is less suitable for HIV-infected patients. Recent guidelines have added pneumococcal conjugate vaccine (PCV) to the list of recommended vaccines.

CONCLUSION

Further studies are needed to determine the optimal vaccines and intervals for subsequent revaccinations during the lifetime.

Immunogenicity and Immunological Memory Induced by the 13-Valent Pneumococcal Conjugate Followed by the 23-Valent Polysaccharide Vaccine in HIV-Infected Adults

Background

Vaccine-induced memory B-cell (MBC) subsets have distinct roles in the establishment of protective immunity; MBCs expressing nonswitched immunoglobulin M (IgM+ MBCs) replenish the MBC pool, whereas MBCs expressing isotype-switched immunoglobulin (sIg+ MBCs) differentiate into plasma cells upon antigen reencounter. We investigated immunogenicity and MBCs induced by combined 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPV23) in human immunodeficiency virus (HIV)-infected adults.

Methods

Forty HIV-seropositive adults receiving ART with undetectable viral loads were enrolled. Seventeen had a CD4+ T-cell count of ≥400 cells/μL (group A), and 23 had a CD4+ T-cell count of 200-399 cells/μL (group B). All adults received PCV13 and, 1 year later, PPV23. Levels of IgM+ MBCs (defined as polysaccharide [PS]-specific CD19+CD10-CD27+CD21++IgM+ MBCs) and sIg+ MBCs (defined as PS-specific CD19+CD10-CD27+CD21++IgM- MBCs) and antibodies against PS14 and PS3 were measured prior and 1 month after each vaccination.

Results

Immunization caused a significant increase in PS antibodies, compared with levels at baseline (P < .001). Group B achieved significantly lower titers than group A (P < .05 for both PS14 and PS3). After receipt of PCV13, levels of IgM+ MBCs were unchanged, whereas levels of sIg+ MBCs increased significantly (P < .05 for PS14 and P < .001 for PS3). In contrast, following PPV23 receipt, levels of IgM+ MBCs were significantly reduced, and levels of sIg+ MBCs remained stable. A positive correlation was observed between baseline IgM+ and sIg+ MBC counts 1 month after PCV13 receipt but not after PPV23 receipt.

Conclusions

PPV23 receipt 12 months after PCV13 receipt improved PCV13 immunogenicity. The reduction in the IgM+ MBC count observed after PPV23 receipt suggests that PPV23 has a depleting effect on PCV13-associated immunological memory.

Clinical Trials Registration

NCT03041051.

Travel vaccination recommendations and infection risk in HIV-positive travellers

BACKGROUND

With the advent of highly active antiretroviral drugs for the treatment of human immunodeficiency virus (HIV) it has become possible for people with HIV to travel to destinations that may place them at risk of a number of infectious diseases. Prevention of infections by vaccination is therefore of paramount importance for these travellers. However, vaccine responsiveness in HIV-positive individuals is not infrequently reduced compared to HIV-negative individuals. An understanding of the expected immune responses to vaccines in HIV-positive travellers is therefore important in planning the best approach to a pretravel consultation.

METHODS

A PubMed search was performed on HIV or acquired immune deficiency syndrome together with a search for specific vaccines. Review of the literature was performed to develop recommendations on vaccinations for HIV-positive travellers to high-risk destinations.

RESULTS

The immune responses to several vaccines are reduced in HIV-positive people. In the case of vaccines for hepatitis A, hepatitis B, influenza, pneumococcus, meningococcus and yellow fever there is a good body of data in the literature showing reduced immune responsiveness and also to help guide appropriate vaccination strategies. For other vaccines like Japanese encephalitis, rabies, typhoid fever, polio and cholera the data are not as robust; however, it is still possible to gain some understanding of the reduced responses seen with these vaccines.

CONCLUSION

This review provides a summary of the immunological responses to commonly used vaccines for the HIV-positive travellers. This information will help guide travel medicine practitioners in making decisions about vaccination and boosting of travellers with HIV.

Long-Term Serological Response to 13-Valent Pneumococcal Conjugate Vaccine Versus 23-Valent Polysaccharide Vaccine in HIV-Infected Adults

Introduction

Long-term comparative immunologic response to 13-valent pneumococcal conjugate vaccine (PCV13) versus 23-valent polysaccharide vaccine (PPV23) among HIV-infected adults has not yet been investigated.

Methods

In this prospective pilot study, we quantified in HIV-positive adults serotype-specific IgG concentrations of the 12 pneumococcal serotypes shared by both vaccines 5 years after vaccination with two doses of PCV13 8 weeks apart (group 1) or one dose of PPV23 (group 2) and compared them with those assessed prior to vaccination (BL) and after 1 year (T1). Comparison of immunogenicity was based on geometric mean concentration (GMC), proportion of individuals with ≥ twofold increase from BL in specific antibody concentration against ≥ 2 serotypes and percentage of individuals with serotype-specific IgG ≥ 0.35 μg/ml, ≥ 1 μg/ml and ≥ individual serotype-specific correlates of protection.

Results

We included 91 subjects (median CD4⁺ 650 cells/µl, > 90% with HIV-RNA < 50 copies/ml); patients in groups 1 (n = 42) and 2 (n = 49) were homogeneous for the main characteristics. GMCs were significantly higher in the PCV13 group than in the PPV23 group for serotype 19F (p = 0.003). Both vaccines revealed higher significant GMCs to most serotypes compared with BL, i.e., eight in group 1 vs. seven in group 2. With respect to T1, GMCs decreased significantly in the PCV13 group for eight vs. ten serotypes in the PPV23 group. More participants in the PCV13 group had ≥ 2 increase from BL in antibody levels to ≥ 2 serotypes compared with the PPV23 group (78.6% vs. 59.2%, p = 0.042). Overall, the percentage of subjects with serotype-specific IgG ≥ 0.35 μg/ml, ≥ 1 μg/ml and ≥ individual serotype-specific correlates of protection was similar between groups.

Conclusion

In this study with HIV-positive adults with a favorable viro-immunologic profile, both vaccines were shown to achieve a long-term durable serologic response. We found minor differences in immunogenicity between the two vaccines, which favored PCV13 over PPV23 5 years after immunization.

Trial Registration

ClinicalTrials.gov identifier, NCT02123433.

Electronic supplementary material

The online version of this article (10.1007/s40121-019-0256-z) contains supplementary material, which is available to authorized users.

Vaccine safety in HIV-infected adults within the Vaccine Safety Datalink Project

OBJECTIVES

We evaluate safety of routine vaccination among adults infected with human immunodeficiency virus (HIV) in five healthcare organizations in the United States.

METHODS

We conducted a retrospective cohort study of HIV-infected adults who received inactivated influenza vaccines, hepatitis B vaccines, pneumococcal vaccines, or tetanus, diphtheria, and acellular pertussis vaccines between 2002 and 2013. We conducted self-controlled case series analysis to estimate the relative risk (RR) for 11 pre-specified adverse events (AEs) requiring medical attention.

RESULTS

Among 20,417 HIV-infected adults (90.2% male), a total of 137,674 vaccine doses were administered. Based on ICD-9 codes, we detected an increased risk of cellulitis and infection (RR: 1.18, 95% CI: 1.03-1.35) among all patients, and an increased risk of stroke/cerebrovascular diseases among patients with an HIV viral load >10,000 copies/ml (adjusted RR: 3.94, 95% CI: 1.32-11.72). Further analyses on chart confirmed cases of stroke/cerebrovascular diseases indicated no statistically significant increased risk (adjusted RR: 1.72, 95% CI: 0.41-7.24). There was no evidence of increased risk for other AEs following routine vaccination in HIV-infected adults.

CONCLUSIONS

Routinely administered vaccines are generally safe for HIV-infected adults.

Vaccination in the Adult Patient Infected with HIV: A Review of Vaccine Efficacy and Immunogenicity

Patients infected with HIV remain at increased risk of mortality and morbidity from diseases that are preventable with vaccines partly due to the persisting immunopathology that results in impaired responses to vaccination despite virologic suppression. Because data on clinical effectiveness in patients who are immunocompromised remain limited, undervaccination of individuals with HIV poses a major concern. Multiple societies have published recommendations on vaccination in individuals infected with HIV. Many of these recommendations are based on extrapolation of data from clinical trials that usually exclude patients with HIV, although there is a growing body of data from patients infected with HIV as well. In this review, we describe the available literature on vaccine response in the adult patient with HIV as measured by immunogenicity or vaccine efficacy.

Pneumococcal vaccination for HIV-infected individuals in Singapore

Susceptibility to infections with pneumococcal bacteria ( Streptococcus pneumoniae) is substantially higher among human immunodeficiency virus (HIV)-infected individuals, and accounts for a significant burden of morbidity and healthcare costs. Pneumococcal vaccination is recommended in most countries for HIV-infected adults. Current policy in Singapore and Australia recommends the use of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) as a booster dose following the use of 13-valent pneumococcal conjugate vaccine (PCV13). Despite this, adherence to this policy has been suboptimal in Singapore. This may be related to the fact that PPSV23 has not been shown to have any impact on pneumococcal carriage (the necessary prerequisite for disease development). PPSV23 has also been associated with immune hyporesponsiveness, raising concerns over the use of this vaccine globally and, in particular, in high-risk populations. The lack of data from studies comparing PCV13 and PPSV23 has also contributed to the suboptimal uptake of pneumococcal vaccines by healthcare professionals for HIV-infected individuals. This review article discusses the key issues and importance of rigorous pneumococcal vaccination programmes for HIV-infected individuals. Current recommendations for pneumococcal vaccination of HIV-infected individuals in Singapore should be adopted more readily to reduce the burden of pneumococcal disease in this high-risk group.

Vaccinations for the HIV-Infected Adult: A Review of the Current Recommendations, Part I

Vaccination is a critical component for ensuring the health of those living with the human immunodeficiency virus (HIV) by protection against vaccine-preventable diseases. Since HIV-infected persons may have reduced immune responses and shorter durations of protection post-vaccination, HIV-specific guidelines have been published by global and national advisory organizations to address these potential concerns. This article provides a comprehensive review of the current guidelines and evidence-based data for vaccinating HIV-infected adults, including guidance on modified vaccine dosing and testing strategies, as well as safety considerations, to enhance protection among this vulnerable population. In the current article, part I of the two-part series, inactivated vaccines with broad indications as well as vaccines for specific risk and age groups will be discussed.

Brief Report: Immunization of HIV-Infected Adults in the UK With Haemophilus influenzae b/Meningococcal C Glycoconjugate and Pneumococcal Polysaccharide Vaccines

U.K. guidelines for vaccinating HIV-infected adults against bacteria are based on limited data. We compared antibody responses between 211 HIV-infected and 73 HIV-uninfected adults vaccinated with pneumococcal polysaccharide vaccine (PPV) and Haemophilus influenzae b/meningococcal C polysaccharide-tetanus toxoid glycoconjugate vaccine (Hib/MenC-TT). IgG responses to Hib/MenC-TT were not significantly different. PPV induced median IgGs >1.3 μg/mL for 10/12 serotypes among HIV-uninfected participants and 5/12 in HIV-infected participants. HIV-uninfected adults had higher post-vaccination IgGs than HIV-infected adults for 4/12 serotypes (P < 0.001). Responses did not associate with CD4 count or viral suppression. In a U.K. HIV-infected population, Hib/MenC-TT induced similar responses to HIV-uninfected adults, whereas PPV induced poor responses.

A case series evaluating the serological response of adult asthma patients to the 23-valent pneumococcal polysaccharide vaccine

BACKGROUND

Asthma is an independent risk factor for invasive pneumococcal disease; however, the immune response of adult asthma patients to pneumococcal vaccination is unknown. We explore the serologic response of patients with moderate to severe asthma to the 23-valent pneumococcal polysaccharide vaccine (PPSV23).

METHODS

Seventeen moderate to severe adult asthma patients that had not been vaccinated against pneumococcus over the 5 previous years were prospectively recruited from a tertiary care asthma clinic. Serum was analyzed for the presence of antibodies to five capsular polysaccharide (CP) antigens (6B, 9V, 19A, 19F, 23F) before and 4 weeks after PPSV23 vaccination.

RESULTS

There was a wide variability in baseline anti-CP antibody concentrations. Other than for serotype 19A, our patients frequently have baseline anti-CP antibody concentrations below 1 µg/mL (35% for serotype 19F, 41% for serotypes 9V and 23F, and 59% for serotype 6B). All post-vaccination geometric mean antibody concentrations were significantly higher than baseline. In the 31 tests where the baseline antibody concentration was <1 µg/mL, 77.4% had at least a twofold increase post-vaccination. Despite this, a large proportion of post-vaccination anti-CP antibody concentrations remained <1 µg/mL (51.6% of tests). Nine patients had at least one anti-CP antibody concentration <1 µg/mL post-vaccination. There was no difference between these patients and the remaining eight patients in demographic or clinical variables.

CONCLUSIONS

Patients with moderate to severe asthma have variable baseline and low post-vaccination antibody concentrations to common CP antigens included in the PPSV23 vaccine. The clinical relevance of these observations remains to be determined since the threshold concentration in adults required for clinical protection from invasive pneumococcal disease is uncertain.

HIV-related pneumococcal disease prevention in adults

INTRODUCTION

HIV-infected persons are particularly susceptible to the development of severe pneumococcal disease, even in the setting of combination antiretroviral therapy (cART), due to slow, incomplete recovery of anti-pneumococcal host defenses. This risk is increased by avoidable aspects of lifestyle, particularly smoking, which intensify immunosuppression. Clearly, more effective preventive measures are needed to counter this threat. Areas covered: This is a detailed review of the published literature focusing on currently available strategies for prevention of pneumococcal infection in HIV-infected patients, including cotrimoxazole prophylaxis, cART, pneumococcal vaccination, and smoking cessation strategies. This is preceded by a consideration of the epidemiology, clinical presentation, risk factors, and outcome of pneumococcal disease. Expert commentary: Cotrimoxazole prophylaxis has been shown to reduce morbidity and mortality in HIV-infected patients, although there is inconsistent data on the preventive efficacy against pneumococcal infections. Some recent studies have documented unchanged incidences of IPD in adult patients in the cART era. With regard to pneumococcal vaccination, routine acceptance of the efficacy of the PCV13/PPV23 sequential administration prime-boost strategy awaits the outcome of clinical trials in those with HIV infection. Smoking cessation, and discontinuation of excessive alcohol consumption and intravenous drug abuse, are priority strategies to prevent severe pneumococcal infection.

Evaluation and Optimization of an ELISA Procedure to Quantify Antibodies Against Pneumococcal Polysaccharides Included in the 13-Valent Conjugate Vaccine

The 13-valent pneumococcal conjugate vaccine (PCV-13) is recommended for HIV-infected people, although its effectiveness in this population remains under evaluation. In this study, we describe the development, optimization, and analytical validation of an ELISA procedure to measure specific antibodies for the pneumococcal polysaccharide serotypes included in PCV13 vaccine, testing sera obtained from HIV-infected outpatients (n = 30) who received the vaccine. The protocol followed the last version of WHO guidelines, based on the new standard 007sp, with the modification of employing Statens Serum Institut (SSI) antigens. We supplied the assay performance validation in terms of sensitivity, reproducibility, precision and accuracy. In addition we detailed optimal antigen-coating concentrations and ELISA conditions common to all 13 serotypes, suitable for laboratories performing these assays in order to standardize the method. Our procedure showed reproducibility and reliability, making it a valid alternative for evaluating the response to pneumococcal serotypes included in PCV13 vaccine.

Immunological efficacy of pneumococcal vaccine strategies in HIV-infected adults: a randomized clinical trial

The aim of this study was to compare the immunologic response to a prime-boost immunization strategy combining the 13-valent conjugate pneumococcal vaccine (PCV13) with the 23-valent polysaccharide pneumococcal vaccine (PPSV23) versus the PPSV23 alone in HIV-infected adults. HIV-infected adults were randomized to receive PCV13 at week 0 followed by PPSV23 at week 4 (n = 31, prime-boost group) or PPSV23 alone at week 4 (n = 33, PPSV23-alone group). Serotype specific IgG geometric mean concentration (GMC) and functional oposonophagocytic (OPA) geometric mean titer (GMT) were compared for 12 pneumococcal serotypes shared by both vaccines at week 8 and week 28. The prime-boost vaccine group were more likely to achieve a ≥2-fold increase in IgG GMC and a GMC >1 ug/ml at week 8 (odds ratio (OR) 2.00, 95% confidence interval (CI) 1.46-2.74, p < 0.01) and week 28 (OR 1.95, 95% CI 1.40-2.70, p < 0.01). Similarly, the prime-boost vaccine group were more likely to achieve a ≥4-fold increase in GMT at week 8 (OR 1.71, 95% CI 1.22-2.39, p < 0.01) and week 28 (OR 1.6, 95% CI 1.15-2.3, p < 0.01). This study adds to evidence supporting current pneumococcal vaccination recommendations combining the conjugate and polysaccharide pneumococcal vaccines in the United States and Europe for HIV-infected individuals.

Immunogenicity and Safety of the 13-Valent Pneumococcal Conjugate Vaccine versus the 23-Valent Polysaccharide Vaccine in Unvaccinated HIV-Infected Adults: A Pilot, Prospective Controlled Study

Objectives

Definition of the optimal pneumococcal vaccine strategy in HIV-infected adults is still under evaluation. We aimed to compare immunogenicity and safety of the 13-valent pneumococcal conjugate vaccine (PCV13) versus the 23-valent polysaccharide vaccine (PPSV23) in HIV-infected adults.

Methods

We performed a pilot, prospective controlled study enrolling HIV-infected pneumococcal vaccine-naïve outpatients, aged 18–65 years with CD4 counts ≥200 cells/μL. Eligible subjects were recruited into two parallel groups: group 1 (n = 50) received two doses of PCV13 eight weeks apart, and group 2 (n = 50) received one dose of PPSV23, as part of their standard of care. Anti-pneumococcal capsular polysaccharide immunoglobulin G concentrations were quantified by ELISA at baseline, 8, 24 and 48 weeks. Clinical and viro-immunological follow-up was performed at the same time points. Unvaccinated, age-matched HIV-negative adults (n = 100) were also enrolled as baseline controls.

Results

Pre-vaccination specific IgG titers for each pneumococcal antigen did not differ between study groups but they were constantly lower than those from the HIV-negative controls. After immunization, significant increases in IgG titers were observed in both study groups at each time point compared to baseline, but response to serotype 3 was blunted in group 1. Antibody titers for each antigen did not differ between study groups at week 48. Overall, the proportion of subjects achieving seroprotection and seroconversion to all serotypes was comparable between groups. A marked decrease in IgG levels over time was observed with both vaccines. No relevant adverse reactions were reported in either group.

Conclusions

In this population with favorable immune profile, no relevant differences were observed in immunogenicity between PCV13 and PPSV23. Both vaccines were safe and well tolerated.

Trial Registration

ClinicalTrials.gov NCT02123433

Quantitative and Functional Antibody Responses to the 13-Valent Conjugate and/or 23-Valent Purified Polysaccharide Vaccine in Aging HIV-Infected Adults

BACKGROUND

The number of aging human immunodeficiency virus-infected (HIV+) individuals living in the United States has substantially grown over the past two decades. Advanced age and HIV infection both increase susceptibility to Streptococcus pneumoniae infection due to B cell dysfunction. The combined impact of these factors on pneumococcal vaccine responses remains unknown.

METHODS

We assessed serum immunoglobulin (Ig) G and IgM levels and opsonophagocytic killing assay (OPA) titers to pneumococcal serotypes 14 and 23F in HIV+ subjects and HIV-uninfected (HIV-) controls 50-65 years old. HIV+ individuals with CD4⁺ T cells/μl (CD4) >200 and ≥1 year of antiretroviral therapy (ART) received either a dose of the 13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide vaccine 8 weeks later (PCV/PPV) as currently recommended (n=15) or a single dose of PPV only (n=22). HIV- controls received PCV/PPV (n=14).

RESULTS

HIV+ PCV/PPV and PPV groups exhibited similar increases in IgG levels and OPA titers for both serotypes after immunization. Postvaccination IgM levels for serotype 23F, but not 14, were significantly higher in HIV+ PCV/PPV compared to PPV groups. IgG and IgM levels for serotype 14 and OPA titers to serotype 23F were significantly reduced in HIV+ compared to HIV- PCV/PPV groups. Serotype-specific IgG levels correlated with OPA titers for all groups.

CONCLUSIONS

Our data suggest that the recommended PCV/PPV regimen may not significantly improve quantitative or functional antibody responses compared to PPV only in aging HIV+ subjects. Continued efforts aimed at improving vaccine responses in this high risk population are warranted.

Impact of HIV on the severity of influenza

Despite current antiretroviral therapy, HIV/AIDS is one of the most prelevant problems in healthcare worldwide. Similarly, influenza viruses are causes of epidemics outbreaks. HIV-infected patients are considered a high risk group for severe influenza infection, although several recent observational studies suggest that not all HIV-infected patients are equally susceptible to complications and that these patients should be stratified by their immunodeficiency status and other factors (such as smoking or comorbidities). Here, we have compiled the most recent data on the impact that HIV has on influenza infection.

Long-term immune responses and comparative effectiveness of one or two doses of 7-valent pneumococcal conjugate vaccine (PCV7) in HIV-positive adults in the era of combination antiretroviral therapy

Introduction

HIV infection impairs maintenance of immunological memory, yet few studies of HIV-positive adults receiving 7-valent pneumococcal conjugate vaccine (PCV7) have followed them beyond the first year. We determined and compared the durability of serological responses and the clinical outcomes of HIV-positive adults annually for five years following vaccination with one or two doses of PCV7.

Methods

In this non-randomized clinical trial, 221 pneumococcal vaccine-naïve HIV-positive adults receiving one (n=109) or two doses four weeks apart (n=112) of PCV7 between 2008 and 2010 were longitudinally followed for evaluation of significant serological response and for episodes of pneumonia and invasive pneumococcal disease.

Results

At the time of vaccination, the two groups were well matched for age, risk factors, combination antiretroviral therapy (cART) coverage, CD4 count and plasma HIV RNA load (PVL). At the end of five years, the CD4 counts for the one- and two-dose groups had increased from 407 and 406 to 550 and 592 cells/µL, respectively, and 82.4 and 81.6% of the participants had fully suppressed PVL. Significant immune responses to ≥2 serotypes persisted for 67.9 vs 78.6%, 64.2 vs 71.4%, 66.1 vs 71.4%, 57.8 vs 69.6% in the second, third, fourth and fifth years after one and two doses of PCV7 in the intention-to-treat analysis, respectively. In multivariate analysis, immunization with two doses of PCV7 (odds ratio (OR) 1.71, 95% confidence interval (CI) 1.10 to 2.65, p=0.016), concurrent cART (OR 2.16, 95% CI 1.16 to 4.00, p=0.015) and CD4 proliferation (OR 1.12, 95% CI 1.01 to 1.27, p=0.031) were predictive of persistent serological responses in the fifth year. Only one patient in the one-dose group had documented pneumococcal pneumonia (non-bacteraemic) and none had invasive pneumococcal disease in the 6.5 years of follow-up.

Conclusions

One or two doses of PCV7 achieve durable seroprotective responses in HIV-treated participants; however, two doses may be more robust than one dose in a larger study population or in real-world populations with less cART coverage.

Bacterial meningitis in patients with HIV: A population-based prospective study

OBJECTIVE

We studied occurrence, disease course, and prognosis of community-acquired bacterial meningitis in HIV-infected adults in the Netherlands.

METHODS

We performed a nationwide, prospective cohort study. Patients over 16 years old with bacterial meningitis were included. Data on patient history, symptoms and signs on admission, laboratory findings, radiologic examination, treatment, and outcome were collected prospectively. For HIV-positive patients additional information was collected retrospectively.

RESULTS

From March 2006 to December 2013, 1354 episodes of community-acquired meningitis were included in the cohort. Thirteen patients were HIV-infected (1.0%). The annual incidence of bacterial meningitis was 8.3-fold higher (95%CI 4.6-15.1, P < 0.001) among HIV-infected patients as compared to the general population (10.79 [95%CI 5.97-19.48] vs 1.29 [95%CI 1.22-1.37] per 100.000 patients per year). Predisposing factors (other than HIV), clinical symptoms and signs, ancillary investigations, causative organisms and outcome were comparable between HIV-infected and patients without HIV infection.

CONCLUSIONS

HIV-infected patients in the Netherlands have a 8.3-fold higher risk for bacterial meningitis as compared to the general population despite cART therapy. Clinical presentation and outcome of patients with acute bacterial meningitis with and without HIV are similar.

Alterations in serotype-specific B cell responses to the 13-valent pneumococcal conjugate vaccine in aging HIV-infected adults

BACKGROUND

Advanced age and human immunodeficiency virus (HIV) infection are associated with increased pneumococcal disease risk. The impact of these factors on cellular responses to vaccination is unknown.

METHODS

HIV-infected (HIV+) individuals 50-65 years old with CD4(+) Tcells/μl (CD4) >200 on antiretroviral therapy (ART) ≥1 year received either the 13-valent pneumococcal conjugate vaccine followed by the 23-valent pneumococcal polysaccharide vaccine (PCV/PPV) or PPV only. HIV-uninfected (HIV-) controls received PCV/PPV. Phenotype distribution and surface expression of complement receptor CD21 and tumor necrosis factor superfamily receptors (TNFRs) were compared on serotype-specific B cells postvaccination.

RESULTS

Postvaccination serotype-specific B cell percentages were significantly lower in HIV+ PCV/PPV compared to PPV groups, but similar between HIV+ or HIV- PCV/PPV groups. Transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI)(+) serotype-specific B cell percentages were significantly decreased in HIV+ PCV/PPV compared to PPV groups. CD21(+) serotype-specific B cells were significantly higher in HIV- compared to HIV+ PCV/PPV groups.

CONCLUSIONS

An initial dose of PCV reduced the frequency, but not phenotype distribution, of serotype-specific B cells and also lowered TACI expression in aging HIV+ subjects postvaccination with PPV. These findings suggest that PCV does not enhance cellular responses to revaccination with PPV.

Pneumococcal vaccination among HIV-infected adult patients in the era of combination antiretroviral therapy

HIV-infected patients remain at higher risk for pneumococcal disease than the general population despite immune reconstitution and suppression of HIV replication with combination antiretroviral therapy. Vaccination with 23-valent pneumococcal polysaccharide vaccine (PPV23) composed of T-cell-independent antigens has been recommended to reduce the risk of pneumococcal disease in HIV-infected adults. However, given the heterogeneity of study design, execution and subjects enrolled, studies examining serological responses to PPV23 yielded conflicting results and observational studies of clinical effectiveness only provided moderate evidence to support the routine use of PPV23 in HIV-infected adults. Pneumococcal conjugate vaccine (PCV), with conjugation of the capsular polysaccharide to a protein carrier, is more immunogenic than PPV23 and has been demonstrated to protect against pneumococcal disease in HIV-infected children and recurrent invasive pneumococcal disease in HIV-infected adolescents and adults. Guidelines have recently been revised to recommend that HIV-infected patients aged 19 y or older receive one dose of 13-valent pneumococcal conjugate vaccine (PCV13) followed by a booster vaccination with PPV23. In this paper, we review the studies using different vaccination strategies to improve immunogenicity among HIV-infected adult patients.

Travel risk assessment, advice and vaccinations in immunocompromised travellers (HIV, solid organ transplant and haematopoeitic stem cell transplant recipients): A review

International travellers with immunocompromising conditions such as human immunodeficiency virus (HIV) infection, solid organ transplantation (SOT) and haematopoietic stem cell transplantation (HSCT) are at a significant risk of travel-related illnesses from both communicable and non-communicable diseases, depending on the intensity of underlying immune dysfunction, travel destinations and activities. In addition, the choice of travel vaccinations, timing and protective antibody responses are also highly dependent on the underlying conditions and thus pose significant challenges to the health-care providers who are involved in pre-travel risk assessment. This review article provides a framework of understanding and approach to aforementioned groups of immunocompromised travellers regarding pre-travel risk assessment and management; in particular travel vaccinations, infectious and non-infectious disease risks and provision of condition-specific advice; to reduce travel-related mortality and morbidity.

Immunogenicity and Safety of 13-Valent Pneumococcal Conjugate Vaccine in HIV-Infected Adults Previously Vaccinated With Pneumococcal Polysaccharide Vaccine

BACKGROUND

Persons with human immunodeficiency virus (HIV) infection are at increased risk of pneumococcal disease. We evaluated the safety and immunogenicity of 13-valent pneumococcal conjugate vaccine (PCV13) in this population.

METHODS

HIV-infected persons ≥ 18 years of age who were previously vaccinated with ≥ 1 dose of 23-valent pneumococcal polysaccharide vaccine (PPSV23) and had CD4 cell counts ≥ 200 cells/mm(3) and HIV viral loads <50 000 copies/mL were enrolled in this 3-dose PCV13 open-label study.

RESULTS

A total of 329 subjects received ≥ 1 dose, and 279 received 3 doses administered at 6-month intervals. Increases in anticapsular polysaccharide immunoglobulin G concentrations and opsonophagocytic antibody titers were demonstrated 1 month after each of the 3 doses of PCV13. Antibody levels were generally similar after each dose. The responses were similar whether subjects had previously received 1 or ≥ 2 doses of PPSV23. Pain at the injection-site was the most common local reaction. Severe injection site or systemic events were uncommon.

CONCLUSIONS

Vaccination with PCV13 induces anticapsular immunoglobulin G and opsonophagocytic antibody responses in HIV-infected adults with prior PPSV23 vaccination and CD4 cell counts ≥ 200 cells/mm(3). The observations support the use of PCV13 in this population.

CLINICAL TRIALS REGISTRATION

NCT00963235.

Pneumococcal vaccine and patients with pulmonary diseases

Chronic pulmonary diseases are chronic diseases that affect the airways and lung parenchyma. Examples of common chronic pulmonary diseases include asthma, bronchiectasis, chronic obstructive lung disease, lung fibrosis, sarcoidosis, pulmonary hypertension, and cor pulmonale. Pulmonary infection is considered a significant cause of mortality in patients with chronic pulmonary diseases. Streptococcus pneumoniae is the leading isolated bacteria from adult patients with community-acquired pneumonia, the most common pulmonary infection. Vaccination against S. pneumoniae can reduce the risk of mortality, especially from more serious infections in both immunocompetent and immunocompromised patients. Patients with chronic pulmonary diseases who take steroids or immunomodulating therapy (eg, methotrexate, anti-tumor necrosis factor inhibitors), or who have concurrent sickle cell disease or other hemoglobinopathies, primary immunodeficiency disorders, human immunodeficiency virus infection/acquired immunodeficiency syndrome, nephrotic syndrome, and hematologic or solid malignancies should be vaccinated with both 13-valent pneumococcal conjugate vaccine and the pneumococcal polysaccharide vaccine 23-valent.