Immunogenicity and immunologic memory after hepatitis B virus booster vaccination in HIV-infected children receiving highly active antiretroviral therapy

Type I interferons induce an epigenetically distinct memory B cell subset in chronic viral infection

Memory B cells (MBCs) are key providers of long-lived immunity against infectious disease, yet in chronic viral infection, they do not produce effective protection. How chronic viral infection disrupts MBC development and whether such changes are reversible remain unknown. Through single-cell (sc)ATAC-seq and scRNA-seq during acute versus chronic lymphocytic choriomeningitis viral infection, we identified a memory subset enriched for interferon (IFN)-stimulated genes (ISGs) during chronic infection that was distinct from the T-bet+ subset normally associated with chronic infection. Blockade of IFNAR-1 early in infection transformed the chromatin landscape of chronic MBCs, decreasing accessibility at ISG-inducing transcription factor binding motifs and inducing phenotypic changes in the dominating MBC subset, with a decrease in the ISG subset and an increase in CD11c+CD80+ cells. However, timing was critical, with MBCs resistant to intervention at 4 weeks post-infection. Together, our research identifies a key mechanism to instruct MBC identity during viral infection.

State-of-the-Science of human papillomavirus vaccination in women with human immunodeficiency Virus: Summary of a scientific workshop

The burden of cervical cancer is disproportionately distributed globally, with the vast majority of cases occurring in low- and middle-income countries. Women with human immunodeficiency virus (HIV) (WWH) are at increased risk of human papillomavirus (HPV) infection and cervical cancer as compared to HIV-negative individuals. HPV vaccination remains a priority in regions with a high burden of cervical cancer and high HIV prevalence. With HPV vaccines becoming more accessible, optimal use beyond the initial World Health Organization-recommended target population of 9 to 14-year-old girls is an important question. In March 2022, a group of experts in epidemiology, immunology, and vaccinology convened to discuss the state-of-the-science of HPV vaccination in WWH. This report summarizes the proceedings: review of HIV epidemiology and its intersection with cervical cancer burden, immunology, HPV vaccination including reduced-dose schedules and experience with other vaccines in people with HIV (PWH), HPV vaccination strategies and knowledge gaps, and outstanding research questions. Studies of HPV vaccine effectiveness among WWH, including duration of protection, are limited. Until data from ongoing research is available, the current recommendation for WWH remains for a multi-dose HPV vaccination regimen. A focus of the discussion included the potential impact of HIV acquisition following HPV vaccination. With no data currently existing for HPV vaccines and limited information from non-HPV vaccines, this question requires further research. Implementation research on optimal HPV vaccine delivery approaches for WWH and other priority populations is also urgently needed.

Immune Responses to HBV Vaccine in People Living with HIV (PLWHs) Who Achieved Successful Treatment: A Prospective Cohort Study

BACKGROUND

Understanding immune responses after HBV vaccination is important to prevent HBV infection in PLWH and to achieve successful treatment.

METHODS

Thirty-two PLWHs with CD4⁺ cell count > 350 cells/µL and HIV RNA < 200 copies/mL were vaccinated with 20 µg of HBV vaccine at weeks 0, 4, and 24 in this prospective study. We measured total HIV DNA levels, HBsAb titers and HBsAg-specific T-cell responses during follow-up time.

RESULTS

All patients achieved protective HBsAb titer after immunization. The magnitude of the IFN-r and TNF-a response to HBsAg was 22.0 (IQR: 6.5-65.0) and 106.50 (IQR: 58.5-203.0) spot-forming cells (SFC)/10⁵ PBMC, respectively at week 0. The level of IFN-r secreted at weeks 12 and weeks 36 to 48 was comparable with that at week 0. However, IFN-r response was higher at weeks 12 than that at weeks 36 to 48 (p = 0.02). The level of TNF-a secreted at weeks 12 was higher than that at week 0 (p < 0.001). Total HIV DNA levels were 2.76 (IQR: 2.47-3.07), 2.77 (IQR: 2.50-3.09), 2.77 (IQR: 2.41-2.89) log₁₀ copies/10⁶ PBMCs at weeks 0, 12, 36 to 48, respectively. No correlation was observed between IFN-r and TNF-a levels and HBsAb titer as well as total HIV DNA levels after immunization.

CONCLUSION

Humoral immunity was satisfactory, but cellular immunity and decline in HIV reservoir were not optimal after HBV vaccine immunization in these patients.

Undetectable Anti-HBs Antibodies: Need of a Booster Dose for HIV-1-Infected Individuals

HBV vaccination effectively prevents HBV transmission and the development of liver cancer. Disease progression and liver-related complications are more common in HIV-1/HBV co-infected than HBV mono-infected individuals. A considerable body of literature, which will be reviewed here, indicates that response to HBV vaccine is suboptimal in HIV-1-infected individuals and that the poor maintenance of protective immunity to HBV vaccines in these individuals is an important medical issue. Several factors affect HBV vaccine response during HIV-1 infection including CD4+ T cell counts, B cell response, vaccine formulation, schedules, and timing of antiretroviral therapy (ART). The initial response to HBV vaccination also plays a critical role in the sustainability of antibody responses in both HIV-1-infected and uninfected vaccinees. Thus, regular follow-up for antibody titer and a booster dose is warranted to prevent HBV transmission in HIV-1 infected people.

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.

The role of hepatitis B vaccine challenge dose in patients with underlying health conditions

We have evaluated the immunological response to Hepatitis B virus (HBV) booster vaccine dose in 129 adults with underlying diseases in comparison with 694 subjects at occupational risk of infection, who have previously completed the primary series and resulted with anti-HBs <10 mIU/mL. After booster dose, 60.5% of the patients with underlying diseases and 14.8% of the subjects at occupational risk resulted seronegative. By comparing two groups, rate of subjects with anamnestic response was higher in at occupational risk group respect to that at risk for medical conditions (OR: 5.99 [95%IC, 3.81-9.41], p < .001). This difference was associated to gender (males/females: OR: 0.619 [95%IC, 0.421-0.910], p = .015) and age (better response for younger people, p = .011).

Hepatitis B Vaccination and Waning Hepatitis B Immunity in Persons Living with HIV

PURPOSE OF REVIEW

Persons with HIV are at a higher risk for acquiring HBV (hepatitis B virus) than the general population due to shared modes of transmission and are significantly more likely to develop and die from sequelae of chronic HBV infection. Early vaccination is key to achieving HBV protective immunity, but response rates are still much lower than in the general population, ranging from 35 to 70%. Individuals with HIV also experience more rapidly waning immunity than those without HIV. Strategies to augment initial response and improve long-term immunity in individuals with HIV include alterations in dose, frequency, and the use of immune adjuvants.

RECENT FINDINGS

Recent studies have focused on the use of different vaccine formulations, the use of vaccine adjuvants, increased number and strength of vaccine dosages, increased dose frequency, alternative routes of administration, dual vaccinations, and the use of booster vaccines. Although no consensus has been reached on the use of certain vaccination regimens, three and four double-dose vaccine schedules via the intramuscular route have demonstrated higher initial response rates. Early vaccination when CD4 cell counts are greater than 350/mm³ with low viral loads has been shown to improve initial response, along with completion of immunization series. Adjuvants such as TLR4 and TLR9 agonists appear to improve response to HBV vaccination, but further research is needed in individuals with HIV. Persons with HIV have significant lower initial and long-term seroresponse rates after HBV vaccination than immunocompetent individuals. Recent and ongoing studies continue to evaluate multiple strategies to improve these rates within a uniquely susceptible population.

HBV vaccination and PMTCT as elimination tools in the presence of HIV: insights from a clinical cohort and dynamic model

BACKGROUND

Sustainable Development Goals set a challenge for the elimination of hepatitis B virus (HBV) infection as a public health concern by the year 2030. Deployment of a robust prophylactic vaccine and enhanced interventions for prevention of mother to child transmission (PMTCT) are cornerstones of elimination strategy. However, in light of the estimated global burden of 290 million cases, enhanced efforts are required to underpin optimisation of public health strategy. Robust analysis of population epidemiology is particularly crucial for populations in Africa made vulnerable by HIV co-infection, poverty, stigma and poor access to prevention, diagnosis and treatment.

METHODS

We here set out to evaluate the current and future role of HBV vaccination and PMTCT as tools for elimination. We first investigated the current impact of paediatric vaccination in a cohort of children with and without HIV infection in Kimberley, South Africa. Second, we used these data to inform a new parsimonious model to simulate the ongoing impact of preventive interventions. By applying these two approaches in parallel, we are able to determine both the current impact of interventions, and the future projected outcome of ongoing preventive strategies over time.

RESULTS

Existing efforts have been successful in reducing paediatric prevalence of HBV infection in this setting to < 1%, demonstrating the success of the existing vaccine campaign. Our model predicts that, if consistently deployed, combination efforts of vaccination and PMTCT can significantly reduce population prevalence (HBsAg) by 2030, such that a major public health impact is possible even without achieving elimination. However, the prevalence of HBV e-antigen (HBeAg)-positive carriers will decline more slowly, representing a persistent population reservoir. We show that HIV co-infection significantly reduces titres of vaccine-mediated antibody, but has a relatively minor role in influencing the projected time to elimination. Our model can also be applied to other settings in order to predict impact and time to elimination based on specific interventions.

CONCLUSIONS

Through extensive deployment of preventive strategies for HBV, significant positive public health impact is possible, although time to HBV elimination as a public health concern is likely to be substantially longer than that proposed by current goals.

Effect of HIV exposure and timing of antiretroviral therapy initiation on immune memory responses to diphtheria, tetanus, whole cell pertussis and hepatitis B vaccines

OBJECTIVES

We evaluated memory responses and antibody persistence to diphtheria-toxoid, tetanus-toxoid, whole-cell-pertussis (DTwP), and Hepatitis-B vaccines in HIV-unexposed, HIV-exposed-uninfected and HIV-infected children previously randomized to initiate time-limited ART at 6-10 weeks (ART-Immed) or when clinically/immunologically indicated (ART-Def).

METHODS

All children received DTwP booster at 15-18 months. Antibodies were measured for pertussis-toxoid, filamentous haemagglutinin (FHA), diphtheria-toxoid, tetanus-toxoid, and hepatitis-B prior to booster, 1-2 weeks post-booster and at 24 months of age.

RESULTS

Pre-booster antibody GMC were lower in HIV-infected groups than HIV-unexposed children for all epitopes. Post-booster and at 24 months of age, the ART-Def group had lower GMCs and antibody proportion ≥0.1 IU/ml for tetanus-toxoid and diphtheria-toxoid compared to HIV-unexposed children. At 24 months of age, the ART-Immed group had higher GMCs, and more likely to maintain antibody titres ≥1.0 IU/ml to tetanus-toxoid and diphtheria-toxoid compared to HIV-unexposed children. Compared to HIV-unexposed children, at 15 and 24 months of age, persistence of antibody to HBsAg of ≥10 mIU/ml was similar in the ART-Immed group but lower among the ART-Def group. Antibody kinetics indicated more robust memory responses in HIV-exposed-uninfected than HIV-unexposed children to diphtheria-toxoid and wP.

CONCLUSION

HIV-infected children not on ART at primary vaccination had poorer memory responses, whereas HIV-exposed-uninfected children mounted robust memory responses.

Serological responses to revaccination against HBV in HIV-positive patients born in the era of nationwide neonatal HBV vaccination

BACKGROUND

Serological responses to revaccination against hepatitis B virus (HBV) are unclear in HIV-positive adults who had undergone neonatal HBV vaccination and whose antibodies against HBV had waned in the era of combination antiretroviral therapy (cART).

METHODS

Between 2000 and 2017, 666 HIV-positive men who have sex with men (MSM) who were born after 1986, when nationwide neonatal HBV vaccination programme was implemented in Taiwan, were included for analyses. A serological response was defined when a hepatitis B surface antibody (anti-HBs) titre ≥10 mIU/mL was measured 4-24 weeks after the third dose of HBV vaccination.

RESULTS

During the study period, 295 (48.7%) HIV-positive MSM (mean age, 23.2 years) who had lost HBV seroprotection were eligible for revaccination; 171 (58.0%) received at least 1 dose (20-μg) of HBV vaccine and 116 (39.3%) completed the 3-dose schedule. The serological response rate to 3 doses of HBV revaccination was 74.0% and the rate of high-titre response (anti-HBs titre ≥100 mIU/mL) was 46.0%. The CD4 count before the first dose (per 50-cell/μL increment, adjusted odds ratio, 1.14; 95% confidence interval, 1.01-1.29) was positively associated with the serological response. The incident rate of HBV infection was 9.2 per 1000 person-years of follow-up among the patients who were non-responders after revaccination.

CONCLUSIONS

Despite HBV vaccination in the neonatal period, the serological response rate to HBV revaccination in HIV-positive MSM was modest and could wane rapidly. Regular testing of anti-HBs should be integrated into the HIV care despite cART containing HBV-active agents.

Assessment of the HBV vaccine response in a group of HIV-infected children in Morocco

BACKGROUND

Since its development in the early 1980s, Hepatitis B virus (HBV) vaccine has been proven to be highly protective. However, its immunogenicity may be ineffective among HIV-infected children. In Morocco, HBV vaccine was introduced in 1999, and since then all infants, including vertically HIV-infected infants, have been following the vaccination schedule, implemented by the Moroccan ministry of health. An assessment of the immunization of these children is important to optimize efforts aimed at tackling Hepatitis B coinfection, within the country.

METHODS

Forty-nine HIV-infected children (HIV group) and 112 HIV uninfected children (control group) were enrolled in this study. Samples were tested by Elisa (Monolisa Anti-HBs, Biorad) to quantify the anti-HBs antibodies. The % of lymphocyte subsets i.e. CD4+ T cells, CD8+ T cells, B cells, and NK, was determined by flow cytometry, using CellQuest Pro software (Becton-Dickinson), and for HIV group, HIV viral load was measured by real time PCR assay (Abbott). All variables were statistically compared in the two groups.

RESULTS

The median age was 51 ± 35 months for the HIV group and 50 ± 36 months (p > 0.05) for the control group. Female represented 63% and 41% (p = 0.01), among the HIV group and the control group, respectively. Among HIV-infected children, 71.4% (35/49) were under HAART therapy at the enrollment in the study. Seroprotection titer i.e. anti-HBs ≥10mUI/ml among control group was 76% (85/112), and only 29% (14/49) among the perinatally HIV-infected children (p < 0.0001). Lower % of CD4 + T cells was observed in HIV-infected children with a poor anti-HBs response.

CONCLUSION

In this studied group, we have shown that despite the vaccination of HIV-children with HBV vaccine, 71% did not show any seroprotective response. These findings support the need for monitoring HBV vaccine response among HIV-infected children in Morocco, in order to revaccinate non-immunized children.

Persistence of Hepatitis B Immunity Following 3-dose Infant Primary Series in HIV-infected Thai Adolescents and Immunologic Response to Revaccination

BACKGROUND

HIV infection may alter immunologic response and the establishment of immune memory to infant hepatitis B virus (HBV) vaccination. This study aimed to determine the need to revaccinate perinatally HIV-infected Thai adolescents.

METHODS

Cross-sectional serologic tests for HBV, including hepatitis B surface antigen, anti-hepatitis B surface antibody (anti-HBs) and anti-hepatitis B core antibody (anti-HBc), were performed in perinatally HIV-infected adolescents. Adolescents having anti-HBs <100 mIU/mL with negative anti-HBc and immune reconstitution from highly active antiretroviral therapy (HAART) were revaccinated using regular (10 μg) 3-dose schedule given intramuscularly at 0-, 2- and 6-month intervals.

RESULTS

Of 193 adolescents who received 3-dose infant HBV vaccination, 6 were receiving HAART during vaccination, median (interquartile range) current age 14.5 (11.7-16.2) years, 7 (3.6%) had positive anti-HBc (indicating breakthrough infection), of which 4 (2%) had positive hepatitis B surface antigen (indicating chronic infection). Twenty-two (11.4%) adolescents had protective anti-HBs concentration >10 mIU/mL. Of 164 revaccinated adolescents, 142 (86.6%) had HIV viral load <40 copies/mL. Anti-HBs seroconversion rates >10 mIU/mL were 58.0% (94/162) after the first dose and 97.5% (158/162) after the third dose of revaccination. Forty-five (28%) subjects responded to the first dose with anti-HBs antibody ≥100 mIU/mL had a shorter median duration with CD4 count <15% than their counterparts (6.2 vs. 11.1 months; P = 0.049).

CONCLUSIONS

Only half of perinatally HIV-infected adolescents were able to elicit anti-HBs response with a single-dose HBV vaccine. Revaccination with 3-dose schedule is required in perinatally HIV-infected adolescents who did not initiate HAART at the time of infant vaccination.

Immunogenicity of a Booster Dose of Quadrivalent Meningococcal Conjugate Vaccine in Previously Immunized HIV-Infected Children and Youth

BACKGROUND

The US Advisory Committee on Immunization Practices recommends a booster dose of quadrivalent meningococcal conjugate vaccine (MCV4) after initial immunization for patients at high risk for meningococcal infection.

METHODS

The International Maternal Pediatric Adolescents AIDS Clinical Trials (IMPAACT) P1065 trial evaluated the use of MCV4 in human immunodeficiency virus (HIV)-infected children and youth. The final step of this trial was an open-label study of an MCV4 booster dose 3.5 years after primary MCV4 immunization. Antibody titers were evaluated at the time of the booster vaccine and 1, 4, and 24 weeks after the booster. Immunogenicity was measured by rabbit serum bactericidal antibody (rSBA) against each meningococcal serogroup. Immunologic memory was defined as either seroprotection (rSBA titer ≥1:128) or a ≥4-fold increase 1 week after the booster dose. Primary response was defined as either a ≥4-fold response or seropositivity 4 weeks after the booster in the absence of immunologic memory. Adverse events were assessed for 4 weeks after the booster dose.

RESULTS

Of 174 participants with serology results at entry and 1 and 4 weeks later, the percentage with protective antibody levels at entry varied according to serogroup, ranging from a low of 26% for serogroup C to a high of 68% for serogroup A. A memory response to at least 1 serogroup occurred in 98% of the participants: 93% each for serogroups A and Y, 88% for serogroup C, and 94% for serogroup W-135; 83% had a memory response to all 4 serogroups. Overall, rates of any memory or primary response were ≥90% for all serogroups. No serious adverse events were encountered.

CONCLUSIONS

A booster dose of MCV4 elicited a memory response in 88% to 94% of previously immunized HIV-infected participants depending on serogroup, including those who lacked a protective titer level for that serogroup before booster vaccination.

Hepatitis B virus vaccination in HIV-infected people: A review

HBV immunization is highly recommended in people infected with HIV. However, the classical schedule used in the general population has been shown to be insufficient in people living with HIV. This review summarizes the main studies dealing with HBV vaccination in people living with HIV, depending on their baseline status (in particular, never vaccinated, already vaccinated, or with an isolated anti-HBc serological profile). It shows that reinforced 40µg intramuscular HBV vaccination schedules are now frequently recommended, either initially in people never vaccinated, or in the lack of an anamnestic response in other situations. Adjuvants cannot be currently recommended. Anti-HBs titers have to be checked 1 to 2 months following the last vaccine dose, and annually thereafter a booster is necessary if antiHBs titers decrease below 10 mIU/mL. In patients with a CD4 cell count <200/µL, guidelines recommend starting the vaccination regimen as soon as possible after HAART has been started.

Immunogenicity of Hepatitis B Vaccine in HIV Exposed Uninfected Infants

There is paucity of knowledge about the immunogenicity of vaccines in infants who have been exposed to HIV in-utero but have remained uninfected. The authors studied the immunogenicity of 3 doses of recombinant hepatitis B vaccine at 6,10,14 wk of age in HIV exposed but uninfected (HEU) infants. After 3 mo of last dose of the vaccine, out of 26 infants, 23 (89.5 %) infants were found to be responders (Anti HBs IgG titres ≥ 10 mIU/ml) and 3 (11.5 %) babies remained non responders (Anti HBs IgG titres < 10 mIU/ml). The proportion of babies who were non responders were higher when compared to similar studies done on unexposed and uninfected infants, suggesting a poorer immunogenicity of hepatitis B vaccine in these infants.

Long-term effect of highly active antiretroviral therapy on immunologic features in children

BACKGROUND

Highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus infection (HIV) into a chronic condition. The effects of long-term HAART on the immune system activity of early infected children are not fully understood. Hence, the aim of this review is to investigate immune system recovery and residual alteration in HIV-infected children receiving HAART in high-income countries.

METHODS

A systematic review was performed by searches of PubMed and references of the relevant articles. Studies published between January 1, 2000 and April 1, 2014 and conducted in high-income countries reporting data on immunological features in HIV-infected children receiving HAART were included in this review.

RESULTS

Fifty-three articles were included in this review. Present knowledge on B-cell and T-cell function, immunoglobulin production, response to vaccine and innate immune system activity in HIV-infected children receiving HAART is discussed.

CONCLUSION

Starting therapy as soon as diagnosis is ascertained and monitoring vaccine response in children under HAART are the most important tools to safeguard immunological function in HIV-infected children.

Hepatitis B vaccination for reducing morbidity and mortality in persons with HIV infection

BACKGROUND

Hepatitis B vaccine has been recommended for use in people living with HIV (PLHIV) mostly because of the similarities in routes of infection and their prevalence in the same geographic areas. PLHIV may not develop sero-protection after receiving standard hepatitis B vaccine due to their compromised immune status.

OBJECTIVES

To evaluate the efficacy of hepatitis B virus vaccine in PLHIV compared to placebo or no vaccine.

SEARCH METHODS

We searched 6 English language databases in July 2012, and updated the search in June 2013 and August 2014. We searched the grey literature, conference proceedings, specialised web sites, and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials of hepatitis B vaccine compared to placebo or no vaccine, evaluating relevant outcomes of efficacy and safety.

DATA COLLECTION AND ANALYSIS

Two review authors independently sought and extracted data on study design, participants, hepatitis B infection, hepatitis B related morbidity and mortality, anti-HBs immunogenicity and adverse effects related to vaccines from published articles or through correspondence with authors. Data were analysed qualitatively.

MAIN RESULTS

One double-blind randomised controlled trial with 26 participants who were on antiretroviral therapy (ART), comparing hepatitis B vaccine to placebo conducted in Spain met our eligibility criteria and was included in this review. The study ran for three years and participants were followed up on a monthly basis. The study reported adequate humoral response to vaccine at 12 months and no local or systematic side effects in both intervention and control groups. This humoral response was lost when the participants stopped taking ART. The sample size of the study was small and the study was conducted in a high income setting unlike the areas of highest burden of hepatitis B and HIV co-infections.

AUTHORS' CONCLUSIONS

The evidence from this study is insufficient to support any recommendations regarding the use of hepatitis B vaccine in PLHIV. Neither does this evidence demonstrate that hepatitis B vaccine is unsafe in PLHIV. Further randomised controlled trials in high prevalence areas are required to generate evidence on the long term efficacy and safety of hepatitis B vaccine in PLHIV with and without ART. Different regimens and routes of administration should also be explored.

Long-term immune responses to vaccination in HIV-infected patients: a systematic review and meta-analysis

Vaccine-induced antibodies may wane more quickly in persons living with human immunodeficiency virus (HIV) than in healthy individuals. We reviewed the literature on vaccines routinely recommended in HIV-infected patients to estimate how seroprotection decreases over time in those who initially responded to immunization. For each study retrieved from the literature, the decrease of seroprotection was modeled with a log binomial generalized linear model, and data were pooled in a meta-analysis to provide estimates of seroprotection 2 and 5 years after the last vaccine administration. Our analyses confirmed that the duration of seroprotection was shorter in HIV-infected patients and that with current guidelines, a substantial proportion of patients would have lost protective antibodies before a booster was proposed. We therefore discuss the implications for the monitoring of antibody levels and timing of revaccination in these patients.

2013 IDSA clinical practice guideline for vaccination of the immunocompromised host

An international panel of experts prepared an evidenced-based guideline for vaccination of immunocompromised adults and children. These guidelines are intended for use by primary care and subspecialty providers who care for immunocompromised patients. Evidence was often limited. Areas that warrant future investigation are highlighted.

HIV/HBV coinfection in children and antiviral therapy

Small cohort studies from countries where both HIV and HBV are endemic demonstrate prevalence rates of chronic hepatitis B in HIV-infected children of between 1 and 49%. While data on coinfected children are limited, results from studies in adults with HIV/HBV coinfection raise the concern that coinfected children may be at a higher risk of liver disease, hepatic fibrosis and cirrhosis. With the scale-up of combination antiretroviral therapy worldwide, of which lamivudine is included in most first-line regimens, coinfected children treated with lamivudine risk development of HBV resistance mutations. This article summarizes the current literature relevant to HIV/HBV coinfection in children, the options for treatment and highlights priorities for future research.

Antibody persistence and immunologic memory after sequential pneumococcal conjugate and polysaccharide vaccination in HIV-infected children on highly active antiretroviral therapy

BACKGROUND

The capacity of pneumococcal vaccination to confer memory in HIV-infected children is critical for durable protection.

METHODS

HIV-infected children 2-<19 years administered two doses of pneumococcal conjugate vaccine (PCV7) and one dose of polysaccharide vaccine (PPV) on HAART were randomized 4-5 years later to receive a PCV7 or PPV booster. Total and high avidity antibodies to serotypes 1 (PPV) and 6B and 14 (PCV7 and PPV) were determined by ELISA. Memory was defined as persistence of ≥ 0.5 mcg/mL of serotype-specific antibody on day 0 or change from <0.5 mcg/mL to ≥ 0.5 mcg/mL between day 0 and week 1, or, ≥ 4-fold antibody rise between day 0 and week 1.

RESULTS

Prior to boosting, 4-5 years after the previous PCV7-PCV7-PPV series, geometric mean concentrations (GMCs) were 0.46 mcg/mL (serotype 1), 1.31 mcg/mL (serotype 6B), and 1.47 mcg/mL (serotype 14), with concentrations ≥ 0.5 mcg/mL in 41% (serotype 1) to 82% (serotypes 6B and 14). Memory based on antibody concentration ≥ 0.5 mcg/mL before or 1 week after boosting with PCV7 or PPV was demonstrated in 42-61% for serotype 1 and 87-94% for serotypes 6B and 14, with lower rates based on day 0 to week 1 ≥ 4-fold antibody rise (serotype 1, 3-13%; serotype 6B, 13-31%; serotype 14, 29-53%). Antibody concentrations post-boosting were greater following PCV7 than PPV for serotypes 6B and 14. Ratios of highly avid to total antibody pre- and post-boosting were 0.5-0.8. Predictors of memory included higher CD4% (nadir before HAART and at P1024 and P1061s entry), CD19% (at P1024 and P1061s entry), and antibody response after the PCV7-PCV7-PPV primary series and lower viral load (at P1024 and P1061s entry) and age.

CONCLUSIONS

Protective antibody concentrations, high avidity, and booster responses to PCV7 or PPV indicative of memory were present 4-5 years after PCV7-PCV7-PPV in HIV-infected children on HAART.

Hepatitis B virus prevalence and vaccine response in HIV-infected children and adolescents on combination antiretroviral therapy in Kigali, Rwanda

OBJECTIVE

The aim of this study was to determine the prevalence of hepatitis B virus (HBV) infection in a cohort of HIV-infected Rwandan children and adolescents on combination antiretroviral therapy (cART), and the success rate of HBV vaccination in those children found to be HBV negative.

METHODS

HIV-infected children and adolescents (age 8-17 years) receiving cART with CD4 T-cells count ≥200 cells/mm and/or ≥15% and without prior HBV vaccination (by history, vaccination cards and clinic records) underwent serologic testing for past (negative HBV surface antigen [HBsAg] with positive antibody to HBV core antigen [cAb] and to HBsAg [anti-HBs]) or active HBV infection (positive HBsAg). Children with any positive HBV serologic tests were excluded from further vaccination; all others completed 3 HBV immunizations with 10 µg of ENGERIX-B. Anti-HBs titer was measured 4-6 weeks after the last immunization.

RESULTS

Of 88 children, 6 (7%) children had active HBV infection and 8 (9%) had past HBV infection. The median (interquartile range) age, CD4 T-cell count and cART duration were 12.3 (10.1-13.9) years, 626 (503 to 942) cells/mm and 1.9 (1.5-2.7) years, respectively. Seventeen children had detectable plasma HIV-1 RNA. Seventy-3 children completed 3 immunizations with median (interquartile range) postimmunization anti-HBs concentration of 151 mIU/mL (1.03-650). Overall, 52 children (71%, 95% confidence interval: 61-82) developed a protective anti-HBs response. HIV-1 RNA and CD4 T-cell count were independent predictors of a protective anti-HBs response. Protective anti-HBs response was achieved in 82% of children with undetectable HIV-1 RNA and 77% with CD4 T cells ≥350/mm.

CONCLUSIONS

The substantial HBV prevalence in this cohort suggests that HIV-infected Rwandan children should be screened for HBV before cART initiation. HIV viral suppression and CD4 T cells ≥350/mm favored the likelihood of a protective response after HBV vaccination.

Long-term response rates of successful hepatitis B vaccination in HIV-infected patients

BACKGROUND

Data on long-term response rates after successful primary hepatitis B (HBV) vaccination in HIV-infected patients are scarce.

OBJECTIVE

To evaluate the durability of an effective anti-HBs titer up to 5 years after primary vaccination in a cohort of 155 HIV-infected adults.

METHODS

From a previous multicenter HBV vaccination trial we selected patients with an anti-HBs titer of ≥10 IU/l 28 weeks after the first vaccination. The anti-HBs titer was measured in annually stored plasma samples up to 5 years after vaccination. Patients with decreasing anti-HBs titers <10 IU/I were defined as transient responders (TR) and with persistent anti-HBs titers ≥10 IU/I as long-term responders (LTR^).

RESULTS

We included 155 patients, 87 were TR and 68 LTR. Mean age, percentage of female participants and duration of HAART use at primary vaccination were similar in LTR and TR. Anti-HBs level after primary vaccination was the strongest predictor for the durability of anti-HBs. Anti-HBs >100-1000 IU/I and >1000 resulted in an OR 8.3, 95% CI 3.38-20.16; p<0.0001 and OR 75.6, 95% CI 13.41-426.45; p<0.0001 versus anti-HBs titer of 10-100 IU/I after primary vaccination respectively. The mean time to loss of an effective anti-HBs titer was 2.0, 3.7 and 4.4 years respectively, for patients with an anti-HBs titer of 10-100 IU/I, >100-1000 IU/I and >1000 IU/I at primary vaccination. An undetectable HIV-RNA load and use of HAART during vaccination and at follow-up were, though not significantly, associated a higher long-term persistence of an effective antibody titer.

CONCLUSION

The durability of an effective anti-HBs level appears to be significantly related to the height of the antibody titers after the primary immunization procedure. Schedules to improve the vaccination response in HIV-infected patients therefore seem to be justified. Whether a HBV booster is indicated remains to be elucidated.

Immune reconstitution and vaccination outcome in HIV-1 infected children: present knowledge and future directions

Current evidence on routine immunization of HIV-1 infected children point out the need for a special vaccine schedule in this population. However, optimal strategies for identifying individuals susceptible to infections, and then offering them sustained protection through appropriate immunization schedule, both in terms of timing and number of vaccine doses, still remain to be elucidated. Understanding the degree of immune recovery after HAART initiation is important in guiding administration of routine vaccination in HIV-1 infected children. Although quantitative measures (e.g., CD4+ T-cell counts and immunoglobulin levels) are frequently performed to evaluate immune parameters, these measures do not fully mirror functional immune recovery. Here, we will review the status of single mandatory and recommended vaccines for HIV-1 infected children in relation to immune recovery after HAART initiation with the aim of identifying new means to help design personalized vaccine schedules for this population.

Immunogenicity and safety of 1 vs 2 doses of quadrivalent meningococcal conjugate vaccine in youth infected with human immunodeficiency virus

OBJECTIVE

To compare the immunogenicity of 1 vs 2 doses of meningococcal polysaccharide conjugate vaccine (MCV4) in youth infected with human immunodeficiency virus (HIV).

STUDY DESIGN

P1065 was a phase I/II immunogenicity and safety trial of MCV4 in 324 youth infected with HIV performed at 27 sites of the International Maternal Pediatric Adolescent AIDS Clinical Trials Group network in the US. At entry subjects received 1 dose of MCV4. At 24 weeks, those with screening cluster of differentiation 4 (CD4)% ≥ 15 were randomized to receive a second dose or not, and all with screening CD4% <15 received a second dose. Immunogenicity was evaluated as the proportion of subjects with a ≥ 4-fold rise from entry in serum bactericidal antibody against each meningococcal serogroup (SG) at weeks 28 and 72. Logistic regression models adjusting for HIV disease severity were used to evaluate the effect of 1 vs 2 MCV4 doses among those with screening CD4% ≥ 15.

RESULTS

Subjects randomized to receive 2 vs 1 MCV4 dose had significantly higher response rates to all SGs at week 28 and to all except Neisseria meningitidis SG Y at week 72, with adjusted ORs of 2.5-5.6. In 31 subjects with screening CD4% <15 who received 2 MCV4 doses, response rates ranged from 22%-55% at week 28 and 6%-28% at week 72.

CONCLUSION

In youth infected with HIV with a CD4% ≥ 15, a second dose of MCV4 given 6 months after the initial dose significantly improves response rates at 28 and 72 weeks. Subjects with CD4% <15 at entry had lower response rates despite 2 doses of MCV4.

HIV and Hepatitis B coinfection among perinatally HIV-infected Thai adolescents

OBJECTIVES

This study aimed to determine the prevalence of hepatitis B virus (HBV) coinfection and HBV seropositivity in perinatally HIV-infected adolescents. A secondary objective was to describe the clinical characteristics of adolescents with chronic HBV/HIV coinfection.

MATERIALS AND METHODS

Multicenter cross-sectional study of perinatally HIV-infected adolescents aged 12-25 years. HBV surface antigen, surface antibody (anti-HBs) and core antibody (anti-HBc) were measured. Coinfection was defined as having persistently positive HBV surface antigen. Seroprotective antibody from immunization was defined as having anti-HBs ≥10 mIU/mL with negative anti-HBc. HBV DNA quantitation and rtM204V/I mutation analysis (lamivudine resistance-associated mutation) were performed in adolescents with chronic HBV infection.

RESULTS

From November 2010 to March 2011, 521 patients were enrolled. Mean (SD) of CD4 lymphocyte count was 685 (324) cells/μL. The prevalence of HBV/HIV coinfection was 3.3% (95% confidence interval: 1.9-5.2%). Protective antibody against HBV was found in 18% of population, and this was significantly higher among adolescents who received than those who did not receive HBV revaccination after receiving antiretroviral therapy (93% versus 6%, P < 0.01). Among adolescents with chronic HBV infection, 88% have received lamivudine; however, 69% have HBV DNA >10 copies/mL and 75% had the rtM204V/I mutation.

CONCLUSIONS

The prevalence of HBV coinfection in HIV-infected Thai adolescents was 3.3%. Most HIV-infected adolescents had no HBV protective antibody; therefore, revaccination with HBV vaccine is encouraged. The high prevalence of HBV-lamivudine resistance underscores the importance of HBV screening prior to antiretroviral therapy initiation to guide the selection of optimal regimen for coinfected children.

Immunogenicity, immunologic memory, and safety following measles revaccination in HIV-infected children receiving highly active antiretroviral therapy

BACKGROUND

Response rates and immunologic memory following measles vaccination are reduced in human immunodeficiency virus (HIV)-infected children in the absence of highly active antiretroviral therapy (HAART).

METHODS

HIV-infected children 2 to <19 years old receiving HAART and with HIV loads <30,000 copies/mL, CD4% ≥15, and ≥1 prior measles-mumps-rubella vaccination (MMR) were given another MMR. Measles antibody concentrations before and 8, 32, and 80 weeks postvaccination were determined by plaque reduction neutralization (PRN). A subset was given another MMR 4-5 years later, and PRN antibody was measured before and 7 and 28 days later.

RESULTS

At entry, 52% of 193 subjects were seroprotected (PRN ≥120 mIU/mL). Seroprotection increased to 89% 8 weeks postvaccination, and remained at 80% 80 weeks postvaccination. Of 65 subjects revaccinated 4-5 years later, 85% demonstrated memory based on seroprotection before or 7 days after vaccination. HIV load ≤400 copies/mL at initial study vaccination was associated with higher seroprotection rates, greater antibody concentrations, and memory. Grade 3 fever or fatigue occurred in 2% of subjects.

CONCLUSIONS

Measles revaccination induced high rates of seroprotection and memory in children receiving HAART. Both endpoints were associated with HIV viral load suppression.

CLINICAL TRIALS REGISTRATION

NCT00013871 (www.clinicaltrials.gov).

The recombinant hepatitis B surface antigen vaccine in persons with HIV: is seroconversion sufficient for long-term protection?

A cohort of human immunodeficiency virus (HIV)-infected individuals with documented vaccine-induced hepatitis B surface antibody (HBsAb) seroconversion was evaluated retrospectively to determine factors associated with loss of protective levels of HBsAb. After a median follow-up of 43 months, 111 of the 152 participants (73%) maintained protective levels of HBsAb. HIV RNA suppression at vaccination was associated with persistence of protective levels of HBsAb (odds ratio, 3.83; P < .01). Booster doses were provided for those with loss of protective antibody levels, and hepatitis B virus-specific immune memory, as evaluated with T-cell proliferation assays, was poor despite the observation that boosters successfully reinduced protective levels of HBsAb.

Immunization in special populations

In summary, immunizations in special populations require understanding the underlying disease and how it might affect the immune system's ability to mount an antibody response to vaccines or predispose certain patient populations to developing certain serious infections. There is still a great need for research on the optimal timing of vaccines after transplants, how to assess protection and development of a protective antibody response after immunization, and whether certain groups (eg, HIV) need to be revaccinated after a certain amount of time if their antibody levels decline. In addition, there are limited data on efficacy of the newer vaccines in these special patient populations, which also requires further investigation.

Vaccination in HIV-infected individuals

Vaccinations are key to limiting the increased risk of severe infectious diseases in HIV-infected patients for whom the risk–benefit ratio has been re-evaluated. Vaccine safety and immunogenicity depend on both vaccine type and immune deficiency, while vaccine-induced immune activation promotes a transient increase in viral load. Vaccine immunogenicity is reduced and wanes more rapidly, strengthening the need for revaccination. While inactivated vaccines are safe, attenuated vaccines are theoretically contraindicated, but the risk of infectious diseases outweighs the risks of severe adverse events in endemic areas, where the majority of HIV-infected individuals live, thus allowing their use when immune deficiency is moderate. Immune reconstitution with HAART has improved vaccine immune response, highlighting the importance of global access to and early initiation of therapy.

GM-CSF Fails to Improve Immune Responses to Booster Hepatitis B Vaccination in HIV-Infected Individuals

BACKGROUND

Hepatitis B (HBV) vaccination is an important preventive intervention for HIV-infected population. Data regarding booster HBV vaccine for persons with low HBV surface antibody (sAb) titers after vaccination in this immunocompromised population is lacking.

METHODS

We randomized 60 HIV-infected subjects lacking HBV protection after completion of 3 doses of HBV vaccine to receive a booster dose of HBV vaccine with 250mcg GM-CSF as an adjuvant or booster vaccine alone.

RESULTS

GM-CSF was safe with expected side effects. However, only 35% of persons receiving GM-CSF developed protective sAb while 50% in vaccine only arm developed protection (P = 0.47). Overall, only 28% of subjects maintained protective sAb 1 year after vaccination.

CONCLUSIONS

GM-CSF failed to improve responses to the booster HBV vaccination. Overall, response was poor with only 42% of persons responding at one month post-vaccination confirming booster vaccination with the current HBV vaccine has poor immunogenicity among HIV-infected persons. Further research is needed to develop optimal vaccination strategies in HIV-infected persons.

Impaired humoral response to vaccines among HIV-exposed uninfected infants

Little is known about the vaccine protective response for infants born from HIV-infected mothers. We evaluated the antibody response to hepatitis B, tetanus, and diphtheria vaccine in vertically HIV-exposed uninfected infants and compared them to those of control infants not exposed to the virus. The quantitative determination of specific neutralizing antibodies against hepatitis B, diphtheria, and tetanus were performed blindly on serum samples. The results showed that 6.7% of the HIV-exposed uninfected individuals were nonresponders to hepatitis B vaccine (anti-HBs titer, <10 mIU/ml), and 64.4% were very good responders (anti-HBs titer, ≥1,000 mIU/ml), whereas only 3.6% of the nonexposed infants were nonresponders (χ(2)=10.93; 1 df). The HIV-exposed uninfected infants showed protective titers for diphtheria and tetanus but lower geometric mean anti-tetanus titers compared to those of the HIV-unexposed infants. Our data point to the necessity of evaluating vaccine immune responses in these children and reinforced that alterations in lymphocyte numbers and functions reported for newborns from HIV-infected mothers interfere with the vaccine response.

Prevalence of protective level of hepatitis B antibody 3 years after revaccination in HIV-infected children on antiretroviral therapy

After responding to highly active antiretroviral therapy (HAART), HIV-infected children had a good response to hepatitis B immunization. However, there are limited data on the durability of antibody to hepatitis B surface antigen (anti-HBs) in these children. The primary objective of this study is to determine the prevalence of protective anti-HBs level 3 years after a 3-dose HBV revaccination among HIV-infected children with immune recovery (CD4 cell ≥ 15%) while on HAART. The secondary objective is to assess immunologic memory among children who had waning of anti-HBs. An anti-HBs level of ≥ 10 mIU/mL was defined as a protective antibody level. Sixty-nine HIV-infected children who had history of a 3-dose HBV revaccination while receiving HAART were enrolled. The mean (SD) of CD4 cell and duration of HAART at time of revaccination was 27.2% (6.7) and 5.9 years (0.4), respectively. The proportion of children with protective anti-HBs level 3 years after the revaccination was 71.0% [95% CI, 58.8-81.3]. The geometric mean titer was 114(SD 5)IU/mL. By multivariate logistic analysis, the predictors for protective anti-HBs level 3 years after revaccination were CD4 cell count ≥ 500 cells/mm³ at the time of vaccination (p = 0.04) and anti-HBs level ≥ 100 IU/mL at 1 month after completion of the 3-dose vaccination (p < 0.001). Anamnestic response after one booster dose was demonstrated among 14 of 17 children who had waning protective anti-HBs level (82.4% [95% CI, 62.2-102.6]). Our findings support the recommendation of giving a 3-dose HBV vaccination to HIV-infected children with immune recovery while receiving HAART.

Randomized study of intradermal compared to intramuscular hepatitis B vaccination in HIV-infected children without severe immunosuppression

HIV infected individuals have poorer response to hepatitis B vaccine (HBV) compared to normal host. Intradermal administration (i.d.) facilitates the exposure of antigen to antigen-presenting cells compared to intramuscular administration (i.m.). HIV-infected children aged 1-18 years with CD4%≥15% or 200 cells/mm(3) who had negative HBs Ag, antiHBs, and antiHBc were randomized to receive 3-dose of HBV via i.d. (2 μg/dose) or i.m. (10 μg/dose) route at months 0, 2, and 6. AntiHBs titers were measured at months 2, 6 and 7 after first HBV. AntiHBs≥10 mIU/mL was considered protective and AntiHBs>100 mIU/mL was considered good response. Participants included 41 in i.d. and 39 in i.m. arms. 64% had completed 3-doses HBV during infancy. The mean (SD) of age, nadir CD4% and current CD4% were 12 (3.3) years, 10.6 (7.9)% and 28 (8.0)% respectively. 91% were on HAART and 84% had undetectable HIV-RNA. Proportion of children with protective antiHBs in i.d. vs. i.m. group were 19.5% vs. 25.6% at month 2, 56.1% vs. 76.9% at month 6, and 90.2% vs. 92.3% at month 7 (NS, all). The geometric mean (95% confidence interval) of antiHBs titer in i.d. vs. i.m. group were 112.5 (34.4-367.6) vs. 141.2 (49.4-404.1) mIU/mL at month 2 (p=0.74), 70.4 (39.8-124.4) vs. 132.1 (79.4-219.8) mIU/mL at month 6 (p=0.10), and 157.0 (103.0-239.3) vs. 458.9 (324.0-647.0) mIU/mL at month 7 (p<0.001). However, only 56.1% of the i.d. arm had good response to HBV compared to 82.1% in the i.m. arm (p=0.01). The predictors for being a good responder to HBV were i.m. administration [OR 4.0, 95%CI 1.4-11.8, p=0.012] and body weight <35 kg at baseline [OR 3.8, 95%CI 1.3-10.8, p=0.013]. No adverse events grade 3/4 occurred. In conclusion, HIV-infected children without severe immune suppression, both i.d. and i.m. routes of HBV resulted in similar rates of protective antibody titers. However, high antibody titers to HBV were more common with i.m.; therefore, i.m. administration is preferred.