Persistence of vaccine immunity against hepatitis B virus and response to revaccination in vertically HIV-infected adolescents on HAART

Heterogeneity and Hierarchy of Immune Response to Primary Immunization in HIV-Infected Children on HAART and the Impact of an Additional Dose of Vaccine

The nature of vaccine response inferiority is not well studied in children living with HIV (CLHIV). The authors investigated Hepatitis B Virus (HBV) and Diphtheria/Pertussis/Tetanus toxoid (DPT) vaccination responses following primary immunization in CLHIV (n = 42) and healthy controls (HC) (n = 38) and the effect of an additional vaccine dose. Antibody responses, CD4 and HBV-specific T/B cells were analysed using CMIA/ELISA and flow-cytometry. CLHIV had significantly lower baseline median antibody titres for all vaccines than HC (p <0.02). Differential seroprotection rates observed in CLHIV were, 4.8% for pertussis; 9.5% for HBV; 26.2% for diphtheria and 66.7% for tetanus. WHO staging significantly influenced anti-HBs levels (p = 0.0095). HBsAg-specific CD4+T-cells were significantly higher in CLHIV than HC (p = 0.042). An additional vaccine dose (HBV and Tdap) conferred a higher protection rate for tetanus and diphtheria (p <0.040) in CLHIV. These findings suggest that CLHIV exhibit a hierarchy of vaccine responses affecting antibody levels and protection rate, which was rescued by administering additional vaccine dose.

Lower frequency of T stem cell memory (TSCM) cells in hepatitis B vaccine nonresponders

Despite the availability of an effective vaccine and antiviral treatments, hepatitis B is still a global public health problem. Hepatitis B vaccination can prevent the disease. Vaccination induces long-lasting protective immune memory, and the identification of memory cell subsets can indicate the effectiveness of vaccines. Here, we compared the frequency of CD4⁺ memory T cell subsets between responders and nonresponders to HB vaccination. Besides, the frequency of IFN-γ⁺ memory T cells was compared between studied groups. Study participants were grouped according to their anti-HBsAb titer. For restimulation of CD4⁺ memory T cells, peripheral blood mononuclear cells (PBMCs) were cultured in the presence of HBsAg and PHA for 48 h. Besides, PMA, ionomycin, and brefeldin were added during the last 5 h of incubation to induce IFN-γ production. Flow cytometry was used for analysis. There was a statistically significant difference in the frequency of CD4⁺CD95⁺, CD4⁺CD95^Hi, and CD4⁺CD95^low/med T stem cell memory (T_SCM) cells between responder and nonresponder groups. However, the comparison of the frequency of memory T cells producing IFN-γ showed no differences. Our results identified a possible defect of immunological CD4⁺ memory T cell formation in nonresponders due to their lower frequency of CD4⁺ T_SCM cells.

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.

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.

Long-term protection after hepatitis B vaccination in people living with HIV

BACKGROUND

Hepatitis B vaccine is important in people living with HIV (PLHIV) since both viruses have the same transmission routes and co-infection has greater morbidity. PLHIV usually have poor response to hepatitis B vaccine. The duration of immunity in PLHIV is unknown. The objective of this study is to evaluate the duration of serological response and clinical protection provided by hepatitis B vaccination in PLHIV.

METHODS

Retrospective study of a PLHIV cohort primarily vaccinated for hepatitis B virus (HBV) from 2001 to 2002. Markers of infection and protection from HBV were investigated in those individuals who were still attending the outpatient clinic, in São Paulo, Brazil from 2012 to 2014. Three groups were analyzed. Group 1: adults who responded to primary vaccine series. Group 2: non-responders to primary vaccine series. Group 3: subjects from both Groups 1 and 2 who did not receive any booster doses after seroconversion.

RESULTS

A cohort of 121 PLHIV was analyzed for seroconversion and persistence of anti-HBs. The majority were female (54.5%) and mean age was 50.1years. After 11years, none of the patients had serologic evidence of HBV infection. Overall, 41/58 (70.7%) of the initial responders (Group 1) had maintained anti-HBs≥10mIU/mL. Greater CD4+ values and anti-HBs>100mIU/mL at the time of first vaccine series were associated with persistence of anti-HBs. During the time of evaluation, 35/63 (55.6%) of the initial non-responders (Group 2) successfully seroconverted (anti-HBs≥10mIU/mL) in response to one or more booster doses. From the time of their seroconversion, 70 of the patients did not receive any further booster doses (Group 3). After 10years, 54/70 (77.1%) of these individuals has maintained anti-HBs≥10mIU/mL.

CONCLUSIONS

Evaluation of long-term immunity for hepatitis B in PLHIV following vaccination showed a strong persistence of anti-HBs and no serologic evidence of HBV infection. Boosters may be effective in PLHIV non-responders to primary vaccination.

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.

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.

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.

Hepatitis B vaccine antibody response and the risk of clinical AIDS or death

BACKGROUND

Whether seroresponse to a vaccine such as hepatitis B virus (HBV) vaccine can provide a measure of the functional immune status of HIV-infected persons is unknown.This study evaluated the relationship between HBV vaccine seroresponses and progression to clinical AIDS or death.

METHODS AND FINDINGS

From a large HIV cohort, we evaluated those who received HBV vaccine only after HIV diagnosis and had anti-HBs determination 1-12 months after the last vaccine dose. Non-response and positive response were defined as anti-HBs <10 and ≥ 10 IU/L, respectively. Participants were followed from date of last vaccination to clinical AIDS, death, or last visit. Univariate and multivariable risk of progression to clinical AIDS or death were evaluated with Cox regression models. A total of 795 participants vaccinated from 1986-2010 were included, of which 41% were responders. During 3,872 person-years of observation, 122 AIDS or death events occurred (53% after 1995). Twenty-two percent of non-responders experienced clinical AIDS or death compared with 5% of responders (p<0.001). Non-response to HBV vaccine was associated with a greater than 2-fold increased risk of clinical AIDS or death (HR 2.47; 95% CI, 1.38-4.43) compared with a positive response, after adjusting for CD4 count, HIV viral load, HAART use, and delayed type hypersensitivity skin test responses (an in vivo marker of cell-mediated immunity). This association remained evident among those with CD4 count ≥ 500 cells/mm³ (HR 3.40; 95% CI, 1.39-8.32).

CONCLUSIONS

HBV vaccine responses may have utility in assessing functional immune status and risk stratificating HIV-infected individuals, including those with CD4 count ≥ 500 cells/mm³.

Hepatitis B immunity and response to booster vaccination in children with inflammatory bowel disease treated with infliximab

OBJECTIVES

Hepatitis B virus (HBV) reactivation has been described in patients treated with infliximab for inflammatory bowel disease (IBD). This has resulted in a "black box" warning. Although universal vaccination against hepatitis B was implemented in the United States in 1991, up to 10% of vaccine recipients fail to respond with adequate anti-hepatitis B surface antibodies (anti-HBs) levels after a primary series of vaccinations. In addition, anti-HBs levels are expected to decline with time. The objectives of this study were to determine HBV immunity in children with IBD on infliximab therapy and to determine response to a booster dose of the HBV vaccine in patients who were found to be non-immune.

METHODS

This was a prospective cross-sectional, single-center study that included 100 pediatric IBD patients on infliximab. Serologic specimens were tested for hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), and anti-HBs. Patients with an anti-HBs level ≥10 mIU/ml were considered to be immune. One booster dose was given to non-immune patients and a serum sample was collected after 4 weeks to assess the presence of anamnestic response (anti-HBs level ≥10 mIU/ml after booster).

RESULTS

The mean age of the patients was 17.9 (±4.0) years. None of the patients were positive for HBsAg or anti-HBc. In all, 87 patients were vaccinated against HBV and 49/87 (56%) had immunity to HBV as defined by anti-HBs level ≥10 mIU/ml. The mean concentration of anti-HBs levels in immune patients was 295.6 (±350.6) mIU/ml. Older age, lower albumin levels, and the presence of pancolitis were associated with the absence of protective antibodies; however, infliximab dose, frequency, duration, and the concurrent use of immunomodulators were not significantly different between immune and non-immune patients. Thirty-four patients received booster immunization and 26/34 (76%) had an anamnestic response. Interestingly, non-responders were given infliximab with higher frequency (every 5.9 ± 1.2 weeks vs. every 7.1 ± 1.8 weeks, P=0.01). Overall, 75/87 (86%) of previously immunized patients were considered immune against HBV infection.

CONCLUSIONS

In pediatric IBD patients seen at a large, urban tertiary care facility in the United States, a significant minority (13%) have not been vaccinated against HBV. Nearly one-half of all patients (and 44% of previously vaccinated patients) did not have protective anti-HBs levels. Moreover, of those previously vaccinated, a significant minority (14%) appear at risk for HBV because protective anti-HBs levels were absent and could not be elicited through booster immunization. Given the high risk for severe HBV infection in this group, efforts should be made to screen for HBV immunity at the time of IBD diagnosis. Booster immunization should be considered in patients without protective antibodies.

Interaction between pediatric HIV infection and measles

Infections by measles virus and by HIV cause a state of immunodeficiency in the host. While measles virus leads to a transient immunodeficiency with depression of cellular mediated immunity, natural HIV infection leads to a progressive immunodeficiency of both humoral and cellular immunity. This review will focus on the interaction between HIV and measles virus in pediatric patients. Different scenarios of virus interaction will be dissected and their implications for a practical approach in terms of the individual patient and strategies to eliminate measles virus will be discussed.

Short communication: immunogenicity of an inactivated influenza vaccine and postvaccination influenza surveillance in HIV-infected and noninfected children and adolescents

Individuals infected with HIV are at higher risk for severe cases of seasonal influenza infection and should receive annual doses of vaccine. Our objectives were to evaluate the immunogenicity of an influenza vaccine in 37 HIV-infected patients (HIV group) compared to 29 uninfected individuals (control group) and to carry out a clinical and virological surveillance of influenza during a 6-month follow-up. Both groups received the vaccine recommended for the southern hemisphere in 2008. Antibody responses to antigens H1N1, H3N2, and B were measured in blood samples at vaccination (T0) and after 1 month (T1). Influenza surveillance was performed by weekly telephone calls for a follow-up period of 6 months. Nasal washes were taken from subjects with respiratory symptoms. The direct immunofluorescence assay in house polymerase chain reaction (PCR) and real-time PCR were used for the detection of different respiratory viruses. The median age of the participants was 13.3 years (sd = 2.2) and 12.1 years (sd = 1.3) for the HIV group and control group, respectively. One month after vaccination (T1), both groups showed significant increases in the antibody geometric mean titers (GMTs) for all antigens. However, healthy controls showed higher values for antigens A/H1N1 and A/H3N2 (p = 0.002 and 0.001, respectively). There was a higher increase in the percentage of HIV-uninfected subjects with protective A/H1N1 antibodies (96.6%) compared to HIV-infected vaccinees (67.6%) at T1 (p = 0.004). Rhinovirus (27.7%) and coronavirus (22.5%) were the most prevalent agents identified in HIV-infected individuals. In the control group, the viruses most frequently found were rhinovirus (24.2%) and adenovirus (21.2%). The seroprotection rate for the H1N1 antigen was higher in the control group, which also showed a greater increase in GMTs for H1N1 and H3N2 antigens after immunization. Viral agents were identified in 39/60 (65%) episodes of respiratory infections from the HIV-infected group and in 17/32 episodes (53.1%) from the control group (p = 0.273).

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.