Vaccination In HIV-infected Individuals Research Articles

Effectiveness of COVID-19 primary and booster vaccination in HIV-infected individuals

Effectiveness of COVID-19 primary and booster vaccination in HIV-infected individuals

Impact on HIV-1 RNA Levels and Antibody Responses Following SARS-CoV-2 Vaccination in HIV-Infected Individuals.

This study aims to assess the immunological response and impact on virological control of the mRNA vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among people living with HIV (PLWH). In this single-center observational study, all PLWH were offered vaccination with mRNA1273 or BNT162b2. Both anti-N and anti-S1-receptor binding domain (RBD) antibodies were measured together with HIV-1 RNA levels after the first dose (M0) and then at 1 (M1), 2 (M2) and 6 (M6) months later. A total of 131 individuals (median age: 54 years [IQR: 47.0-60.5]; male: 70.2%; median baseline CD4 T-cell: 602/µl [IQR 445.0-825.5]; median nadir CD4 T-cells 223/µl [IQR 111.0-330.0]) were included. All participants were positive for anti-RBD antibodies at 30 days, 60 days and 6 months after the first dose, with no statistical difference between those with HIV-1 RNA below or >20 copies/ml. HIV-1 RNA data were collected for 128 patients at baseline and 30 days after the first dose; for 124 individuals, 30 days after the second dose; and for 83 patients, 6 months after the first dose. Nineteen (14.8%) of 128 had detectable HIV-1 RNA (>20 copies/ml) at M0, 13/128 (10.2%) at M1 (among which 5 were newly detectable), 15/124 (12.1%) at M2 (among which 5 were newly detectable), and 8/83 (9.6%) at M6. No serious adverse effects were reported. All participants elicited antibodies after two doses of mRNA vaccines, with only a minor impact on HIV-1 RNA levels over a 6-month period.

The Results of Clinical Trials of Recombinant Vaccine Virus, MVA Strain, Expressing Genes of Human Immunodeficiency Virus

Although successes in antiretroviral therapy (ART) turned AIDS from lethal illness into sluggishly progressing disease, its prevention and treatment remain one of the most socially significant concerns. The increase in the number of patients infected with human immunodeficiency virus (HIV), especially in the USA, South America and Europe, determines the need in creating a vaccine against this disease. Existing vaccination practice has demonstrated efficiency of priming/boosting scheme for the development of immune responses. As anti-vector immunity of priming vector can constrain the response to boosting immunization with the same vaccine, heterologous priming/boosting vector constructs are used. An ideal AIDS vaccine would prevent virus dissemination and control viral replication, but it also must be safe for HIV-infected contingent. The vaccination of HIV-infected individuals is used for enhancing immune-mediated elimination of persistently HIV-infected CD4+ Т-cells during long-term ART in order to purge the latently infected viral reservoirs. The paper considers the results of clinical trials of DNA-anti-HIV/AIDS vaccines and recombinant MVA strain of vaccinia virus, expressing different combination of HIV genes, which demonstrated the safety and tolerability both, in HIV-infected and non-HIV-infected volunteers. All implemented schedules of vaccination induced cell-mediated and humoral immune responses in all volunteers. And though there are no data on acquiring AIDS by HIV-uninfected volunteers from groups at low risk of HIV-infection, there are no grounds to conclude the sufficiency of induced protection for the prevention of possible HIV infection.

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

BackgroundThe 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).MethodsThe 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.FindingsOur 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.InterpretationWe 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.FundingHMGG is funded by a public research grant of ZonMw (project number 522004005).

Analysis of protective immune responses to seasonal influenza vaccination in HIV-infected individuals

ABSTRACT Owing to their increased susceptibility to influenza infection, HIV+ individuals are recommended to receive annual influenza vaccination. However, influenza vaccination induced production of anti-influenza neutralization antibodies (Nab) is successful only in some viral-suppressed antiretroviral therapy (ART) treated HIV+ subjects. Additionally, the mechanism of antibody response induced by influenza vaccine in antiretroviral-treated HIV+ subjects is unclear. In this study, we conducted a cohort study which contains 40 HIV+ ART-treated individuals to whom one dose of seasonal influenza vaccine was administered. Blood samples were collected on day 0, 7, 14, and 28 post-vaccination, and serologic responses were characterized by ELISA and micro-neutralization to measure the total antibodies and Nab against influenza vaccines. Transcriptional profiling of peripheral blood mononuclear cells (PBMCs) and immunological assays was measured. Increased levels of proliferation of CD4+T cells and B cells with their corresponding subtypes were observed in HIV-infected subjects at day 7 (D7) following vaccination compared to pre-vaccination. Moreover, proliferation of CD4+T cells and B cells (D7) was correlated with influenza-specific H1N1 Nab at day 28 (D28). Our study could also demonstrate that apoptosis of CD4+T cells and B cells (D7) were inversely correlated with influenza-specific H1N1 Nab. Based on the Nab response after vaccination to each influenza subtypes (D28), HIV+ subjects were stratified as influenza vaccine responders and influenza vaccine non-responders (“responders” ≥ 4-fold increase from day 0; “non-responders” < 4-fold increase from day 0). A selected list of biological pathways (H1N1and H3N2: olfactory transduction, B: phagosome) enriched with transcripts were significantly altered in (ART) treated HIV+ subjects among Nab production responders. This study demonstrated a more detailed mechanism of immune regulation on influenza induced antibody response and revealed some knowledge regarding bioinformatics of vaccine responders and non-responder in influenza induced antibody production in ART-treated HIV patients.

Race-related differences in functional antibody response to pneumococcal vaccination in HIV-infected individuals

BackgroundBoth HIV positivity and African American (AA) ethnicity are associated with increased incidence of invasive pneumococcal disease (IPD). Poor immune response to pneumococcal polysaccharide-based vaccines may contribute to the race related increased frequency of IPD in African American HIV positive individuals. MethodsCaucasian and AA HIV-infected (HIV+) individuals 40–65 years old with CD4+ T cells/µl (CD4) >200 on antiretroviral therapy (ART) received either the 13-valent pneumococcal conjugate vaccine (PCV) followed by the 23-valent pneumococcal polysaccharide vaccine (PPV) or PPV only. Serum IgG, IgM and opsonophagocytic antibody responses to serotypes 14 and 23F as well as serum IgG and opsonophagocytic antibody responses to serotype 19A were measured pre- and post-vaccination. We measured serum markers of inflammation in all participants and performed single cell gene expression profiling at the baseline by HD Biomark in Caucasians and African Americans. ResultsThere were no significant differences in pre-immunization inflammatory markers or post-vaccination IgG and IgM concentrations between Caucasian and African American participants. However, we found significantly lower opsonophagocytic activity in response to serotypes 14 and 19A in the AA group compared to the Caucasian group. There was no association between inflammatory markers and immune response to vaccination, however we found extensive biomodal variation in gene expression levels in single IgM+ memory B cells. Differentially expressed genes may be related to differences in the immune response between ethnic groups. ConclusionsDistinct racial differences were found in the functional immune response following either PPV and/or PCV/PPV immunization in HIV-positive adults, although these differences were serotype dependent. Decreased ability to respond to vaccination may in part explain racial disparities in pneumococcal disease epidemiology.ClinicalTrials.gov ID: NCT03039491.

Human Papillomavirus Correlates With Histologic Anal High-Grade Squamous Intraepithelial Lesions in Hispanics With HIV.

To estimate the magnitude of association between anal infection with high-risk human papilloma virus (HR-HPV) types and severity of biopsy-confirmed histopathological anal squamous intraepithelial lesions (SILs) among a clinic-based sample of HIV-infected adults in Puerto Rico. This cross-sectional study analyzed data from medical records of adult patients who visited a specialized anal neoplasia clinic from June 2015 to December 2017 (n = 239); sociodemographics, behavioral risk factors, medical history, clinical data, and pathology reports were collected. The magnitude of association between anal HR-HPV and severity of anal SIL, adjusted for potential confounders, was assessed using a multinomial logistic model. A 78.7% of patients had anal HR-HPV infection, 43.9% had histopathological low-grade SIL (LSIL), and 37.7% had histopathological high-grade SIL (HSIL). The prevalence of anal HR-HPV infection was 63.6% among patients with no anal SIL, 70.5% for those with LSIL and 95.6% for those with HSIL. After adjusting for different predictors, patients with anal HR-HPV infection were more likely to have HSIL (odds ratio, 11.0; 95% confidence interval, 3.2-37.2) than those without anal HR-HPV infection, whereas no significant excess was observed for LSIL (odds ratio, 1.4; 95% confidence interval, 0.6-3.1). This study showed a strong association between anal HR-HPV infection and HSIL. Likewise, a high prevalence of anal HR-HPV infection and presence of anal SIL was observed among HIV-infected individuals. Our result highlights the importance of screening for anal HR-HPV infection and anal SIL and optimizing strategies for HPV vaccination in HIV-infected individuals.

A randomized controlled safety/efficacy trial of therapeutic vaccination in HIV-infected individuals who initiated antiretroviral therapy early in infection.

Despite substantial clinical benefits, complete eradication of HIV has not been possible using antiretroviral therapy (ART) alone. Strategies that can either eliminate persistent viral reservoirs or boost host immunity to prevent rebound of virus from these reservoirs after discontinuation of ART are needed; one possibility is therapeutic vaccination. We report the results of a randomized, placebo-controlled trial of a therapeutic vaccine regimen in patients in whom ART was initiated during the early stage of HIV infection and whose immune system was anticipated to be relatively intact. The objectives of our study were to determine whether the vaccine was safe and could induce an immune response that would maintain suppression of plasma viremia after discontinuation of ART. Vaccinations were well tolerated with no serious adverse events but produced only modest augmentation of existing HIV-specific CD4+ T cell responses, with little augmentation of CD8+ T cell responses. Compared with placebo, the vaccination regimen had no significant effect on the kinetics or magnitude of viral rebound after interruption of ART and no impact on the size of the HIV reservoir in the CD4+ T cell compartment. Notably, 26% of subjects in the placebo arm exhibited sustained suppression of viremia (<400 copies/ml) after treatment interruption, a rate of spontaneous suppression higher than previously reported. Our findings regarding the degree and kinetics of plasma viral rebound after ART interruption have potentially important implications for the design of future trials testing interventions aimed at achieving ART-free control of HIV infection.

Low expression of activation marker CD69 and chemokine receptors CCR5 and CXCR3 on memory T cells after 2009 H1N1 influenza A antigen stimulation in vitro following H1N1 vaccination of HIV-infected individuals

Unlike well-studied antibody responses to pandemic 2009 H1N1 influenza A virus vaccines in human immunodeficiency virus-infected (HIV+) individuals, less well understood are cell-mediated immune (CMI) responses to this antigen in this susceptible population. We investigated such influenza-specific CMI responses in 61 HIV+ individuals and in 20 HIV-negative (HIV-) healthy controls. Each was vaccinated with a single licensed dose of inactivated, split-virion vaccine comprised of the influenza A/California/7/2009 (H1N1) virus-like strain. Cells collected just prior to vaccination and at 1 and 3 months afterwards were stimulated in vitro with dialyzed vaccine antigen and assayed by flow cytometry for cytokines TNF-α, IFN-γ, IL-2, and IL-10, for degranulation marker CD107a, as well as phenotypes of memory T-cell subpopulations. Comparable increases of cytokine-producing and CD107a-expressing T cells were observed in both HIV+ subjects and healthy HIV-controls. However, by 3 months post-vaccination, in vitro antigen stimulation of peripheral blood mononuclear cells induced greater expansion in controls of both CD4 and CD8 central memory and effector memory T cells, as well as higher expression of the activation marker CD69 and chemokine receptors CCR5 and CXCR3 than in HIV+ subjects. We concluded CD4+ and CD8+ memory T cells produce cytokines at comparable levels in both groups, whereas the expression after in vitro stimulation of molecules critical for cell migration to infection sites are lower in the HIV+ than in comparable controls. Further immunization strategies against influenza are needed to improve the CMI responses in people living with HIV.

P0588 : Immune response to hepatitis B vaccination in HIV infected individuals with isolated antibodies to HBV core antigen

P0588 : Immune response to hepatitis B vaccination in HIV infected individuals with isolated antibodies to HBV core antigen

Immunogenicity of the Bivalent Oral Cholera Vaccine Shanchol in Haitian Adults With HIV Infection.

We evaluated immune responses following bivalent oral cholera vaccination (Shanchol [Shantha Biotechnics]; BivWC) in a cohort of 25 human immunodeficiency virus (HIV)-infected adults in Haiti. Compared with adults without HIV infection, vaccination in HIV-infected individuals resulted in lower vibriocidal responses against Vibrio cholerae O1, and there was a positive relationship between the CD4(+) T-cell count and vibriocidal responses following vaccination. Nevertheless, seroconversion occurred at a rate of 65% against the Ogawa serotype and 74% against the Inaba serotype in adults with HIV infection. These results suggest that the vaccine retains substantial immunogenicity in adults with HIV infection and may benefit this population by protecting against cholera.

Influenza vaccination in HIV-infected individuals: Systematic review and assessment of quality of evidence related to vaccine efficacy, effectiveness and safety

BackgroundInfluenza infection in HIV-infected individuals is associated with increased severity of illness. We performed a systematic review of the available evidence on efficacy, effectiveness and safety of seasonal influenza vaccination in HIV-infected individuals. DesignSystematic review, meta-analysis and assessment of evidence quality. MethodsUsing a previous systematic review as starting point, we searched MEDLINE, EMBASE and Cochrane data base for studies on efficacy, effectiveness or safety of trivalent inactivated influenza vaccines (TIV) in HIV-infected individuals. Evidence quality was assessed for each outcome using the GRADE methodology. ResultsThree randomized-controlled trials and three cohort studies were identified, including a total of 1562 HIV-infected individuals. In adults, TIV prevented laboratory-confirmed influenza with a pooled efficacy of 85% (95% CI, 22–97%) (evidence quality: moderate), but no significant effects on other clinical outcomes were observed (evidence quality: moderate to low). One cohort study showed an effectiveness of 71% (95% CI, 44–85%) for prevention of laboratory-confirmed influenza, whereas no effect on influenza-like illness was found. However, risk of bias was high in all observational studies. In children aged 6–59 months, efficacy of TIV in preventing laboratory-confirmed influenza was 11% (95% CI, −30 to 54%) (evidence quality: moderate). Regarding other endpoints, no statistically significant effects were reported (evidence quality: moderate to low). No severe adverse events following influenza vaccination were observed in these studies. ConclusionThis systematic review indicates that TIV is effective in preventing influenza infection in HIV-infected adults but not in young children. For both age-groups, only limited evidence exists for other outcomes, indicating a need for further studies.

Non-Immunogenicity of Overlapping Gag Peptides Pulsed on Autologous Cells after Vaccination of HIV Infected Individuals

BackgroundHIV Gag-specific CD4+ and CD8+ T-cell responses are important for HIV immune control. Pulsing overlapping Gag peptides on autologous lymphocytes (OPAL) has proven immunogenic and effective in reducing viral loads in multiple pigtail macaque studies, warranting clinical evaluation.MethodologyWe performed a phase I, single centre, placebo-controlled, double-blinded and dose-escalating study to evaluate the safety and preliminary immunogenicity of a novel therapeutic vaccine approach ‘OPAL-HIV-Gag(c)’. This vaccine is comprised of 120 15mer peptides, overlapping by 11 amino acids, spanning the HIV Gag C clade sequence proteome, pulsed on white blood cells enriched from whole blood using a closed system, followed by intravenous reinfusion. Patients with undetectable HIV viral loads (<50 copies/ml plasma) on HAART received four administrations at week 0, 4, 8 and 12, and were followed up for 12 weeks post-treatment. Twenty-three people were enrolled in four groups: 12 mg (n = 6), 24 mg (n = 7), 48 mg (n = 2) or matching placebo (n = 8) with 18 immunologically evaluable. T-cell immunogenicity was assessed by IFNγ ELIspot and intracellular cytokine staining (ICS).ResultsThe OPAL-HIV-Gag(c) peptides were antigenic in vitro in 17/17 subjects. After vaccination with OPAL-HIV-Gag(c), 1/6 subjects at 12 mg and 1/6 subjects at 24 mg dose groups had a 2- and 3-fold increase in ELIspot magnitudes from baseline, respectively, of Gag-specific CD8+ T-cells at week 14, compared to 0/6 subjects in the placebo group. No Gag-specific CD4+ T-cell responses or overall change in Rev, Nef, Tat and CMV specific responses were detected. Marked, transient and self-limiting lymphopenia was observed immediately post-vaccination (4 hours) in OPAL-HIV-Gag(c) but not in placebo recipients, with median fall from 1.72 to 0.67 million lymphocytes/mL for active groups (P<0.001), compared to post-placebo from 1.70 to 1.56 lymphocytes/ml (P = 0.16).Conclusion/SignificanceDespite strong immunogenicity observed in several Macaca nemestrina studies using this approach, OPAL-HIV-Gag(c) was not significantly immunogenic in humans and improved methods of generating high-frequency Gag-specific T-cell responses are required.Name of RegistryClinicalTrials.gov, Registry number: NCT01123915, URL trial registry database: http://www.clinicaltrials.gov/ct2/results?term=OPAL-HIV-1001&Search=Search

Antigen-specific B cells responding to pneumococcal polysaccharide vaccination in newly diagnosed HIV infected individuals. (P4264)

Abstract The peripheral blood of newly diagnosed HIV infected individuals is subjected to high uncontrolled viral titers. The decimation of both T and B cells thus leaves these individuals highly susceptible to opportunistic infections, including Streptococcus pneumoniae, despite the availability of vaccines. We have previously shown using directly labeled fluorescent pneumococcal polysaccharides that the majority of pneumococcal polysaccharide-specific B cells in healthy individuals were IgM+ memory B cells. Using this method, we identified specific deficiencies in B cell populations responding to pneumococcal polysaccharide vaccination in HIV infected individuals. Namely, a significant decrease in pneumococcal polysaccharide-specific IgM+ memory B cells compared to healthy individuals. Consequently, HIV infected individuals showed reduced antibody response and opsonophagocytic titers compared to healthy individuals. Furthermore, we correlated changes in pneumococcal polysaccharide-specific B cell populations post-vaccination with individual CD4 T cell counts. We observed a decreasing trend in pneumococcal polysaccharide-specific IgM+ memory B cells with lower CD4 T cell counts. These data indicate that the loss of pneumococcal polysaccharide-specific IgM+ memory B cells in HIV infected individuals correlates with CD4 counts and results in poor responsiveness to pneumococcal vaccination.

Immune response after vaccination of HIV infected individuals receiving HAART with overlapping gag peptides pulsed on autologous cells

Methods We performed a phase I, single centre, placebo-controlled, double-blinded and dose-escalating study to evaluate the safety and preliminary immunogenicity of a novel vaccine approach Opal-HIV-Gag(c). This vaccine is constituted by 120 15mer peptides, overlapping by 11 amino acids spanning the entire HIV Gag C Durban consensus sequence proteome, pulsed on white blood cells enriched from whole blood using a closed system, followed by intravenously reinfusion. Patients with well controlled HIV on HAART received four vaccinations administered at week 0, 4, 8 and 12, and were followed up for 12 weeks posttreatment. Eighteen people were enrolled in three groups: 12mg (n=6), 24mg (n=6) or matching placebo (n=6). An additional group (48mg, n=2) was not evaluable. Immunogenicity was assessed by IFNg ELIspot/ICS.

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.

Vaccination of HIV-Infected Adults

Vaccination has been shown to be one of the most powerful tools to decrease morbidity and mortality caused by an array of infectious diseases. The risk and complications of some vaccine-preventable diseases is higher in HIV-infected individuals, underscoring the importance of vaccination in these patients. However, the immune response upon vaccination is generally impaired and shorter lasting in HIV-infected individuals, especially in those with low CD4+ T-lymphocyte counts and detectable HIV RNA, as compared with healthy controls. Even in patients responding to antiretroviral treatment, an impaired immune response may persist despite normalization of the CD4+-cell count. Caution with live-attenuated vaccines is warranted in HIV-infected individuals with low CD4 T-lymphocyte counts. Decisions regarding administering a live-attenuated vaccine should be made after weighing the risks and benefits on an individual basis. In this article the immunology of vaccination in HIV-infected individuals, as well as the most relevant caveats of vaccination in this patient group, are reviewed in addition to the currently available information concerning the influenza A/H1N1 2009 monovalent vaccine.

Optimal timing of routine vaccination in HIV-infected persons

Vaccine recommendations for those with HIV require continual updating as additional research becomes available. Timing of vaccinations among HIV-infected individuals is a key area of uncertainty. This is particularly true for those who may soon initiate highly active antiretroviral therapy (HAART) because immune reconstitution due to HAART often improves responses to vaccines. However, risks of delaying vaccination include that the patient may be exposed to the pathogen or lost to follow-up before vaccination. We review recent studies on the timing of routine vaccination of HIV-infected individuals.

Antibody response after influenza vaccination in HIV-infected individuals: a consecutive 3-year study

In a consecutive 3-year study the antibody response after immunization with influenza vaccine of a cohort of HIV-infected adults was studied. The haemagglutination-inhibiting (HAI) antibody titres after vaccination correlated with the number of CD4+ T lymphocytes (p<0.001), the prevaccination antibody titres (p<0.001), and the proliferative response to anti-CD3 (p<0.001). Severely impaired antibody responses were observed in HIV-infected individuals with CD4+ T-lymphocyte counts ≤100×106/l. Significantly higher prevaccination antibody titres were observed in healthy controls in the 2nd or 3rd year of vaccination, but not in HIV-infected individuals. Annually repeated vaccination of HIV-infected individuals did not lead to higher postvaccination antibody titres. Annual vaccination of HIV-infected individuals with CD4+ T-lymphocyte counts exceeding 100×106/l seems to be worthwhile, although it may not be expected to render the same level of protection against influenza as in non-infected individuals.