Humoral immune responses to COVID-19 vaccination in people living with HIV receiving suppressive antiretroviral therapy

Immune Responses against the Omicron Variant of SARS-CoV-2 after a Third Dose of COVID-19 Vaccine in Patients Living with Human Immunodeficiency Virus (PLWH): Comparison with Healthcare Workers

We compared immune responses against the omicron variant of SARS-CoV-2 after a third dose of the coronavirus disease 2019 (COVID-19) vaccine between people living with human immunodeficiency (PLWH) and healthcare workers (HCWs). In this prospective observational study, PLWH and HCWs vaccinated with at least two doses of vaccine were enrolled. We analyzed neutralizing responses using the GenScript SARS-CoV-2 surrogate virus neutralization test kit. Twenty-nine PLWH and 114 HCWs were included to analyze immune responses after the third vaccination. Most PLWH (86.2%) had fully suppressed viral loads and CD4 T cell counts were well-controlled (median 670.0 cells/μL). The neutralizing responses against the omicron variant in PLWH were not significantly different from those in HCWs (43.94% vs. 51.77%, p = 0.42). However, neutralizing responses against the omicron variant were significantly impaired by about 50% compared with wild type SARS-CoV-2 in PLWH (43.94% vs. 97.46%, p < 0.001) and HCWs (51.77% vs. 97.74%, p < 0.001). Although neutralizing responses against the omicron variant in well-controlled PLWH were comparable to those of HCWs, the responses were much lower than those against wild type in both PLWH and HCWs. Therefore, the risk of breakthrough SARS-CoV-2 infection due to the currently circulating omicron variant is still high despite three doses of vaccine in PLWH and will not differ from HCWs.

Evolution of anti-SARS-CoV-2 spike protein titers after two-dose of COVID-19 vaccination among people living with HIV

Background

A community COVID-19 outbreak caused by the B.1.1.7 SARS-CoV-2 variant occurred in Taiwan in May 2021. High-risk populations such as people living with HIV (PLWH) were recommended to receive two doses of COVID-19 vaccines. While SARS-CoV-2 vaccines have demonstrated promising results in general population, real-world information on the serological responses remains limited among PLWH.

Methods

PLWH receiving the first dose of SARS-CoV-2 vaccine from 2020 to 2021 were enrolled. Determinations of anti-SARS-CoV-2 spike IgG titers were performed every one to three months, the third dose of the SARS-CoV-2 vaccine or confirmed SARS-CoV-2 infection. All serum samples were tested for anti-nucleocapsid antibody and those tested positive were excluded from analysis.

Results

A total of 1189 PLWH were enrolled: 829 (69.7%) receiving two doses of the AZD1222 vaccine, 232 (19.5%) of the mRNA-1273 vaccine, and 128 (10.8%) of the BNT162b2 vaccine. At all time-points, PLWH receiving two doses of mRNA vaccines had consistently higher antibody levels than those receiving the AZD1222 vaccine (p <0.001 for all time-point comparisons). Factors associated with failure to achieve an anti-spike IgG titer >141 BAU/mL within 12 weeks, included type 2 diabetes mellitus (DM) (adjusted odds ratio [aOR], 2.24; 95% CI, 1.25-4), a CD4 T cell count <200 cells/mm³ upon receipt of the first dose of vaccination (aOR, 3.43; 95% CI, 1.31-9) and two homologous AZD1222 vaccinations (aOR, 16.85; 95%CI, 10.13-28). For those receiving two doses of mRNA vaccines, factors associated with failure to achieve an anti-spike IgG titer >899 BAU/mL within 12 weeks were a CD4 T cell count <200 cells/mm³ on first-dose vaccination (aOR, 3.95; 95% CI, 1.08-14.42) and dual BNT162b2 vaccination (aOR, 4.21; 95% CI, 2.57-6.89).

Conclusions

Two doses of homologous mRNA vaccination achieved significantly higher serological responses than vaccination with AZD1222 among PLWH. Those with CD4 T cell counts <200 cells/mm³ and DM had consistently lower serological responses.

Humoral and T-cell mediated response after administration of mRNA vaccine BNT162b2 in frail populations

Patients with frailty are considered to be at greater risk to get severe infection from SARS-CoV-2. One of the most effective strategies is vaccination. In our study we evaluated both the humoral immune response elicited by the vaccination at different time points, and the T-cell response in terms of interferon (IFN)-γ production in frail patients and healthy donors. Fifty-seven patients (31 patients undergoing hemodialysis and 26 HIV positive subjects) and 39 healthcare workers were enrolled. All participants received two doses of the mRNA vaccine BNT162b2. Healthcare workers showed a significantly higher antibody titer than patients twenty-one days after the first dose (p < 0.001). From the same time point we observed for both groups a decay of the antibody levels with a steeper slope of decline in the patients group. Regarding T-cell response the only significant difference between non-reactive and reactive subjects was found in median antibody levels, higher in the responders group than in non-responders. The healthcare workers seem to better respond to the vaccination in terms of antibodies production; the lack of T-cell response in about 50% of the participants seems to suggest that in our study population both humoral and cell-mediated response decline over time remarking the importance of the booster doses, particularly for frail patients.

Attenuated humoral responses in HIV infection after SARS-CoV-2 vaccination are linked to global B cell defects and cellular immune profiles

People living with HIV (PLWH) on suppressive antiretroviral therapy (ART) can have residual immune dysfunction and often display poorer responses to vaccination. We assessed in a cohort of PLWH (n=110) and HIV negative controls (n=64) the humoral and spike-specific B-cell responses following 1, 2 or 3 SARS-CoV-2 vaccine doses. PLWH had significantly lower neutralizing antibody (nAb) titers than HIV-negative controls at all studied timepoints. Moreover, their neutralization breadth was reduced with fewer individuals developing a neutralizing response against the Omicron variant (BA.1) relative to controls. We also observed a delayed development of neutralization in PLWH that was underpinned by a reduced frequency of spike-specific memory B cells (MBCs) and pronounced B cell dysfunction. Improved neutralization breadth was seen after the third vaccine dose in PLWH but lower nAb responses persisted and were associated with global, but not spike-specific, MBC dysfunction. In contrast to the inferior antibody responses, SARS-CoV-2 vaccination induced robust T cell responses that cross-recognized variants in PLWH. Strikingly, a subset of PLWH with low or absent neutralization had detectable functional T cell responses. These individuals had reduced numbers of circulating T follicular helper cells and an enriched population of CXCR3 + CD127 + CD8 + T cells after two doses of SARS-CoV-2 vaccination, which may compensate for sub-optimal serological responses in the event of infection. Therefore, normalisation of B cell homeostasis could improve serological responses to vaccines in PLWH and evaluating T cell immunity could provide a more comprehensive immune status profile in these individuals and others with B cell imbalances.

A Systematic Review of COVID-19 Vaccine Antibody Responses in People With HIV

HIV infection is a significant independent risk factor for severe coronavirus disease 2019 (COVID-19) disease and death. We summarize COVID-19 vaccine responses in people with HIV (PWH). A systematic literature review of studies from January 1, 2020, to March 31, 2022, of COVID-19 vaccine immunogenicity in PWH from multiple databases was performed. Twenty-eight studies from 12 countries were reviewed. While 22 (73%) studies reported high COVID-19 vaccine seroconversion rates in PWH, PWH with lower baseline CD4 counts, CD4/CD8 ratios, or higher baseline viral loads had lower seroconversion rates and immunologic titers. Data on vaccine-induced seroconversion in PWH are reassuring, but more research is needed to evaluate the durability of COVID-19 vaccine responses in PWH.

Immunogenicity and efficacy of COVID-19 vaccines in people living with HIV: a systematic review and meta-analysis

OBJECTIVES

Available data show that COVID-19 vaccines may be less effective in people living with HIV (PLWH) who are at increased risk for severe COVID-19. This meta-analysis aimed to compare the immunogenicity and efficacy of COVID-19 vaccines in PLWH with healthy individuals.

METHODS

Pubmed/Medline, EMBASE, and the Cochrane Library were searched. Risk ratios of seroconversion were separately pooled using random-effects meta-analysis, and a systematic review without meta-analysis of SARS-CoV-2 antibody titer levels was performed after the first and second doses of a COVID-19 vaccine.

RESULTS

A total of 22 studies with 6522 subjects met the inclusion criteria. After the first vaccine dose, seroconversion in PLWH was comparable to that in healthy individuals. After a second dose, seroconversion was slightly lower in PLWH compared with healthy controls, and antibody titers did not seem to be significantly affected or reduced among participants of both groups.

CONCLUSION

COVID-19 vaccines show favorable immunogenicity and efficacy in PLWH. A second dose is associated with consistently improved seroconversion, although it is slightly lower in PLWH than in healthy individuals. Additional strategies, such as a booster vaccination with messenger RNA COVID-19 vaccines, might improve seroprotection for these patients.

Coronavirus Antibody Responses before COVID-19 Pandemic, Africa and Thailand

Prior immune responses to coronaviruses might affect human SARS-CoV-2 response. We screened 2,565 serum and plasma samples collected from 2013 through early 2020, before the COVID-19 pandemic began, from 2,250 persons in 4 countries in Africa (Kenya, Nigeria, Tanzania, and Uganda) and in Thailand, including persons living with HIV-1. We detected IgG responses to SARS-CoV-2 spike (S) subunit 2 protein in 1.8% of participants. Profiling against 23 coronavirus antigens revealed that responses to S, subunit 2, or subunit 1 proteins were significantly more frequent than responses to the receptor-binding domain, S-Trimer, or nucleocapsid proteins (p<0.0001). We observed similar responses in persons with or without HIV-1. Among all coronavirus antigens tested, SARS-CoV-2, SARS-CoV-1, and Middle East respiratory syndrome coronavirus antibody responses were much higher in participants from Africa than in participants from Thailand (p<0.01). We noted less pronounced differences for endemic coronaviruses. Serosurveys could affect vaccine and monoclonal antibody distribution across global populations.

Immunogenicity and Safety of COVID-19 Vaccines among People Living with HIV: A Systematic Review and Meta-Analysis

BACKGROUND

The immunogenicity and safety of COVID-19 vaccines among people living with human immunodeficiency virus (PLWH) are unclear. We aimed to evaluate the immunogenicity and safety of COVID-19 vaccines among PLWH.

METHODS

We systematically searched PubMed, EMBASE, and Web of Science from 1 January 2020 to 28 April 2022 and included observational studies, randomized clinical trials, and non-randomized clinical trials reporting extractable data about the immunogenicity and safety of COVID-19 vaccines among PLWH.

RESULTS

A total of 34 eligible studies covering 4517 PLWH were included. The pooled seroconversion rates among PLWH after the first and second doses were 67.51% (95% confident interval (CI) 49.09-85.93%) and 96.65% (95%CI 95.56-97.75%), respectively. The seroconversion was similar between PLWH and healthy controls after the first (risk ratio (RR) = 0.89, 95%CI 0.76-1.04) and the second (RR = 0.97, 95%CI 0.93-1.00) dose. Moreover, the geometric mean titer (GMT) showed no significant difference between PLWH and healthy controls after the first dose (standardized mean difference (SMD) = 0.30, 95%CI -1.11, 1.70) and the second dose (SMD = -0.06, 95%CI -0.18, 0.05). Additionally, the pooled incidence rates of total adverse events among PLWH after the first and the second dose were 46.55% (95%CI 28.29-64.82%) and 30.96% (95%CI 13.23-48.70%), respectively. There was no significant difference in risks of total adverse events between PLWH and healthy controls after the first (RR = 0.86, 95%CI 0.67-1.10) and the second (RR = 0.88, 95%CI 0.68-1.14) dose.

CONCLUSIONS

The available evidence suggested that the immunogenicity and safety of COVID-19 vaccines among PLWH were acceptable. There was no significant difference in the seroconversion rates and incidence rates of adverse events of COVID-19 vaccines between PLWH and healthy controls.

COVID-19 vaccine effectiveness among people living with and without HIV in South Carolina, USA: protocol of a population-based cohort study

INTRODUCTION

Despite the effectiveness of COVID-19 vaccines in preventing severe COVID-19 outcomes, a small percentage of fully vaccinated persons will develop symptomatic or asymptomatic infections with SARS-CoV-2, which is referred to as 'breakthrough COVID-19'. People living with HIV (PLWH) appear to have an elevated risk of severe COVID-19 outcomes, yet the effectiveness of the COVID-19 vaccine in this population remains unclear due to the limited research efforts in this population in the real world. This study aims to characterise and compare the breakthrough COVID-19 (eg, prevalence and disease severity) between PLWH and non-PLWH and then examine whether HIV markers play a role in COVID-19 vaccine effectiveness within the PLWH population.

METHODS AND ANALYSIS

This cohort study will merge electronic health records data from multiple data sources in South Carolina (SC), including the 'HIV Cohort' (n=12 203) identified from the statewide Enhanced HIV/AIDS Reporting System, 'Vaccine Cohort' from the Statewide Immunisation Online Network which provides patient-level immunisation records (n=~1.71 million), and 'COVID-19 Cohort' which includes healthcare encounters and COVID-19 diagnosis information for all individuals who were tested for COVID-19 (n=~3.41 million). The PLWH will be matched with a comparison group of non-PLWH by the propensity score matching method. To distinguish the role of immunity level in affecting the vaccine effectiveness, we will conduct subgroup analyses to compare the outcome of virally controlled and immunosuppressed PLWH with non-PLWH. Conditional logistic regression and generalised linear models will be employed to analyse the relationship between HIV status and protection durability by adjusting for potential confounders.

ETHICS AND DISSEMINATION

The study was approved by the Institutional Review Board at the University of South Carolina (Pro00117583) as a Non-Human Subject study. The study's findings will be published in peer-reviewed journals and disseminated at national and international conferences and through social media.

Immunogenicity to COVID-19 mRNA vaccine third dose in people living with HIV

In order to investigate safety and immunogenicity of SARS-CoV-2 vaccine third dose in people living with HIV (PLWH), we analyze anti-RBD, microneutralization assay and IFN-γ production in 216 PLWH on ART with advanced disease (CD4 count <200 cell/mm3 and/or previous AIDS) receiving the third dose of a mRNA vaccine (BNT162b2 or mRNA-1273) after a median of 142 days from the second dose. Median age is 54 years, median CD4 nadir 45 cell/mm3 (20-122), 93% HIV-RNA < 50 c/mL. In 68% of PLWH at least one side-effect, generally mild, is recorded. Humoral response after the third dose was strong and higher than that achieved with the second dose (>2 log2 difference), especially when a heterologous combination with mRNA-1273 as third shot is used. In contrast, cell-mediated immunity remain stable. Our data support usefulness of third dose in PLWH currently receiving suppressive ART who presented with severe immune dysregulation.

SARS CoV-2 mRNA vaccination exposes latent HIV to Nef-specific CD8+ T-cells

Efforts to cure HIV have focused on reactivating latent proviruses to enable elimination by CD8+ cytotoxic T-cells. Clinical studies of latency reversing agents (LRA) in antiretroviral therapy (ART)-treated individuals have shown increases in HIV transcription, but without reductions in virologic measures, or evidence that HIV-specific CD8+ T-cells were productively engaged. Here, we show that the SARS-CoV-2 mRNA vaccine BNT162b2 activates the RIG-I/TLR - TNF - NFκb axis, resulting in transcription of HIV proviruses with minimal perturbations of T-cell activation and host transcription. T-cells specific for the early gene-product HIV-Nef uniquely increased in frequency and acquired effector function (granzyme-B) in ART-treated individuals following SARS-CoV-2 mRNA vaccination. These parameters of CD8+ T-cell induction correlated with significant decreases in cell-associated HIV mRNA, suggesting killing or suppression of cells transcribing HIV. Thus, we report the observation of an intervention-induced reduction in a measure of HIV persistence, accompanied by precise immune correlates, in ART-suppressed individuals. However, we did not observe significant depletions of intact proviruses, underscoring challenges to achieving (or measuring) HIV reservoir reductions. Overall, our results support prioritizing the measurement of granzyme-B-producing Nef-specific responses in latency reversal studies and add impetus to developing HIV-targeted mRNA therapeutic vaccines that leverage built-in LRA activity.

Determinants of antibody response to severe acute respiratory syndrome coronavirus 2 mRNA vaccines in people with HIV

We identified determinants of SARS-CoV-2 mRNA vaccine antibody response in people with HIV (PWH). Antibody response was higher among PWH less than 60 years, with CD4+ cell count superior to 350 cells/μl and vaccinated with mRNA-1273 by Moderna compared with BNT162b2 by Pfizer-BioNTech. Preinfection with SARS-CoV-2 boosted the antibody response and smokers had an overall lower antibody response. Elderly PWH and those with low CD4+ cell count should be prioritized for booster vaccinations.

Surrogate neutralization responses following severe acute respiratory syndrome coronavirus 2 vaccination in people with HIV: comparison between inactivated and mRNA vaccine

OBJECTIVE

People with HIV (PWH) co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at higher odds of severe diseases. Whereas the immunogenicity of mRNA vaccine and adenovirus-vectored vaccine was similar between PWH in stable condition and healthy adults, the effects of inactivated vaccines are not known.

DESIGN

Prospective longitudinal observational study in real-world setting.

METHODS

Adult PWH in care and planning to receive either inactivated (day 0 and day 28) or mRNA-based (day 0 and day 21) vaccine against SARS-CoV-2 were recruited, with blood samples collected over 6 months for surrogate virus neutralization test (sVNT). Demographic and clinical data including age, sex, CD4 + cell count, and suppressed viral load (SVL) status were transcribed for analyses, by simple and multivariable linear regression models, and multivariable linear generalized estimating equations (GEE).

RESULTS

A total of 611 HIV patients, 91% male patients, were recruited, of whom 423 and 184 have received mRNA-based and inactivated vaccine, respectively. The seroconversion rate was 99% for mRNA-based vs, 86% for inactivated vaccine [odds ratio (OR) = 21.56, P  = 0.004]. At 6 months, mRNA-based vaccine continued to give a higher response (94 vs. 57%, P  < 0.001). The temporal pattern varied between the two vaccines. By GEE, mRNA-based vaccine ( B  = 40.59, P  < 0.001) and latest SVL status ( B  = 10.76, P  = 0.01) were positively associated with sVNT level, but not latest CD4 + cell count.

CONCLUSION

In HIV patients, inactivated vaccine gave a lower peak and shorter duration of sVNT responses compared with mRNA vaccine. The results suggested that different strategies may be needed in boosting the immunity in anticipation of the emergence of variants in the community.

Humoral Immune Response to Inactivated COVID-19 Vaccination at the 3rd Month among People Living with HIV

Background: Research on the immune response to inactivated COVID-19 vaccination among people living with HIV (PLWH) is limited, especially among those with low CD4+ T lymphocyte (CD4 cell) count. This cross-sectional study aimed to assess the humoral immune response to inactivated COVID-19 vaccination among PLWH compared to HIV negative controls (HNC) and to determine the impact of CD4 cell count on vaccine response among PLWH. Methods: The neutralizing antibodies (nAbs) and the specific IgM and IgG-binding antibody responses to the inactivated COVID-19 vaccine at the third month after the second dose of inactivated COVID-19 vaccination were measured among 138 PLWH and 35 HNC. Multivariable logistic regression and multiple linear regression models were conducted to identify factors associated with the seroconversion rate of antibodies and the magnitude of anti-SARS-CoV-2 antibody titers, respectively. Results: At the end of the third month after two doses of vaccination, the seroconversion rates of IgG were comparable between PLWH (8.7%; 95%CI, 3.9-13.5%) and HNC (11.4%; 95%CI, 0.3-22.5%), respectively. The median titers and seroconversion rate of nAbs among PLWH were 0.57 (IQR: 0.30-1.11) log 10 BAU/mL and 29.0% (95%CI: 21.3-36.8%), respectively, both lower than those in HNC ( P ＜0.05). After adjusting for age, sex, comorbidities, and CD4 cell count, the titers and seroconversion rate of nAbs were comparable between PLWH and HNC (P＞0.05). Multivariable regression analyses showed that CD4 cell count＜200 /μL was independently associated with lower titers and seroconversion rate of nAbs among PLWH ( P ＜0.05). A positive correlation was observed between the CD4 cell count and nAbs titers in PLWH (Spearman'sρ=0.25, P =0.034). Conclusion: Our study concluded that the immune response to inactivated COVID-19 vaccination among PLWH was independently associated with CD4 cell count, PLWH with lower CD4 cell count showed a weaker humoral immune response, especially those with CD4 cell count＜200 /μL. This finding suggests that expanding COVID-19 vaccination coverage among PLWH is impendency. In addition, aggressive ART should be carried out for PLWH, especially for those with low CD4 cell count, to improve the immune response to vaccines.

Disentangling the relative importance of T cell responses in COVID-19: leading actors or supporting cast?

The rapid development of multiple vaccines providing strong protection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been a major achievement. There is now compelling evidence for the role of neutralizing antibodies in protective immunity. T cells may play a role in resolution of primary SARS-CoV-2 infection, and there is a widely expressed view that T cell-mediated immunity also plays an important role in vaccine-mediated protection. Here we discuss the role of vaccine-induced T cells in two distinct stages of infection: firstly, in protection from acquisition of symptomatic SARS-CoV-2 infection following exposure; secondly, if infection does occur, the potential for T cells to reduce the risk of developing severe COVID-19. We describe several lines of evidence that argue against a direct impact of vaccine-induced memory T cells in preventing symptomatic SARS-CoV-2 infection. However, the contribution of T cell immunity in reducing the severity of infection, particularly in infection with SARS-CoV-2 variants, remains to be determined. A detailed understanding of the role of T cells in COVID-19 is critical for next-generation vaccine design and development. Here we discuss the challenges in determining a causal relationship between vaccine-induced T cell immunity and protection from COVID-19 and propose an approach to gather the necessary evidence to clarify any role for vaccine-induced T cell memory in protection from severe COVID-19.

People with HIV receiving suppressive antiretroviral therapy show typical antibody durability after dual COVID-19 vaccination, and strong third dose responses

Background:

Longer-term humoral responses to two-dose COVID-19 vaccines remain incompletely characterized in people living with HIV (PLWH), as do initial responses to a third dose.

Methods:

We measured antibodies against the SARS-CoV-2 spike protein receptor-binding domain, ACE2 displacement and viral neutralization against wild-type and Omicron strains up to six months following two-dose vaccination, and one month following the third dose, in 99 PLWH receiving suppressive antiretroviral therapy, and 152 controls.

Results:

Though humoral responses naturally decline following two-dose vaccination, we found no evidence of lower antibody concentrations nor faster rates of antibody decline in PLWH compared to controls after accounting for sociodemographic, health and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after two doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though anti-Omicron responses were consistently weaker than against wild-type. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses.

Conclusion:

PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after two- and three-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

Characterization of Serum and Mucosal SARS-CoV-2-Antibodies in HIV-1-Infected Subjects after BNT162b2 mRNA Vaccination or SARS-CoV-2 Infection

Only limited data are available regarding the immunogenicity of the BNT162b2 mRNA vaccine in HIV-1+ patients. Therefore, we investigated the humoral immune response after BNT162b2-mRNA vaccination or SARS-CoV-2 infection in HIV-1+ patients on antiretroviral therapy compared to HIV-1-uninfected subjects. Serum and saliva samples were analysed by SARS-CoV-2 spike-specific IgG and IgA ELISAs and a surrogate neutralization assay. While all subjects developed anti-spike IgG and IgA and neutralizing antibodies in serum after two doses of BNT162b2 mRNA vaccine, the HIV-1+ subjects displayed significantly lower neutralizing capacity and anti-spike IgA in serum compared to HIV-1-uninfected subjects. Serum levels of anti-spike IgG and neutralizing activity were significantly higher in vaccinees compared to SARS-CoV-2 convalescents irrespective of HIV-1 status. Among SARS-CoV-2 convalescents, there was no significant difference in spike-specific antibody response between HIV-1+ and uninfected subjects. In saliva, anti-spike IgG and IgA antibodies were detected both in vaccinees and convalescents, albeit at lower frequencies compared to the serum and only rarely with detectable neutralizing activity. In summary, our study demonstrates that the BNT162b2 mRNA vaccine induces SARS-CoV-2-specific antibodies in HIV-1-infected patients on antiretroviral therapy, however, lower vaccine induced neutralization activity indicates a lower functionality of the humoral vaccine response in HIV-1+ patients.