Durability of antibody responses after receipt of the monovalent 2009 pandemic influenza A (H1N1) vaccine among HIV-infected and HIV-uninfected adults

Immunogenicity and safety of live attenuated and recombinant/inactivated varicella zoster vaccines in people living with HIV: A systematic review

Few papers focus their attention on VZV vaccination effectiveness among people living with HIV (PLWH). Flanking the live attenuated vaccine (VZL) available, a newly recombinant vaccine (RZV) was recently introduced and approved for HZ prevention among adults. PLWH represents a population on which a particular attention should be applied, in order to guarantee the vaccine efficacy and safety. We performed a literature search in USNLM, PubMed, PubMed Central, PMC and Cochrane Library. From all the publications found eligible, data were extracted and processed per population, vaccine type, immunogenicity and ADRs. The review of the 13 included studies shows that both RZV and VZL are immunogenic and have an acceptable safety profile in adults and children living with HIV. However, given the lack of research available about vaccine efficacy in preventing VZV and HZ in PLWH, additional studies need to be performed, in order to achieve a full completeness of data.

Spatial technologies to evaluate the HIV-1 reservoir and its microenvironment in the lymph node

The presence of the HIV-1 reservoir, a group of immune cells that contain intact, integrated, and replication-competent proviruses, is a major challenge to cure HIV-1. HIV-1 reservoir cells are largely unaffected by the cytopathic effects of viruses, antiviral immune responses, or antiretroviral therapy (ART). The HIV-1 reservoir is seeded early during HIV-1 infection and augmented during active viral replication. CD4+ T cells are the primary target for HIV-1 infection, and recent studies suggest that memory T follicular helper cells within the lymph node, more precisely in the B cell follicle, harbor integrated provirus, which contribute to viral rebound upon ART discontinuation. The B cell follicle, more specifically the germinal center, possesses a unique environment because of its distinct property of being partly immune privileged, potentially allowing HIV-1-infected cells within the lymph nodes to be protected from CD8+ T cells. This modified immune response in the germinal center of the follicle is potentially explained by the exclusion of CD8+ T cells and the presence of T regulatory cells at the junction of the follicle and extrafollicular region. The proviral makeup of HIV-1-infected cells is similar in lymph nodes and blood, suggesting trafficking between these compartments. Little is known about the cell-to-cell interactions, microenvironment of HIV-1-infected cells in the follicle, and trafficking between the lymph node follicle and other body compartments. Applying a spatiotemporal approach that integrates genomics, transcriptomics, and proteomics to investigate the HIV-1 reservoir and its neighboring cells in the lymph node has promising potential for informing HIV-1 cure efforts.

Explorative study regarding influenza vaccine hesitancy among HIV-infected patients

There are scarce data regarding influenza vaccination among people with HIV infection (PWHIV). The goal of this explorative study is to assess hesitancy toward influenza vaccination in a group of PWHIV during the COVID-19 pandemic. A questionnaire was administered to 219 patients vaccinated at our clinic during the 2020–2021 campaign. It evaluated subjects’ adherence to influenza vaccine over the last three seasonal vaccination campaigns, vaccine confidence, complacency and convenience, and the effect of the pandemic on the choice to become vaccinated. The population was divided into two groups: fully adherent to influenza vaccine (all three campaigns, 117 patients) and non-fully adherent (one or two campaigns, 102 patients). Adherence increased in the non-fully adherent group in 2020–2021, but the pandemic did not affect the choice. Misbeliefs emerged: the influenza vaccine was considered protective against SARS-CoV-2 (22.8% of the total population); almost half of all patients thought the influenza vaccine could improve their CD4 T cell level (57.3% in fully adherent, 40.2% in non-fully adherent, p < .05). In 2020–2021 campaign, three quarters of the non-fully adherent group would not have been vaccinated in a location other than our clinic (75.5% vs. 88.9% in the fully adherent group, p < .05). Conclusively, offering a secure and private space for vaccination against influenza seems to encourage vaccination; healthcare professionals should improve counseling to increase adherence and correct misbeliefs.

A Single Dose SARS-CoV-2 Replicon RNA Vaccine Induces Cellular and Humoral Immune Responses in Simian Immunodeficiency Virus Infected and Uninfected Pigtail Macaques

The ongoing COVID-19 vaccine rollout is critical for reducing SARS-CoV-2 infections, hospitalizations, and deaths worldwide. Unfortunately, massive disparities exist in getting vaccines to vulnerable populations, including people living with HIV. Preliminary studies indicate that COVID-19 mRNA vaccines are safe and immunogenic in people living with HIV that are virally suppressed with potent antiretroviral therapy but may be less efficacious in immunocompromised individuals. This raises the concern that COVID-19 vaccines may be less effective in resource poor settings with limited access to antiretroviral therapy. Here, we evaluated the immunogenicity of a single dose COVID-19 replicon RNA vaccine expressing Spike protein (A.1) from SARS-CoV-2 (repRNA-CoV2S) in immunocompromised, SIV infected and immune competent, naïve pigtail macaques. Moderate vaccine-specific cellular Th1 T-cell responses and binding and neutralizing antibodies were induced by repRNA-CoV2S in SIV infected animals and naïve animals. Furthermore, vaccine immunogenicity was elicited even among the animals with the highest SIV viral burden or lowest peripheral CD4 counts prior to immunization. This study provides evidence that a SARS-CoV-2 repRNA vaccine could be employed to induce strong immunity against COVID-19 in HIV infected and other immunocompromised individuals.

Mapping the Lineage Relationship between CXCR5+ and CXCR5- CD4+ T Cells in HIV-Infected Human Lymph Nodes

CXCR5 is a key marker of follicular helper T (T_FH) cells. Using primary lymph nodes (LNs) from HIV-infected patients, we identified a population of CXCR5⁻ CD4⁺ T cells with T_FH-cell-like features. This CXCR5⁻ subset becomes expanded in severe HIV infection and is characterized by the upregulation of activation markers and high PD-1 and ICOS surface expression. Integrated analyses on the phenotypic heterogeneity, functional capacity, T cell receptor (TCR) repertoire, transcriptional profile, and epigenetic state of CXCR5⁻PD-1⁺ICOS⁺ T cells revealed a shared clonal relationship with T_FH cells. CXCR5⁻PD-1⁺ICOS⁺ T cells retained a poised state for CXCR5 expression and exhibited a migratory transcriptional program. TCR sequence overlap revealed a contribution of LN-derived CXCR5⁻PD-1⁺ICOS⁺ T cells to circulating CXCR5⁻ CD4⁺ T cells with B cell help function. These data link LN pathology to circulating T cells and expand the current understanding on the diversity of T cells that regulate B cell responses during chronic inflammation.

Follicular helper T (T_FH) cells are critical for antibody production. Del Alcazar et al. showed that T_FH cells can lose their characteristic chemokine receptor, giving rise to migratory populations of CXCR5⁻ T cells that retain B cell help function and are poised for CXCR5 expression.

The Acute Respiratory Infection Consortium: A Multi-Site, Multi-Disciplinary Clinical Research Network in the Department of Defense

Introduction

Acute respiratory infections (ARI) result in substantial annual morbidity among military personnel and decrease operational readiness. Herein, we summarize the research efforts of the Infectious Disease Clinical Research Program (IDCRP) related to ARIs.

Methods

The ARI Research Area of the IDCRP was established in response to the 2009 emergence of pandemic influenza A/H1N1. That year, IDCRP investigators deployed the ARI Consortium Natural History Study (ARIC NHS), a multi-centered, longitudinal observational study to assess etiology, epidemiology, and clinical characteristics of influenza-like illness (ILI) and severe acute respiratory infections (SARI) in the U.S. military. The success of this initial effort spurred implementation of several new initiatives. These include the FluPlasma trial, designed to evaluate the efficacy of hyperimmune anti-influenza plasma for the treatment of severe influenza; the self-administered live-attenuated influenza vaccine (SNIF) trial, which assessed the immunogenicity and acceptance of a self-administered live-attenuated influenza vaccine in military personnel; the Study to Address Threats of ARI in Congregate Military Populations (ATARI), a prospective study of ILI transmission, etiology and epidemiology in recruits; and the Flu Breath Test (FBT) study, a preliminary study of exhaled volatile organic compounds (VOC) in influenza patients. In addition, the InFLUenza Patient-Reported Outcome (FLU-PRO) survey, a daily diary to measure influenza symptoms during clinical trials, was developed. Lastly, the Pragmatic Assessment of Influenza Vaccine Effectiveness in the DoD (PAIVED) study, a two-year randomized trial designed to compare the effectiveness of the three types of licensed vaccines, launched in Fall 2018.

Results

The on-going ARIC NHS has enrolled over 2000 ILI and SARI cases since its inception, providing data on burden and clinical manifestations of ARI in military personnel and their families. The FluPlasma 2 trial concluded subject enrollment in 2018. Preliminary results from ATARI study show a high frequency of respiratory viruses circulating during the first two weeks of recruit training. Based on assessment of FLU-PRO responses, which were found to be reliable and reproducible, the survey may be a useful tool in clinical trials and epidemiological studies. The Flu Breath Study will complete enrollment in 2019. Findings from PAIVED are intended to provide evidence needed for assessing influenza vaccination policy in the military.

Conclusions

The ARI burden in the armed services remains significant every year and the threat is dynamic given emergent and evolving threats, such as influenzas. With strong successes to date, future initiatives of the ARI Research Area will focus on interventional studies, ARI transmission dynamics in congregate military settings, and determinants of risk of pandemic influenza and other emergent respiratory viruses.

Single-Cell Technologies Applied to HIV-1 Research: Reaching Maturity

The need for definitive answers probably explains our natural tendency to seek simplicity. The reductionist “bulk” approach, in which a mean behavior is attributed to a heterogeneous cell population, fulfills this need by considerably helping the conceptualization of complex biological processes. However, the limits of this methodology are becoming increasingly clear as models seek to explain biological events occurring in vivo, where heterogeneity is the rule. Research in the HIV-1 field is no exception: the challenges encountered in the development of preventive and curative anti-HIV-1 strategies may well originate in part from inadequate assumptions built on bulk technologies, highlighting the need for new perspectives. The emergence of diverse single-cell technologies set the stage for potential breakthrough discoveries, as heterogeneous processes can now be investigated with an unprecedented depth in topics as diverse as HIV-1 tropism, dynamics of the replication cycle, latency, viral reservoirs and immune control. In this review, we summarize recent advances in the HIV-1 field made possible by single-cell technologies, and contextualize their importance.

Immunogenicity and Safety of the Measles Vaccine in HIV-Infected Children: An Updated Systematic Review

Children infected with human immunodeficiency virus (HIV) are at increased risk of measles morbidity and mortality. We searched abstracts from the PubMed, Embase, and Latin American and Caribbean Center on Health Sciences Information databases for articles published from the earliest date available through September 26, 2017. The primary outcome of interest was serological responses to measles vaccine, stratified by HIV infection status. A total of 2,858 potentially eligible articles were identified, and the final review included 12 studies published between 1992 and 2013, 9 of which reported data on vaccine safety. The studies we included represented 3,573 children, of whom at least 335 were infected with HIV, 788 were HIV-exposed but not infected, and 1,478 were unexposed to HIV. Four of the 12 studies found statistically significant reductions in seropositivity among HIV-infected children compared with HIV-uninfected children within 4 months of vaccination (prevalence ratio range, 0.44-0.70), and forest plots provided visual trends of decreasing immunity over time among HIV-infected children in 2 additional studies. No vaccine-related deaths or serious adverse events were reported. This updated review demonstrated limitations of the existing published literature but supported evidence of reduced immunogenicity of measles vaccine among HIV-infected children, supporting the World Health Organization recommendation to revaccinate HIV-infected children against measles following immune reconstitution with combination antiretroviral therapy.

The receptor repertoire and functional profile of follicular T cells in HIV-infected lymph nodes

Follicular helper CD4⁺ T cells (T_FH) play an integral role in promoting B cell differentiation and affinity maturation. Whereas T_FH cell frequencies are increased in lymph nodes (LNs) from individuals infected with HIV, humoral immunity remains impaired during chronic HIV infection. Whether HIV inhibits T_FH responses in LNs remains unclear. Advances in this area have been limited by the difficulty of accessing human lymphoid tissues. Here, we combined high-dimensional mass cytometry with T cell receptor repertoire sequencing to interrogate the composition of T_FH cells in primary human LNs. We found evidence for intact antigen-driven clonal expansion of T_FH cells and selective utilization of specific complementarity-determining region 3 (CDR3) motifs during chronic HIV infection, but the resulting T_FH cells acquired an activation-related T_FH cell signature characterized by interleukin-21 (IL-21) dominance. These IL-21⁺ T_FH cells contained an oligoclonal HIV-reactive population that preferentially accumulated in patients with severe HIV infection and was associated with aberrant B cell distribution in the same LN. These data indicate that T_FH cells remain capable of responding to HIV antigens during chronic HIV infection but become functionally skewed and oligoclonally restricted under persistent antigen stimulation.

Neutralization and hemagglutination-inhibition antibodies following influenza vaccination of HIV-infected and HIV-uninfected pregnant women

Background

We previously reported that despite HIV-infected pregnant women had modest humoral immune responses to inactivated influenza vaccine (IIV) measured by hemagglutination-inhibition (HAI) assay, the observed vaccine efficacy against influenza disease was higher than predicted by HAI; suggesting that IIV may confer protection to HIV-infected individuals by additional mechanisms. We evaluated the response to IIV by microneutralization (MN) and HAI assays and correlated both methods in HIV-infected and HIV-uninfected pregnant women.

Methods

MN and HAI antibodies were measured pre-vaccination and approximately one-month post-vaccination in 80 HIV-infected and 75 HIV-uninfected women who received IIV. Geometric mean titers (GMTs), fold-change in titers and seroconversion rates were determined for the three influenza stains in the vaccine.

Results

After vaccination there were significant increases in MN and HAI GMTs for the three vaccine strains in both HIV-infected and HIV-uninfected women. HIV-infected women had, however, a lower immune response compared to HIV-uninfected. Fold-increases were 2 to 3-times higher for MN assay compared to HAI assay for the influenza-A strains. Also a higher percentage of women seroconverted by MN than by HAI assay for the influenza-A strains. There was high positive correlation between MN and HAI assays, except for the B/Victoria strain at pre-vaccination.

Conclusions

In general, the MN assay was more sensitive than the HAI assay. Microneutralization antibodies might correlate better with protection against influenza infection.

Evaluation of T and B memory cell responses elicited by the pandemic H1N1 vaccine in HIV-infected and HIV-uninfected individuals

BACKGROUND

This study was to compare B and T memory cells elicited by a single dose monovalent 2009 influenza A (H1N1) vaccine (strain A/California/7/2009 H1N1) in HIV⁺ and HIV^- groups, and to analyze the impact of the prior seasonal vaccines to the immunogenicity of this vaccine.

METHODS

Blood samples were collected before vaccination (day 0) and at days 28 and 180. Participants were categorized into HIV^-/LAIV, HIV^-/TIV and HIV⁺/TIV subgroups according to the trivalent live-attenuated or inactivated (LAIV or TIV) seasonal influenza vaccines they received previously. The IgG⁺ memory B cells (B_Mem) and IFNγ⁺ T cells were measured against antigens including the H1N1 vaccine, the hemagglutinin (HA) and neuraminidase (NA) proteins or peptide pools of the pandemic and the seasonal H1N1 strains, respectively.

RESULTS

Overall B_Mem responses increased significantly at day 28 but returned to baseline by day 180 in all three subgroups. The average frequency of the H1N1-specific B_Mem at day 28 for the HIV^-/LAIV, HIV^-/TIV and HIV⁺/TIV groups was 2.14%, 1.26% and 1.67%, respectively, and the average fold change was 14.39, 3.81 and 3.93, respectively. The differences of B_Mem between HIV^-/LAIV and the two TIV subgroups were significant. For the IFNγ response, the overall spot counts ranged widely between 0 and 958/10⁶ PBMCs. The group average spot counts to H1N1 vaccine was 89, 102, and 30 at day 28 for HIV^-/LAIV, HIV^-/TIV and HIV⁺/TIV subgroups, respectively. The average increase of IFNγ response at day 28 vs day 0 in all three subgroups did not reach 2-fold.

CONCLUSION

Participants with a prior LAIV seasonal vaccine, as compared to a TIV seasonal vaccine, responded significantly better to the monovalent H1N1 vaccine. Excluding LAIV participants, no difference was seen between the HIV⁺ and HIV^- subject groups in terms of B_Mem. The B_Mem response declined at 6months.

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

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

Vitamin D levels and influenza vaccine immunogenicity among HIV-infected and HIV-uninfected adults

BACKGROUND

Vaccination is the most important preventive strategy against influenza, however post-vaccination antibody responses are often inadequate especially among HIV-infected persons. Vitamin D deficiency has been suggested to adversely influence immune responses and is highly prevalent among HIV-infected adults. Therefore, we evaluated the association between 25-hydroxyvitamin D [25(OH)D] levels and post-influenza vaccination responses.

METHODS

We conducted a prospective cohort study evaluating the immunogenicity of monovalent influenza A (H1N1) vaccination among both HIV-infected and HIV-uninfected adults (18-50years of age) during the 2009-2010 influenza season. Antibody titers were evaluated at baseline, day 28, and 6months post-vaccination using hemagluttination inhibition assays. Serum 25(OH)D levels were measured at day 28. Univariate and multivariate regression analyses examined the association between 25(OH)D levels [categorized as <20ng/ml (deficiency) vs. ⩾20ng/ml] with the primary outcome of seroconversion. Secondary outcomes included seroprotection; a ⩾4-fold increase in titers; and geometric mean titers post-vaccination. Analyses were repeated using 25(OH)D levels as a continuous variable.

RESULTS

A total of 128 adults [64 HIV-infected (median CD4 count 580cells/mm(3)) and 64 HIV-uninfected] were included. Seroconversion at day 28 post-vaccination was achieved in fewer HIV-infected participants compared with HIV-uninfected participants (56% vs. 74%, p=0.03). Vitamin D deficiency was more prevalent among HIV-infected persons vs. HIV-uninfected persons (25% vs. 17%), although not significantly different (p=0.39). There were no associations found between lower 25(OH)D levels and poorer antibody responses at day 28 or 6months for any of the study outcomes among either HIV-infected or HIV-uninfected adults.

CONCLUSION

Vitamin D deficiency was common among both HIV-infected and HIV-uninfected adults, but lower levels did not predict antibody responses after H1N1 (2009) influenza vaccination. Low 25(OH)D levels do not explain poorer post-vaccination responses among HIV-infected persons.

Influenza vaccination of pregnant women protects them over two consecutive influenza seasons in a randomized controlled trial

BACKGROUND

We assessed the persistence of hemagglutinin inhibition (HAI) antibodies and the vaccine efficacy (VE) of trivalent inactivated influenza vaccine (IIV3) following vaccination of a cohort of pregnant South African women during a second influenza season.

METHODS

A cohort of women who participated in a randomized placebo-controlled trial on the safety, immunogenicity and efficacy of IIV3 in 2011 had HAI titers measured in 2012 and were monitored for influenza illness until the end of 2012.

RESULTS

The proportion of women with HAI titers ≥1:40 was significantly greater in vaccinees (63%) compared to placebo-recipients (22%; p < 0.001). VE in 2012 was 63.8% (95% confidence interval [95%CI]: -33.7%, 90.2%); combined VE for 2011 and 2012 was 58.3% (95%CI: 0.2%, 82.6%).

CONCLUSION

The majority of women who received IIV3 during pregnancy had HAI titers above the putative threshold for protection against influenza illness one year after vaccination and showed a trend towards protection against influenza disease.

Randomized Controlled Trial to Compare Immunogenicity of Standard-Dose Intramuscular Versus Intradermal Trivalent Inactivated Influenza Vaccine in HIV-Infected Men Who Have Sex With Men in Bangkok, Thailand

BACKGROUND

Individuals infected with human immunodeficiency virus (HIV) are at increased risk for severe influenza, yet immune responses to standard-dose intramuscular (IM) influenza vaccine are suboptimal in this population. Intradermal (ID) delivery of influenza vaccine might improve immune response through enhanced stimulation of dendritic cells.

METHODS

We conducted a randomized, double-blind, controlled trial to compare the immunogenicity of off-label standard-dose (15 µg) ID vs standard-dose (15 µg) IM inactive influenza vaccine in HIV-infected men in Bangkok, Thailand. The primary study outcome was seroconversion (minimum titer of 1:40 and ≥4-fold rise in antibody titer) at 1 month postvaccination based on serum hemagglutination inhibition antibody titers against each vaccine strain. Adverse events (AEs) in the 7 days following vaccination were also assessed.

RESULTS

We enrolled 400 HIV-infected participants; 200 were randomly assigned to receive IM and 200 ID vaccine. Vaccine arms were well-balanced with respect to age, CD4 cell count, HIV RNA load, and antiretroviral treatment. Percentage of seroconversion to all (ID 14% vs IM 15%; P = .8) or at least 1 (ID 69% vs IM 68%; P = .7) of the 3 vaccine strains did not differ significantly between ID vs IM vaccine recipients. A higher proportion of participants who received ID vaccine had mild injection-site AEs compared with participants who received IM vaccine (77% vs 27%).

CONCLUSIONS

There were no significant differences in the immunogenicity of standard-dose ID vs IM influenza vaccine in this HIV-infected population in Thailand. Additional strategies to enhance immune responses to influenza vaccine among HIV-infected persons are needed.

CLINICAL TRIALS REGISTRATION

NCT01538940.

Immunogenicity and sustainability of the immune response in Brazilian HIV-1-infected individuals vaccinated with inactivated triple influenza vaccine

HIV-infected individuals have a higher risk of serious illnesses following infection by infection with influenza. Although anti-influenza vaccination is recommended, immunosuppression may limit their response to active immunization. We followed-up a cohort of HIV-infected individuals vaccinated against influenza to assess the immunogenicity and sustainability of the immune response to vaccination. Individuals were vaccinated 2011 with inactivated triple influenza vaccine (TIV), and they had received in 2010 the monovalent anti-A(H1N1)pdm09 vaccine. The sustainability of the immune response to A(H1N1)pdm09 at 12 months after monovalent vaccination fell, both in individuals given two single or two double doses. For these individuals, A(H1N1)pdm09 component from TIV acted as a booster, raising around 40% the number of seroprotected individuals. Almost 70% of the HIV-infected individuals were already seroprotected to A/H3N2 at baseline. Again, TIV boosted over 90% the seroprotection to A/H3N2. Anti-A/H3N2 titers dropped by 20% at 6 months after vaccination. Pre-vaccination seroprotection rate to influenza B (victoria lineage) was the lowest among those tested, seroconversion rates were higher after vaccination. Seroconversion/protection after TIV vaccination did not differ significantly across categories of clinical and demographic variables. Anti-influenza responses in Brazilian HIV-infected individuals reflected both the previous history of virus circulation in Brazil and vaccination.

Long-term seroprotective response of trivalent seasonal influenza vaccine in HIV-infected children, regardless of immunogenicity before immunisation

Influenza vaccination can reduce disease in HIV-infected children. The durability of the antibody response after trivalent influenza vaccine is important for management. The aim of this prospective study was to assess the durability of seroprotection for trivalent influenza vaccine strains and the factors effecting seroprotective response regardless of immunogenicity before trivalent influenza vaccine at one and six months after immunisation. Hemagglutination inhibition assay was done at one and six months. Seventy-five HIV-infected children were enrolled after vaccination. Four children were lost to follow-up. None of the children had confirmed influenza infection between immunisation and hemagglutination inhibition at six months after influenza vaccination. Seventy-one children were included in the final analysis and immunogenicity of trivalent influenza vaccine strains at one and six months. Of these, 27 (38%) had complete seroprotection (Group A) and 44 (62%) had non-complete seroprotection (Group B). Sex, age and the body mass index of both groups were not different from each other (p > 0.05). There was a higher mean CD4 level and more children with RNA ≤40 copies/mL among Group A compared with Group B (p < 0.05). Other factors did not differ significantly. The durability of the seroprotective response after trivalent influenza vaccine was associated with a high CD4 level and virological suppression before vaccination.

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.

Vaccination in HIV-infected adults

Vaccines are critical components for protecting HIV-infected adults from an increasing number of preventable diseases. However, missed opportunities for vaccination among HIV-infected persons persist, likely due to concerns regarding the safety and efficacy of vaccines, as well as the changing nature of vaccine guidelines. In addition, the optimal timing of vaccination among HIV-infected adults in regards to HIV stage and receipt of antiretroviral therapy remain important questions. This article provides a review of the current recommendations regarding vaccines among HIV-infected adults and a comprehensive summary of the evidence-based literature of the benefits and risks of vaccines among this vulnerable population.

Durability of protective antibody titres is not enhanced by a two-dose schedule of an ASO3-adjuvanted pandemic H1N1 influenza vaccine in adult HIV-1-infected patients

The immune response after influenza vaccination is impaired in HIV-infected individuals and can be enhanced by a second dose. The durability of the antibody protection and its clinical benefit is not known. We investigated clinical symptoms and antibody titres against H1N1 influenza A following no dose, 1 dose, or 2 doses of an ASO3-adjuvanted H1N1 vaccine in HIV-infected patients. Seroprotection was found in 7.9%, 52.2%, and 57.3% of patients who received no dose, 1 dose, and 2 doses of the vaccine, respectively (p-value for group comparison < 0.001), after a median of 8.2 ± 1.6 months. Clinical symptoms suggestive of an influenza-like illness were slightly more frequently reported in the unvaccinated group. Vaccinated HIV-infected patients were more likely to be seroprotected at follow-up, but there was no difference comparing those who had received 1 or 2 doses of the vaccine.

Immune response after a single dose of the 2010/11 trivalent, seasonal influenza vaccine in HIV-1-infected patients and healthy controls

BACKGROUND

Immune response rates following influenza vaccination are often lower in HIV-infected individuals. Low vitamin D levels were correlated with weak immune response in cancer patients and are known to be lower in HIV-infected patients.

METHODS

Diagnostic study to determine immune response against the H1N1v component after a single, intramuscular dose of the 2010/11 seasonal, trivalent influenza vaccine (TIV) in adult HIV-infected and healthy controls scheduled for influenza vaccination (ClinicalTrials.gov Identifier: NCT01017172). Influenza A/H1N1 antibody titers (AB) were determined before and 21 days after vaccination by hemagglutination inhibition assay.

RESULTS

Immune response was not different between HIV-infected patients (n = 36) and healthy controls (n = 42) who were previously naïve to the H1N1v component of the TIV. Comparing HIV-infected patients (n = 55) and healthy controls (n = 63) who had received 1 or 2 doses of an AS03 adjuvanted H1N1 vaccine in the previous winter season (2009/10), seroconversion rate and the geometric mean AB titer after TIV of the HIV-infected patients were more than twice as high compared to healthy controls. This difference was mainly driven by the 2-dose schedule for HIV patients in 2009/10. Vitamin D levels were lower in HIV patients but did not correlate with immune response.

CONCLUSION

HIV-infected patients who had received 1 or 2 doses of an adjuvanted H1N1 vaccine in the previous year (2009/10) had a significant higher seroconversion rate following TIV as compared to healthy controls, indicating a stronger memory cell response due to the 2-dose schedule.

HIV-infected patients show impaired cellular immune response to influenza vaccination compared to healthy subjects

Detailed data on cellular immune response to influenza vaccination in HIV-infected patients are lacking. We analyzed cellular (IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IFN-γ, TNF-α, GM-CSF) and humoral (IgG and IgM) immune response in 81 HIV-infected and 30 HIV-negative subjects, before (T0) and 4 weeks (T1) after receiving a single dose of trivalent MF59-adjuvanted influenza vaccine. No difference in humoral response (IgG or IgM) was demonstrated between the two groups. While an increase in most cytokines from T0 to T1 was observed in HIV-uninfected subjects, cytokines production did not significantly increased in HIV-infected patients. Exploring Th1 response, higher CD8 cells count was significantly associated with lower post-vaccination IFNγ levels, while a higher CD4 cells count was associated with a greater response. Exploring Th2 response, higher HIV viral load was significantly associated with reduced post-vaccination IL-10 levels. In conclusion, in HIV-infected patients influenza vaccination could have good efficacy in sustaining humoral response but cellular response appeared impaired.

Long-term immunogenicity of two doses of 2009 A/H1N1v vaccine with and without AS03(A) adjuvant in HIV-1-infected adults

OBJECTIVE

In immunocompromised patients, alternative schedules more immunogenic than the standard influenza vaccine regimen are necessary to enhance and prolong vaccine efficacy. We previously reported that the AS03A-adjuvanted 2009 A/H1N1v vaccine yielded a higher short-term immune response than the nonadjuvanted one in HIV-1-infected adults. This study reports the long-term persistence of the immune response.

DESIGN AND METHODS

In a prospective, multicenter, randomized, patient-blinded trial, two doses of AS03A-adjuvanted H1N1v vaccine containing 3.75 μg haemagglutinin (n = 155; group A) or nonadjuvanted H1N1v vaccine containing 15 μg haemagglutinin (n = 151; group B), were administered 21 days apart. Haemagglutination inhibition and neutralizing antibodies were assessed 6 and 12 months after vaccination.

RESULTS

In group A and B, the seroprotection rates were 83.7 and 59.4% at month 6, and 70.4 and 49.3 at month 12, respectively. In a multivariate analysis, persistence of seroprotection 12 months after vaccination was negatively associated with current smoking (odds ratio = 0.6, P = 0.03) and positively related with the AS03A-adjuvanted H1N1v vaccine (odds ratio = 2.7, P = 0.0002).

CONCLUSION

In HIV-1-infected adults, two doses of adjuvanted influenza vaccine induce long-term persistence of immune response up to 1 year after vaccination.

Antibody persistence after Pandemic H1N1 2009 influenza vaccination among healthcare workers in Pune, India

The healthcare workers having seroprotection at 3 weeks (n = 127) following Pandemic H1N1 2009 influenza vaccination were followed up for antibody persistence. Seroprotection at 12 mo (60.2%) was significantly lower as compared with 3 weeks (74.7%), 3 mo (77.8%) and 6 mo (75.4%). The vaccine provided seroprotection up to one year.

Immune response after one or two doses of pandemic influenza A (H1N1) monovalent, AS03-adjuvanted vaccine in HIV infected adults

INTRODUCTION

Continued research is needed to evaluate and improve the immunogenicity of influenza vaccines in HIV infected patients. We aimed to determine the antibody responses after one or two doses of the AS03-adjuvanted pandemic influenza A (H1N1) vaccine in HIV infected patients.

METHOD

Following the influenza season 2009/2010, 219 HIV infected patients were included and divided into three groups depending on whether they received none (n=60), one (n=31) or two (n=128) doses of pandemic influenza A (H1N1) vaccine. At inclusion, antibody titers for all patients were analyzed and compared to pre-pandemic antibody titers analyzed from serum samples in a local storage facility.

RESULTS

4-9 months after a single immunization, we found a seroprotection rate of 77.4% and seroconversion rate of 67.7%. After two immunizations the rates increased significantly to seroprotection rate of 97.7% and seroconversion rate of 86.7%.

CONCLUSION

A single dose of AS03-adjuvanted pandemic influenza A (H1N1) vaccine created an adequate immune response in HIV infected patients lasting as long as 4-9 months. Two doses improved the immunogenicity further.

Serological response to influenza A H1N1 vaccine (Pandemrix®) and seasonal influenza vaccine 2009/2010 in renal transplant recipients and in hemodialysis patients

In the present study, antibody response to seasonal influenza vaccination and to the adjuvanted one-shot influenza A H1N1 vaccine (Pandemrix(®)) was investigated in 57 hemodialysis (HD) patients and 48 renal transplant (RT) recipients. Specific antibodies were measured by hemagglutination inhibition (HI) test using a pandemic H1N1 strain and a seasonal H3N2 virus. HI titers of ≥1:40 were considered as protective. Hemodialysis patients showed seroprotection against pandemic H1N1 in 35.1%, against seasonal influenza in 36.8% and against both in 14.0%. In comparison, renal transplant recipients developed protective antibody titers against the pandemic H1N1 virus in 47.9%, against the seasonal H3N2 strain in 31.3% and against both in 18.8%. HD patients and renal transplant recipients younger than 60 years developed protective antibody response to the pandemic influenza H1N1 vaccine in 50.0% of the HD patients and 55.2% of the RT recipients and against seasonal influenza in 45.0/20.7% (HD/RT) of the cases. Patients aged ≥60 years showed seroprotection against pandemic influenza in 27.0/36.8% (HD/RT) and against seasonal influenza in 32.4/47.4% (HD/RT). Side effects were reported in only four patients. In hemodialysis patients and renal transplant recipients, vaccination against pandemic H1N1 and seasonal influenza is well tolerated. However, more than a half of these patients did not develop seroprotective antibody levels. Thus, new vaccines and altered vaccination regimes are likely necessary to achieve relevant antibody levels in these patient groups.

Higher memory responses in HIV-infected and kidney transplanted patients than in healthy subjects following priming with the pandemic vaccine

Background

Memory responses require immune competence. We assessed the influence of priming with AS03-adjuvanted pandemic vaccine (Pandemrix®) on memory responses of HIV patients, kidney recipients (SOT) and healthy controls (HC).

Method

Participants (HIV: 197, SOT: 53; HC: 156) were enrolled in a prospective study and 390/406 (96%) completed it. All had been primed in 2009/2010 with 1 (HC) or 2 (patients) doses of Pandemrix®, and were boosted with the 2010/2011 seasonal influenza vaccine. Geometric mean titres and seroprotection rates were measured 12 months after priming and 4 weeks after boosting. Primary and memory responses were directly compared in 191 participants (HCW: 69, HIV: 71, SOT: 51) followed during 2 consecutive seasons.

Results

Most participants (HC: 77.8%, HIV: 77.6%, SOT: 66%) remained seroprotected at 12 months post-priming. Persisting A/09/H1N1 titers were high in HIV (100.2) and HC (120.1), but lower in SOT (61.4) patients. Memory responses reached higher titers in HIV (507.8) than in HC (253.5) and SOT (136.9) patients. Increasing age and lack of HAART reduced persisting and memory responses, mainly influenced by residual antibody titers. Comparing 2009/2010 and 2010/2011 titers in 191 participants followed for 2 seasons indicated lower post-2010/2011 titers in HC (240.2 vs 313.9), but higher titers in HIV (435.7 vs 338.0) and SOT (136 vs 90.3) patients.

Conclusions

Priming with 2 doses of Pandemrix® elicited persistent antibody responses and even stronger memory responses to non-adjuvanted seasonal vaccine in HIV patients than 1 dose in healthy subjects. Adjuvanted influenza vaccines may improve memory responses of immunocompromised patients.

Trial Registration

ClinicalTrials.gov NCT01022905

H1N1pdm09 adjuvanted vaccination in HIV-infected adults: a randomized trial of two single versus two double doses

Background

Since human immunodeficiency virus (HIV)-infected individuals are at increased risk of severe disease from pandemic influenza A (H1N1pdm09), vaccination was recommended as a prevention strategy. The aim of the present study was to evaluate the safety, immunogenicity and persistence of the immune response after vaccination against pandemic influenza A (H1N1pdm09) with an adjuvanted vaccine in human immunodeficiency virus (HIV)-infected adults using two single and two double doses.

Methodology/Principal Findings

Open label, randomized trial to evaluate the immune response following H1N1pdm09 vaccination in HIV-infected participants compared to HIV-negative controls (NCT01155037). HIV-infected participants were randomized to receive 2 single (3.75 µg hemagglutinin) or 2 double (7.5 µg hemagglutinin) doses of the vaccine, 21 days apart. Controls received one dose of the vaccine. The primary endpoint was seroconversion as measured by hemagglutination inhibition assay. Two hundred fifty six HIV-infected participants (129 and 127 randomized to single and double doses, respectively) and 71 HIV-negative controls were enrolled. Among HIV-infected participants, seroconversion increased from 46.7% and 51.7% after the first dose to 77.2% and 83.8% after the second dose of the vaccine using single and double doses, respectively. Participants aged >40 years showed higher seroconversion compared to younger participants. Seroconversion among HIV-infected women and those with nadir CD4<200 cells/mm³ was significantly higher with double doses. Persistence of protective antibodies six months after vaccination was achieved by 80% and 89.9% of the HIV-infected participants who received single and double doses, respectively.

Conclusions/Significance

Our results support the recommendation of two double doses of adjuvanted H1N1pdm09 vaccine for HIV-infected individuals, particularly women, and those aged >40 years or with nadir CD4<200 cells/mm³, to achieve antibody levels that are both higher and more sustained.

Trial Registration

ClinicalTrials.gov NCT01155037

Naturally-acquired influenza-specific CD4+ T-cell proliferative responses are impaired in HIV-infected African adults

Background

Seasonal influenza has been associated with greater morbidity and mortality in AIDS patients. Highly-active antiretroviral therapy (HAART) has led to some reduction in influenza-related complications but the nature of naturally-acquired T-cell immunity to influenza virus in an African setting, and how this changes with immune reconstitution following HAART is unknown. We measured influenza-specific CD4⁺ T-cell immunity in unimmunized HIV-infected Malawian adults and then investigated immune reconstitution following HAART.

Methods

Peripheral blood mononuclear cells were isolated from HIV-infected and HIV-uninfected Malawian adults. CFSE proliferation and CD154 expression flow cytometry-based assays were used to measure influenza-specific CD4⁺ T-cell immunity.

Results

We found lower naturally-acquired proliferative influenza-specific CD4⁺ T-cell responses in AIDS patients that was also present in asymptomatic HIV-infected adults with relatively high CD4 counts (>350 cells/µl). Influenza-specific CD4⁺ T-cell immune reconstitution in HIV-infected patients on HAART for 12 months was poor despite a marked reduction in viral load and an increase in CD4 count. This poor immune reconstitution was characterised by a low influenza-specific proliferative CD4⁺ T-cell response and reduced proportions of CD154-expressing influenza-specific CD4⁺ T-cells in peripheral blood.

Conclusion

Our data suggest that asymptomatic HIV-infected adults may also be at risk of influenza-related complications and that HAART alone may not circumvent this risk in AIDS patients. This study highlights the need to identify possible interventions early in HIV infection to reduce the risk of influenza and to intensify influenza surveillance in these susceptible African populations.

Safety and immunogenicity of 2009 pandemic H1N1 influenza vaccination in perinatally HIV-1-infected children, adolescents, and young adults

BACKGROUND

The safety and immunogenicity of high-dose pandemic H1N1 (pH1N1) vaccination in perinatally human immunodeficiency virus type 1 (HIV-1)-infected children, adolescents, and young adults are unknown.

METHODS

Two 30-μg doses of 2009 Novartis pH1N1 monovalent vaccine (Fluvirin) were administered 21-28 days apart to perinatally HIV-1-infected children, adolescents, and young adults. Antibodies were measured by hemagglutination inhibition (HAI) assay at baseline, 21-28 days after first vaccination, 7-13 days after the second vaccination, and 7 months after the first vaccination.

RESULTS

Among the 155 participants, 54 were aged 4-8 years, 51 were aged 9-17 years, and 50 were aged 18-24 years. After 2 doses of Fluvirin, seroresponse (≥ 4-fold rise in HAI titers) was demonstrated in 79.6%, 84.8%, and 83% of participants in the aforementioned age groups, respectively, and seroprotection (HAI titers ≥ 40) was shown in 79.6%, 82.6%, and 85.1%, respectively. Of those lacking seroresponse (n = 43) or seroprotection (n = 37) after the first vaccination, 46.5% and 40.5% achieved seroresponse or seroprotection, respectively, after the second vaccination. Among participants who lacked seroprotection at entry, a "complete response" (both seroresponse and seroprotection) after first vaccination was associated with higher baseline log(10) HAI titer and non-Hispanic ethnicity. No serious vaccine-related events occurred.

CONCLUSION

Two doses of double-strength pH1N1 vaccine are safe and immunogenic and may provide improved protection against influenza in perinatally HIV-1-infected children and youth.

CLINICAL TRIALS REGISTRATION

NCT00992836.

Pandemic H1N12009 influenza and HIV: a review of natural history, management and vaccine immunogenicity

PURPOSE OF REVIEW

The 2009 pandemic HIN1 influenza strain (H1N12009) produced more severe disease and increased risk for mortality. As an at-risk population for more severe influenza illness, particular concern regarding HIV patients triggered a focused effort to evaluate disease burden and vaccine efficacy in these populations.

RECENT FINDINGS

As with other immune-compromised individuals, most HIV-infected individuals recovered without major consequence. Although HIV infection was assumed to be a risk factor for more severe disease and death, the published literature does not indicate this to be so. Neuraminadase inhibitors were well tolerated by this population and there was no evidence of clinically significant pharmacokinetic interactions with antiretroviral therapy. Immunogenicity was increased with H1N12009 vaccine compared to the historical results of nonpandemic vaccines and optimized by the use of adjuvants. Booster dosing was also of benefit. H1N12009 vaccine was generally well tolerated without evidence of detrimental effect on HIV status.

SUMMARY

The worse case scenario was not realized for H1N12009 in the general population or in those with HIV. Immunization with adjuvant represents a key measure to protect this population from H1N12009 and other future novel influenza strains.

Response to 2009 pandemic and seasonal influenza vaccines co-administered to HIV-infected and HIV-uninfected former drug users living in a rehabilitation community in Italy

BACKGROUND

2009 A(H1N1) pandemic influenza vaccination was recommended as a priority to essential workers and high-risk individuals, including HIV-infected patients and people living in communities.

METHODS

HIV-infected and HIV-uninfected former drug-users (18-60 years old) living in a rehabilitation community (San Patrignano, Italy) received one dose of a MF59-adjuvanted 2009 pandemic influenza vaccine and one dose of a 2009-2010 seasonal trivalent inactivated influenza vaccine (containing A/Brisbane/59/2007(H1N1), A/Brisbane/10/2007(H3N2), B/Brisbane/60/2008) simultaneously. Antibodies against each vaccine antigen were determined at the time of vaccination and one and six months post-vaccination by hemagglutination-inhibition test.

RESULTS

49 HIV-infected and 60 HIV-uninfected subjects completed the study. Most (98%) HIV-infected participants were on antiretroviral treatment, the median CD4+ cell count was 350 (IQR 300)cells/μl and viremia was suppressed in 91.8% of cases. One month post-vaccination, no significant changes in immune-virological parameters were observed. One month post-vaccination, the immune responses to both pandemic and seasonal vaccine met the EMA-CPMP criteria for immunogenicity of influenza vaccines in both HIV-infected and HIV-uninfected subjects. No difference in vaccine responses was observed between the two groups. Six months after vaccination, the percentages of vaccinees with antibody titres ≥1:40 and antibody geometric mean titres significantly decreased in both groups. However, they were significantly lower in HIV-infected than in HIV-uninfected vaccinees. In subjects who had been primed to seasonal influenza the year before (through either vaccination or natural infection), levels of antibodies against 2009 A(H1N1) were higher than those measured in unprimed subjects, both one month and six months post-vaccination.

CONCLUSIONS

The co-administration of a single dose of 2009 pandemic MF59-adjuvanted influenza vaccine with a seasonal vaccine provided a protective immune response in both HIV-infected and HIV-uninfected individuals. Subjects who had been primed to seasonal influenza in the year preceding the pandemic had a more vigorous and long-lasting antibody response to 2009 pandemic vaccine.

Long-term immunogenicity after one and two doses of a monovalent MF59-adjuvanted A/H1N1 Influenza virus vaccine coadministered with the seasonal 2009-2010 nonadjuvanted Influenza virus vaccine in HIV-infected children, adolescents, and young adults in a randomized controlled trial

Few data are available on the safety and long-term immunogenicity of A/H1N1 pandemic influenza vaccines for HIV-infected pediatric patients. We performed a randomized controlled trial to evaluate the safety and long-term immunogenicity of 1 versus 2 doses of the 2009 monovalent pandemic influenza A/H1N1 MF59-adjuvanted vaccine (PV) coadministered with the seasonal 2009-2010 trivalent nonadjuvanted influenza vaccine (SV) to HIV-infected children, adolescents, and young adults. A total of 66 HIV-infected patients aged 9 to 26 years were randomized to receive one (group 1) or two (group 2) doses of PV coadministered with 1 dose of SV. The main outcome was the seroconversion rate for PV at 1 month. Secondary outcomes were the geometric mean titer ratios and the seroprotection rates at 1 month for all vaccines, seroconversion rates at 1 month for SV, and longitudinal changes of antibody titers (ABTs) at 1, 2, 6, and 12 months for all vaccines. Groups 1 and 2 had similar CD4 counts and HIV RNA levels during the study. The seroconversion rate for PV was 100% at 1 month in both groups. ABTs for PV were high during the first 6 months and declined below seroprotection levels thereafter. Longitudinal changes in ABTs were similar in groups 1 and 2 for both PV and SV. The side effects of vaccination were mild and mostly local. In HIV-infected children, adolescents, and young adults, the immune response triggered by a single dose of PV was similar to that obtained with a double dose and was associated with long-term antibody response.

Reduced immune response to influenza A (H1N1) 2009 monovalent vaccine in HIV-infected Japanese subjects

We evaluated the immunogenicity and safety of the influenza A (H1N1) 2009 monovalent vaccine in HIV-infected Japanese subjects. A total of 182 HIV-infected and 42 HIV-uninfected subjects were enrolled, and antibody (ab) titers were measured by hemagglutination-inhibition assay at baseline and 32.3±10.4 and 29.7±3.3 days after vaccination, respectively. In the HIV-infected cohort, ab titers ≥ 1:40 at baseline and post-vaccination were 12.6% and 49.5%, respectively. The seroconversion rate, defined as either an ab titer ≤ 1:10 before and ≥ 1:40 after or ≥ 1:10 before and ≥ 4-fold increase in ab titer, was only 38.5% in the HIV-infected cohort, whereas the rate was 85.7% in the HIV-uninfected cohort. Multivariate logistic regression analysis showed that the CD4 cell count was the only significant predictor of a positive vaccine response. There were no serious adverse events in any of the subjects receiving the vaccine. Additional study is warranted to identify a more effective method of vaccinating HIV-infected Japanese subjects.