Glycoprotein Enzyme-linked Immunosorbent Assay Research Articles

Analysis of antibody dynamics in Chinese children aged 1-3 years after single-dose varicella vaccination: A 42 months prospective study

ABSTRACT In China, children aged 12 months receive only a single dose of the varicella vaccine and the incidence of varicella remains high. This study aims to evaluate the changes in immunity among children aged 1–3 years following a single dose of the varicella vaccine, providing a scientific basis for determining the optimal age for a second vaccination. This prospective cohort study employed glycoprotein enzyme-linked immunosorbent assay (gpELISA) for antibody detection. The changes in IgG antibody levels over time post-vaccination were analyzed using a restricted cubic spline (RCS) fitted binary logistic regression model. Varicella surveillance data were collected from the National Notifiable Disease Reporting System (NNDRS). Following a peak in varicella incidence in 2019, the incidence shifted toward older age groups. The cohort study results revealed a seropositivity rate of 100% in children during the 18 months post-vaccination, which subsequently declined to 71.6% by the 42 months. The geometric mean concentration (GMC) decreased from 307.6mIU/mL to 115.2mIU/mL. Additionally, 14 children contracted varicella during the follow-up period, resulting in a breakthrough rate of 2.85%. RCS analysis indicated that antibody levels fell below the protective threshold 18.69 months post-vaccination, with a non-linear decline in the odds ratio(OR) of maintaining antibody concentrations ≥ 50mIU/mL(p < .001, Pnonlinear ≤ 0.001). This study demonstrates that the long-term protective efficacy of a single dose of the varicella vaccine diminishes over time in children, underscoring the necessity of implementing a two-dose vaccination strategy. The findings provide scientific evidence for determining the optimal timing for administering the second dose of the vaccine.

Cat alpha-1-acid glycoprotein enzyme-linked immunosorbent assay: performance characteristics and reference intervals.

The aim of this study was to evaluate performance of a feline-specific ELISA for the measurement of alpha-1-acid glycoprotein (AGP) and to establish a reference interval (RI). Surplus serum samples with low (~200 µg/ml), medium (~450 µg/ml) and high (~745 and 930 µg/ml) AGP concentrations were used to assess the intra- and inter-assay coefficients of variation (CVs). The quality goal for bioanalytical method validation was a CV of <20%. Linearity was assessed by serial dilution of a sample with a high AGP concentration. Spike recovery was evaluated by mixing samples with low, medium and high AGP concentrations at different ratios. To establish the RI, residual serum samples from 51 healthy adult cats that were presented for health examinations or blood donation between August 2020 and June 2021 were included. The intra-assay CV was 8.5%, 4.3% and 4.0%, and the inter-assay CV was 18.8%, 15.5% and 11.5% for serum samples with low, medium and high AGP concentrations, respectively. Excellent linearity (R2 = 0.98) was demonstrated for AGP concentrations ranging between 251.6 and 954.4 µg/ml. Average recovery was 95.0-99.7%. The right-sided RI for AGP was 328 µg/ml (90% confidence interval 300-354). Age had a statistically significant impact (increasing values with older age, P = 0.0026), but sex did not (P = 0.44), on AGP concentrations. The ELISA was accurate and showed acceptable precision with the modification of dilution used in this study. AGP concentrations in this population appeared to increase with increasing age.

Immune response of a two-dose heterologous Ebola vaccine regimen: summary of three African clinical trials using a single validated Filovirus Animal Nonclinical Group enzyme-linked immunosorbent assay in a single accredited laboratory

This analysis evaluated the immune response to the two-dose, heterologous Ad26.ZEBOV, MVA-BN-Filo Ebola virus vaccine regimen, administered 56-days apart, from multiple African sites based on results from one analytic laboratory. Immunogenicity across three trials (EBL2002, EBL2004/PREVAC, EBL3001) conducted in East and West Africa is summarised. Vaccine-induced Ebola glycoprotein-binding antibody concentrations were analysed by Q2 Solutions laboratory at baseline, 21 days (EBL2002 and EBL3001) or 28 days (EBL2004) post-dose 2 (regimen completion), and 12 months post-dose 1 using the validated Filovirus Animal Nonclinical Group Ebola glycoprotein enzyme-linked immunosorbent assay (ELISA). Responders were defined as those with a >2.5-fold increase from baseline or the lower limit of quantification (LLOQ) if<LLOQ at baseline. At 21 or 28 (21/28) days post-dose 2, the geometric mean concentration (GMC) range was 3810-7518 ELISA units (EU)/mL (percent responders: ≥98%) in adults, 9929-13532 EU/mL (≥98%) in adolescents aged 12-17 years, 10,212-17388 EU/mL (≥99%) in older children, and 22,568-25111 EU/mL (≥98%) in younger children. When stratified by country, GMCs at 21/28 days post-dose 2 were generally similar among adults and within paediatric cohorts (percent responders: 95%-100%). At month 12, GMC range was 259-437 EU/mL (percent responders: 49%-88%) in adults and 386-1139 EU/mL (70%-100%) in paediatric participants. Based on data from a single laboratory using a single validated assay, Ad26.ZEBOV, MVA-BN-Filo induced a strong humoral immune response, with ≥95% of participants across countries classified as responders at 21/28 days post-dose 2 (regimen completion), regardless of age. Janssen Vaccines & Prevention BV; Innovative Medicines Initiative.

Immunological characteristics of MAV/06 strain of varicella-zoster virus vaccine in an animal model

BackgroundVaricella-zoster virus (VZV) is a pathogen that causes chickenpox and shingles in humans. Different types of the varicella vaccines derived from the Oka and MAV/06 strains are commercially available worldwide. Although the MAV/06 vaccine was introduced in 1990s, little was known about immunological characteristics.ResultsHere, we evaluated B and T cell immune response in animals inoculated with the Oka and MAV/06 vaccines as well as a new formulation of the MAV/06 vaccine. A variety of test methods were applied to evaluate T and B cell immune response. Plaque reduction neutralization test (PRNT) and fluorescent antibody to membrane antigen (FAMA) assay were conducted to measure the MAV/06 vaccine-induced antibody activity against various VZVs. Glycoprotein enzyme-linked immunosorbent assay (gpELISA) was used to compare the degree of the antibody responses induced by the two available commercial VZV vaccines and the MAV/06 vaccine. Interferon-gamma enzyme-linked immunosorbent spot (IFN-γ ELISpot) assays and cytokine bead array (CBA) assays were conducted to investigate T cell immune responses. Antibodies induced by MAV/06 vaccination showed immunogenicity against a variety of varicella-zoster virus and cross-reactivity among the virus clades.ConclusionsIt is indicating the similarity of the antibody responses induced by commercial varicella vaccines and the MAV/06 vaccine. Moreover, VZV-specific T cell immune response from MAV/06 vaccination was increased via Th1 cell response. MAV/06 varicella vaccine induced both humoral and cellular immune response via Th1 cell mediated response.

Phase 3, open-label, Russian, multicenter, single-arm trial to evaluate the immunogenicity of varicella vaccine (VARIVAX™) in healthy infants, children, and adolescents

ABSTRACT Varicella (chickenpox) is a common, highly contagious disease caused by primary infection with varicella zoster virus (VZV), which can result in bacterial superinfection, central nervous system complications, and hospitalization. Stage 2 of this Phase 3 open-label study (ClinicalTrials.gov identifier: NCT03843632) enrolled 100 healthy infants, children, and adolescents (12 months–6 years, n = 37; 7–12 years, n = 33; 13–17 years, n = 30) without a clinical history of varicella. Participants aged 12 months–12 years were administered 1 dose of VARIVAX™ 0.5 mL (Varicella Virus Vaccine Live [Oka/Merck]) and adolescents aged 13–17 years were administered 2 doses 6 weeks apart. For participants seronegative at baseline (VZV antibody titer <1.25 glycoprotein enzyme-linked immunosorbent assay [gpELISA] units/mL), immunogenicity was assessed by seroconversion (VZV antibody titer ≥5 gpELISA units/mL) and VZV antibody geometric mean titers 6 weeks after the final dose. For participants who were VZV seropositive at baseline (VZV antibody titer ≥1.25 gpELISA units/mL), immunogenicity was assessed by antibody titer geometric mean fold rise and percentage of participants with ≥4-fold rise in antibody titer 6 weeks after the final dose. A Vaccine Report Card was used to report solicited and unsolicited adverse events through 42 days post-vaccination. After series completion among seronegative participants across age groups (n = 74), 98.6% demonstrated seroconversion 6 weeks post-vaccination; among seropositive participants (n = 26), 65.4% had ≥4-fold rise in antibody titer 6 weeks post-vaccination. No new safety signals were observed. Administering VARIVAX to infants, children, and adolescents resulted in an acceptable immune response with a safety profile consistent with the licensed product.

The Safety and Immunologic Effectiveness of the Live Varicella-Zoster Vaccine in Patients Receiving Tumor Necrosis Factor Inhibitor Therapy : A Randomized Controlled Trial.

The safety and effectiveness of live virus vaccines, such as the varicella-zoster vaccine, are unknown in patients with inflammatory diseases receiving immunomodulatory therapy such as tumor necrosis factor inhibitors (TNFis). To evaluate the safety and immunogenicity of the live attenuated zoster vaccine (ZVL) in patients receiving TNFis. Randomized, blinded, placebo-controlled trial. (ClinicalTrials.gov: NCT02538341). Academic and community-based rheumatology, gastroenterology, and dermatology practices. Adults aged 50 years or older receiving TNFis for any indication. Random assignment to ZVL versus placebo. Glycoprotein enzyme-linked immunosorbent assay (gpELISA) and enzyme-linked immunosorbent spot (ELISpot) from serum and peripheral blood mononuclear cells measured at baseline and 6 weeks after vaccination. Suspected varicella infection or herpes zoster was clinically assessed using digital photographs and polymerase chain reaction on vesicular fluid. Between March 2015 and December 2018, 617 participants were randomly assigned in a 1:1 ratio to receive ZVL (n = 310) or placebo (n = 307) at 33 centers. Mean age was 62.7 years (SD, 7.5); 66.1% of participants were female, 90% were White, 8.2% were Black, and 5.9% were Hispanic. The most common TNFi indications were rheumatoid arthritis (57.6%) and psoriatic arthritis (24.1%); TNFi medications were adalimumab (32.7%), infliximab (31.3%), etanercept (21.2%), golimumab (9.1%), and certolizumab (5.7%). Concomitant therapies included methotrexate (48.0%) and oral glucocorticoids (10.5%). Through week 6, no cases of confirmed varicella infection were found; cumulative incidence of varicella infection or shingles was 0.0% (95% CI, 0.0% to 1.2%). At 6 weeks, compared with baseline, the mean increases in geometric mean fold rise as measured by gpELISA and ELISpot were 1.33 percentage points (CI, 1.17 to 1.51 percentage points) and 1.39 percentage points (CI, 1.07 to 1.82 percentage points), respectively. Potentially limited generalizability to patients receiving other types of immunomodulators. This trial informs safety concerns related to use of live virus vaccines in patients receiving biologics. The National Institute of Arthritis and Musculoskeletal and Skin Diseases and the American College of Rheumatology.

Phase 3, open-label, Russian, multicenter, single-arm trial to evaluate the immunogenicity of varicella vaccine (VARIVAX™) in healthy adults

ABSTRACT Varicella (chickenpox) is a common, highly contagious disease caused by primary infection with varicella zoster virus (VZV). Adults typically experience more severe symptoms than children and have a higher risk of developing complications. Stage 1 of this Phase 3 open-label study enrolled healthy adults in Russia aged 18–75 years without a clinical history of varicella infection. Eligible participants (n = 50) were administered 2 doses of VARIVAX™ (Varicella Virus Vaccine Live [Oka/Merck]) 0.5 mL 6 weeks apart. For participants seronegative at baseline (VZV antibody titer <1.25 glycoprotein enzyme-linked immuno-sorbent assay [gpELISA] units/mL), immunogenicity was assessed by seroconversion (VZV antibody titer ≥5 gpELISA units/mL) and assessment of geometric mean titers of VZV antibody as measured by gpELISA 6 weeks after Dose 2. For VZV seropositive participants at baseline (VZV antibody titer ≥1.25 gpELISA units/mL), immunogenicity was assessed by geometric mean fold rise in antibody titer and percentage of participants with a ≥ 4-fold rise in antibody titer 6 weeks after Dose 2. A Vaccine Report Card was used to record solicited and unsolicited adverse events through 42 days post-vaccination. All participants who were seronegative (n = 26) at baseline demonstrated seroconversion 6 weeks after Dose 2. Among participants who were seropositive at baseline (n = 23), 60.9% had a ≥4-fold rise in antibody titer 6 weeks after Dose 2. Vaccination was generally well tolerated, with no new safety signals identified. Administration of 2 doses of VARIVAX in adults in Russia results in acceptable immune responses with safety data consistent with the licensed product (Clinicaltrials.gov identifier: NCT03843632).

Baseline Asymptomatic Malaria Infection and Immunogenicity of Recombinant Vesicular Stomatitis Virus-Zaire Ebola Virus Envelope Glycoprotein.

The effect of malaria infection on the immunogenicity of the recombinant vesicular stomatitis virus-Zaire Ebola virus envelope glycoprotein (GP) vaccine (rVSVΔG-ZEBOV-GP) (ERVEBO) is unknown. The Sierra Leone Trial to Introduce a Vaccine Against Ebola (STRIVE) vaccinated 7998 asymptomatic adults with rVSVΔG-ZEBOV-GP during the 2014-2016 Ebola epidemic. In STRIVE's immunogenicity substudy, participants provided blood samples at baseline and at 1, 6, and 9-12 months. Anti-GP binding and neutralizing antibodies were measured using validated assays. Baseline samples were tested for malaria parasites by polymerase chain reaction. Overall, 506 participants enrolled in the immunogenicity substudy and had ≥1 postvaccination antibody titer. Of 499 participants with a result, baseline malaria parasitemia was detected in 73 (14.6%). All GP enzyme-linked immunosorbent assay (ELISA) and plaque reduction neutralization test (PRNT) geometric mean titers (GMTs) at 1, 6, and 9-12 months were above baseline, and 94.1% of participants showed seroresponse by GP-ELISA (≥2-fold rise and ≥200 ELISA units/mL), while 81.5% showed seroresponse by PRNT (≥4-fold rise) at ≥1 postvaccination assessment. In participants with baseline malaria parasitemia, the PRNT seroresponse proportion was lower, while PRNT GMTs and GP-ELISA seroresponse and GMTs showed a trend toward lower responses at 6 and 9-12 months. Asymptomatic adults with or without malaria parasitemia had robust immune responses to rVSVΔG-ZEBOV-GP, persisting for 9-12 months. Responses in those with malaria parasitemia were somewhat lower.

Cross-Sectional Study of Varicella Zoster Virus Immunity in Healthy Korean Children Assessed by Glycoprotein Enzyme-Linked Immunosorbent Assay and Fluorescent Antibody to Membrane Antigen Test.

The prevalence of varicella is especially high among children in the age group of 4–6 years in South Korea, regardless of vaccination. We investigated the immune status of healthy children enrolled in day-care centers and compared pre- and post-vaccination immunity. Antibody titers were measured using a glycoprotein enzyme-linked immunosorbent assay (gpEIA) kit, and the seroconversion rate was assessed using a fluorescent antibody to membrane antigen (FAMA) test. Among 541 vaccinated children, 109 (20.1%) had breakthrough varicella. However, 13 (72.2%) of the 18 unvaccinated children had a history of varicella. The gpEIA geometric mean titers (GMTs) of pre- and 5 weeks post-vaccination in 1-year-old children were 14.7 and 72 mIU/mL, respectively, and the FAMA seroconversion rate was 91.1%. The gpEIA GMTs of 2-, 3-, 4-, 5-, and 6-year-old children were 104.1, 133.8, 223.5, 364.1, and 353.0 mIU/mL, respectively. Even though the gpEIA GMT increased with age, the pattern of gpEIA titer distribution in 4- to 6-year-old vaccinees without varicella history represented both waning immunity and natural boosting immunity. These results suggest that some vaccinees are vulnerable to varicella infection. Therefore, it is necessary to consider a two-dose varicella vaccine regimen in South Korea.

Immunogenicity and safety of a live herpes zoster vaccine in hematopoietic stem cell transplant recipients

BackgroundHerpes zoster (HZ) infection of hematopoietic stem cell transplant (HSCT) patients is of clinical concern. Vaccination could help restore immunity to varicella zoster virus (VZV); however, temporal changes in immunogenicity and safety of live HZ vaccines after HSCT is still unclear. The aim of this study was to elucidate the temporal immunogenicity and safety of the HZ vaccine according to time since HSCT and to determine optimal timing of vaccination.MethodsLive HZ vaccine was administered to patients 2–5 years or > 5 years post-HSCT. Control groups comprised patients with a hematologic malignancy who received cytotoxic chemotherapy and healthy volunteers. Humoral and cellular immunogenicity were measured using a glycoprotein enzyme-linked immunosorbent assay (gpELISA) and an interferon-γ (IFN-γ) enzyme-linked immunospot (ELISPOT) assay. Vaccine-related adverse events were also monitored.ResultsFifty-six patients with hematologic malignancy (41 in the HSCT group and 15 in the chemotherapy group) along with 30 healthy volunteers were enrolled. The geometric mean fold rises (GMFRs) in humoral immune responses of the 2–5 year and > 5 year HSCT groups, and the healthy volunteer group, were comparable and significantly higher than that of the chemotherapy group (3.15, 95% CI [1.96–5.07] vs 5.05, 95% CI [2.50–10.20] vs 2.97, 95% CI [2.30–3.83] vs 1.42, 95% CI [1.08–1.86]). The GMFR of cellular immune responses was highest in the HSCT 2–5 year group and lowest in the chemotherapy group. No subject suffered clinically significant adverse events or reactivation of VZV within the follow-up period.ConclusionOur findings demonstrate that a live HZ vaccine is immunogenic and safe when administered 2 years post-HSCT.

Immune response to varicella-zoster virus before and after renal transplantation

BackgroundHerpes zoster (HZ) risk is high in renal transplant recipients. Vaccination prior to transplantation may provide a useful strategy for the prevention of HZ in the posttranplantation period. However, it is not known whether immunity to varicella-zoster virus (VZV) is affected due to treatment surrounding transplantation. MethodsBoth humoral and cellular immunity to VZV were determined prior to and 2–3 years after renal transplantation in 60 adult patients, and 62 matched healthy controls. VZV-specific cellular immunity was measured by an interferon gamma (IFNγ) enzyme-linked immunospot (ELISpot) assay and by analyzing T-cell functionality using flowcytometry. VZV-IgG levels were measured using an in-house glycoprotein enzyme-linked immunosorbent assay (gpELISA). ResultsUsing paired analysis, it was determined that numbers of IFNγ-producing cells did not change after transplantation, but were significantly lower in transplant recipients after transplantation than in controls (p = 0.028). Patients in whom the post-transplant period was complicated by rejection or any acute infection (excluding HZ) had a lower number of IFNγ-producing cells than patients who did not. VZV IgG levels did not differ from controls, but a significant decrease was observed after transplantation (p < 0.0001). ConclusionsVZV-specific cellular immunity, which is essential in the prevention of HZ, did not markedly change in patients following renal transplantation. This suggests that preventive vaccination before transplantation may be beneficial. Our results extend knowledge on VZV immunity after transplantation, vital when considering strategies for the prevention of HZ in these patients.

Immunogenicity of Inactivated Varicella Zoster Vaccine in Autologous Hematopoietic Stem Cell Transplant Recipients and Patients With Solid or Hematologic Cancer.

BackgroundIn phase 3 trials, inactivated varicella zoster virus (VZV) vaccine (ZVIN) was well tolerated and efficacious against herpes zoster (HZ) in autologous hematopoietic stem cell transplant (auto-HSCT) recipients and patients with solid tumor malignancies receiving chemotherapy (STMc) but did not reduce HZ incidence in patients with hematologic malignancies (HMs). Here, we describe ZVIN immunogenicity from these studies.MethodsPatients were randomized to ZVIN or placebo (4 doses). Immunogenicity was assessed by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and VZV interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) assay in patients receiving all 4 doses without developing HZ at the time of blood sampling.ResultsEstimated geometric mean fold rise ratios (ZVIN/placebo) by gpELISA and IFN-y ELISPOT ~28 days post–dose 4 were 2.02 (95% confidence interval [CI], 1.53–2.67) and 5.41 (95% CI, 3.60–8.12) in auto-HSCT recipients; 1.88 (95% CI, 1.79–1.98) and 2.10 (95% CI, 1.69–2.62) in patients with STMc; and not assessed and 2.35 (95% CI, 1.81–3.05) in patients with HM.ConclusionsZVIN immunogenicity was directionally consistent with clinical efficacy in auto-HSCT recipients and patients with STMc even though HZ protection and VZV immunity were not statistically correlated. Despite a lack of clinical efficacy in patients with HM, ZVIN immunogenicity was observed in this population. Immunological results did not predict vaccine efficacy in these 3 populations.Clinical trial registrationNCT01229267, NCT01254630.

Immunogenicity and safety of a new live attenuated herpes zoster vaccine (NBP608) compared to Zostavax® in healthy adults aged 50 years and older

A multi-centre, randomised, double-blinded, active-controlled, parallel-group clinical trial was carried out to assess the immunogenicity and safety of NBP608—a newly developed live-attenuated zoster vaccine in Korea—relative to Zostavax® in healthy adults aged 50 years or older. Immune responses to the vaccine were evaluated by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and enzyme-linked immunosorbent spot (ELISPOT) assays using the interferon (IFN)-γ and interleukin (IL)-2 FluoroSpot kit 6 weeks after vaccination. Safety was monitored for 26 weeks based on subjects’ diaries, spontaneous reports from subjects, and history taking by the investigators. A total of 845 subjects participated in the screening, and 823 received the vaccination (413 in the NBP608 group and 411 in the comparator group). The gpELISA-determined geometric mean fold rise from baseline to post NBP608 vaccination was 2.75 [95% confidence interval, CI (2.57, 2.94)]. The gpELISA-determined adjusted geometric mean titers (GMTs) of NBP608 and the comparator were 1346.37 [95% CI (1273.99, 1422.87)] and 1674.94 [95% CI (1585.35, 1769.58)], respectively. The adjusted GMT ratio of NBP608 to the comparator was 0.80 [95% CI (0.75, 0.87)]. There was no statistically significant difference between two groups in terms of the geometric mean spot numbers determined by IFN-γ and IL-2 ELISPOT assays at 6 weeks post vaccination (P = 0.7232, 0.3844). The incidence of adverse events (AEs) within 6 weeks post vaccination was 49.82% overall (410/823, 941 cases), 50.73% (209/412, 474 cases) in the NBP608 group, and 48.91% (201/411, 467 cases) in the comparator group. The difference in AE rate between the two groups was not statistically significant (P = 0.6010). Most AEs were mild, with a rate of 83.12% in the NBP608 group and 75.37% in the comparator group. Thus, NBP608 is non-inferior to Zostavax® in terms of inducing the immune response and can be safely administered to adults aged 50 years or older.ClinicalTrials.gov Identifier: NCT03120364.

Increased incidence of herpes zoster in patients on renal replacement therapy cannot be explained by intrinsic defects of cellular or humoral immunity to varicella-zoster virus

BackgroundPatients in need of long-term renal replacement therapy (RRT) are known to be at increased risk of herpes zoster, occurring when the latently present varicella-zoster virus (VZV) reactivates. In this study we investigated immunity to VZV in patients receiving RRT, with the aim of better understanding the mechanism behind the increased risk. MethodsPatients treated for at least three months with hemodialysis or peritoneal dialysis, and matched healthy controls (HC) were included. Cellular immunity to varicella-zoster virus (VZV) was studied using an interferon-γ (IFNγ) enzyme-linked immunospot (ELISpot) assay, flow-cytometric analysis of cytokine production and a proliferation assay. Humoral immunity was determined by measuring immunoglobulin (Ig)G antibody levels to VZV using an in-house glycoprotein enzyme-linked immunosorbent assay (ELISA). Multiple regression was used to assess variables of influence on measures of cellular and humoral immunity to VZV in patients receiving RRT. ResultsSimilar numbers of IFNγ spot-forming cells and levels of VZV-IgG were found in 97 patients and 89 HC. Age and transplantation history were negatively associated with cellular immunity (p = 0.001 and p = 0.012, respectively) while treatment modality, gender and urea levels were not. No variables were found to be associated with VZV-IgG levels. ConclusionsIncreased incidence of herpes zoster in patients receiving RRT cannot be explained by intrinsic defects of cellular or humoral immunity to VZV as measured by the methods used in this study, although older age and previous transplantation were associated with decreased cellular immunity to VZV. Herpes zoster susceptibility might be caused by a diminished function of otherwise capable T cells in a uremic environment.

Safety and Immunogenicity of Zoster Vaccine Live in Human Immunodeficiency Virus-Infected Adults With CD4+ Cell Counts >200 Cells/mL Virologically Suppressed on Antiretroviral Therapy.

Herpes zoster (HZ) risk is increased in human immunodeficiency virus (HIV)-infected persons. Live attenuated zoster vaccine (ZV) reduces HZ incidence and severity in adults; safety and immunogenicity data in HIV-infected adults are limited. We conducted a randomized, double-blind, placebo-controlled trial in HIV-infected adults virally suppressed on antiretroviral therapy (ART). Participants, stratified by CD4+ count (200-349 or ≥350 cells/µL), were randomized 3:1 to receive ZV or placebo on day 0 and week 6. The primary endpoint was serious adverse event or grade 3/4 signs/symptoms within 6 weeks after each dose. Immunogenicity (varicella zoster virus [VZV]-specific glycoprotein enzyme-linked immunosorbent assay and interferon-γ enzyme-linked immunospot assay responses) was assessed at 6 and 12 weeks postvaccination. Of 395 participants (296 ZV vs 99 placebo), 84% were male, 47% white, 29% black, and 22% Hispanic; median age was 49 years. Safety endpoints occurred in 15 ZV and 2 placebo recipients (5.1% [95% confidence interval {CI}, 2.9%-8.2%] vs 2.1% [95% CI, .3%-7.3%]; P = .26). Injection site reactions occurred in 42% of ZV (95% CI, 36.3%-47.9%) vs 12.4% of placebo recipients (95% CI, 6.6%-20.6%) (P < .001). Week 12 median natural log VZV antibody titer was higher for ZV (6.30 [Q1, Q3, 5.64, 6.96]) vs placebo (5.48 [Q1, Q3, 4.63, 6.44]; P < .001) overall and in the high CD4+ stratum (P = .003). VZV antibody titers were similar after 1 or 2 ZV doses. Polymerase chain reaction-confirmed HZ occurred in 2 participants (1 ZV; 1 placebo); none was vaccine strain related. Two doses of ZV in HIV-infected adults suppressed on ART with CD4+ counts ≥200 cells/µL were safe and immunogenic. NCT00851786.

Optimal Timing of Zoster Vaccination After Shingles: A Prospective Study of the Immunogenicity and Safety of Live Zoster Vaccine.

BackgroundZoster vaccination is recommended for people with a history of herpes zoster (HZ), but the most effective timing of vaccine administration after zoster illness is unresolved. This prospective observational study compared the immunogenicity and safety of administering HZ vaccine at 6-12 months and 1-5 years after zoster illness.Materials and MethodsBlood samples were collected before the administration of live zoster vaccine and 6 weeks after vaccination. Varicella-zoster virus (VZV) IgG concentrations and T-cell responses were assessed by glycoprotein enzyme-linked immunosorbent assay and interferon-γ enzyme-linked immunospot assay (ELISPOT), respectively.ResultsThe baseline geometric mean value (GMV) of VZV IgG was higher in the 6-12 months group than in the 1-5 years group (245.5 IU/mL vs. 125.9 IU/mL; P = 0.021). However, the GMV increased significantly in both groups (P = 0.002 in the 6-12 months group; P <0.001 in the 1-5 years group). The results of the ELISPOT assay were not significant for differences of the GMV between baseline and 6-week post-vaccination groups, while the GMV increased significantly in both groups (P = 0.001 in the 6-12 months group; P <0.001 in the 1-5 years group).ConclusionThe immunogenicity of zoster vaccine may be similar whether administered 6-12 months, or >1 year after zoster illness.Trial RegistrationClinicalTrials.gov Identifier: NCT02704572

Evaluation of immunogenicity and safety of VARIVAX™ New Seed Process (NSP) in children

ABSTRACTPrior to availability of an effective vaccine, an estimated 4 million cases of varicella occurred annually in the United States, resulting in 10,000 hospitalizations and over 100 deaths. With the increased usage of a two-dose varicella vaccine (as recommended by the ACIP), approval of other VZV-containing products and the adoption of varicella vaccination in additional countries, the demand for VZV-containing vaccines has increased. This study (NCT02062502) evaluated the safety, tolerability, and immunogenicity of VARIVAX™ (VAR, varicella vaccine live) manufactured using a new seed manufacturing process (VARNSP) compared to the currently licensed VAR.Healthy children 12–23 months were randomized (1:1) into Group 1 (2 doses of VARNSP given concomitantly with M-M-R™ II, ∼3 months apart) versus Group 2 (2 doses of VAR given concomitantly with M-M-R™ II, ∼3 months apart). Serum samples collected prior to vaccination on Day 1 and 6 weeks Postdose 1 were tested for antibody to VZV using a glycoprotein enzyme-linked immunosorbent assay (gpELISA). Safety was assessed Days 1 to 42 following each vaccination.Six weeks Postdose 1, the response rate (percent of subjects with VZV antibody titer ≥5 gpELISA units/mL) of VARNSP was non-inferior compared to VAR. Vaccine-related adverse events (AEs) were comparable with the exception of measles-like rash, where a greater number of rashes were observed with VAR than VARNSP. The 2 vaccination groups were comparable with incidence rates of AEs, injection-site AEs, vaccine-related AEs, systemic AEs, and serious AEs.This new process is an important innovation for the extreme demand of sustaining sufficient supplies of varicella vaccine to protect our communities against diseases caused by VZV.

Immunogenicity of Inactivated Varicella Zoster Vaccine (ZVIN) in Autologous Hematopoietic Stem Cell Transplant (auto-HSCT) Recipients

BackgroundRecipients of auto-HSCT have an increased risk of herpes zoster (HZ) infection; however, live attenuated varicella-zoster virus (VZV) vaccine is contraindicated in these patients. In this pivotal Phase III study (V212-001; NCT01229267) inactivated VZV vaccine (ZVIN) reduced the rate of HZ infection compared with placebo (estimated vaccine efficacy, 63.8%) and was well tolerated. Immunogenicity of ZVINin recipients of auto-HSCT was assessed in the Phase III study as an exploratory objective.MethodsAdults undergoing auto-HSCT were randomized to receive either ZVIN(n = 560) or placebo (n = 564), administered in a 4-dose regimen. Doses 1 through 4 were administered ~30 days before and ~30, ~60, and ~90 days following auto-HSCT. VZV-specific immune responses were measured at Day 1, ~28 days post-vaccinations 3 and 4, and annually until the end of the study. VZV-specific antibody responses were measured by glycoprotein enzyme-linked immunosorbent assay (gpELISA) in all patients; cell-mediated immune responses were measured by VZV interferon-gamma enzyme-linked immunospot (IFN-γ ELISPOT) assay in a randomized subset of patients (n = 403).ResultsGeometric mean titers (GMT) were significantly higher and the ratios of the gpELISA and IFN-γ ELISPOT were significantly greater in the ZVINgroup compared with the placebo group (Tables 1 and 2).Table 1. GMT 28 days post-dose 4 (PD4) Vaccine Placebo gpELISA n = 102 n = 108 241.8 (95% CI: 186.2, 313.9)105.8 (95% CI: 84.6, 132.3) IFN-γ ELISPOT n = 102 n = 116 62.8 (95% CI: 45.8, 86.2)10.4 (95% CI: 7.9, 13.7)Table 2. Ratios of geometric mean fold rise between the vaccine and placebo groups (ZVIN/placebo) gpELISA (n = 764) IFN-γ ELISPOT (n = 339) Pre-vaccination and 28 days PD4 1.79 (95% CI: 1.39, 2.32)5.41 (95% CI: 3.60, 8.12) Pre-vaccination and 1 year PD4 1.30 (95% CI: 0.99, 1.71)4.12 (95% CI: 2.62, 6.47)ConclusionZVIN elicited higher VZV-specific humoral and cell-mediated responses in adult auto-HSCT recipients when compared with placebo ~28 days and ~1 year post-dose 4. These results indicate that ZVIN is immunogenic in these patients who are ineligible for live attenuated HZ vaccine, which is consistent with previously observed clinical efficacy.Disclosures M. Boeckh, Merck: Investigator, Research Contractor and Scientific Advisor, Consulting fee and Research support; GlaxoSmithKline: Research Contractor, Research support; A. Arvin, Merck: Scientific Advisor, Consulting fee; K. Mullane, Merck: Scientific Advisor, Grant recipient; D. J. Winston, Merck: Grant Investigator and Scientific Advisor, Consulting fee and Grant recipient; J. Brown, Merck: Clinical adjudication and site investigator and Investigator, Consulting fee; Cellerant Therapeutics: Consultant, Cellerant developing and executing clinical trials of myeloid progenitor cells in neutropenia for which I hold the patent; S. Pergam, Merck: Consultant and Investigator, Consulting fee; K. Hurtado, Merck: Employee and Shareholder, Salary; L. Pang, Merck: Employee and Shareholder, Salary; I. Lee, Merck: Employee, Salary; Z. Popmihajlov, Merck & Co., Inc.: Employee and Shareholder, Salary

Immunogenicity and safety of zoster vaccine live administered with quadrivalent influenza virus vaccine

ObjectivesRandomized, blinded, placebo-controlled trial to evaluate the safety and immunogenicity of ZOSTAVAX™ (ZV) administered concomitantly with quadrivalent inactivated influenza vaccine (IIV4) in adults≥50years of age (NCT02519855). MethodsOverall, 440 participants were randomized into the Concomitant Group (CG) and 442 into the Sequential Group (SG). The CG received ZV and IIV4 at separate injection sites on Day 1 and matching placebo at Week 4. The SG received placebo and IIV4 (2015–2016 influenza season) at separate injection sites on Day 1 and ZV at Week 4. Immunogenicity endpointsVaricella-zoster virus (VZV) antibody geometric mean titer (GMT) and geometric mean fold-rise (GMFR) from baseline to 4weeks postvaccination, measured by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and adjusted for age and prevaccination titer. Influenza strain-specific GMT at baseline and 4weeks postvaccination was measured by hemagglutination inhibition (HAI) assay. Safety endpointsInjection-site and systemic adverse experiences (AEs) within 28days following any vaccination and serious AEs throughout the study. ResultsThe adjusted VZV antibody GMT ratio (CG/SG) was 0.87 (95%CI: 0.80, 0.95), meeting the prespecified noninferiority criterion. The VZV antibody GMFR in the CG was 1.9 (95%CI: 1.76, 2.05), meeting the acceptability criterion. Influenza antibody GMT ratios for A/H1N1, A/H3N2, B/Yamagata and B/Victoria were 1.02 (95%CI: 0.88, 1.18), 1.10 (95%CI: 0.94, 1.29), 1.00 (95%CI: 0.88, 1.14), and 0.99 (95%CI: 0.87, 1.13), respectively. The frequency of vaccine-related injection-site and systemic AEs was comparable between groups. No vaccine-related serious AE was observed. ConclusionThe concomitant administration of ZV and IIV4 to adults≥50years of age induced VZV-specific and influenza-specific antibody responses that were comparable to those following administration of either vaccine alone, and was generally well tolerated.

Evaluation of a bovine pregnancy-associated glycoprotein enzyme-linked immunosorbent assay kit for serological diagnosis of pregnancy in sheep

ABSTRACT: Pregnancy diagnosis is an important tool for farm management. Ultrasonography is the main technique used for pregnancy diagnosis in ewes. As an alternative, radioimmunoassay (RIA) allows accurate and early detection of pregnancy-associated glycoproteins (PAGs) in sheep blood. However, radioactive-based techniques, as RIA, have been increasingly inadvisable due to environmental risk. Homology between ovine and bovine PAGs is high, and ELISA kits used for PAGs detection in cattle are safer than RIA. Thus, this study aimed to evaluate the feasibility of PAGs detection for pregnancy diagnosis in sheep serum samples using an ELISA kit produced for cattle. The sensitivity and specificity of the ELISA kit were 93.5% and 98.9%, respectively, whereas positive and negative predictive values were 99.0% and 93.1%, respectively, in comparison to ultrasonography diagnostic (control). PAGs reached consistently detectable concentrations in ovine serum around 33 days after mating. Accuracy of the ELISA test was 96.1% from 33 days of pregnancy until lambing. After parturition, PAGs were still detectable seven days post-lambing. However, from 21 days post-parturition, PAGs from the previous pregnancy were no longer detected in serum samples. In conclusion, the bovine ELISA kit can accurately detect pregnancy in sheep 33 days following mating, while PAGs levels from the previous gestation are no longer detected from 21 days post-partum. The evaluated ELISA test is a reliable tool for pregnancy diagnosis in sheep at random stages and as a complementary exam at early gestation.