Safety and immunogenicity of 2-dose heterologous Ad26.ZEBOV, MVA-BN-Filo Ebola vaccination in healthy and HIV-infected adults: A randomised, placebo-controlled Phase II clinical trial in Africa

Background We investigated safety, tolerability, and immunogenicity of the heterologous 2-dose Ebola vaccination regimen in healthy and HIV-infected adults with different intervals between Ebola vaccinations. Methods and findings In this randomised, observer-blind, placebo-controlled Phase II trial, 668 healthy 18- to 70-year-olds and 142 HIV-infected 18- to 50-year-olds were enrolled from 1 site in Kenya and 2 sites each in Burkina Faso, Cote d’Ivoire, and Uganda. Participants received intramuscular Ad26.ZEBOV followed by MVA-BN-Filo at 28-, 56-, or 84-day intervals, or saline. Females represented 31.4% of the healthy adult cohort in contrast to 69.7% of the HIV-infected cohort. A subset of healthy adults received booster vaccination with Ad26.ZEBOV or saline at Day 365. Following vaccinations, adverse events (AEs) were collected until 42 days post last vaccination and serious AEs (SAEs) were recorded from signing of the ICF until the end of the study. The primary endpoint was safety, and the secondary endpoint was immunogenicity. Anti-Ebola virus glycoprotein (EBOV GP) binding and neutralising antibodies were measured at baseline and at predefined time points throughout the study. The first participant was enrolled on 9 November 2015, and the date of last participant’s last visit was 12 February 2019. No vaccine-related SAEs and mainly mild-to-moderate AEs were observed among the participants. The most frequent solicited AEs were injection-site pain (local), and fatigue, headache, and myalgia (systemic), respectively. Twenty-one days post-MVA-BN-Filo vaccination, geometric mean concentrations (GMCs) with 95% confidence intervals (CIs) of EBOV GP binding antibodies in healthy adults in 28-, 56-, and 84-day interval groups were 3,085 EU/mL (2,648 to 3,594), 7,518 EU/mL (6,468 to 8,740), and 7,300 EU/mL (5,116 to 10,417), respectively. In HIV-infected adults in 28- and 56-day interval groups, GMCs were 4,207 EU/mL (3,233 to 5,474) and 5,283 EU/mL (4,094 to 6,817), respectively. Antibody responses were observed until Day 365. Ad26.ZEBOV booster vaccination after 1 year induced an anamnestic response. Study limitations include that some healthy adult participants either did not receive dose 2 or received dose 2 outside of their protocol-defined interval and that the follow-up period was limited to 365 days for most participants. Conclusions Ad26.ZEBOV, MVA-BN-Filo vaccination was well tolerated and immunogenic in healthy and HIV-infected African adults. Increasing the interval between vaccinations from 28 to 56 days improved the magnitude of humoral immune responses. Antibody levels persisted to at least 1 year, and Ad26.ZEBOV booster vaccination demonstrated the presence of vaccination-induced immune memory. These data supported the approval by the European Union for prophylaxis against EBOV disease in adults and children ≥1 year of age. Trial registration ClinicalTrials.gov NCT02564523

Download Full-text

Safety and immunogenicity of 2-dose heterologous Ad26.ZEBOV, MVA-BN-Filo Ebola vaccination in children and adolescents in Africa: A randomised, placebo-controlled, multicentre Phase II clinical trial

PLoS Medicine ◽

10.1371/journal.pmed.1003865 ◽

2022 ◽

Vol 19 (1) ◽

pp. e1003865

Author(s):

Zacchaeus Anywaine ◽

Houreratou Barry ◽

Omu Anzala ◽

Gaudensia Mutua ◽

Sodiomon B. Sirima ◽

...

Keyword(s):

Immune Responses ◽

Phase Ii ◽

Dose Regimen ◽

Ebola Virus ◽

Geometric Mean ◽

Central Africa ◽

Paediatric Population ◽

Multicentre Phase ◽

Link Type ◽

Western Africa

Background Reoccurring Ebola outbreaks in West and Central Africa have led to serious illness and death in thousands of adults and children. The objective of this study was to assess safety, tolerability, and immunogenicity of the heterologous 2-dose Ad26.ZEBOV, MVA-BN-Filo vaccination regimen in adolescents and children in Africa. Methods and findings In this multicentre, randomised, observer-blind, placebo-controlled Phase II study, 131 adolescents (12 to 17 years old) and 132 children (4 to 11 years old) were enrolled from Eastern and Western Africa and randomised 5:1 to receive study vaccines or placebo. Vaccine groups received intramuscular injections of Ad26.ZEBOV (5 × 1010 viral particles) and MVA-BN-Filo (1 × 108 infectious units) 28 or 56 days apart; placebo recipients received saline. Primary outcomes were safety and tolerability. Solicited adverse events (AEs) were recorded until 7 days after each vaccination and serious AEs (SAEs) throughout the study. Secondary and exploratory outcomes were humoral immune responses (binding and neutralising Ebola virus [EBOV] glycoprotein [GP]-specific antibodies), up to 1 year after the first dose. Enrolment began on February 26, 2016, and the date of last participant last visit was November 28, 2018. Of the 263 participants enrolled, 217 (109 adolescents, 108 children) received the 2-dose regimen, and 43 (20 adolescents, 23 children) received 2 placebo doses. Median age was 14.0 (range 11 to 17) and 7.0 (range 4 to 11) years for adolescents and children, respectively. Fifty-four percent of the adolescents and 51% of the children were male. All participants were Africans, and, although there was a slight male preponderance overall, the groups were well balanced. No vaccine-related SAEs were reported; solicited AEs were mostly mild/moderate. Twenty-one days post-MVA-BN-Filo vaccination, binding antibody responses against EBOV GP were observed in 100% of vaccinees (106 adolescents, 104 children). Geometric mean concentrations tended to be higher after the 56-day interval (adolescents 13,532 ELISA units [EU]/mL, children 17,388 EU/mL) than the 28-day interval (adolescents 6,993 EU/mL, children 8,007 EU/mL). Humoral responses persisted at least up to Day 365. A limitation of the study is that the follow-up period was limited to 365 days for the majority of the participants, and so it was not possible to determine whether immune responses persisted beyond this time period. Additionally, formal statistical comparisons were not preplanned but were only performed post hoc. Conclusions The heterologous 2-dose vaccination was well tolerated in African adolescents and children with no vaccine-related SAEs. All vaccinees displayed anti-EBOV GP antibodies after the 2-dose regimen, with higher responses in the 56-day interval groups. The frequency of pyrexia after vaccine or placebo was higher in children than in adolescents. These data supported the prophylactic indication against EBOV disease in a paediatric population, as licenced in the EU. Trial registration ClinicalTrials.gov NCT02564523.

Download Full-text

Immunogenicity, Lot Consistency, and Extended Safety of rVSVΔG-ZEBOV-GP Vaccine: A Phase 3 Randomized, Double-Blind, Placebo-Controlled Study in Healthy Adults

The Journal of Infectious Diseases ◽

10.1093/infdis/jiz241 ◽

2019 ◽

Vol 220 (7) ◽

pp. 1127-1135 ◽

Cited By ~ 8

Author(s):

Scott A Halperin ◽

Rituparna Das ◽

Matthew T Onorato ◽

Kenneth Liu ◽

Jason Martin ◽

...

Keyword(s):

Risk Factors ◽

Ebola Virus ◽

Geometric Mean ◽

Healthy Adults ◽

Controlled Study ◽

Enzyme Linked Immunosorbent Assay ◽

High Dose ◽

Double Blind Study ◽

Virus Envelope ◽

Double Blind

Abstract Background This double-blind study assessed immunogenicity, lot consistency, and safety of recombinant vesicular stomatitis virus-Zaire Ebola virus envelope glycoprotein vaccine (rVSVΔG-ZEBOV-GP). Methods Healthy adults (N = 1197) were randomized 2:2:2:2:1 to receive 1 of 3 consistency lots of rVSVΔG-ZEBOV-GP (2 × 107 plaque-forming units [pfu]), high-dose 1 × 108 pfu, or placebo. Antibody responses pre-/postvaccination (28 days, 6 months; in a subset [n = 566], months 12, 18, and 24) were measured. post hoc analysis of risk factors associated with arthritis following vaccination was performed. Results ZEBOV-GP enzyme-linked immunosorbent assay (ELISA) geometric mean titers (GMTs) increased postvaccination in all rVSVΔG-ZEBOV-GP groups by 28 days (>58-fold) and persisted through 24 months. The 3 manufacturing lots demonstrated equivalent immunogenicity at 28 days. Neutralizing antibody GMTs increased by 28 days in all rVSVΔG-ZEBOV-GP groups, peaking at 18 months with no decrease through 24 months. At 28 days, ≥94% of vaccine recipients seroresponded (ZEBOV-GP ELISA, ≥2-fold increase, titer ≥200 EU/mL), with responses persisting at 24 months in ≥91%. Female sex and a history of arthritis were identified as potential risk factors for the development of arthritis postvaccination. Conclusions Immune responses to rVSVΔG-ZEBOV-GP persisted to 24 months. Immunogenicity and safety results support continued rVSVΔG-ZEBOV-GP development. Clinical Trials Registration NCT02503202.

Download Full-text

4. MenACWY-TT Long-Term Antibody Persistence Following Adolescent Vaccination and Evaluation of a Booster Dose: A Review of Clinical Data

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.049 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S24-S24

Author(s):

Paula Peyrani ◽

Chris Webber ◽

Cindy Burman ◽

Paul Balmer ◽

John L Perez

Keyword(s):

Immune Responses ◽

Conjugate Vaccine ◽

Booster Dose ◽

Geometric Mean ◽

Booster Vaccination ◽

Primary Vaccination ◽

The United States ◽

The European Union ◽

Adolescent Vaccination

Abstract Background A peak in meningococcal carriage and invasive meningococcal disease (IMD) occurs during adolescence and young adulthood. In the United States, preventive vaccination with a quadrivalent meningococcal (MenACWY) conjugate vaccine is recommended at age 11–12 years, with a booster dose given at age 16 years. MenACWY-TT (Nimenrix®), a MenACWY tetanus toxoid conjugate vaccine, was first licensed in 2012 and is available in the European Union and 50 other countries. Immune responses to other MenACWY conjugate vaccines decline over several years following vaccination. Here, we review 2 recent studies evaluating the long-term persistence of MenACWY-TT immune responses in adolescents as well as safety and immunogenicity of a booster dose given 10 years after primary vaccination. Methods Both studies (ClinicalTrials.gov NCT01934140, NCT03189745) were extensions of phase 2 or 3 studies of subjects 11–17 years of age given a single dose of MenACWY-TT or MenACWY polysaccharide vaccine (MenACWY-PS). Immune responses through 10 years after primary vaccination and after a Year 10 MenACWY-TT booster dose were measured by serum bactericidal antibody assays using baby rabbit complement (rSBA). Specific endpoints included percentages of subjects with rSBA titers ≥1:8 and ≥1:128 and geometric mean titers (GMTs). Booster dose safety and tolerability were also evaluated. Results In both studies, the percentages of subjects with rSBA titers ≥1:8 through 10 years postvaccination were generally higher or similar among MenACWY-TT (69.3%–91.2% at Year 10; n=137–163) compared with MenACWY-PS (24.4%–88.9%; n=45–53) recipients for all 4 serogroups (Figure); similar results were observed for GMTs (146.0–446.9 vs 12.9–191.0 at Year 10). One month after a MenACWY-TT booster dose, 97.7%–100% of subjects across groups had titers ≥1:8 (Figure), and GMTs were markedly higher than prebooster values. No new safety signals were identified following the booster dose. Figure 1. Subjects in each of the 2 studies with rSBA titers ≥1:8 before and at 1 month, 5 years, and 10 years after primary vaccination with MenACWY-TT or MenACWY-PS at 11–17 years of age and 1 month after booster vaccination with MenACWY-TT at 10 years following primary vaccination. Conclusion Functional antibodies for all 4 serogroups persisted through 10 years after MenACWY-TT adolescent vaccination, suggesting that this vaccine may help prevent IMD throughout the lengthy risk period in this group. A MenACWY-TT booster dose may further extend protection regardless of the primary vaccine received. Funded by Pfizer. Disclosures Paula Peyrani, MD, Pfizer Inc (Employee, Shareholder) Chris Webber, MD, Pfizer Inc (Employee, Shareholder) Cindy Burman, PharmD, Pfizer Inc (Employee, Shareholder) Paul Balmer, PhD, Pfizer Inc (Employee, Shareholder) John L. Perez, MD, MA, Pfizer Inc (Employee, Shareholder)

Download Full-text

Comparative Immunogenicity and Safety Trial of 2 Different Schedules of Single-visit Intradermal Rabies Postexposure Vaccination

Clinical Infectious Diseases ◽

10.1093/cid/ciy983 ◽

2018 ◽

Vol 69 (5) ◽

pp. 797-804 ◽

Cited By ~ 10

Author(s):

Patrick Soentjens ◽

Katrien De Koninck ◽

Achilleas Tsoumanis ◽

Natacha Herssens ◽

Dorien Van Den Bossche ◽

...

Keyword(s):

Geometric Mean ◽

Comparative Trial ◽

Booster Vaccination ◽

Primary Vaccination ◽

Embryo Cell ◽

Healthy Adults ◽

Cell Vaccine ◽

Single Visit ◽

Safety Endpoint ◽

One Year

Abstract Background Effective and safe single-visit rabies vaccination for pre- and postexposure prophylaxis (PrEP and PEP) could substantially simplify rabies prevention and therefore increase compliance. Methods In a comparative trial, 303 healthy adults received a primary vaccination that consisted of 2 intradermal (ID) doses of 0.1 mL of the purified chicken embryo cell vaccine (PCEV) during a single visit. One year later, participants were randomly assigned to receive either 4 or 2 ID PEP booster doses of 0.1 mL PCEV during a single visit. The primary endpoint for immunogenicity was the percentage of participants with an adequate antibody level (>0.5 IU/mL) 7 days after the booster doses. The safety endpoint was the proportion of participants who developed adverse events (AEs) following primary and/or booster vaccination. Results All participants, except 1 (99.3%) in each study group, had a rabies antibody titer >0.5 IU/mL on day 7 following the booster schedules. Participants exposed to the 4-dose PEP schedule had a geometric mean titer of 20 IU/mL vs 14 IU/mL for the 2-dose PEP schedule (P = .0228). Local reactions at the injection site following PrEP and PEP were mild and transient and only seen in 14.9% and 49.6%–53% of the participants, respectively. No serious AEs were reported. Conclusions In healthy adults, a 2-dose (2 × 0.1 mL) single-visit ID PEP schedule was as immunologically adequate and safe as a 4-dose (4 × 0.1 mL) single-visit PEP schedule 7 to 28 months following a 2-dose (2 × 0.1 mL) single-visit ID PREP. Clinical Trials Registration EudraCT 2014-00183612.

Download Full-text

High-dose oral and intravenous rifampicin for the treatment of tuberculous meningitis in predominantly HIV-positive Ugandan adults: a phase II open-label randomised controlled trial

Clinical Infectious Diseases ◽

10.1093/cid/ciab162 ◽

2021 ◽

Author(s):

Fiona V Cresswell ◽

David B Meya ◽

Enock Kagimu ◽

Daniel Grint ◽

Lindsey te Brake ◽

...

Keyword(s):

Adverse Events ◽

Phase Ii ◽

Tuberculous Meningitis ◽

Geometric Mean ◽

Standard Of Care ◽

Hiv Positive ◽

High Dose ◽

Open Label ◽

Dose Oral ◽

Csf Levels

Abstract Background High-dose rifampicin may improve outcomes of tuberculous meningitis (TBM). Little safety or pharmacokinetic (PK) data exist on high-dose rifampicin in HIV co-infection, and no cerebrospinal fluid (CSF) PK data exist from Africa. We hypothesized that high-dose rifampicin would increase serum and CSF concentrations without excess toxicity. Methods In this phase II open-label trial, Ugandan adults with suspected TBM were randomised to standard-of-care control (PO-10, rifampicin 10mg/kg/day), intravenous rifampicin (IV-20, 20mg/kg/day), or high-dose oral rifampicin (PO-35, 35mg/kg/day). We performed PK sampling on day 2 and 14. The primary outcomes were total exposure (AUC0-24), maximum concentration (Cmax), CSF concentration and grade 3-5 adverse events. Results We enrolled 61 adults, 92% were HIV-positive, median CD4 count was 50cells/µL (IQR 46–56). On day 2, geometric mean plasma AUC0-24hr was 42.9h.mg/L with standard-of-care 10mg/kg dosing, 249h.mg/L for IV-20 and 327h.mg/L for PO-35 (P<0.001). In CSF, standard-of-care achieved undetectable rifampicin concentration in 56% of participants and geometric mean AUC0-24hr 0.27mg/L, compared with 1.74mg/L (95%CI 1.2–2.5) for IV-20 and 2.17mg/L (1.6–2.9) for PO-35 regimens (p<0.001). Achieving CSF concentrations above rifampicin minimal inhibitory concentration (MIC) occurred in 11% (2/18) of standard-of-care, 93% (14/15) of IV-20, and 95% (18/19) of PO-35 participants. Higher serum and CSF levels were sustained at day 14. Adverse events did not differ by dose (p=0.34) Conclusion Current international guidelines result in sub-therapeutic CSF rifampicin concentration for 89% of Ugandan TBM patients. High-dose intravenous and oral rifampicin were safe, and respectively resulted in exposures ~6- and ~8-fold higher than standard-of-care, and CSF levels above the MIC

Download Full-text

Study Design and Baseline Characteristics of the CARDINAL Trial: A Phase 3 Study of Bardoxolone Methyl in Patients with Alport Syndrome

American Journal of Nephrology ◽

10.1159/000513777 ◽

2021 ◽

pp. 1-10

Author(s):

Glenn M. Chertow ◽

Gerald B. Appel ◽

Sharon Andreoli ◽

Sripal Bangalore ◽

Geoffrey A. Block ◽

...

Keyword(s):

Kidney Function ◽

Alport Syndrome ◽

Genetic Disorder ◽

Geometric Mean ◽

Genetic Diagnosis ◽

Significant Loss ◽

The European Union ◽

Phase 3 ◽

Double Blind ◽

Histologic Diagnosis

Introduction: Alport syndrome is a rare genetic disorder that affects as many as 60,000 persons in the USA and a total of 103,000 persons (<5 per 10,000) in the European Union [1, 2]. It is the second most common inherited cause of kidney failure and is characterized by progressive loss of kidney function that often leads to end-stage kidney disease. Currently, there are no approved disease-specific agents for therapeutic use. We designed a phase 3 study (CARDINAL; NCT03019185) to evaluate the safety, tolerability, and efficacy of bardoxolone methyl in patients with Alport syndrome. Methods: The CARDINAL phase 3 study is an international, multicenter, double-blind, placebo-controlled, randomized registrational trial. Eligible patients were of ages 12–70 years with confirmed genetic or histologic diagnosis of Alport syndrome, eGFR 30–90 mL/min/1.73 m2, and urinary albumin to creatinine ratio (UACR) ≤3,500 mg/g. Patients with B-type natriuretic peptide values >200 pg/mL at baseline or with significant cardiovascular histories were excluded. Patients were randomized 1:1 to bardoxolone methyl or placebo, with stratification by baseline UACR. Results: A total of 371 patients were screened, and 157 patients were randomly assigned to receive bardoxolone methyl (n = 77) or placebo (n = 80). The average age at screening was 39.2 years, and 23 (15%) were <18 years of age. Of the randomized population, 146 (93%) had confirmed genetic diagnosis of Alport syndrome, and 62% of patients had X-linked mode of inheritance. Mean baseline eGFR was 62.7 mL/min/1.73 m2, and the geometric mean UACR was 141.0 mg/g. The average annual rate of eGFR decline prior to enrollment in the study was −4.9 mL/min/1.73 m2 despite 78% of the patient population receiving ACE inhibitor (ACEi) or ARB therapy. Discussion/Conclusion: CARDINAL is one of the largest interventional, randomized controlled trials in Alport syndrome conducted to date. Despite the use of ACEi or ARB, patients were experiencing significant loss of kidney function prior to study entry.

Download Full-text

A phase IV, multi-centre, randomized clinical trial comparing two pertussis-containing vaccines in pregnant women in England and vaccine responses in their infants

BMC Medicine ◽

10.1186/s12916-021-02005-5 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Christine Elizabeth Jones ◽

Anna Calvert ◽

Jo Southern ◽

Mary Matheson ◽

Nick Andrews ◽

...

Keyword(s):

Clinical Trial ◽

Randomized Clinical Trial ◽

Pertussis Toxin ◽

Geometric Mean ◽

Control Group ◽

Primary Immunization ◽

Link Type ◽

In Pregnancy ◽

Pertussis Antigens ◽

Phase Iv

Abstract Background Pertussis vaccines containing three or five pertussis antigens are recommended in pregnancy in many countries, but no studies have compared the effect on infants’ antigen-specific immunoglobulin G (IgG) concentrations. The aim of this study was to compare anti-pertussis IgG responses following primary immunization in infants of mothers vaccinated with TdaP5-IPV (low dose diphtheria toxoid, tetanus toxoid, acellular pertussis [five antigens] and inactivated polio) or TdaP3-IPV in pregnancy (three pertussis antigens). Methods This multi-centre phase IV randomized clinical trial was conducted in a tertiary referral centre and primary care sites in England. Women were randomized to receive TdaP5-IPV (n = 77) or TdaP3-IPV (n = 77) at 28–32 gestational weeks. A non-randomized control group of 44 women who had not received a pertussis-containing vaccine in pregnancy and their 47 infants were enrolled post-partum. Results Following infant primary immunization, there was no difference in the geometric mean concentrations (GMCs) of anti-pertussis toxin, filamentous haemagglutinin or pertactin IgG between infants born to women vaccinated with TdaP5-IPV (n = 67) or TdaP3-IPV (n = 63). However, the GMC of anti-pertussis toxin IgG was lower in infants born to TdaP5-IPV- and TdaP3-IPV-vaccinated mothers compared to infants born to unvaccinated mothers (n = 45) (geometric mean ratio 0.71 [0.56–0.90] and 0.78 [0.61–0.98], respectively); by 13 months of age, this difference was no longer observed. Conclusion Blunting of anti-pertussis toxin IgG response following primary immunization occurs in infants born to women vaccinated with TdaP5-IPV and TdaP3-IPV, with no difference between maternal vaccines. The blunting effect had resolved by 13 months of age. These results may be helpful for countries considering which pertussis-containing vaccine to recommend for use in pregnancy. Trial registration ClinicalTrials.gov, NCT02145624, registered 23 May 2014

Download Full-text

Randomized, Blinded, Dose-Ranging Trial of an Ebola Virus Glycoprotein Nanoparticle Vaccine With Matrix-M Adjuvant in Healthy Adults

The Journal of Infectious Diseases ◽

10.1093/infdis/jiz518 ◽

2019 ◽

Vol 222 (4) ◽

pp. 572-582 ◽

Cited By ~ 6

Author(s):

Louis Fries ◽

Iksung Cho ◽

Verena Krähling ◽

Sarah K Fehling ◽

Thomas Strecker ◽

...

Keyword(s):

Public Health ◽

Immune Response ◽

Ebola Virus ◽

Vaccine Development ◽

Phase 1 ◽

Healthy Adults ◽

Wild Type ◽

Dose Ranging ◽

Further Development ◽

Human Vaccine

Abstract Background Ebola virus (EBOV) epidemics pose a major public health risk. There currently is no licensed human vaccine against EBOV. The safety and immunogenicity of a recombinant EBOV glycoprotein (GP) nanoparticle vaccine formulated with or without Matrix-M adjuvant were evaluated to support vaccine development. Methods A phase 1, placebo-controlled, dose-escalation trial was conducted in 230 healthy adults to evaluate 4 EBOV GP antigen doses as single- or 2-dose regimens with or without adjuvant. Safety and immunogenicity were assessed through 1-year postdosing. Results All EBOV GP vaccine formulations were well tolerated. Receipt of 2 doses of EBOV GP with adjuvant showed a rapid increase in anti-EBOV GP immunoglobulin G titers with peak titers observed on Day 35 representing 498- to 754-fold increases from baseline; no evidence of an antigen dose response was observed. Serum EBOV-neutralizing and binding antibodies using wild-type Zaire EBOV (ZEBOV) or pseudovirion assays were 3- to 9-fold higher among recipients of 2-dose EBOV GP with adjuvant, compared with placebo on Day 35, which persisted through 1 year. Conclusions Ebola virus GP vaccine with Matrix-M adjuvant is well tolerated and elicits a robust and persistent immune response. These data suggest that further development of this candidate vaccine for prevention of EBOV disease is warranted.

Download Full-text

Phase II, dose ranging study of the safety and immunogenicity of single dose West Nile vaccine in healthy adults ≥50 years of age

Vaccine ◽

10.1016/j.vaccine.2012.08.063 ◽

2012 ◽

Vol 30 (47) ◽

pp. 6656-6664 ◽

Cited By ~ 39

Author(s):

Gustavo H. Dayan ◽

Joan Bevilacqua ◽

Dorothy Coleman ◽

Aileen Buldo ◽

George Risi

Keyword(s):

Single Dose ◽

Phase Ii ◽

Healthy Adults ◽

West Nile ◽

Dose Ranging

Download Full-text

Serological response to rabies virus induced by commercial vaccines in cattle

Ciência Rural ◽

10.1590/0103-8478cr20161044 ◽

2017 ◽

Vol 47 (10) ◽

Author(s):

Mathias Martins ◽

João Motta de Quadros ◽

Eduardo Furtado Flores ◽

Rudi Weiblen

Keyword(s):

Rabies Virus ◽

Neutralizing Antibodies ◽

Vaccine Dose ◽

Booster Vaccination ◽

Serological Response ◽

Serum Samples ◽

Anamnestic Response ◽

Post Vaccination ◽

Antibody Titers ◽

One Year

ABSTRACT: The antibody response to rabies virus (RABV) induced by commercial vaccines in heifers was investigated. For this, 84 heifers were vaccinated twice (30 days interval) with each of four vaccines (G1 = 14 animals; G2 = 24; G3 = 22 and G4 = 24) and received a booster vaccination 360 days later. Serum samples collected at different intervals after vaccination and 30 days after booster were submitted to a virus neutralizing (VN) assay for RABV antibodies. Thirty days after the second vaccine dose, 92% of the immunized animals presented VN titers ≥0.5UI/mL (geometric medium titers [GMT] 1.7 to 3.8UI/mL). At the day of the booster (360 days post-vaccination); however, the percentage of animals harboring antibody titers ≥0.5UI/mL had dropped to 31% (0-80% of the animals, depending on the vaccine), resulting in lower GMT (0.1 to 0.6UI/mL). Booster vaccination at day 360 resulted in a detectable anamnestic response in all groups, resulting in 83% of animals (65 to 100%) harboring VN titers ≥0.5UI/mL thirty days later (GMT 0.6 to 4.3UI/mL). These results indicated that these vaccines were able to induce an adequate anti-RABV response in all animals after prime vaccination (and after booster as well). However, the titers decreased, reaching titers <0.5UI/mL in approximately 70% of animals within the interval before the recommended booster. Thus, booster vaccination for rabies in cattle using the current vaccines should be performed before the recommended one-year interval, as to maintain neutralizing antibodies levels in most vaccinated animals.

Download Full-text