Commonly used trivalent vaccines contain one influenza B virus lineage and may be ineffective against viruses of the other B lineage. We evaluated the efficacy of a candidate inactivated quadrivalent ...influenza vaccine (QIV) containing both B lineages.
In this multinational, phase 3, observer-blinded study, we randomly assigned children 3 to 8 years of age, in a 1:1 ratio, to receive the QIV or a hepatitis A vaccine (control). The primary end point was influenza A or B confirmed by real-time polymerase chain reaction (rt-PCR). Secondary end points were rt-PCR-confirmed, moderate-to-severe influenza and rt-PCR-positive, culture-confirmed influenza. The vaccine efficacy and the effect of vaccination on daily activities and utilization of health care resources were assessed in the total vaccinated cohort (2584 children in each group) and the per-protocol cohort (2379 children in the QIV group and 2398 in the control group).
In the total vaccinated cohort, 62 children in the QIV group (2.40%) and 148 in the control group (5.73%) had rt-PCR-confirmed influenza, representing a QIV efficacy of 59.3% (95% confidence interval CI, 45.2 to 69.7), with efficacy against culture-confirmed influenza of 59.1% (97.5% CI, 41.2 to 71.5). For moderate-to-severe rt-PCR-confirmed influenza, the attack rate was 0.62% (16 cases) in the QIV group and 2.36% (61 cases) in the control group, representing a QIV efficacy of 74.2% (97.5% CI, 51.5 to 86.2). In the per-protocol cohort, the QIV efficacy was 55.4% (95% CI, 39.1 to 67.3), and the efficacy against culture-confirmed influenza 55.9% (97.5% CI, 35.4 to 69.9); the efficacy among children with moderate-to-severe influenza was 73.1% (97.5% CI, 47.1 to 86.3). The QIV was associated with reduced risks of a body temperature above 39°C and lower respiratory tract illness, as compared with the control vaccine, in the per-protocol cohort (relative risk, 0.29 95% CI, 0.16 to 0.56 and 0.20 95% CI, 0.04 to 0.92, respectively). The QIV was immunogenic against all four strains. Serious adverse events occurred in 36 children in the QIV group (1.4%) and in 24 children in the control group (0.9%).
The QIV was efficacious in preventing influenza in children. (Funded by GlaxoSmithKline Biologicals; ClinicalTrials.gov number, NCT01218308.).
•Recombinant inactivated pertussis vaccines are safe in non-pregnant women.•Lower-dose genetically-inactivated pertussis toxin has comparable immunogenicity.•Monovalent recombinant pertussis vaccine ...shows favorable immunogenicity and safety.
A phase 2 randomized-controlled safety and immunogenicity trial evaluating different doses of recombinant acellular pertussis vaccine containing genetically-inactivated pertussis toxin (PTgen) was conducted in women of childbearing age in Thailand to identify formulations to advance to a trial in pregnant women.
A total of 250 women were randomized 1:1:1:1:1 to receive one dose of one of three investigational vaccines including low-dose recombinant pertussis-only vaccine containing 1 μg PTgen and 1 μg FHA (ap1gen), tetanus, reduced-dose diphtheria (Td) combined to ap1gen (Tdap1gen) or combined to recombinant pertussis containing 2 μg PTgen and 5 μg FHA (Tdap2gen), or one dose of licensed recombinant TdaP vaccine containing 5 μg PTgen and 5 μg FHA (Boostagen®, TdaP5gen) or licensed Tdap vaccine containing 8 μg of chemically inactivated pertussis toxoid (PTchem), 8 μg FHA, and 2.5 μg pertactin (PRN) (BoostrixTM, Tdap8chem). Serum Immunoglobulin G (IgG) antibodies against vaccine antigens were measured before and 28 days after vaccination by ELISA. To advance to a trial in pregnant women, formulations had to induce a PT-IgG seroresponse rate with a 95% confidence interval (95% CI) lower limit of ≥ 50%.
Between 5 and 22 July 2018, a total of 250 women with median age of 31 years were enrolled. Post-vaccination PT-IgG seroresponse rates were 92% (95% CI 81–98) for ap1gen, 88% (95% CI 76–95) for Tdap1gen, 80% (95% CI 66–90) for Tdap2gen, 94% (95% CI 83–99) for TdaP5gen, and 78% (95% CI 64–88) for Tdap8chem. Frequencies of injection site and systemic reactions were comparable between the groups. No serious adverse events were reported during the 28-day post-vaccination period.
All recombinant acellular pertussis vaccines were safe and immunogenic in women of childbearing age, and all met pre-defined immunogenicity criteria to advance to a trial in pregnant women.
Clinical Trial Registration: Thai Clinical Trial Registry, TCTR20180321004.
In response to global interest in the development of a universal influenza vaccine, the Bill & Melinda Gates Foundation, PATH, and the Global Funders Consortium for Universal Influenza Vaccine ...Development convened a meeting of experts (London, UK, May 2018) to assess the role of a standardized controlled human influenza virus infection model (CHIVIM) towards the development of novel influenza vaccine candidates. This report (in two parts) summarizes those discussions and offers consensus recommendations. This article (Part 1) covers challenge virus selection, regulatory and ethical considerations, and issues concerning standardization, access, and capacity. Part 2 covers specific methodologic considerations.
Current methods for influenza vaccine development and licensure require large costly field trials. The CHIVIM requires fewer subjects and the controlled setting allows for better understanding of influenza transmission and host immunogenicity. The CHIVIM can be used to identify immune predictors of disease for at-risk populations and to measure efficacy of potential vaccines for further development.
Limitations to the CHIVIM include lack of standardization, limited access to challenge viruses and assays, lack of consensus regarding role of the CHIVIM in vaccine development pathway, and concerns regarding risk to study participants and community. To address these issues, the panel of experts recommended that WHO and other key stakeholders provide guidance on standardization, challenge virus selection, and risk management. A common repository of well-characterized challenge viruses, harmonized protocols, and standardized assays should be made available to researchers. A network of research institutions performing CHIVIM trials should be created, and more study sites are needed to increase capacity.
Experts agreed that a research network of institutions working with a standardized CHIVIM could contribute important data to support more rapid development and licensure of novel vaccines capable of providing long-lasting protection against seasonal and pandemic influenza strains.
Background. Protection against dengue requires immunity against all 4 serotypes of dengue virus (DENV). Experimental challenge may be useful in evaluating vaccine-induced immunity. Methods. Ten ...subjects previously vaccinated with a live attenuated tetravalent dengue vaccine (TDV) and 4 DENV-naive control subjects were challenged by subcutaneous inoculation of either 10 3 plaque-forming units (PFU) of DENV-1 or 10 5 PFU of DENV-3. Two additional subjects who did not develop DENV-3 neutralizing antibody (NAb) from TDV were revaccinated with 10 4 PFU of live attenuated DENV-3 vaccine to evaluate memory response. Results. All 5 TDV recipients were protected against DENV-1 challenge. Of the 5 TDV recipients challenged with DENV-3, 2 were protected. All DENV-3—challenge subjects who developed viremia also developed elevated liver enzyme levels, and 2 had values that were >10 times greater than normal. Of the 2 subjects revaccinated with DENV-3 vaccine, 1 showed a secondary response to DENV-2, while neither showed such response to DENV-3. All 4 control subjects developed dengue fever from challenge. Protection was associated with presence of NAb, although 1 subject was protected despite a lack of measurable NAb at the time of DENV-1 challenge. Conclusions. Vaccination with TDV induced variable protection against subcutaneous challenge. DENV-3 experimental challenge was associated with transient but marked elevations of transaminases.
Highlights • AS03-adjuvanted H7N1 vaccine formulations were evaluated in adults ≥65 years of age. • Post-dose 2, 69.6%–88.7% of participants per group had HI antibody titers ≥1:40. • Cross-reactivity ...to a vaccine-heterologous H7N9 strain was observed. • All H7N1 vaccine formulations had a clinically acceptable safety profile.
The safety and immunogenicity of four adjuvanted formulations of an investigational tetravalent dengue purified inactivated vaccine (DPIV) were evaluated in a predominantly dengue-primed population ...in Puerto Rico. In this placebo-controlled, randomized, observer-blind, phase I trial, 100 healthy adults were randomized 1:1:1:1:1 to receive DPIV at Day (D)0 and D28 (1 μg per dengue virus DENV type 1-4 adjuvanted with either alum, AS01
or AS03
, or 4 μg per DENV type adjuvanted with alum) or saline placebo. Functional antibody responses were assessed using a microneutralization assay at D56, Month (M)7, and M13. All DPIV formulations were well tolerated and no safety signals were identified through M13. The M13 according-to-protocol (ATP) immunogenicity cohort included 83 participants. The ATP analysis of immunogenicity was performed only on the 78 subjects seropositive for ≥ 1 DENV type at baseline: 69 tetravalent, three trivalent, two bivalent, and four monovalent. In all DPIV groups, geometric mean antibody titers (GMTs) increased from D0 to D56 and waned modestly through M13, while remaining well above prevaccination levels. The 4 μg + alum and the AS01
- and AS03
-adjuvanted formulations were highly immunogenic, with M13-neutralizing antibody GMTs against all four DENV types above 1,000. M13/D0 GMT ratios were highest in the 1 μg + AS03
group (ranging 3.2-3.7 depending on the DENV type). These results encourage continued clinical development of DPIV (ClinicalTrials.gov: NCT01702857).
Hepatitis E (HE) during pregnancy can be fatal; there are no prospective risk estimates for HE and its complications during pregnancy. We followed 2,404 pregnant women for HE and pregnancy outcomes ...from 1996 to 1998. Subjects from Nepal were enrolled at an antenatal clinic with pregnancy of ≤ 24 weeks. Most women (65.1%) were anti-HE virus negative. There were 16 cases of HE (6.7 per 1,000); three mothers died (18.8%) having had intrauterine fetal death (IUFD). Thirteen mothers survived: five preterm and seven full-term deliveries, one IUFD. HE among seronegative women was the sole cause of maternal death and increased the risk of IUFD (relative risk RR: 10.6; 95% confidence interval CI: 4.29-26.3) and preterm delivery (RR: 17.1, 95% CI 7.56-38.5). HE vaccination of females in at-risk regions before or as they attain reproductive age would reduce their risk for preterm delivery, IUFD, and maternal death.
•AS03-adjuvanted H9N2 vaccine demonstrated robust immunogenicity in adults.•A single-dose vaccination strategy may be feasible for adjuvanted H9N2 vaccines.•The adjuvanted formulations permit an ...8-fold antigen dose reduction (1.9vs 15µg).•An anamnestic immune response was observed after a third dose 182days post-dose 1.•All formulations had a clinically acceptable safety profile.
Avian influenza A H9N2 strains have pandemic potential.
In this randomized, observer-blind study (ClinicalTrials.gov: NCT01659086), 420 healthy adults, 18–64years of age, received 1 of 10 H9N2 inactivated split-virus vaccination regimens (30 participants per group), or saline placebo (120 participants). H9N2 groups received 2 doses (days 0, 21) of 15µg hemagglutinin (HA) without adjuvant, or 1.9µgHA+AS03A, 1.9µgHA+AS03B, 3.75µgHA+AS03A, or 3.75µgHA+AS03B; followed by the same H9N2 formulation or placebo (day 182). AS03 is an adjuvant system containing α-tocopherol (AS03A: 11.86mg; AS03B: 5.93mg) and squalene in an oil-in-water emulsion. Immunogenicity (hemagglutination inhibition HI and microneutralization assays) and safety were assessed up to day 546.
All adjuvanted formulations exceeded regulatory immunogenicity criteria at days 21 and 42 (HI assay), with seroprotection and seroconversion rates of ≥94.9% and ≥89.8% at day 21, and 100% and ≥98.1% at day 42. Immunogenicity criteria were also met for unadjuvanted vaccine, with lower geometric mean titers. In groups administered a third vaccine dose (day 182), an anamnestic immune response was elicited with robust increases in HI and microneutralization titers. Injection site pain was reported more frequently with adjuvanted vaccines. No vaccine-related serious adverse events were observed.
All H9N2 vaccine formulations were immunogenic with a clinically acceptable safety profile; adjuvanted formulations were 4–8 times dose-sparing (3.75–1.9vs 15µgHA).
Registered on ClinicalTrials.gov: NCT01659086.
Highlights • Adjuvanted H7N1 vaccine formulations had a clinically acceptable safety profile. • Beneficial AS03 adjuvant effect was demonstrated for all adjuvanted vaccine groups. • Post-dose 2, all ...adjuvanted H7N1 formulations met regulatory acceptance criteria. • Regulatory acceptance criteria were not met after 1 adjuvanted H7N1 vaccine dose. • Cross-reactivity to the H7N9 virus was observed.
Outbreaks of adenovirus type 4 (Ad4) acute respiratory disease (ARD) have reemerged among US military personnel during the past decade. A prospective epidemiological investigation of 678 military ...recruits was conducted at Fort Jackson, South Carolina, in the fall of 1998; 115 (17%) of the recruits were hospitalized for febrile ARD. Adenovirus types 4, 3, and 21 were recovered from the cultures of 70 (72%), 7 (7%), and 2 (2%) of 97 recruits, respectively. In addition, 69 (83%) of the 83 hospitalized and 82 (49%) of the 166 nonhospitalized unit contacts had seroconversion to Ad4, which indicates the very high susceptibility and communicability of Ad4 among military recruits. Young age (<20 years) and male sex increased the risk for anti-Ad4 seroconversion. Recruits from tropical areas had higher preexisting immunity than did recruits from temperate regions. Military recruits are highly susceptible to Ad4 infections. Prompt reinstitution of an adenovirus vaccination program in this high-risk population is urgently needed.
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