Evaluation of a recombinant five-antigen Staphylococcus aureus vaccine: The randomized,single-centre phase 1a/1b clinical trials

BackgroundStaphylococcus aureus is an important pathogen that causes hospital and community infections. To control Staphylococcus aureus infection and reduce the usage of antibiotics, we evaluated the safety and immunogenicity of a recombinant five-antigen Staphylococcus aureus vaccine (rFSAV) in healthy adults.MethodsWe conducted a randomized, double-blind, placebo-controlled phase 1a study and a randomized, open-label phase 1b study. In phase 1a, we randomly allocated 144 healthy participants in a ratio of 1:1:1:1 to receive the low-(60 μg), middle-(120 μg), and high-dose (240 μg) vaccine or placebo at day 0, 3, 7 and 14. In phase 1b, 144 healthy participants were randomly allocated at a ratio of 1:1:1:1 to receive 0–3–7, 0/0–7, 0/0–3–7, 0/0–7–14 regimens to estimate the optimal strategy. The primary study endpoint was the incidence of solicited adverse events post-vaccination. The immunogenicity endpoints included the level of specific antibodies to five antigens after vaccination, as well as the cellular immune responses and functional antibodies.ResultsThere were 31 (86%), 30 (83%), and 32 (89%) of 36 participants in the low-, middle-, and high-dose group reported solicited adverse events, respectively, most of the adverse events were mild or moderate. In phase 1b, the dose-adjusted rFSAV (90 μg) showed a better safety profile in the four immune procedures, and no vaccine-related serious adverse events were reported. The antigen-specific binding antibodies started to increase at day 7 and reached the peak around day 14 to 21. The cellular immune responses and functional antibodies also were substantially above background levels.ConclusionsrFSAV is safe, well tolerated in healthy adults, elicits rapid and robust specific humoral and cellular immune responses with unconventional immunization procedure in phase 1a and 1b. It deserves to be noted and further explored.Clinical Trials Registration: NCT02804711 and NCT03966040.     

SA4Ag,a 4-antigen Staphylococcus aureus vaccine,rapidly induces high levels of bacteria-killing antibodies

BackgroundStaphylococcus aureus is a leading cause of healthcare-associated infections. No preventive vaccine is currently licensed. SA4Ag is an investigational 4-antigen S. aureus vaccine, composed of capsular polysaccharide conjugates of serotypes 5 and 8 (CP5 and CP8), recombinant surface protein clumping factor A (rmClfA), and recombinant manganese transporter protein C (rMntC). This Phase 1 study aimed to confirm the safety and immunogenicity of SA4Ag produced by the final manufacturing process before efficacy study initiation in a surgical population.MethodsHealthy adults (18–<65 years) received one intramuscular SA4Ag injection. Serum functional antibodies were measured at baseline and Day 29 post-vaccination. An opsonophagocytic activity (OPA) assay measured the ability of vaccine-induced antibodies to CP5 and CP8 to kill S. aureus clinical isolates. For MntC and ClfA, antigen-specific immunogenicity was assessed via competitive Luminex® immunoassay (cLIA) and via fibrinogen-binding inhibition (FBI) assay for ClfA only. Reactogenicity and adverse event data were collected.ResultsOne hundred participants were vaccinated. SA4Ag was well tolerated, with a satisfactory safety profile. On Day 29, OPA geometric mean titers (GMTs) were 45,738 (CP5, 95% CI: 38,078–54,940) and 42,652 (CP8, 95% CI: 32,792–55,477), consistent with 69.2- and 28.9-fold rises in bacteria-killing antibodies, respectively; cLIA GMTs were 2064.4 (MntC, 95% CI: 1518.2–2807.0) and 3081.4 (ClfA, 95% CI: 2422.2–3920.0), consistent with 19.6- and 12.3-fold rises, respectively. Similar to cLIA results, ClfA FBI titers rose 11.0-fold (GMT: 672.2, 95% CI: 499.8–904.2). The vast majority of participants achieved the pre-defined biologically relevant thresholds: CP5: 100%; CP8: 97.9%, ClfA: 87.8%; and MntC 96.9%.ConclusionsSA4Ag was safe, well tolerated, and rapidly induced high levels of bacteria-killing antibodies in healthy adults. A Phase 2B efficacy trial in adults (18–85 years) undergoing elective spinal fusion is ongoing to assess SA4Ag’s ability to prevent postoperative invasive surgical site and bloodstream infections caused by S. aureus.Clinicaltrials.gov Identifier: NCT02364596.     

Safety,tolerability, and immunogenicity of a 4-antigen Staphylococcus aureus vaccine (SA4Ag): Results from a first-in-human randomised,placebo-controlled phase 1/2 study

BackgroundA prophylactic Staphylococcus aureus four-antigen vaccine (SA4Ag) is under development for prevention of invasive S. aureus disease. A preliminary S. aureus three-antigen vaccine (SA3Ag) was reformulated to include a novel manganese transporter protein (MntC or rP305A). This study describes the first-in-human dose-finding, safety, and immunogenicity results for SA4Ag.MethodsIn this double-blind, sponsor-unblind, placebo-controlled, phase 1/2 study, 454 healthy adults aged 18–64 years were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; antigen-specific immunogenicity was assessed using a four-plex competitive Luminex® immunoassay (cLIA).ResultsA high proportion of SA4Ag recipients met the pre-defined antibody thresholds for each antigen at Day 29. A substantial and dose-level dependent immune response was observed for rP305A, with up to 18-fold rises in cLIA titres at Day 29. Robust functional responses were demonstrated, with >80-fold and >20-fold rises in OPA assay titres at Day 29 using S. aureus strains expressing capsular polysaccharide serotypes 5 and 8, respectively. Durable antibody responses were observed through month 12, gradually waning from peak levels achieved by days 11–15. SA4Ag was well tolerated, and no vaccine-related serious adverse events were reported.ConclusionsSingle-dose vaccination of SA4Ag in healthy adults aged 18–64 years safely induced rapid and robust functional immune responses that were durable through month 12, supporting further development of this vaccine. Trial registration number: NCT01364571     

Immunogenicity and safety of booster dose of S-268019-b or BNT162b2 in Japanese participants: An interim report of phase 2/3, randomized,observer-blinded,noninferiority study

In this randomized, observer-blinded, phase 2/3 study, S-268019-b (n = 101), a recombinant spike protein vaccine, was analyzed for noninferiority versus BNT162b2 (n = 103), when given as a booster ≥6 months after 2-dose BNT162b2 regimen in Japanese adults without prior SARS-CoV-2 infection. Interim results showed noninferiority of S-268019-b versus BNT162b2 in co-primary endpoints for neutralizing antibodies on day 29: geometric mean titer (GMT) (124.97 versus 109.70; adjusted-GMT ratio [95% CI], 1.14 [0.94–1.39]; noninferiority P-value, <0.0001) and seroresponse rate (both 100%; noninferiority P-value, 0.0004). Both vaccines elicited anti-spike-protein immunoglobulin G antibodies, and produced T-cell response (n = 29/group) and neutralizing antibodies against Delta and Omicron pseudovirus and live virus variants (n = 24/group) in subgroups. Most participants reported low-grade reactogenicity on days 1–2, the most frequent being fatigue, fever, myalgia, and injection-site pain. No serious adverse events were reported. In conclusion, S-268019-b was safe and showed robust immunogenicity as a booster, supporting its use as COVID-19 booster vaccine.     

Immunogenicity and safety of sabin-strain based inactivated poliovirus vaccine replacing salk-strain based inactivated poliovirus vaccine: An innovative application of different strain-IPVs replacement

BackgroundA domestic Sabin strain-based inactivated poliovirus vaccine (Sabin IPV) was approved by China Food and Drug Administration in 2017 as a replacement for the Salk strain-based inactivated poliovirus vaccine (Salk IPV) that has been in use in China for over 10 years. The present post-marketing trial was implemented in China to assess the immunogenicity and safety of replacing the Salk IPV with the Sabin IPV in the last two immunizations of the standard three-dose schedule.MethodsWe conducted a randomized, controlled clinical trial with two groups that received three doses of IPVs at the age of 2, 3, and 4 months: the Salk-Sabin-Sabin group and the Salk-Salk-Salk group. Blood samples were collected before vaccination and 30–40 days after the third dose of vaccination. The seroconversion rates and antibody geometric mean titers (GMTs) were calculated and analyzed to evaluate immunogenicity. The safety of both immunization schedules was also monitored and analyzed.ResultsOf 360 recruited healthy infants, all three IPV doses were administered and blood collection was completed in 330 infants. All participants (100%) in both groups were seropositive for all three poliovirus types after the last vaccination. There were significant differences between the two groups (P < 0.001) in the GMTs for antibodies against poliovirus types 1 and 2, but no significant difference was observed for antibodies against type 3 (P = 0.009). A non-inferiority t-test showed that the post-immunization GMTs for all three types in the Salk-Sabin-Sabin group were not inferior to those in the Salk-Salk-Salk group (P < 0.001). Safety assessment indicated that there was no significant difference in the incidence of all adverse events between the two groups (P = 0.806).ConclusionsThe Salk-Sabin-Sabin IPV immunization schedule is not inferior to the Salk-Salk-Salk IPV schedule in terms of both immunogenicity and safety.Clinical trial number: NCT04051736.     

Safety,tolerability, and immunogenicity of a single dose 4-antigen or 3-antigen Staphylococcus aureus vaccine in healthy older adults: Results of a randomised trial

BackgroundThe decline in immune function with age is a challenge to vaccine development. Following an initial study in adults aged 18–64 years, this study evaluated the safety and immunogenicity of Staphylococcus aureus (S. aureus) 4-antigen (SA4Ag) and 3-antigen (SA3Ag) vaccine in older adults. SA3Ag included capsular polysaccharide serotypes 5 and 8 (CP5 and CP8) conjugated to the nontoxic mutant form of diphtheria toxin (CRM₁₉₇) and a recombinant version of clumping factor A (ClfA). SA4Ag included these antigens, with the addition of a recombinant manganese transporter C (rP305A or MntC). Both vaccines were unadjuvanted.MethodsIn this double-blind, sponsor-unblinded, placebo-controlled, phase 1/2 study, 284 healthy adults (aged 65–85 years) were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A, SA3Ag, or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; immunogenicity was also assessed using a competitive Luminex® immunoassay (cLIA). T-cell responses were measured in a small subgroup of subjects using intracellular cytokine staining (ICS) assays.ResultsThe results demonstrated rapid and robust functional immune responses to all antigens in healthy older adults. A high proportion of active vaccine recipients met the pre-defined antibody thresholds for each antigen at Day 29. SA4Ag elicited a dose-level response to rP305A with up to a 13-fold rise in cLIA titres at Day 29. Opsonophagocytic activity (OPA) assays showed >50- and >20-fold rises in functional titres using S. aureus strains expressing CP5 and CP8, respectively, at Day 29. T-cell cytokine responses were not substantially above background levels. There were no safety concerns in this study population and no increases in adverse events with higher rP305A dose levels.ConclusionsSingle-dose vaccination of SA4Ag and SA3Ag in healthy adults aged 65–85 years safely induced rapid and robust functional immune responses, supporting further development of SA4Ag for the prevention of S. aureus disease in adults up to age 85 years. Trial registration number: NCT01643941.     

A Phase 2 randomized,observer-blind,placebo-controlled,dose-ranging trial of aluminum-adjuvanted respiratory syncytial virus F particle vaccine formulations in healthy women of childbearing age

ObjectiveRespiratory syncytial virus (RSV) causes significant morbidity and mortality in infants. We are developing an RSV fusion (F) protein nanoparticle vaccine for immunization of third trimester pregnant women to passively protect infants through transfer of RSV-specific maternal antibodies. The present trial was performed to assess the immunogenicity and safety of several formulations of RSV F vaccine in 1-dose or 2-dose schedules.MethodsPlacebo, or vaccine with 60 μg or 120 μg RSV F protein and 0.2, 0.4, or 0.8 mg aluminum, were administered intramuscularly on Days 0 and 28 to healthy women 18–35 years old. Immunogenicity was assessed from Days 0 through 91 based on anti-F IgG and palivizumab-competitive antibody (PCA) by ELISA, and RSV A and B neutralizing antibodies by microneutralization (MN) assay. Solicited adverse events were collected through Day 7 and unsolicited adverse events through Day 91.ResultsAll formulations were well-tolerated, with no treatment-related serious adverse events. Anti-F IgG and PCA responses were correlated and increased after both doses, while MN increased significantly only after the first dose, then plateaued. The timeliest and most robust antibody responses followed one dose of 120 μg RSV F protein and 0.4 mg aluminum, but persistence through 91 days was modestly (∼25%) superior following two doses of 60 μg RSV F protein and 0.8 mg aluminum. Western blot analysis showed RSV infections in active vaccinees were reduced by 52% overall (p = 0.009 overall) over the Day 0 through 90 period.ConclusionsRSV F nanoparticle vaccine formulations were well tolerated and immunogenic. The optimal combination of convenience and rapid response for immunization in the third trimester occurred with 120 μg RSV F and 0.4 mg aluminum, which achieved peak immune responses in 14 days and sufficient persistence through 91 days to allow for passive transfer of IgG antibodies to the fetus. NCT01960686.     

Safety and immunogenicity of a multidose vial formulation of 13-valent pneumococcal conjugate vaccine administered with routine pediatric vaccines in healthy infants in India: A phase 4, randomized,open-label study

PurposeThis phase 4, randomized, open-label, multicenter study in healthy Indian infants and toddlers evaluated the safety, tolerability, and immunogenicity of the 13-valent pneumococcal conjugate vaccine (PCV13) formulated in a multidose vial (MDV) or single prefilled syringe (PFS).MethodsHealthy Indian infants (6 weeks of age) were randomized 1:1 to receive either PCV13-MDV or PCV13-PFS concomitant with routine pediatric vaccines. Subjects received a single dose of either PCV13-MDV or PCV13-PFS as a 4-dose schedule (infant series: 1 dose at 6, 10, and 14 weeks of age; toddler dose: 12 months of age). Safety was assessed, including local reactions, systemic events, and adverse events (AEs). Immunogenicity 1 month after both the infant series and toddler dose was measured by concentrations of serotype-specific immunoglobulin G (IgG) antibodies and opsonophagocytic activity titers.ResultsRates and severities of local reactions and systemic events up to 7 days after each dose of either PCV13-MDV or PCV13-PFS were generally similar, with the majority being of mild or moderate severity. PCV13-MDV had a safety profile comparable with PCV13-PFS; both groups experienced a similar frequency of AEs. PCV13-MDV elicited immune responses comparable with those induced by PCV13-PFS. Clear boosting of immune responses after the PCV13-MDV toddler dose was observed; ≥96% of subjects showed serotype-specific IgG concentrations at or above the defined thresholds 1 month after the PCV13-MDV toddler dose.ConclusionsPCV13-MDV was safe, well tolerated, and immunogenic in healthy Indian infants and toddlers when coadministered with routine pediatric vaccinations. Safety and immunogenicity of PCV13-MDV was comparable with PCV13-PFS.Clinical Trial RegistrationClinicaltrials.gov: NCT03548337.     

Single Ad26.COV2.S booster dose following two doses of BBIBP-CorV vaccine against SARS-CoV-2 infection in adults: Day 28 results of a phase 1/2 open-label trial

BackgroundThe inactivated COVID-19 whole-virus vaccine BBIBP-CorV has been extensively used worldwide. Heterologous boosting after primary vaccination can induce higher immune responses against SARS-CoV-2 than homologous boosting. The safety and immunogenicity after 28 days of a single Ad26.COV2.S booster dose given at different intervals after 2 doses of BBIBP-CorV are presented.MethodsThis open-label phase 1/2 trial was conducted in healthy adults in Thailand who had completed 2-dose primary vaccination with BBIBP-CorV. Participants received a single booster dose of Ad26.COV2.S (5 × 10¹⁰ virus particles) 90–240 days (Group A1; n = 360) or 45–75 days (Group A2; n = 66) after the second BBIBP-CorV dose. Safety and immunogenicity were assessed over 28 days. Binding IgG antibodies to the full-length pre-fusion Spike and anti-nucleocapsid proteins of SARS-CoV-2 were measured by enzyme-linked immunosorbent assay. The SARS-CoV-2 pseudovirus neutralization assay and live virus microneutralization assay were used to quantify the neutralizing activity of antibodies against ancestral SARS-CoV-2 (Wuhan-Hu-1) and the delta (B.1.617.2) and omicron (B.1.1.529/BA.1 and BA.2) variants. The cell-mediated immune response was measured using a quantitative interferon (IFN)-γ release assay in whole blood.ResultsSolicited local and systemic adverse events (AEs) on days 0–7 were mostly mild, as were unsolicited vaccine-related AEs during days 0–28, with no serious AEs. On day 28, anti-Spike binding antibodies increased from baseline by 487- and 146-fold in Groups A1 and A2, and neutralizing antibodies against ancestral SARS-CoV-2 by 55- and 37-fold, respectively. Humoral responses were strongest against ancestral SARS-CoV-2, followed by the delta, then the omicron BA.2 and BA.1 variants. T-cell–produced interferon-γ increased approximately 10-fold in both groups.ConclusionsA single heterologous Ad26.COV2.S booster dose after two BBIBP-CorV doses was well tolerated and induced robust humoral and cell-mediated immune responses measured at day 28 in both interval groups.Clinical Trials Registration. NCT05109559.     

Cellular and humoral responses to an HIV DNA prime by electroporation boosted with recombinant vesicular stomatitis virus expressing HIV subtype C Env in a randomized controlled clinical trial

BackgroundHIV subtypes B and C together account for around 60% of HIV-1 cases worldwide. We evaluated the safety and immunogenicity of a subtype B DNA vaccine prime followed by a subtype C viral vector boost.MethodsFourteen healthy adults received DNA plasmid encoding HIV-1 subtype B nef/tat/vif and env (n = 11) or placebo (n = 3) intramuscularly (IM) via electroporation (EP) at 0, 1, and 3 months, followed by IM injection of recombinant vesicular stomatitis virus encoding subtype C Env or placebo at 6 and 9 months. Participants were assessed for safety, tolerability of EP, and Env-specific T-cell and antibody responses.ResultsEP was generally well tolerated, although some device-related adverse events did occur, and vaccine reactogenicity was mild to moderate. The vaccine stimulated Env-specific CD4 + T-cell responses in greater than 80% of recipients, and CD8 + T-cell responses in 30%. Subtype C Env-specific IgG binding antibodies (bAb) were elicited in all vaccine recipients, and antibody-dependent cell-mediated cytotoxicity (ADCC) responses to vaccine-matched subtype C targets in 80%. Negligible V1/V2 and neutralizing antibody (nAb) responses were detected.ConclusionsThis prime/boost regimen was safe and tolerable, with some device-related events, and immunogenic. Although immunogenicity missed targets for an HIV vaccine, the DNA/rVSV platform may be useful for other applications.Trial registration.Clinicaltrials.gov: NCT02654080.     

A randomized phase I study of the safety and immunogenicity of three ascending dose levels of a 3-antigen Staphylococcus aureus vaccine (SA3Ag) in healthy adults

BackgroundStaphylococcus aureus is a common cause of healthcare-acquired morbidity and mortality and increased healthcare resource utilization. A prophylactic vaccine is being developed that may reduce this disease burden.MethodsVolunteers in good general health aged 50–85 (n = 312) and 18–24 (n = 96) years were randomized to receive a single intramuscular dose of one of three dose levels of a non-adjuvanted, 3-antigen S. aureus vaccine (SA3Ag) or placebo. SA3Ag antigens included capsular polysaccharides 5 and 8 (CP5 and CP8), each conjugated to cross-reactive material 197 (CRM₁₉₇), and recombinant clumping factor A (ClfA). Safety, tolerability, and immunogenicity were evaluated.ResultsAt day 29 post-vaccination, robust immune responses were observed in both age cohorts at all three SA3Ag dose levels. In the primary analysis population, the 50- to 85-year age stratum, geometric mean-fold-rises in competitive Luminex^® immunoassay antibody titers from baseline ranged from 29.2 to 83.7 (CP5), 14.1 to 31.0 (CP8), and 37.1 to 42.9 (ClfA), all (P < 0.001) exceeding the pre-defined two-fold rise criteria. Similar rises in opsonophagocytic activity assay titers demonstrated functionality of the immune response. Most injection-site reactions were mild in severity and there were no substantial differences (SA3Ag vs. placebo) with regard to systemic or adverse events.ConclusionsIn this study of healthy adults aged 50–85 and 18–24 years, SA3Ag elicited a rapid and robust immune response and was well tolerated, with no notable safety concerns.     

Factors affecting antibody responses to immunizations in infants born to women immunized against pertussis in pregnancy and unimmunized women: Individual-Participant Data Meta-analysis

BackgroundExploring factors that affect immune responses to immunizations in infants born to women immunized with tetanus-diphtheria-acellular-pertussis (Tdap) in pregnancy compared with unimmunized women is important in designing immunization programs.MethodsIndividual-participant data meta-analysis of 8 studies reporting post-immunization immunoglobulin G (IgG) levels to vaccine antigens in infants born to either women immunized with Tdap in pregnancy or unimmunized women, using mixed-effects models.ResultsIn infants of Tdap-immunized women, two-fold higher levels of anti-pertussis toxin (PT) and anti-diphtheria-toxoid (DT) IgG pre-primary immunization were associated with 9% and 10% lower post-primary immunization levels, (geometric mean ratio [GMR], PT: 0.91; 95% CI, 0.88–0.95,n = 494, DT: 0.9; 0.87–0.93,n = 519). Timing of immunization in pregnancy did not affect post-primary immunization anti-Bordetella pertussis, anti-tetanus-toxoid (TT) and anti-DT IgG levels. Spacing of infant immunization did not affect post-primary immunization anti-B. pertussis and anti-DT levels. In infants of Tdap-immunized women, two-fold higher levels of anti-PT and anti-filamentous haemagglutinin (FHA) IgG pre-primary immunization were associated with lower post-booster immunization levels, (GMR, PT: 0.91; 0.85–0.97,n = 224, FHA: 0.92; 0.85–0.99,n = 232). Timing of immunization in pregnancy did not affect post-booster immunization anti-Bordetella pertussis, anti-tetanus-toxoid (TT) and anti-DT IgG levels. Spacing of infant immunization did not affect post-booster immunization anti-PT, anti-pertactin (PRN), anti-TT and anti-DT IgG levels.In infants of unimmunized women, two-fold higher IgG levels of some vaccine antigens pre-primary immunization were associated with 8–17% lower post-primary immunization levels (GMR, PT 0.92, 95% CI:0.88–0.97, n = 373; FHA:0.88, 95% CI:0.85–0.92,n = 378; PRN:0.84, 95% CI:0.81–0.88, n = 367; TT:0.88, 95% CI:0.83–0.93, n = 241; DT: 0.83, 95% CI:0.79–0.87,n = 278). Two-fold higher levels of anti-FHA IgG pre-primary immunization were associated with 8% lower post-booster immunization levels (GMR, 0.92; 95% CI: 0.86–0.99,n = 138).DiscussionIncreased IgG levels pre-primary immunization is associated with reduced post-primary and post-booster immunization levels for some antigens in infants of women immunized or unimmunized in pregnancy, but their clinical significance is uncertain.     

Safety and immunogenicity of a trivalent recombinant PcpA,PhtD, and PlyD1 pneumococcal protein vaccine in adults,toddlers, and infants: A phase I randomized controlled study

BackgroundPneumococcal protein vaccines (PPrVs) may provide improved protection over currently available polysaccharide and conjugated polysaccharide vaccines. Here, we examined the safety and immunogenicity of a trivalent recombinant PPrV containing PcpA, PhtD, and PlyD1.MethodsThis was a phase I, single-center, randomized, observer-blind study with safety review between cohorts. Adults (18–50 years; n = 30) and then toddlers (12–13 months; n = 30) were randomized 2:1 to receive aluminum-adjuvanted trivalent PPrV (PPrV + adj) containing 50 μg per antigen or placebo. Infants (42–49 days; n = 220) were next randomized to be injected at 6, 10, and 14 weeks of age with 10 μg PPrV + adj or placebo (n = 60; 2:1); 25 μg PPrV + adj, 25 μg unadjuvanted PPrV, or placebo (n = 100; 2:2:1); and 50 μg PPrV + adj or placebo (n = 60; 2:1). Solicited reactions were recorded for 7 days and unsolicited adverse events for 30 days after each vaccination. Concentrations of antibodies to the three vaccine antigens were measured by enzyme-linked immunosorbent assay.ResultsTenderness/pain was the most frequent injection-site reaction. Abnormal crying and irritability (infants), loss of appetite (toddlers), and headache, malaise, and myalgia (adults) were the most frequent systemic reactions. Reactions were mostly mild or moderate, resolved within 3 days, were not adjuvant- or dose-dependent, and were not increased by repeated vaccination. No immediate adverse events, hypersensitivity reactions, or treatment-related serious adverse events were reported. In all PPrV + adj cohorts, at least 75% of subjects had a ≥2-fold increase in all three antibody concentrations. In infants, antibody concentrations were higher with PPrV + adj than with unadjuvanted PPrV, higher with three than two vaccinations, and similar at the different vaccine doses.ConclusionsThe candidate trivalent PPrV was safe and immunogenic in adults, toddlers, and infants. Addition of aluminum adjuvant improved immunogenicity in infants without changing the safety profile.     

Immunogenicity and safety of an AS03-adjuvanted H5N1 pandemic influenza vaccine in Korean adults: A phase IV,randomized, open-label,controlled study

BackgroundAS03-adjuvanted H5N1 pandemic influenza vaccines have been assessed in an extensive clinical development program conducted in North America, Europe, and Asia including children from 6 months of age, adults, and elderly adults. We evaluated AS03-H5N1 in Korean adults 18 through 60 years of age.MethodsThis Phase IV, randomized, study was conducted to assess the immunogenicity, reactogenicity, and safety of two doses (3.75 μg of hemagglutinin antigen) of A/Indonesia/5/2005 (H5N1) adjuvanted with AS03 given 21 days apart in Korean adults. Antibody responses were assessed using hemagglutination-inhibition (HI) assays against the vaccine strain and a vaccine-heterologous strain (A/Vietnam/1194/2004) 21 days after the second dose. A control group (safety) received a licensed seasonal inactivated trivalent influenza vaccine (TIV). Reactogenicity was assessed for 7 days after each vaccination, and unsolicited adverse events were assessed for 182 days following vaccination in both study groups (NCT01730378).ResultsAS03-H5N1 was immunogenic and elicited robust HI antibody responses with seroconversion rates of 100% for the vaccine strain and 69.1% for the heterologous strain (N = 81). HI antibody responses fulfilled the European licensure criteria for immunogenicity (primary endpoint). The incidence of local and systemic solicited adverse events (reactogenicity) was higher with AS03-H5N1 than TIV. There was no apparent difference in the rate of unsolicited adverse events in the AS03-H5N1 and TIV groups.ConclusionThe results indicate that AS03-H5N1 vaccine is immunogenic with reactogenicity and safety findings that are consistent with the established profile of AS03-H5N1 vaccine.     

Lot-to-lot consistency,safety, tolerability,and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine,in healthy adults aged ≥50 years: A randomized phase 3 trial (PNEU-TRUE)

BackgroundOlder adults are at risk of pneumococcal disease and associated morbidity and mortality. This phase 3 study (V114-020) assessed lot-to-lot consistency across safety and immunogenicity outcomes for V114, a 15-valent pneumococcal conjugate vaccine (PCV), in healthy adults aged ≥ 50 years.MethodsAdults were randomized in a 3:3:3:1 ratio to receive a single dose of one of three lots of V114 or 13-valent PCV (PCV13), stratified by age (50–64 years, 65–74 years, and ≥ 75 years). Serotype-specific opsonophagocytic activity (OPA) and immunoglobulin G (IgG) antibodies were evaluated at baseline (Day 1) and 30 days post-vaccination. Non-serious and serious adverse events (AEs) were evaluated post-vaccination through 14 days and Month 6, respectively.ResultsOf 2340 participants enrolled, 2282 (97.5%) completed the study. Proportions of participants experiencing ≥ 1 AE were 81.0%, 77.4%, and 78.0% for V114 lots 1, 2, and 3, respectively. Comparison of V114 combined lots with PCV13 showed that proportions of participants experiencing AEs, solicited AEs, and serious AEs were comparable for both vaccines, with the exception of injection-site pain (more frequently reported with V114). OPA geometric mean titers (GMTs) and IgG geometric mean concentrations (GMCs) at 30 days post-vaccination were comparable across V114 lots, and all lots met predefined equivalence criteria for all 15 vaccine serotypes (lower and upper limits of the 95% confidence intervals of serotype-specific OPA GMT ratios for all possible pairwise comparisons across the three lots were within the equivalence margin of 0.5–2.0). Serotype-specific OPA GMTs and IgG GMCs were comparable in the V114 combined lots and PCV13 groups for the 13 shared serotypes and higher in the V114 group for serotypes unique to V114 (22F and 33F).ConclusionsV114 is well tolerated with a consistent safety profile and immune response across manufacturing lots.Clinical trials registration: NCT03950856 (www.clinicaltrials.gov); 2018-004266-33 (EudraCT).     

Safety and immunogenicity of fully liquid and lyophilized formulations of an investigational trivalent group B streptococcus vaccine in healthy non-pregnant women: Results from a randomized comparative phase II trial

BackgroundWe evaluated the safety and immunogenicity of liquid and lyophilized formulations of an investigational trivalent group B streptococcus (GBS) vaccine in non-pregnant women and assessed the formulations’ equivalence in terms of serotype-specific immune response.MethodsThis phase II, randomized, comparative, observer-blind trial enrolled healthy non-pregnant women 18–40 years of age. Women received a single dose of fully liquid (n = 529) or lyophilized (n = 521) trivalent GBS vaccine on day 1. Safety assessments were performed up to day 181 (study termination). Serotype Ia/Ib/III-specific immunoglobulin G (IgG) antibodies were measured in sera from women on day 1 (pre-vaccination) and day 31. Equivalence between the two formulations was demonstrated if the two-sided 95% confidence interval (CI) for the ratio (liquid/lyophilized) of the geometric mean concentrations (GMCs) on day 31 was contained in a (0.5, 2.0) interval for each serotype.ResultsSolicited and unsolicited adverse events were reported at similar rates for both formulations. Serious adverse events were reported for six (1.1%) liquid GBS and nine (1.7%) lyophilized GBS vaccinated women, none of which were considered related to vaccination or fatal. On day 31, serotype-specific IgG concentrations were 8–16-fold higher than on day 1 in both groups. Equivalence of the liquid to the lyophilized formulation 30 days post-vaccination was demonstrated as the 95% CIs of the GMC ratios were within the pre-specified interval for the three serotypes: GMC ratios were 1.02 (95% CI: 0.79, 1.32) for serotype Ia, 0.93 (0.71, 1.21) for serotype Ib and 0.99 (0.76, 1.30) for serotype III.ConclusionsBoth formulations of the investigational trivalent GBS vaccine had favorable safety profiles and induced similar GBS serotype-specific antibody concentrations. This study demonstrated that the fully liquid formulation was equivalent to the lyophilized formulation in healthy non-pregnant women in terms of immunogenicity for all three serotypes.Clinical Trials RegistrationNCT02270944.     

A phase 3, randomized,double-blind study to evaluate the immunogenicity and safety of 3 lots of 20-valent pneumococcal conjugate vaccine in pneumococcal vaccine-naive adults 18 through 49 years of age

IntroductionIntroduction of pneumococcal conjugate vaccines (PCVs), including the 13-valent PCV (PCV13), has considerably reduced pneumococcal disease burden. However, additional serotypes not in PCV13 continue to present a substantial disease burden. The 20-valent PCV (PCV20) was developed to expand protection against pneumococcal disease beyond PCV13. As part of the phase 3 clinical development program, the current study assessed consistency of immune responses across 3 lots of PCV20 and described the safety profile of PCV20.MethodsThis phase 3, randomized, multicenter, double-blind study of pneumococcal vaccine-naive adults 18–49 years of age randomized 1710 participants in a 2:2:2:1 ratio to receive 1 of 3 lots of PCV20 or PCV13. Immunogenicity was assessed through serotype-specific opsonophagocytic activity (OPA) titers before and approximately 1 month (28–42 days) after vaccination. Reported local reactions within 10 days, systemic events within 7 days, adverse events (AEs) within 30 days, and serious AEs (SAEs) and newly diagnosed chronic medical conditions (NDCMCs) within 6 months after vaccination were evaluated.ResultsEquivalence in immune responses (OPA geometric mean titers) for all 20 vaccine serotypes was demonstrated across the 3 PCV20 lots. Robust responses, assessed by OPA geometric mean fold rises, percentage of participants achieving ≥4-fold rises, and percentage of participants with OPA titers ≥lower limit of quantitation, were observed after PCV20. Reported rates of local reactions, systemic events, and AEs were similar between the pooled PCV20 lots and PCV13; most events were mild or moderate. Reported rates of SAEs and NDCMCs were low and similar between the PCV20 and PCV13 groups.ConclusionsThree different lots of PCV20 demonstrated robust and consistent immunogenicity. The safety and tolerability of PCV20 was acceptable and similar to that of PCV13. (Clinicaltrials.gov: NCT03828617).     

Immunogenicity and safety of 7-valent pneumococcal conjugate vaccine (PCV7) in children aged 2–5 years in China

BackgroundThe widespread use of pneumococcal conjugate vaccines (PCVs) has significantly decreased pneumococcal disease worldwide. However, China has not adopted PCVs in their national immunization schedules and had only approved these vaccines for children aged 2–15 months by 2020.MethodsIn an open-label trial, enrolled healthy children aged 2–5 years old were randomized 1:1 and divided into a 7-valent pneumococcal conjugate vaccine (PCV7) group and a Haemophilus influenzae type b conjugate vaccine (Hib) group. Children in the PCV7 group received a single dose of PCV7, and the Hib group received a single dose of Hib vaccine. Blood samples were collected before and 6 months after vaccination. Immunogenicity and safety of PCV7 were assessed at prespecified time points.ResultsSix months after a single dose of PCV7, children in the PCV7 group for all 7 serotypes, IgG mean concentrations (GMCs) and opsonophagocytic geometric mean titres (GMTs) were significantly higher (P < .001) than at baseline, and the proportion of IgG ≥ 0.35 µg/mL ranged from 90.0% to 100%. Although the antibody level increased with age, preexisting antibodies did not induce hyporesponsiveness to PCV7. In the Hib group, the antibody levels were not significantly different or had changed slightly at 6 months. PCV7 was well tolerated in all age groups, and no serious adverse events (AEs) emerged during this study.ConclusionsA single dose of PCV7 was immunogenic and safe for Chinese children aged 2–5 years, and the preexisting antibodies against the PCV7 serotypes did not change the response to vaccination. The findings supported the effectiveness of PCV7 in this age group. PCVs with broader serotype coverage are expected to expand pneumococcal disease protection.     

Immunogenicity and safety of concomitant MF59-adjuvanted influenza vaccine and 23-valent pneumococcal polysaccharide vaccine administration in older adults

BackgroundConcomitant administration of influenza and pneumococcal vaccines facilitates their uptake by older adults; however, data on immunogenicity and safety of concomitant administration of adjuvanted trivalent inactivated influenza vaccine (aIIV3) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) have not been reported.MethodsSubjects aged ≥65 years (N = 224) were randomized 1:1:1:1 to receive MF59-aIIV3 alone, MF59-aIIV3 + PPSV23 in contralateral arms, MF59-aIIV3 + PPSV23 in the same arm or PPSV23 alone (Clinical Trial Number – NCT02225327). Hemagglutination inhibition assay and multiplex opsonophagocytic killing assay were used to compare immunogenicity after single or concomitant vaccination.ResultsAll groups met immunogenicity criteria for the influenza vaccine in older adults with similar seroconversion rates and geometric mean fold-increases, irrespective of concomitant vaccinations and injection site. For each pneumococcal serotype, opsonic index (OI) increased markedly after the PPSV23 vaccination, irrespective of the concomitant influenza vaccine. All subjects showed an OI ≥ 8 for serotypes 6B, 18C and 19A post-vaccination, with a suggestion that the ipsilateral concomitant vaccination might be associated with higher OIs for some antigens. Local and systemic adverse events were more common in subjects receiving PPSV23 compared to those receiving aIIV3 alone.ConclusionsNo interference was observed with antibody responses to influenza or pneumococcal antigens when aIIV3 and PPSV23 were administered concomitantly.