The inactivated quadrivalent influenza vaccine (IIV4) and the 23-valent pneumococcal polysaccharide vaccine (PPSV23) have been administered for years and could be administered concomitantly if necessary. However, the immunogenicity and safety of the concomitant administration of these two vaccines have not been well documented, especially in the Chinese population. In this study, 480 participants aged 60 years and older were randomly assigned to the concomitant administration group (C group) or the separate administration group (S group) to receive IIV4 and PPSV23 either concomitantly or separately. Blood samples were collected before and 28 days after each vaccination. The antibodies against four influenza virus strains and twenty-three pneumococcus serotypes were tested. The results showed that the geometric mean titer (GMT) ratios (C group to S group) for the four influenza strains ranged from 0.72 to 0.95, with the lower limits of the 95% confidence intervals (CIs) ranging from 0.51 to 0.75, and the geometric mean concentration (GMC) ratios for the 23 pneumococcal serotypes ranged from 0.80 to 1.00, with the lower limits of 95% CIs ranging from 0.67 to 0.86. All values met the predefined criteria for non-inferiority. The incidence of adverse events was 0.63% in the C group and 1.56% in the S group. No serious adverse events were observed. In conclusion, the immunogenicity of the concomitant administration of IIV4 and PPSV23 was non-inferior to that of the separate administration, and the safety profile was favorable in adults aged 60 years and older in China.

Objectives: To determine whether a Sabin strain inactivated poliovirus booster (sIPV) given concomitantly (same day, different sites) with MMRV or inactivated hepatitis A vaccine (HepA) is non-inferior in immunogenicity and comparable in safety to separate administration at the 18-month visit. Methods: Open-label, randomized Phase IV trial in healthy children (18~22 months), allocated 2:2:2:1:1 to sIPV&MMRV, sIPV&HepA, sIPV-only, MMRV-only, or HepA-only. Primary endpoints were Day-30 seroconversion rates (SCRs) for poliovirus types 1–3 (sIPV arms) and for HepA (HepA arms). Results: Of 892 screened, 889 were randomized; baseline characteristics were balanced. By Day 30, seroprotection was 100% for PV types 1–3 in all sIPV-containing arms. SCRs were high and similar across concomitant vs. separate administration; all pairwise SCR differences met non-inferiority (−10% margin). Adjusted post-vaccination GMTs were comparable across serotypes. For HepA, Day-30 SPoR was 99.3% vs. 100.0%, and adjusted GMC was 412.2 vs. 465.9 (p = 0.2224). For MMRV, Day-30 SPoR was 100% in both groups with similar adjusted GMCs. Within 30 days, overall adverse reactions were 14.5%/17.4%/16.3%/7.3%/10.8% (sIPV&MMRV/sIPV&HepA/sIPV-only/MMRV-only/HepA-only), mostly mild to moderate; no vaccine-related SAEs (NCT06442449). Conclusions: Same-day sIPV co-administration with MMRV or HepA was non-inferior and well tolerated, supporting programmatic adoption.

Objectives To determine whether a Sabin-strain inactivated poliovirus booster (sIPV) given concomitantly (same day, different sites) with MMRV or inactivated hepatitis A vaccine (HepA) is non-inferior in immunogenicity and comparable in safety to separate administration at the 18-month visit. Methods Open-label, randomized Phase IV trial in healthy children (18 months + 4), allocated 2:2:2:1:1 to sIPV&MMRV, sIPV&HepA, sIPV-only, MMRV-only, or HepA-only. Primary endpoints were Day-30 seroconversion rates (SCRs) for poliovirus types 1–3 (sIPV arms) and for HepA (HepA arms). Results Of 892 screened, 889 were randomized; baseline characteristics were balanced. By Day 30, seroprotection was 100% for PV types 1–3 in all sIPV-containing arms. SCRs were high and similar across concomitant vs separate administration; all pairwise SCR differences met non-inferiority (−10% margin). Adjusted post-vaccination GMTs were comparable across serotypes. For HepA, Day-30 SPoR was 99.3% vs 100.0% and adjusted GMC 412.2 vs 465.9 (P=0.2224). For MMRV, Day-30 SPoR was 100% in both groups with similar adjusted GMCs. Within 30 days, overall adverse reactions were 14.5% / 17.4% / 16.3% / 7.3% / 10.8% (sIPV&MMRV / sIPV&HepA / sIPV-only / MMRV-only / HepA-only), mostly mild–moderate; no vaccine-related SAEs. (NCT06442449) Conclusions Same-day sIPV co-administration with MMRV or HepA was non-inferior and well tolerated, supporting programmatic adoption.

Background: The previous study assessed the immune durability of the Sabin strain inactivated poliovirus vaccine (sIPV) at four years of age; an update on its long-term persistence is warranted. Methods: This Phase IV, open-label, parallel-controlled observational study, required by China’s National Medical Products Administration (NMPA), involves 6.5-year-old children who received four doses of sIPV or Salk IPV (wIPV) at 2, 3, 4, and 18 months during the Phase III trial. Participants are recruited in a 2:1 ratio and contribute blood samples for polio-neutralizing antibody (nAb) assays to determine non-inferiority of immune persistence. Results: The study enrolled 483 participants aged 6.5 years in the 5-year Immune Persistence Set (IPS2), with 318 in the sIPV group and 165 in the wIPV group. Additionally, 387 participants (255 sIPV, 132 wIPV) with samples at six-time points were included in the Full Sequence Immune Persistence Set (IPS3). In IPS2, seropositivity rates (SPRs) for nAbs against serotypes 1–3 were over 99% in sIPV and 98% in wIPV. At 6.5 years, geometric mean titers (GMTs) were significantly higher in the sIPV group 543.96, 179.59 and 362.72 compared to the wIPV group 190.75, 81.05 and 203.95 for serotypes 1, 2 and 3, respectively. Participants in IPS3 demonstrated comparable SPRs and GMTs to IPS2, with values of 566.01 vs. 187.41 for serotype I, 177.55 vs. 78.01 for serotype II, and 365.47 vs. 190.31 for serotype III in the sIPV and wIPV groups, respectively. From one-month post-booster to 6.5 years, nAb GMTs showed declines: 19.35-fold for serotype I, 28.12-fold for serotype II, and 32.45-fold for serotype III in the sIPV group, and 23.42-fold, 23.83-fold, and 34.54-fold in the wIPV group, respectively. Non-inferiority of nAb SPRs and GMTs for sIPV compared to wIPV among participants aged 6.5 years was confirmed for all serotypes in IPS2 and IPS3. Conclusions: The sIPV maintains good immunological persistence five years after four doses of vaccination, with nAb GMT exceeding the seroprotecting threshold, suggesting that booster doses might be currently unwarranted.

This randomized, double-blind, phase IV study (NCT05731115) assessed the lot-to-lot consistency, immunogenicity, and safety of three manufacturing lots of a 23-valent pneumococcal polysaccharide vaccine (PPV23) in 1800 healthy Chinese adults aged 40-65 y. The participants were enrolled and randomized into three groups at a 1:1:1 ratio, with each group receiving one dose of PPV23 from one of three manufacturing lots. Blood samples were collected pre-vaccination and at 30 d post-vaccination for serotype-specific IgG antibody testing. The primary objective was to demonstrate lot-to-lot consistency via equivalence evaluation in 40-65 y old Chinese adults, assessed by geometric mean concentration (GMC) of IgG antibodies at 30 d post-vaccination. Safety data were collected for up to 30 d after vaccination. The results showed that GMC ratio 95% confidence intervals (CIs) in all 23 serotypes were within the predefined equivalence criteria of (0.5, 2). Although the incidence of adverse reactions (AR) may have varied among the three lots, the clinical impact is likely minimal, given that the vast majority (93.2%) were mild in severity. No serious adverse events (SAEs) related to vaccination were reported during the study. This study confirmed that the three manufacturing lots of PPV23 (Sinovac Biotech Co. Ltd.) demonstrated manufacturing consistency and can elicit satisfactory immune responses for all 23 serotypes and no safety concerns were identified.Trial registration: ClinicalTrial.gov identifier: NCT05731115.