Discussion
injection-site, myalgia, Injection-site pain, fatigue, A/H1N1
ADVERSE EVENTS, EVENT, INFLUENZA B, EMA, ADVERSE EFFECTS, EVENTS
This study was conducted on subjects aged 9–40 years, while a previous study by Dhamayanti et al. was conducted on infants to children aged 8 years [The inclusion of a fourth strain in QIV did not interfere with the EMA criteria for immune responses in adult vaccine recipients. In adults, post-vaccination seroprotection rates were ≥99%, seroconversion rates were >59%, and post-vaccination/pre-vaccination GMT ratios were ≥7.3 for all four vaccine strains. These data demonstrate that the presence of a second influenza B strain in QIV does not negatively affect the immune response to the other strains. Moreover, the immune responses to all strains contained in the two vaccines were robust, with the highest responses to the A/California/7/2009 (H1N1) strain.The seroconversion rates regarding the percentage of subjects with increasing antibody titer ≥4 times and transition of seronegative to seropositive and of QIV were not significantly different from those of TIV. The superior QIV immunogenicity is expected to correspond with superior protection against influenza B relative to TIV in a season when there is lineage mismatch or cocirculation of two influenza B lineages. These findings are similar to those of the meta-analysis study by Moa in 2015, which confirmed that the inactivated QIV had similar efficacy against the three strains shared in common with the TIV (A/H1N1, A/H3N2, and the B lineage included in the TIV) [This study also showed that the immunogenicity of the three batches of QIV was equivalent for the four strains. Batch-to-batch equivalence of all three batches of QIV was demonstrated for all four strains. The seroprotection rates of three batches for A/California/7/2009 (X-179A) (H1N1) pdm09, A/Hong Kong/4801/2014 (X-263) (H3N2), B/Texas/2/2013, and B/Phuket/3073/2013 were (99.3; 100; 99.3), (99.3; 99.2; 100), (88.8; 95.5; 94.8), and (98.5; 100; 98.5), respectively. The increase in the overall post-vaccination GMTs for each pair of batches for each strain was not different.During this study, no serious AEs related to the vaccine were observed. This study found comparable reactogenicity and safety profiles between the QIV candidate and the TIV in both adult and adolescent groups. Both vaccines were well-tolerated by both age groups. Local and systemic reactogenicity profiles were also similar between the vaccine groups. Most reactions were mild or moderate in severity and lasted for 1–3 days. Most solicited injection-site and systemic reactions with either vaccine were mild to moderate and resolved within a few days.Injection-site pain was the most frequently reported solicited local event, and fatigue and myalgia were the commonly reported solicited systemic events among the studies. A meta-analysis study by Moa in 2015 showed the same result, injection-pain was more common in QIV compared to TIV [The QIV and TIV groups showed similar rates of systemic AEs. In both vaccine groups, mild myalgia was the most frequent systemic AE. These findings are similar to those reported by Wang et al. [Frequencies of unsolicited AEs in the 28 days following vaccination with QIV were similar between the adult and adolescent groups. These data are consistent with the results of a meta-analysis of five randomized clinical trials, demonstrating no significant difference between QIV and TIV in terms of the frequency of aggregated local and systemic AEs within 7 days after vaccination [QIV and TIV have similar reactogenicity and AE profiles, with no apparent adverse effects on the tolerability of the higher antigen content in QIV (60 μg HA for 4 strains compared with 22.5 μg for 3 strains in the TIV). Furthermore, the safety profiles of the two vaccine groups were comparable. The results of this study demonstrated that the additional B strain in QIV did not compromise safety compared with TIV. These findings are similar to those of the meta-analysis, which were no statistically significant differences between the adverse events in QIV and TIV groups [In this study, immunogenicity was only assessed 28 days after the last vaccination. Hence, we do not know the duration of antibody responses to the 4 strains. Further study is needed to evaluate the antibody persistence of the QIV.