Pharmacovigilance capacity strengthening for WHO prequalification: The case of the trivalent influenza vaccine manufactured by Instituto Butantan

A randomized, double-blind, non-inferiority trial comparing the immunogenicity and safety of two seasonal inactivated influenza vaccines in adults

BACKGROUND

To enhance the production and availability of influenza vaccines in different regions of the world is paramount to mitigate the global burden of this disease. Instituto Butantan developed and manufactured an embryonated egg-based inactivated split-virion trivalent seasonal influenza vaccine as part of a technology transfer partnership with Sanofi Pasteur.

METHODS

This is a phase IV, randomized, double-blind, active-controlled, multicenter clinical trial including adults 18-60 and > 60 years recruited during the 2019 southern hemisphere influenza season. Subjects were randomized 1:1 to receive either the Sanofi Pasteur Trivalent Seasonal Influenza Vaccine (SP-TIV) or Instituto Butantan Trivalent Seasonal Influenza Vaccine (IB-TIV). Hemagglutinin inhibition antibody titers were assessed pre-vaccination and 21 days post-vaccination.

RESULTS

624 participants were randomized and vaccinated. In both intention-to-treat and per-protocol analysis, non-inferiority of the SP-TIV versus IB-TIV was demonstrated for the three influenza strains. In the per-protocol analysis, the SP-GMT/IB-GMT ratios for H1N1, H3N2, and B were 0.9 (95%CI, 0.7-1.1), 1.2 (95%CI, 1.0-1.4), and 1.1 (95%CI, 0.9-1.3), respectively. Across vaccination groups, the most common adverse reactions (AR) were limited to the injection-site, including pain and tenderness. The majority of the ARs were graded 1 and/or 2 and lasted less than one day. No serious adverse reaction was observed.

CONCLUSION

This study demonstrated the non-inferiority of the immunogenicity of a single-dose of Instituto Butantan versus a single dose of the Sanofi Pasteur Seasonal Trivalent Influenza Vaccine in adults. Both vaccines were well tolerated and presented similar safety profiles.

Immunogenicity and safety levels of inactivated quadrivalent influenza vaccine in healthy adults via meta-analysis

Objective: The aim of the current study was to evaluate immunogenicity and safety levels of human inactivated quadrivalent influenza vaccine (QIV) which includes two A strains (A/H1N1, A/H3N2) and two B lineages (B/Victoria, B/Yamagata) in healthy adults via meta-analysis. Methods: Searches were conducted in PubMed, Cochrane Library, ClinicalTrials.gov, and EMBASE databases published in 2011-2020 according to inclusion and exclusion criteria. The purpose was to collect and perform meta-analysis of related randomized clinical trial (RCT) data concerning safety and immunogenicity levels of human QIV compared with inactivated trivalent influenza vaccine (TIV). Results: A total of 9 literatures were included. There was no significant difference in the seroconversion(SCR) and seroprotection(SPR) between QIV and TIV for influenza A strains (A/H1N1, A/H3N2) and the B lineage included in the TIV. QIV showed superior efficacy for the B lineage not included in the TIV: SCR RR of 2.20 (95%CI: 1.44-3.37, p = .0003) and SPR RR of 1.34 (95%CI: 1.10-1.63, p = .004) for B/Victoria, and SCR RR of 1.88 (95%CI: 1.53-2.31, p < .00001) and SPR RR of 1.11 (95%CI: 1.03-1.19, p = .006) for B/Yamagata, respectively. There were no significant differences between QIV and TIV for local and systemic adverse events(AE) post-vaccination. Conclusion: In adults 18-64 years old, QIV not only produced similar immunogenicity and safety levels to TIV, but also had better immunogenicity against influenza B vaccine strains not included in TIV.

Active pharmacovigilance of the seasonal trivalent influenza vaccine produced by Instituto Butantan: A prospective cohort study of five target groups

Introduction

Active pharmacovigilance studies are pivotal to better characterize vaccine safety.

Methods

These are multicenter prospective cohort studies to evaluate the safety of the 2017 and 2018 seasonal trivalent influenza vaccines (TIVs) manufactured by Instituto Butantan, by means of active pharmacovigilance practices. Elderly, children, healthcare workers, pregnant women, and women in the puerperium period were invited to participate in the study during the 2017 and 2018 Brazilian national seasonal influenza vaccination campaigns. Following immunization, participants were observed for 30 minutes and they received a participant card to register adverse events information. All safety information registered were checked at a clinical site visit 14 days after immunization and by a telephone contact 42 days after immunization for unsolicited Adverse Events (AE) and Guillain-Barré Syndrome (GBS).

Results

A total of 942 volunteers participated in the two studies: 305 elderly, 109 children, 108 pregnant women, 32 women in the postpartum period, and 388 health workers. Overall, the median number of AR per participant ranged from 1 to 4. The lowest median number of AR per participant was observed among healthcare workers (1 AR per participant) and the highest among pregnant women (4 AR per participant). Overall, local pain (46.6%) was the most frequent solicited local AR. The most frequent systemic ARs were: headache (22.5%) followed by fatigue (16.0%), and malaise (11.0%). The majority of solicited ARs (96%) were mild, Grades 1 or 2), only 3% were Grade 3, and 1% was Grade 4. No serious AEs, including Guillain-Barré Syndrome, were reported up to 42 days postvaccination.

Conclusion

The results from the two studies confirmed that the 2017 and 2018 seasonal trivalent influenza vaccines produced by Instituto Butantan were safe and that active pharmacovigilance studies should be considered, when it is feasible, as an important initiative to monitor vaccine safety in the post-marketing period.