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Clinical Trial
. 2024 Sep 26;11(10):ofae559.
doi: 10.1093/ofid/ofae559. eCollection 2024 Oct.

Relative Effectiveness and Immunogenicity of Quadrivalent Recombinant Influenza Vaccine Versus Egg-Based Inactivated Influenza Vaccine Among Adults Aged 18-64 Years: Results and Experience From a Randomized, Double-Blind Trial

Lauren Grant  1 , Jennifer A Whitaker  2 , Sarang K Yoon  3 , Karen Lutrick  4 , Shivam Bhargava  5 , C Perry Brown  6 , Emily Zaragoza  7 , Rebecca V Fink  8 , Jennifer Meece  9 , Kristina Wielgosz  1 , Hana El Sahly  2 , Kurt T Hegmann  3 , Ashley A Lowe  10 , Alia Southworth  5 , Tanya Tatum  6 , Sarah W Ball  8 , Min Z Levine  1 , Matthew S Thiese  3 , Steph Battan-Wraith  8 , John Barnes  1 , Andrew L Phillips  3 , Alicia M Fry  1 , Fatimah S Dawood  1 ; Randomized Assessment of Influenza Vaccine Efficacy Network (RAIVEN)
Collaborators, Affiliations
Clinical Trial

Relative Effectiveness and Immunogenicity of Quadrivalent Recombinant Influenza Vaccine Versus Egg-Based Inactivated Influenza Vaccine Among Adults Aged 18-64 Years: Results and Experience From a Randomized, Double-Blind Trial

Lauren Grant et al. Open Forum Infect Dis. .

Abstract

Background: Immunogenicity studies suggest that recombinant influenza vaccine (RIV) may provide better protection against influenza than standard-dose inactivated influenza vaccines (SD IIV). This randomized trial evaluated the relative vaccine effectiveness (VE) and immunogenicity of RIV versus SD IIV in frontline workers and students aged 18-64 years.

Methods: Participants were randomized to receive RIV or SD IIV and followed for reverse-transcription polymerase chain reaction (RT-PCR)-confirmed influenza during the 2022-2023 influenza season. Sera were collected from a subset of participants before and at 1 and 6 months postvaccination and tested by hemagglutination inhibition for A/H1N1, A/H3N2, B/Yamagata, and B/Victoria and against cell-grown vaccine reference viruses for A/H1N1 and A/H3N2.

Results: Overall, 3988 participants were enrolled and vaccinated (25% of the trial sample size goal); RT-PCR-confirmed influenza occurred in 20 of 1963 RIV recipients and 28 of 1964 SD IIV recipients. Relative VE was 29% (95% confidence interval [CI], -26% to 60%). In the immunogenicity substudy (n = 118), the geometric mean titer ratio (GMTR) comparing RIV to SD IIV at 1 month was 2.3 (95% CI, 1.4-3.7) for cell-grown A/H1N1, 2.1 (95% CI, 1.3-3.4) for cell-grown A/H3N2, 1.1 (95% CI, .7-1.6) for B/Victoria, and 1.4 (95% CI, .9-2.0) for B/Yamagata. At 6 months, GMTRs were >1 against A/H1N1, A/H3N2, and B/Yamagata.

Conclusions: Relative VE of RIV compared to SD IIV did not reach statistical significance, but RIV elicited more robust humoral immune responses to 2 of 4 vaccine viruses at 1 month and 3 of 4 viruses at 6 months after vaccination, suggesting possible improved and sustained immune protection from RIV. Clinical Trials Registration. NCT05514002.

Keywords: clinical trial; immunogenicity; influenza; influenza vaccines; relative effectiveness.

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Conflict of interest statement

Potential conflicts of interest. All authors: No reported conflicts of interest.

Figures

Figure 1.
Figure 1.
Screening, enrollment, and retention in a randomized, double-blind trial comparing the immunogenicity of recombinant influenza vaccine to standard-dose inactivated influenza vaccine among adults aged 18–64 years, 2022–2023 influenza season. aOther reasons for exclusion: did not complete eligibility screening form (n = 492), did not complete enrollment questionnaire (n = 601), not scheduled for vaccination (n = 1883), scheduled but no successful vaccination (n = 93). The modified intention-to-treat population (mITT) comprised participants who were randomized, received a study vaccine, and responded to at least 1 surveillance contact during the influenza circulation period. Abbreviations: mITT, modified intention-to-treat; RIV, recombinant influenza vaccine; SD IIV, standard-dose inactivated influenza vaccine.
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References

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