scholarly journals Induction of Cross-Reactive Hemagglutination Inhibiting Antibody and Polyfunctional CD4+ T-Cell Responses by a Recombinant Matrix-M–Adjuvanted Hemagglutinin Nanoparticle Influenza Vaccine

2020 ◽  
Author(s):  
Vivek Shinde ◽  
Rongman Cai ◽  
Joyce Plested ◽  
Iksung Cho ◽  
Jamie Fiske ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Hemagglutination Inhibition ◽  
Geometric Mean ◽  
Antibody Responses ◽  
High Dose ◽  
Pivotal Phase ◽  
Post Vaccination ◽  
Treatment Groups ◽  
Cell Responses ◽  
Recombinant Hemagglutinin

Abstract Background Recurrent reports of suboptimal influenza vaccine effectiveness have renewed calls to develop improved, broadly cross-protective influenza vaccines. Here, we evaluated the safety and immunogenicity of a novel, saponin (Matrix-M)–adjuvanted, recombinant hemagglutinin (HA) quadrivalent nanoparticle influenza vaccine (qNIV). Methods We conducted a randomized, observer-blind, comparator-controlled (trivalent high-dose inactivated influenza vaccine [IIV3-HD] or quadrivalent recombinant influenza vaccine [RIV4]), safety and immunogenicity trial of qNIV (5 doses/formulations) in healthy adults ≥65 years. Vaccine immunogenicity was measured by hemagglutination-inhibition assays using reagents that express wild-type hemagglutination inhibition (wt-HAI) sequences and cell-mediated immune responses. Results A total of 1375 participants were randomized, immunized, and followed for safety and immunogenicity. Matrix-M–adjuvanted qNIV induced superior wt-HAI antibody responses against 5 of 6 homologous or drifted strains compared with unadjuvanted qNIV. Adjuvanted qNIV induced post-vaccination wt-HAI antibody responses at day 28 that were statistically higher than IIV3-HD against a panel of homologous or drifted A/H3N2 strains, similar to IIV3-HD against homologous A/H1N1 and B (Victoria) strains and similar to RIV4 against all homologous and drifted strains evaluated. The qNIV formulation with 75 µg Matrix-M adjuvant induced substantially higher post-vaccination geometric mean fold increases of influenza HA-specific polyfunctional CD4+ T cells compared with IIV3-HD or RIV4. Overall, similar frequencies of solicited and unsolicited adverse events were reported in all treatment groups. Conclusions qNIV with 75 µg Matrix-M adjuvant was well tolerated and induced robust antibody and cellular responses, notably against both homologous and drifted A/H3N2 viruses. Further investigation in a pivotal phase 3 trial is underway. Clinical Trials Registration NCT03658629.

scholarly journals Induction of Cross-reactive Hemagglutination Inhibiting Antibody and Polyfunctional CD4+ T-cell Responses by a Recombinant Matrix-M-Adjuvanted Hemagglutinin Nanoparticle Influenza Vaccine

2020 ◽  
Author(s):  
Vivek Shinde ◽  
Rongman Cai ◽  
Joyce Plested ◽  
Iksung Cho ◽  
Jamie Fiske ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Geometric Mean ◽  
Antibody Responses ◽  
High Dose ◽  
Pivotal Phase ◽  
Post Vaccination ◽  
Treatment Groups ◽  
Cell Responses ◽  
Recombinant Hemagglutinin ◽  
Different Doses

Background. Recurrent reports of suboptimal influenza vaccine effectiveness have renewed calls to develop improved, broadly cross-protective influenza vaccines. Here, we evaluated the safety and immunogenicity of a novel, saponin (Matrix-M)-adjuvanted, recombinant hemagglutinin (HA) quadrivalent nanoparticle influenza vaccine (qNIV). Methods. We conducted a randomized, observer-blind, comparator-controlled (trivalent high-dose inactivated influenza vaccine [IIV3-HD], or quadrivalent recombinant influenza vaccine [RIV4]), safety and immunogenicity trial of qNIV (in 5 different doses/formulations) in healthy adults aged ≥65 years. Vaccine immunogenicity was measured by hemagglutination-inhibition assays using reagents expressing wild-type HA sequences (wt-HAI) and cell-mediated immune (CMI) responses. Results. A total of 1375 participants were randomized, immunized, and followed for safety and immunogenicity. Matrix-M-adjuvanted qNIV induced superior wt-HAI antibody responses against 5 of 6 homologous or drifted strains evaluated compared to unadjuvanted qNIV. Adjuvanted qNIV induced post-vaccination wt-HAI antibody responses at Day 28 that were: statistically higher than IIV3-HD against a panel of homologous or drifted A/H3N2 strains; similar to IIV3-HD against homologous A/H1N1 and B (Victoria) strains; and similar to RIV4 against all homologous and drifted strains evaluated. The qNIV formulation with 75 μg Matrix-M adjuvant induced substantially higher post-vaccination geometric mean fold-increases of influenza HA-specific polyfunctional CD4+ T-cells compared to IIV3-HD or RIV4. Overall, similar frequencies of solicited and unsolicited adverse events (AEs) were reported in all treatment groups. Conclusions. qNIV with 75 μg Matrix-M adjuvant was well tolerated and induced robust antibody and cellular responses, notably against both homologous and drifted A/H3N2 viruses. Further investigation in a pivotal phase 3 trial is underway.

scholarly journals Frailty Is Associated With Increased Hemagglutination-Inhibition Titers in a 4-Year Randomized Trial Comparing Standard- and High-Dose Influenza Vaccination

2020 ◽  
Vol 7 (5) ◽  
Author(s):  
Nathalie Loeb ◽  
Melissa K Andrew ◽  
Mark Loeb ◽  
George A Kuchel ◽  
Laura Haynes ◽  
...  
Keyword(s):  
Influenza Vaccination ◽  
Hemagglutination Inhibition ◽  
Influenza A ◽  
Standard Dose ◽  
Geometric Mean ◽  
Frailty Index ◽  
Antibody Responses ◽  
High Dose ◽  
Antibody Titers ◽  
The Impact

Abstract Background Although high-dose (HD) vaccines have been reported to stimulate higher antibody responses compared with standard-dose (SD) influenza vaccines, there have been limited studies on the impact of frailty on such responses. Methods We conducted a randomized, double-blind trial (2014/2015 to 2017/2018) of SD versus HD trivalent split-virus vaccine (Fluzone) in 612 study participants aged 65+ over 4 influenza seasons. Hemagglutination inhibition antibody titers for influenza H1N1, H3N2, and B vaccine subtypes were measured at baseline and at 4, 10, and 20 weeks postvaccination and frailty was measured using a validated frailty index. Results Geometric mean antibody titers were significantly higher in HD compared with SD vaccine recipients for all influenza subtypes at all time points postvaccination. However, frailty was positively correlated with 4-week titers and was associated with increased odds of being a vaccine responder. For influenza A subtypes, this was mostly limited to HD recipients. Conclusions Frailty was associated with higher titers and increased antibody responses at 4 weeks after influenza vaccination, which was partially dependent on vaccine dosage. Chronic inflammation or dysregulated immunity, both of which are commonly observed with frailty, may be responsible, but it requires further investigation.

scholarly journals 2737. Comparison of Antibody Responses to Vaccination with a Pure Hemagglutinin Influenza Vaccine (rHA) and Licensed Subvirion Influenza Vaccine Made in Eggs or Cell Culture in Adults 60 Years and Older

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S963-S963
Author(s):  
Moumita Sarker ◽  
Angela Branche ◽  
Michael Peasley ◽  
David Topham
Keyword(s):  
Older Adults ◽  
Influenza Vaccine ◽  
Vaccine Development ◽  
Standard Dose ◽  
Geometric Mean ◽  
The United States ◽  
Antibody Responses ◽  
Influenza B Virus ◽  
Influenza B ◽  
High Dose

Abstract Background Influenza is associated with increased mortality and morbidity for older adults. High-dose egg grown trivalent inactivated influenza vaccine (Fluzone HD) is safe and provides superior immune responses in older adults compared with standard dose (SD). Recently, two new vaccines have been licensed in the United States: cell cultured inactivated vaccine FluCelVax and baculovirus-expressed pure hemagglutinin (HA) vaccine FluBlok. Data from one study demonstrated higher efficacy with FluBlok than SD Fluzone in older adults. There is no data however comparing HD Fluzone to FluBlok and FluCelVax has not been studied at all. The purpose of this study was to assess hemagglutinin inhibition (HAI) antibody responses to vaccination with three vaccines in adults ≥ 60 years. Methods Adults ≥ 60 years were randomly assigned to receive one of the three vaccines: Fluzone HD, FluBlok and FluCelVax (Figure 1). Active influenza-like illness (ILI) surveillance was conducted with bi-weekly telephone calls. Serum samples were collected prior to vaccination and at day 7, 14, 28 and 180 and antibody responses assessed by HAI titer to A/Singapore/INFIMH-16–0019(H3N2), A/Michigan/45/2015(H1N1) and B/Colorado/6/2017 (Victoria) viruses as well as a circulating H3N2 strain. The primary endpoint was a 4-fold rise in antibody titer at day 28. Results 48 subjects were vaccinated in October 2018. Mean age was 69 and 65% were female. Two subjects reported ILI symptoms and one was positive for infection (H1N1). A majority of subjects demonstrated pre-existing antibody to all three viruses (Figure 2, Blue). Geometric mean titers (GMT) for antibody responses to the influenza A viruses were similar for FluBlok (FB) and HD Fluzone (FZ) but lower for FluCelVax(FCB) subjects (Figure 2, Orange). A higher percent of FlubBlok subjects demonstrated 4-fold rise in antibody responses to the Victoria influenza B virus (FB GMT 140 vs. FZ GMT 116, P = 0.26). Conclusion In this small study, antibody responses were similar or higher in older adults after vaccination with FluBlok compared with Fluzone HD with lower responses demonstrated with FluCelvax. Emerging concerns about HA egg adaptation during vaccine development compels further study to determine the appropriate vaccination strategy for this vulnerable population. Disclosures All authors: No reported disclosures.

scholarly journals Live-Attenuated Influenza Vaccine Induces Tonsillar Follicular T Helper Cell Responses That Correlate With Antibody Induction

2019 ◽  
Vol 221 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Sarah Lartey ◽  
Fan Zhou ◽  
Karl A Brokstad ◽  
Kristin G-I Mohn ◽  
Steffen A Slettevoll ◽  
...  
Keyword(s):  
Hemagglutination Inhibition ◽  
Inverse Correlation ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
T Helper ◽  
Post Vaccination ◽  
Cell Responses ◽  
Tfh Cells

Abstract Background Influenza remains a major threat to public health. Live-attenuated influenza vaccines (LAIV) have been shown to be effective, particularly in children. Follicular T helper (TFH) cells provide B-cell help and are crucial for generating long-term humoral immunity. However the role of TFH cells in LAIV-induced immune responses is unknown. Methods We collected tonsils, plasma, and saliva samples from children and adults receiving LAIV prior to tonsillectomy. We measured influenza-specific TFH-cell responses after LAIV by flow cytometry and immunohistochemistry. Systemic and local antibody responses were analysed by hemagglutination inhibition assay and enzyme-linked immunosorbent assay. Results We report that LAIV induced early (3–7 days post-vaccination) activation of tonsillar follicles and influenza-specific TFH-cell (CXCR5+CD57+CD4+ T cell) responses in children, and to a lesser extent in adults. Serological analyses showed that LAIV elicited rapid (day 14) and long-term (up to 1 year post-vaccination) antibody responses (hemagglutination inhibition, influenza-specific IgG) in children, but not adults. There was an inverse correlation between pre-existing influenza-specific salivary IgA concentrations and tonsillar TFH-cell responses, and a positive correlation between tonsillar TFH-cell and systemic IgG induction after LAIV. Conclusions Our data, taken together, demonstrate an important role of tonsillar TFH cells in LAIV-induced immunity in humans.

scholarly journals LB14. Safety and Immunogenicity of High-Dose Quadrivalent Influenza Vaccine Administered by Intramuscular Route in Subjects Aged 65 Years and Older

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S764-S764 ◽  
Author(s):  
Lee-Jah Chang ◽  
Ya Meng ◽  
Helene Janosczyk ◽  
Victoria Landolfi ◽  
H Keipp Talbot ◽  
...  
Keyword(s):  
United States ◽  
Immune Response ◽  
Influenza Vaccine ◽  
Standard Dose ◽  
The United States ◽  
Influenza Vaccines ◽  
High Dose ◽  
Post Vaccination ◽  
B Lineage ◽  
Research Grant

Abstract Background Older adults (≥65 years of age) remain at increased risk of influenza because they do not respond to standard dose influenza vaccines as well as younger adults. A high dose, inactivated trivalent influenza vaccine, IIV3-HD, containing four times the antigen content (60 µg hemagglutinin per influenza strain) of standard-dose influenza vaccines has been available in the United States since 2010. Two distinct B influenza lineages (Victoria and Yamagata) have co-circulated for over a decade, making it difficult to predict which will predominate the next season. IIV4-HD has been developed to address the frequent influenza B strain mismatches by incorporating a strain from each B lineage. This pivotal Phase III study evaluated the safety and immunogenicity of IIV4-HD as compared with two IIV3-HD vaccines. Method A randomized, modified double-blind, multicenter study (NCT03282240) was conducted in 2670 healthy subjects in the United States, who were randomly assigned to receive IIV4-HD, a licensed IIV3-HD, or an IIV3-HD with the alternate B influenza strain. Using the hemagglutinin inhibition (HAI) assay at baseline and 28 days after vaccination, post-vaccination geometric mean titers and seroconversion rates were measured. Safety data were collected through 6 months post-vaccination. Result IIV4-HD was noninferior to the licensed IIV3-HD and the investigational IIV3-HD (containing the alternate B strain) for all four influenza strains as assessed by HAI GMTs and seroconversion rates. Moreover, IIV4-HD induced a superior immune response (HAI GMTs and seroconversion rates) compared with the immune response induced by the IIV3-HD that does not contain the corresponding B strain. Reactogenicity profiles were comparable across all study groups. Most unsolicited adverse events were of Grade 1 or Grade 2 intensity. One serious adverse event considered related by the Investigator was reported in the IIV4-HD group. Conclusion Vaccination of adults 65 years of age and older with IIV4-HD was found to be noninferior to two IIV3-HD vaccines with a similar safety profile. The addition of a second B lineage strain does not adversely affect the safety or immunogenicity profile of IIV4-HD compared with IIV3-HD. Disclosures L. J. Chang, Sanofi Pasteur: Employee, Salary. Y. Meng, Sanofi Pasteur: Employee, Salary. H. Janosczyk, Sanofi Pasteur: Employee, Salary. V. Landolfi, Sanofi Pasteur: Employee, Salary. H. K. Talbot, Sanofi Pasteur: Investigator, Research grant. Gilead: Investigator, Research grant. MedImmune: Investigator, Research grant. Vaxinnate: Safety Board, none. Seqirus: Safety Board, none.

The Effect of Influenza Vaccination History on Changes in Hemagglutination Inhibition Titers After Receipt of the 2015–2016 Influenza Vaccine in Older Adults in Hong Kong

2019 ◽  
Vol 221 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Tiffany W Y Ng ◽  
Ranawaka A P M Perera ◽  
Vicky J Fang ◽  
Emily M Yau ◽  
J S Malik Peiris ◽  
...  
Keyword(s):  
Older Adults ◽  
Hong Kong ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Hemagglutination Inhibition ◽  
Age Groups ◽  
Antibody Responses ◽  
Serum Samples ◽  
Vaccination History ◽  
Antibody Titers

Abstract Background Immune responses to influenza vaccination can be weaker in older adults than in other age groups. We hypothesized that antibody responses would be particularly weak among repeat vaccinees when the current and prior season vaccine components are the same. Methods An observational study was conducted among 827 older adults (aged ≥75 years) in Hong Kong. Serum samples were collected immediately before and 1 month after receipt of the 2015–2016 quadrivalent inactivated influenza vaccine. We measured antibody titers with the hemagglutination inhibition assay and compared the mean fold rise from prevaccination to postvaccination titers and the proportions with postvaccination titers ≥40 or ≥160. Results Participants who reported receipt of vaccination during either of the previous 2 years had a lower mean fold rise against all strains than with those who did not. Mean fold rises for A(H3N2) and B/Yamagata were particularly weak after repeated vaccination with the same vaccine strain, but we did not generally find significant differences in the proportions of participants with postvaccination titers ≥40 and ≥160. Conclusions Overall, we found that reduced antibody responses in repeat vaccinees were particularly reduced among older adults who had received vaccination against the same strains in preceding years.

scholarly journals Effects of Prior Influenza Exposure on Immunogenicity of Influenza Vaccine

2020 ◽  
Author(s):  
Jia-Qian Cao ◽  
Peng-Fei Jin ◽  
Zhao-Zhun Zeng ◽  
Li Zhang ◽  
Fan-Yue Meng ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Influenza Virus ◽  
Immune Responses ◽  
Influenza Vaccine ◽  
Hemagglutination Inhibition ◽  
Cross Reactivity ◽  
Vaccine Effectiveness ◽  
Prior Exposure ◽  
Post Vaccination ◽  
Blood Samples

Abstract Background To investigate effects of prior influenza exposure on vaccine-elicited humor immune responses to circulating influenza variants. Method We randomly selected 360 participants in previous clinical trials stratified by age. Blood samples before and 28 days after vaccination were collected and tested by hemagglutination-inhibition tests against both vaccine strains and circulating variants during the 2015–2016 influenza seasons in China. The antigenic map was plotted and antigenic distance was calculated. Results Subjects with H1-priming had higher cross-reactive antibodies titers against A/JiangsuTinghu/11019/2015(H3N2) compared with subjects with B-priming did (Padjusted=0.038). Subjects with H1-priming also had higher cross-reactive antibodies titers against A/Jiangsu Qinhuai/11059/2015(H3N2) than subjects with both H1 and B priming did (Padjusted=0.036). Nevertheless, subjects with no H1 and B-priming had higher cross-reactive antibodies titers against A/Jiangsu Qinhuai/11059/2015(H3N2) than subjects with both H1 and B priming did (Padjusted=0.012). Antigenic distance was well-matched with serological results. Besides, age-specific differences in human post-vaccination responses against the identical circulating strain was noted. And children had most cross-reactive response to both H3N2 and B-yamagata subtypes. Conclusion Our results suggest that prior exposure to H1 or B influenza virus may influence cross-reactivity of H3-specific post-vaccination responses and consequently could influence the vaccine effectiveness. Our findings also support that there are age-specific differences in human post-vaccination responses.

scholarly journals The Effects of Imprinting and Repeated Seasonal Influenza Vaccination on Adaptive Immunity after Influenza Vaccination

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 663
Author(s):  
Amy C. Sherman ◽  
Lilin Lai ◽  
Mary Bower ◽  
Muktha S. Natrajan ◽  
Christopher Huerta ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Seasonal Influenza ◽  
Geometric Mean ◽  
Fold Change ◽  
Post Vaccination ◽  
Seasonal Influenza Vaccination ◽  
Vaccine Responses ◽  
Immune Factors ◽  
Antibody Secreting Cells

(1) Background: The influenza virus continues to cause significant annual morbidity and mortality. The overall efficacy of seasonal influenza vaccination is suboptimal, which is partly due to host immune factors. The effects of imprinting and repeated seasonal influenza vaccination were investigated to assess for immune factors and mechanisms that impact influenza vaccine responses. (2) Methods: Twenty participants were enrolled into a prospective pilot study based on birth cohort and seasonal influenza immunization history. Immunologic parameters were assessed over a six-month period after the seasonal influenza vaccine was administered. (3) Results: There was no significant imprinting effect, as measured by hemagglutination inhibition (HAI) fold change, HAI geometric mean titer (GMT) for Day 29 or Day 180 post-vaccination and antigen- specific antibody-secreting cells (ASC) for Day 8 post-vaccination. Individuals who had minimal prior seasonal influenza vaccination had a higher magnitude ASC response and a higher HAI fold change post-vaccination than individuals who were repeatedly vaccinated. (4) Conclusions: Repeated seasonal influenza vaccination resulted in a decreased fold change of the immune response, although individuals in this cohort tended to have high HAI titers at baseline that persisted after vaccination. Imprinting effects were not observed in this cohort. These host immune factors should be considered in the development of universal influenza vaccines. ClinicalTrials.gov Identifier: NCT03686514.

scholarly journals Key Determinants of Cell-Mediated Immune Responses: A Randomized Trial of High Dose Vs. Standard Dose Split-Virus Influenza Vaccine in Older Adults

2021 ◽  
Vol 2 ◽  
Author(s):  
Chris P. Verschoor ◽  
Laura Haynes ◽  
Graham Pawelec ◽  
Mark Loeb ◽  
Melissa K. Andrew ◽  
...  
Keyword(s):  
Older Adults ◽  
Immune Responses ◽  
Influenza Vaccine ◽  
Influenza A ◽  
Standard Dose ◽  
Serum Antibody ◽  
High Dose ◽  
Post Vaccination ◽  
Antibody Titers ◽  
Virus Influenza

Background: Efforts to improve influenza vaccine effectiveness in older adults have resulted in some successes, such as the introduction of high-dose split-virus influenza vaccine (HD-SVV), yet studies of cell-mediated immune responses to these vaccines remain limited. We have shown that granzyme B (GrB) activity in influenza A/H3N2 challenged peripheral blood mononuclear cells (PBMC) correlates with protection against influenza following standard dose vaccination (SD-SVV) in older adults. Further, the interferon-γ (IFNγ) to interleukin-10 (IL-10) ratio can be a correlate of protection.Methods: In a double-blind trial (ClinicalTrials.gov NCT02297542) older adults (≥65 years, n = 582) were randomized to receive SD-SVV or HD-SVV (Fluzone®) from 2014/15 to 2017/18. Young adults (20–40 years, n = 79) received SD-SVV. At 0, 4, 10, and 20 weeks post-vaccination, serum antibody titers, IFNγ, IL-10, and inducible GrB (iGrB) were measured in ex vivo influenza-challenged PBMC. iGrB is defined as the fold change in GrB activity from baseline levels (bGrB) in circulating T cells. Responses of older adults were compared to younger controls, and in older adults, we analyzed effects of age, sex, cytomegalovirus (CMV) serostatus, frailty, and vaccine dose.Results: Prior to vaccination, younger compared to older adults produced significantly higher IFNγ, IL-10, and iGrB levels. Relative to SD-SVV recipients, older HD-SVV recipients exhibited significantly lower IFNγ:IL-10 ratios at 4 weeks post-vaccination. In contrast, IFNγ and iGrB levels were higher in younger SD vs. older SD or HD recipients; only the HD group showed a significant IFNγ response to vaccination compared to the SD groups; all three groups showed a significant iGrB response to vaccination. In a regression analysis, frailty was associated with lower IFNγ levels, whereas female sex and HD-SVV with higher IL-10 levels. Age and SD-SVV were associated with lower iGrB levels. The effect of prior season influenza vaccination was decreased iGrB levels, and increased IFNγ and IL-10 levels, which correlated with influenza A/H3N2 hemagglutination inhibition antibody titers.Conclusion: Overall, HD-SVV amplified the IL-10 response consistent with enhanced antibody responses, with little effect on the iGrB response relative to SD-SVV in either younger or older adults. These results suggest that enhanced protection with HD-SVV is largely antibody-mediated.Clinical Trial Registration: ClinicalTrials.gov (NCT02297542).

scholarly journals 2753. Induction of Broadly Cross-Reactive Immune Responses Against A(H3N2) Airuses: Results of a Phase 2 Trial of a Novel Recombinant Hemagglutinin Saponin-Adjuvanted Nanoparticle Seasonal Influenza Vaccine

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S970-S970
Author(s):  
Vivek Shinde ◽  
Rongman Cai ◽  
Joyce S Plested ◽  
Bin Zhou ◽  
Haixia Zhou ◽  
...  
Keyword(s):  
Immune Responses ◽  
Influenza Vaccine ◽  
Seasonal Influenza ◽  
Antibody Responses ◽  
Antigenic Drift ◽  
Influenza Vaccines ◽  
High Dose ◽  
Phase 2 ◽  
Adaptive Mutations ◽  
Phase 2 Trial

Abstract Background We developed a recombinant saponin-adjuvanted (Matrix-M1) quadrivalent hemagglutinin nanoparticle influenza vaccine (qNIV; NanoFlu) for older adults to address two impediments to efficacy of current, predominantly egg-derived, seasonal influenza vaccines: (1) limited protection against antigenic drift variants, particularly H3N2 viruses; and (2) antigenic mismatch between vaccine and circulating strains due to egg-adaptive mutations arising during manufacturing. In a prior Phase 1 trial, we showed that qNIV induced robust, broadly cross-reactive antibody responses against multiple antigenically drifted H3N2 viruses, which were 47–64% better than the egg-derived comparator trivalent high-dose inactivated influenza vaccine (IIV3-HD; Fluzone-High Dose). We undertook a Phase 2 trial to optimize the formulation of qNIV, and to compare qNIV immune responses to those of IIV3-HD and quadrivalent recombinant influenza vaccine (RIV4; FluBlok). Methods In this phase 2 dose and formulation finding RCT, we randomized 1,375 subjects aged ≥65 years to be immunized with 1 of 7 test vaccines: 5 different formulations of qNIV, IIV3-HD, or RIV4; and assessed wild-type hemagglutinin-inhibition (wt-HAI) and microneutralization (wt-MN) antibody responses (Day 0/28/56). Results Matrix-M1-adjuvanted qNIV induced 15–29% higher wt-HAI titers across 5 vaccine homologous or drifted H3N2 strains at Day 28 relative to unadjuvanted qNIV (statistically significantly superior for 5 of 6 strains tested). At Day 28, several qNIV formulations induced significantly superior wt-HAI titers vs. IIV3-HD (39–45%, 17–22%, and 44–48% greater titers for homologous A/Singapore/INFIMH-16–0019/2016—H3N2, historic-drifted A/Switzerland/9715293/2013—H3N2, and forward-drifted A/Wisconsin/19/2017—H3N2, respectively); and comparable HAI titers vs. RIV4. Wt-MN and wt-HAI data showed concordant patterns across treatment groups. Conclusion qNIV induced superior wt-HAI antibody responses vs. IIV3-HD against homologous or drifted H3N2 viruses and similar responses to RIV4. qNIV may address several critical challenges confronting current egg-derived influenza vaccines, especially in the older adult population. Disclosures All authors: No reported disclosures.

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