Abstract
Background:
Influenza A/H7N9 viruses have pandemic potential.
Methods:
We conducted an open-label, randomized, controlled trial of AS03-adjuvanted 2017 inactivated influenza A/H7N9 vaccine (H7N9 IIV) in healthy adults. Group 1 received H7N9 IIV and seasonal quadrivalent influenza vaccine (IIV4) simultaneously, followed by H7N9 IIV three weeks later. Group 2 received IIV4 alone and then two doses of H7N9 IIV at three-week intervals. Group 3 received one dose of IIV4. We used hemagglutination inhibition (HAI) and microneutralization (MN) assays to measure geometric mean titers and seroprotection (≥1:40 titer) to vaccine strains and monitored for safety.
Results:
Among 149 subjects, seroprotection by HAI three weeks after H7N9 IIV dose 2 was 51% (95 %CI 37%-65%) for Group 1 and 40% (95 %CI 25%-56%) for Group 2. Seroprotection by MN at the same timepoint was 84% (95 %CI 72%-93%) for Group 1 and 74% (95 %CI 60%-86%) for Group 2. By 180 days after H7N9 IIV dose 2, seroprotection by HAI or MN was low for Groups 1 and 2. Responses measured by HAI and MN against each IIV4 strain three weeks after IIV4 vaccination were similar in all groups. Solicited local and systemic reactions were similar after a single vaccination, while those receiving simultaneous H7N9 and IIV4 had slightly more reactogenicity. There were no serious adverse events or medically-attended adverse events related to study product receipt.
Conclusions:
Adjuvanted H7N9 IIV was modestly immunogenic whether administered simultaneously or sequentially with IIV4, though responses declined by 180 days. IIV4 was immunogenic regardless of schedule.
Clinical Trials Registration:
1. Introduction
Influenza A viruses from animal reservoirs occasionally cause human disease and are monitored for their pandemic potential. Avian influenza A/H7N9 viruses were first reported in China in March 2013, and annual outbreaks of A/H7N9 human infections were reported through 2017, with sporadic case detections continuing through 2019 [1-3]. Most human cases were exposed to A/H7N9 virus by contact with infected poultry or contaminated environments [4]. While small clusters of human cases have been reported [5], current epidemiological and virological evidence suggest that the A/H7N9 virus has not acquired the ability to sustain human-to-human transmission [6]. As of November 26, 2020, a total of 1568 A/H7N9 human infections had been reported by the World Health Organization (WHO) since 2013 [2,6].
During the fifth annual A/H7N9 outbreak during 2016–17, a strain of A/H7N9 viruses emerged, which was antigenically distinct from earlier epidemics [7]. This “Yangtze River Delta” lineage was associated with the majority of subsequent cases [7]. As of May 2021, the United States (US) Centers for Disease Control and Prevention (CDC) assesses the A/H7N9 Yangtze River Delta lineage influenza viruses as having the highest pandemic risk among all novel influenza viruses assessed [7,8].
Response to influenza A/H7N9 vaccines may be affected by prior exposure to seasonal influenza vaccines. Several observational studies have reported effect modification of previous seasonal influenza vaccination on subsequent seasonal or novel influenza vaccine response [9-15]. Therefore, we undertook a clinical trial to assess the safety, reactogenicity, and immunogenicity of two 3.75 ug doses of AS03-adjuvanted 2017 inactivated influenza A/H7N9 (Yangtze River Delta lineage) vaccine (H7N9 IIV) administered sequentially or simultaneously with seasonal quadrivalent inactivated influenza vaccine (IIV4). Our goals were to assess the performance of this new vaccine against the antigenically distinct “Yangtze River Delta” lineage and to determine whether sequential or simultaneous administration with seasonal influenza vaccine resulted in evidence of interference by either product.
2. Material and methods
2.1. Regulatory reviews and subject consent
The protocol was approved by institutional review boards at the participating NIAID Vaccine and Treatment Evaluation Units and was registered at Clinicaltrials.gov (NCT03318315). All study subjects provided informed consent.
2.2. Study design and procedures
The study was a randomized, unblinded, phase II clinical trial in males and non-pregnant females aged 19 through 64 years. We sought to enroll up to 150 subjects. The trial was designed to assess the safety, reactogenicity, and immunogenicity of an AS03-adjuvanted H7N9 IIV when two doses were administered 21 days apart, either sequentially or simultaneously with 2017–18 licensed IIV4.
We randomized subjects into one of three vaccine groups with allocation 2:2:1. Group 1 received two vaccine doses simultaneously (within 15 min) in opposite arms, H7N9 IIV and IIV4, and they received a second dose of H7N9 IIV approximately 21 days later. Group 1 was the only group to receive two vaccinations simultaneously. Group 2 sequentially received one dose of IIV4, followed by the two-dose series of H7N9 IIV, with each dose approximately 21 days after the preceding dose. Group 3 received one dose of IIV4 as an un-blinded comparison group.
Individuals who met all eligibility criteria (including screening by erythrocyte sedimentation rate, pregnancy test, medical history, and physical exam) within 28 days prior to the first vaccination were eligible for randomization. Individuals were ineligible to participate if they had already received any 2017–2018 seasonal influenza vaccine prior to enrollment.
We measured reactogenicity by the occurrence of solicited injection site (local) and systemic reactions from the time of each study vaccination through 7 days postvaccination. We collected unsolicited non-serious Adverse Events (AEs) from the time of each study vaccination through approximately 21 days postvaccination. We monitored for Serious Adverse Events (SAEs) and Medically-Attended Adverse Events (MAAEs), including New-Onset Chronic Medical Conditions (NOCMCs) and Potentially Immune-Mediated Medical Conditions (PIMMCs), for approximately 12 months after the last study vaccination. Subjects had clinical laboratory evaluations for safety performed on venous blood collected prior to each study vaccination and approximately 7 days postvaccination.
We assessed immunogenicity using influenza hemagglutination inhibition (HAI) and microneutralization (MN) antibody assays against the H7N9 IIV virus on serum samples collected for Group 1 on Days 1 (baseline), 22, and 43, and at approximately 180 days post second H7N9 IIV dose (Day 202), and for Group 2 on Days 22 (baseline), 43, and 64, and at approximately 180 days post second H7N9 IIV dose (Day 223). We also assessed immunogenicity against the IIV4 components from serum samples collected from all groups on Day 1 (baseline) and approximately 21 and 180 days following receipt of IIV4.
2.3. Study products
H7N9 IIV was a monovalent, preservative-free preparation manufactured from a reverse genetics-derived reassortant candidate vaccine virus IDCDC RG56B (H7N9), containing the HA and NA from low pathogenic influenza A/Hong Kong/125/2017 (H7N9) and the PB2, PB1, PA, NP, M and NS from A/Puerto Rico/8/1934 (H1N1) (Lot #UD19639). Seed virus was propagated in embryonated chicken eggs, inactivated, and split per the process used by the manufacturer (Sanofi Pasteur) to produce licensed seasonal IIV4. Sodium phosphate-buffered isotonic sodium chloride solution (PBS) was produced by the manufacturer in accordance with the commercial process for IIV4 (Lot # CD0108AA). AS03 (GSKGSK), is an Adjuvant System containing DL-α-tocopherol and squalene in an oil and water emulsion (Lot # AA03A210A). Vaccine, diluent, and adjuvant were provided under contract to the US Department of Health and Human Services (HHS). The target HA content of H7N9 IIV was 3.75 mcg HA/0.5 mL dose. The actual HA content of H7N9 IIV was 14.45 mcg HA/0.5 mL. The vaccine preparation was adjusted to meet the targeted concentration by including a 1:1 dilution step with Phosphate Buffered Saline (PBS). The adjusted vaccine preparation was mixed 1:1 with AS03 adjuvant resulting in a final mixed vial containing 3.61 mcg of A/H7N9 antigen/PBS diluent plus one dose (0.25 mL) of AS03 adjuvant in a single 0.5 mL dose. The final vaccine preparation had 3.61 mcg HA/0.5 mL dose (3.7% below target) as measured by Single Radial Immunodiffusion (SRID) Assay.
The comparator vaccine (IIV4) was a licensed, quadrivalent, inactivated, subvirion, preservative-free preparation with the influenza strains recommended for the Northern Hemisphere 2017–2018 season (Fluzone Quadrivalent Influenza Vaccine) (Lot # U1876AA) [16]. IIV4 was administered at the licensed and recommended dose.
2.4. Laboratory evaluation
HAI and MN responses were measured at a single laboratory (Southern Research, Birmingham, Alabama) as previously described [12,17-19]. Serum samples were tested against the homologous influenza A/Hong Kong/125/2017 (H7N9) reassortant virus. Serum samples were tested in duplicate, and the geometric mean titer (GMT) of replicate results was used for analysis. The initial dilution was defined as 1:10, and serum samples without activity were scored as 5 [20].
2.5. Statistics
The safety co-primary objective was to assess the safety and reactogenicity following sequential or simultaneous IM administration of 2 doses of AS03-adjuvanted 2017 H7N9 IIV and one dose of IIV4. The immunogenicity co-primary objectives were to 1) assess the serum HAI and MN antibody responses against A/H7N9 at approximately 21 days following receipt of two doses of AS03-adjuvanted 2017 H7N9 IIV administered IM approximately 21 days apart, and 2) assess the serum HAI and MN antibody responses against the seasonal influenza strains at approximately 21 days following receipt of IIV4.
The number and percentage of subjects reporting AEs of each type were summarized by maximum severity and study group for each outcome. Reactogenicity events (local and systemic) were further summarized by the maximum severity reported daily through Day 8 postvaccination. Analyses were conducted using the Safety Analysis population, which included all available data from vaccinated subjects.
Titer results are summarized by study group and timepoint using geometric mean titers (GMTs) and associated 95% confidence intervals (CIs). CIs for geometric mean values are estimated based on the assumption of log-normality. The percentage of vaccinees achieving seroprotection (defined as titer ≥ 40) and seroconversion (defined as seroprotected with a minimum of four-fold rise from baseline) were estimated along with 95% CIs based on exact Clopper-Pearson methodology. The primary immunogenicity outcomes were GMT and seroprotective titer (≥1:40) for each assay, and the primary endpoint was H7N9 IIV immunogenicity measured at 21 days post second vaccination. We report details of results of immunogenicity analyses conducted in the modified intent-to-treat population, which included all available data from vaccinated subjects with results available at baseline and at least one post-baseline timepoint. Analyses of the Per Protocol population excluded all data from subjects ineligible at baseline as well as data collected after any major protocol deviation and data collected more than one day out of window were included as a sensitivity analysis. Details of these analyses are presented in the Online Supplement.
The sample size for this study was selected to obtain sufficient data to produce meaningful preliminary estimates of the serological immune response and rates of common adverse events (AEs) in response to the three vaccination schedules assessed. Analyses were performed using SAS 9.4 (SAS Institute, Cary, NC).
3. Results
3.1. Enrollment and demographics
The first subject was enrolled on February 25, 2018, and the last was enrolled on June 29, 2018. A total of 149 subjects were randomized into Group 1 (n = 61), Group 2 (n = 58), and Group 3 (n = 30) (Fig. 1). One subject randomized to Group 2 erroneously received simultaneous IIV4 and H7N9 IIV vaccination instead of in sequence and was analyzed with Group 2. Among those who received a first vaccination, 138 subjects were included in per protocol immunogenicity analyses conducted at 21 days after the second dose of H7N9 IIV and at 21 days after the single dose of IIV4. Demographic and baseline characteristics were similar across study groups (Table 1). Overall, 44% of subjects were women, 55% were Black or African American, and 15% had received the 2016–17 seasonal influenza vaccine.
Fig. 1.
CONSORT flow diagram.
Table 1.
Study design and demographics of study groups as analyzed.
| Group 1 (n = 62) | Group 2 (n = 53) | Group 3 (n = 34) | |
|---|---|---|---|
| Schedule | |||
| Day 1 | H7N9 IIV + IIV4 | IIV4 | IIV4 |
| Day 21 | H7N9 IIV | H7N9 IIV | N/A |
| Day 43 | N/A | H7N9 IIV | N/A |
| Age in years, mean (standard deviation) | 39.1 (13.1) | 38.1 (11.5) | 35.7 (10.6) |
| Sex, number (%) | |||
| Male | 36 (58%) | 27 (51%) | 21(62%) |
| Female | 26 (42%) | 26 (49%) | 13 (38%) |
| Ethnicity, number (%) | |||
| Not Hispanic or Latino | 60 (97%) | 52 (98%) | 31 (91%) |
| Hispanic or Latino | 2 (3%) | 1 (2%) | 3 (9%) |
| Race, number (%) | |||
| Black or African American | 36 (58%) | 29 (55%) | 17 (50%) |
| White | 22 (35%) | 17 (32%) | 14 (41%) |
| Other | 4 (6%) | 7 (13%) | 3 (9%) |
| BMI, mean (standard deviation) | 29.5 (7.2) | 29.6 (6.7) | 31.6 (7.3) |
| Previous seasonal influenza vaccine (2016–17), number (%) | |||
| No | 52 (84%) | 45 (85%) | 28 (82%) |
| Yes | 9 (15%) | 8 (15%) | 5 (15%) |
| Unknown | 1 (2%) | – | 1 (3%) |
n = number of subjects with available results; GMT = Geometric Mean Titer.
3.2. H7N9 IIV immune response
No subjects had a HAI titer ≥ 1:40 against H7N9 at baseline (Table 2, Fig. 2). Seroprotection and GMT, as measured by HAI, were low at 21 days after the first dose of H7N9 IIV in Groups 1 and 2. Seroprotection as measured by HAI at 21 days post H7N9 IIV dose 2 was 51% (95 %CI 37%-64%) for Group 1 and 38% (95 % CI 25%-54%) for Group 2. GMT, as measured by HAI at 21 days post H7N9 IIV dose 2, was 36.8 (95 %CI 27.7–48.8) for Group 1 and 22.7 (95 %CI 16.9–30.6) for Group 2. As expected, Group 3 H7N9 seroprotection was 0% (95 %CI 0%-12%) and GMT was 6.2 (95 %CI 5.5–7.0) at 21 days post IIV4. By 180 days post dose 2, seroprotection and GMTs were low and similar for both H7N9 IIV groups.
Table 2.
Influenza A/H7N9 vaccine immunogenicity by hemagglutination inhibition and microneutralization, Modified Intent-to-Treat population.
| Group 1 | Group 2 | Group 3 | |
|---|---|---|---|
| Schedule | |||
| Day 1 vaccination | H7N9 IIV + IIV4 | IIV4 | IIV4 |
| Day 21 vaccination | H7N9 IIV | H7N9 IIV | N/A |
| Day 43 vaccination | N/A | H7N9 IIV | N/A |
| Hemagglutination inhibition assay | |||
| Baseline, n= | 59 | 53 | 29 |
| GMT (95 %CI) | 5.7 (5.5, 6.0) | 5.7 (5.3, 6.1) | 5.3 (5.1, 5.5) |
| Titer ≥ 1:40 - % (95% CI) | 0 (0, 6) | 0 (0, 7) | 0 (0, 12) |
| Post dose 1 (day 21), n= | 57 | 53 | 29 |
| GMT (95 %CI) | 9.9 (7.7, 12.7) | 6.5 (5.8, 7.3) | 6.2 (5.5, 7.0) |
| Titer ≥ 1:40 - % (95% CI) | 14 (6, 26) | 2 (0, 10) | 0 (0, 12) |
| Seroconversion, % | 14 (6, 26) | 2 (0, 10) | 0 (0,12) |
| Post dose 2 (day 43), n= | 57 | 50 | NA |
| GMT (95 %CI) | 36.8 (27.7, 48.8) | 6.6 (5.9, 7.4) | NA |
| Titer ≥ 1:40 - % (95% CI) | 51 (37, 65) | 2 (0, 11) | NA |
| Seroconversion, % | 51 (37, 64) | 2 (0, 11) | NA |
| Post dose 3 (day 64), n= | NA | 47 | NA |
| GMT (95 %CI) | NA | 22.7 (16.9, 30.6) | NA |
| Titer ≥ 1:40 - % (95% CI) | NA | 38 (25, 54) | NA |
| Seroconversion, % | NA | 38 (25, 54) | NA |
| 180 days post second dose of AS03-adjuvanted H7N9 Vaccine, n= | 56 | 46 | NA |
| GMT (95 %CI) | 9.8 (7.9, 12.1) | 9.3 (7.2, 12.0) | NA |
| Titer ≥ 1:40 - % (95% CI) | 9 (3, 20) | 13 (5, 26) | NA |
| Seroconversion, % | 9 (3, 20) | 13 (5, 26) | NA |
| Microneutralization assay | |||
| Baseline, n= | 60 | 53 | 29 |
| GMT (95 %CI) | 5.9 (5.4, 6.6) | 5.4 (5.1, 5.7) | 5.5 (5.0, 6.1) |
| Titer ≥ 1:40 - % (95% CI) | 2 (0, 9) | 0 (0, 7) | 0 (0, 12) |
| Post dose 1 (day 21), n= | 59 | 53 | 29 |
| GMT (95 %CI) | 22.3 (16.2, 30.8) | 10.3 (8.4, 12.6) | 9.8 (7.2, 13.2) |
| Titer ≥ 1:40 - % (95% CI) | 33 (22, 47) | 9 (3, 21) | 14 (4, 32) |
| Seroconversion, % | 34 (22, 47) | 9 (3, 21) | 14 (4, 32) |
| Post dose 2 (day 43) | 57 | 50 | NA |
| GMT (95 %CI) | 88.4 (63.2, 123.9) | 18.4 (14.5, 23.4) | NA |
| Titer ≥ 1:40 - % (95% CI) | 84 (72, 93) | 28 (16, 42) | NA |
| Seroconversion, % | 82 (70, 91) | 28 (16, 42) | NA |
| Post dose 3 (day 64) | NA | 47 | NA |
| GMT (95 %CI) | NA | 50.5 (37.4, 68.0) | NA |
| Titer ≥ 1:40 - % (95% CI) | NA | 74 (60, 86) | NA |
| Seroconversion, % | NA | 74 (60, 86) | NA |
| 180 days post second dose of AS03-adjuvanted H7N9 Vaccine, n= | 58 | 46 | NA |
| GMT (95 %CI) | 10.1 (8.0, 12.9) | 8.3 (7.1, 9.7) | NA |
| Titer ≥ 1:40 - % (95% CI) | 7 (2, 17) | 2 (0, 12) | NA |
| Seroconversion, % | 5 (1, 14) | 2 (0, 12) | NA |
n = number of subjects with available results; GMT = Geometric Mean Titer; 95 %CI = 95% Confidence Interval.
Fig. 2.
Hemagglutination inhibition geometric mean titer against H7N9 IIV by study day and study group, modified Intent-to-Treat population.
H7N9 IIV immunogenicity, as measured by MN, indicated one subject in Group 1, had seroprotective titer at baseline (Table 2, Fig. 3). As with HAI response, seroprotection and GMT by MN were low at 21 days after the first dose of H7N9 IIV in Groups 1 and 2. Seroprotection, as measured by MN, at 21 days post H7N9 IIV dose 2 was 84% (95 %CI 72%-93%) for Group 1 and 74% (95 %CI 60%-86%) for Group 2. GMT, as measured by HAI, at 21 days post H7N9 IIV dose 2 was 88.4 (95 %CI 63.2–123.9) for Group 1 and 50.3 (95 % CI 37.4–68.0) for Group 2. Group 3 H7N9 seroprotection was 14% (95 %CI 4%–32%) and GMT was 9.8 (95 %CI 7.2–13.2) at 21 days post IIV4. By 180 days post dose 2, seroprotection and GMTs were low and similar for both H7N9 IIV groups.
Fig. 3.
GMT of MN against H7N9 IIV by study day and study group, modified Intent-to-Treat population.
Analyses by per protocol population were similar in magnitude and trajectory to those in the modified intent-to-treat population (Supplemental Table 1).
3.3. IIV4 immune response
Each study group had a moderate to high proportion of subjects with baseline seroprotective HAI titer for IIV4 influenza A antigens: ≥51% for H1N1 and ≥ 41% for H3N2, while the study groups had a lower proportion of baseline seroprotective HAI titers for IIV4 influenza B antigens: ≤14% for B/Yamagata and ≤ 19% for B/Victoria (Table 3, Fig. 4). Baseline HAI GMTs were generally balanced among groups. HAI responses against each of the four seasonal IIV4 strains increased in each study group at 21 days post IIV4 vaccination by seroprotective titers or GMT, though the responses were greater for influenza A antigens than for influenza B antigens. HAI GMTs to components of the IIV4 were similar in each study group, with largely overlapping 95% confidence intervals at 21 days post IIV4 vaccination (Supplemental Fig. 2). By 180 days post IIV4 vaccination, Group 3 HAI GMTs against IIV4 components were higher than Groups 1 and 2 for H3N2 and both B lineages, but with considerable overlap of 95% confidence intervals (Table 4 and Supplemental Fig. 2). Day 180 post vaccination HAI GMTs against H1N1 were similar for each study group. Analyses by modified intent-to-treat population were also similar to the per protocol population (Supplemental Table 5). Immunogenicity, as measured by MN, showed similar seroprotection and GMT values at the same timepoints (Supplemental Table 6).
Table 3.
Quadrivalent seasonal influenza vaccine immunogenicity by hemagglutination inhibition, Modified Intent-to-Treat population.
| Group 1 | Group 2 | Group 3 | |
|---|---|---|---|
| Day 1 vaccination | H7N9 IIV + IIV4 | IIV4 | IIV4 |
| Day 21 vaccination | H7N9 IIV | H7N9 IIV | N/A |
| Day 43 vaccination | N/A | H7N9 IIV | N/A |
| H1N1 (A/Michigan/45/2015 x-275) | |||
| Baseline, n= | 60 | 53 | 29 |
| GMT (95 %CI) | 64.5 (40.1, 103.6) | 36.1 (21.0, 62.0) | 51.4 (24.2, 109.3) |
| Titer ≥ 1:40 - % (95% CI) | 63 (50, 75) | 51 (37, 65) | 62 (42, 79) |
| 21 days post IIV4, n= | 59 | 53 | 29 |
| GMT | 547.7 (431.0, 696.1) | 503.6 (360.6, 703.1) | 480.4 (290.1, 795.7) |
| Titer ≥ 1:40 - % (95% CI) | 100 (94, 100) | 96 (87, 100) | 93 (77, 99) |
| Seroconversion, % | 53 (39, 66) | 58 (44, 72) | 55 (36, 74) |
| H3N2 (A/Hong Kong/4801/2014 X-263B) | |||
| Baseline, n= | 60 | 53 | 29 |
| GMT (95 %CI) | 46.9 (30.6, 71.8) | 42.5 (27.8, 65.1) | 41.2 (21.8, 78.0) |
| Titer ≥ 1:40 - % (95% CI) | 58 (45, 71) | 62 (48, 75) | 41 (24, 61) |
| 21 days post IIV4, n= | 59 | 53 | 29 |
| GMT | 284.0 (201.6, 400.0) | 289.8 (202.5, 414.7) | 462.6 (314.6, 680.2) |
| Titer ≥ 1:40 - % (95% CI) | 93 (84, 98) | 94 (84, 99) | 100 (88, 100) |
| Seroconversion, % | 49 (36, 63) | 55 (40, 68) | 72 (53, 87) |
| B Yamagata lineage (B/Phuket/3073/2013) | |||
| Baseline, n= | 60 | 53 | 29 |
| GMT (95 %CI) | 7.6 (6.4, 9.2) | 8.9 (7.1, 11.2) | 9.7 (7.1, 13.2) |
| Titer ≥ 1:40 - % (95% CI) | 7 (2, 16) | 9 (3, 21) | 14 (4, 32) |
| 21 days post IIV4, n= | 59 | 53 | 29 |
| GMT | 20.8 (15.2, 28.4) | 23.5 (17.3, 31.9) | 44.4 (29.7, 66.3) |
| Titer ≥ 1:40 - % (95% CI) | 25 (15, 38) | 30 (18, 44) | 62 (42, 79) |
| Seroconversion, % | 19 (10, 31) | 13 (5, 25) | 41 (24, 61) |
| B Victoria lineage (B/Brisbane/60/2008) | |||
| Baseline, n= | 60 | 53 | 29 |
| GMT (95 %CI) | 11.0 (8.7, 14.0) | 13.0 (9.9, 17.1) | 12.2 (7.8, 18.9) |
| Titer ≥ 1:40 - % (95% CI) | 15 (7, 27) | 19 (9, 32) | 17 (6, 36) |
| 21 days post IIV4, n= | 59 | 53 | 29 |
| GMT | 46.1 (33.6, 63.2) | 61.8 (46.0, 82.9) | 64.1 (44.3, 92.7) |
| Titer ≥ 1:40 - % (95% CI) | 54 (41, 67) | 72 (58, 83) | 76 (56, 90) |
| Seroconversion, % | 29 (18, 42) | 47 (33, 61) | 48 (29, 67) |
n = number of subjects with available results; GMT = Geometric Mean Titer; 95 %CI = 95% Confidence Interval.
Fig. 4.
Quadrivalent seasonal influenza vaccine immunogenicity by hemagglutination inhibition, Modified Intent-to-Treat population.
Table 4.
Six-month immunogenicity of quadrivalent seasonal influenza vaccine by hemagglutination inhibition, Modified Intent-to-Treat population.
| Group 1 | Group 2 | Group 3 | |
|---|---|---|---|
| Day 1 vaccination | H7N9 IIV + IIV4 | IIV4 | IIV4 |
| Day 21 vaccination | H7N9 IIV | H7N9 IIV | N/A |
| Day 43 vaccination | N/A | H7N9 IIV | N/A |
| H1N1 (A/Michigan/45/2015 x-275) | |||
| 180 days post IIV4, n= | 59 | 51 | 29 |
| GMT | 130.3 (92.1, 184.2) | 140.9 (95.8, 207.2) | 147.2 (90.1, 240.3) |
| Titer ≥ 1:40 - % (95% CI) | 85 (73, 93) | 82 (69, 92) | 90 (73, 98) |
| Seroconversion, % | 31 (19, 44) | 41 (28, 56) | 34 (18, 54) |
| H3N2 (A/Hong Kong/4801/2014 X-263B) | |||
| 180 days post IIV4, n= | 59 | 50 | 29 |
| GMT | 215.9 (165.6, 281.4) | 203.9 (164.7, 252.5) | 347.9 (239.8, 504.9) |
| Titer ≥ 1:40 - % (95% CI) | 98 (91, 100) | 100 (93, 100) | 100 (88, 100) |
| Seroconversion, % | 51 (37, 64) | 54 (39, 68) | 69 (49, 85) |
| B Yamagata lineage (B/Phuket/3073/2013) | |||
| 180 days post IIV4, n= | 59 | 50 | 29 |
| GMT | 13.4 (10.0, 18.0) | 16.5 (11.9, 22.9) | 25.4 (16.0, 40.3) |
| Titer ≥ 1:40 - % (95% CI) | 19 (10, 31) | 28 (16, 42) | 48 (29, 67) |
| Seroconversion, % | 12 (5, 23) | 14 (6, 27) | 24 (10, 44) |
| B Victoria lineage (B/Brisbane/60/2008) | |||
| 180 days post IIV4, n= | 59 | 51 | 29 |
| GMT | 30.6 (21.3, 44.2) | 35.4 (23.8, 52.7) | 49.4 (33.0, 74.0) |
| Titer ≥ 1:40 - % (95% CI) | 46 (33, 59) | 53 (38, 67) | 66 (46, 82) |
| Seroconversion, % | 25 (15, 38) | 31 (19, 46) | 45 (26, 64) |
n = number of subjects with available results; GMT = Geometric Mean Titer; 95 %CI = 95% Confidence Interval.
3.4. Safety and reactogenicity assessment
Postvaccination reactions were mostly mild. The most common solicited reactions in all groups were pain and tenderness at the injection site (Supplemental Tables 7 and 8, Figs. 5 and 6). Any solicited local reactions after H7N9 IIV dose 1 were 82% (Group 1) and 81% (Group 2), while after dose 2 were 68% (Group 1) and 72% (Group 2). Any systemic reactions after H7N9 IIV dose 1 were 66% (Group 1) and 40% (Group 2), while after dose 2 were 41% (Group 1) and 37% (Group 2). The sequential (Group 2) and IIV4-only (Group 3) groups had similar any local symptoms (60% vs. 68%) and any systemic symptoms (28% vs. 35%) after receiving dose 1. There was one SAE (myocardial infarction) experienced by a subject in Group 2 that occurred 179 days post dose 3 and was deemed to be not related to study product. Abnormal clinical laboratory tests postvaccination were mostly mild and more common in Groups 1 and 2 (Supplemental Table 9). There were 15 MAAEs (1 severe, 9 moderate, and 5 mild). Three of the MAEEs were considered NOCMCs. None of the MAEEs were deemed related to the study product. There was one severe, non-serious unsolicited AE (viral gastroenteritis) deemed unrelated to study product. Eight non-serious moderate grade unsolicited AEs (back pain, dizziness, elevated bilirubin, insomnia, loose stools, vomiting, and two events of axillary pain) were deemed related to study vaccine.
Fig. 5.
Maximum severity of solicited systemic symptoms per subject by day post dose, safety population.
Fig. 6.
Maximum severity of solicited local symptoms per subject by day post dose, safety population.
3.5. Exploratory analysis
Among participants categorized by receipt/non-receipt of 2016–2017 seasonal influenza vaccine in the prior year, antibody response as measured by HAI at 21 days post second vaccine dose were similar with overlapping 95% confidence intervals in Group 1 and Group 2 for GMT and seroconversion (Supplemental Table 10). A similar trend was seen with microneutralization GMT and seroconversion (Supplemental Table 11).
4. Discussion
This was the first study to compare the performance of dosesparing, AS03-adjuvanted 2017 A/H7N9 IIV vaccine given simultaneously or sequentially with seasonal influenza vaccine. As measured by HAI or MN, product-specific H7N9 IIV immunogenicity was poor after a single dose, modest after two doses, and had GMT responses at 21 days post second vaccination with overlapping 95% confidence intervals whether given simultaneously or sequentially with IIV4. Seroprotection to the 2017 H7N9 IIV strain was low at day 180 postvaccination for each group receiving H7N9 IIV. All groups showed increases in HAI and MN GMT against each IIV4 strain at 21 days post IIV4 vaccination, with greater responses for influenza A strains as compared to influenza B strains. Whether given sequentially or simultaneously with the 2017–2018 IIV4 formulation, two doses of 2017 H7N9 IIV were safe and well-tolerated. This safety profile was similar to that seen with an adjuvanted 2013 H7N9 IIV [21].
Given the potential that future H7N9 IIV deployment could target persons who had received seasonal influenza vaccines recently, we conducted this study to understand better whether IIV4 and H7N9 IIV interfered with each other. In this study, all groups had short-term increases in antibody titers against all four seasonal IIV4 strains, and these responses were greater for influenza A strains. GMT responses to each individual IIV4 strain generally had overlapping 95% confidence intervals at all timepoints among the three study groups, though both groups receiving IIV4 alone during dose 1 (Group 2 and Group 3) showed qualitatively higher immune response to components of the IIV4 than did the group receiving IIV4 and H7N9 vaccine simultaneously at dose 1 (Group 1).
Avian influenza vaccines have been poorly immunogenic in humans, requiring the addition of adjuvants or high antigen content to elicit seroprotective responses [21-26]. Study groups receiving AS03-containing vaccines had higher antibody responses at 21 days than MF-59-adjuvanted H7N9 IIV against an antigenically different strain [21]. Further, the AS03-adjuvanted 2017 H7N9 IIV response in our study was lower than the same dose of AS03-adjuvanted 2013 H7N9 IIV studied previously [21]. The low 180-day antibody titers that we observed do not suggest durable protection conferred by the study vaccine, although it is possible that immune priming had been achieved and subsequent boost by H7N9 IIV vaccination or infection would generate protective memory B cell responses. In the absence of efficacy trials for prepandemic influenza vaccines, more research is needed to correlate vaccine immune response with magnitude and durability of protection.
Our study is subject to limitations. The study was not designed to test a formal null hypothesis. Rather, it was intended to obtain sufficient data to determine meaningful estimates of the immune response induced when 2017 H7N9 IIV was administered sequentially or simultaneously with IIV4 and to uncover any safety issues that might be observed in a study of this size.
The risk of human infections with zoonotic influenza viruses exists wherever humans and animal influenza reservoirs are in close contact. H7N9 control efforts have been successful, and since October 1, 2017, there have been only three reported human infections by H7N9 virus [27]. However, continued vigilance is critical, as avian influenza viruses with pandemic potential have reemerged after periods of limited detection in the past, and human infections with new zoonotic influenza subtypes continue to occur regularly [28].
Supplementary Material
Acknowledgements
We thank the DMID 17-0077 study team; in particular Tena Knudsen, Wendy Buchanan, and Dr. Chris Roberts for clinical operations oversight and contributions to the clinical study design and Sonnie Kim for oversight of immunogenicity analyses. GlaxoSmithKline Biologicals SA was provided the opportunity to review a preliminary version of this manuscript for factual accuracy but the authors are solely responsible for final content and interpretation. We thank the members of the data and safety monitoring board for their oversight and the subjects for participating in this trial. The vaccine and adjuvants were provided by the US Department of Health and Human Services Biomedical Advanced Research and Development Authority from the national prepandemic influenza vaccine stockpile and were manufactured by Sanofi Pasteur (H7N9 vaccine) and GlaxoSmithKline (AS03 adjuvant).
Funding
This project was funded in whole or part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contracts HHSN272201300016I (Cincinnati Children’s Hospital Medical Center), 75N93021C00012 (The Emmes Company), HHSN272200800057C (University of Maryland, Baltimore), HHSN272201300023I (Vanderbilt University), and NIAID’s Preclinical Services Contract No. HHSN272201200003I/HHS N27200003 for immunogenicity assessments by Southern Research. Partial support of the University of Maryland, Baltimore, Institute for Clinical & Translational Research (ICTR) was provided by the National Center for Advancing Translational Sciences (NCATS) Clinical Translational Science Award (CTSA) grant number 1UL1TR003098. The vaccine and adjuvants were provided by the US Department of Health and Human Services Biomedical Advanced Research and Development Authority from the national prepandemic influenza vaccine stockpile and were manufactured by Sanofi Pasteur (H7N9 vaccine), and GlaxoSmithKline (AS03 adjuvant).
Footnotes
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Disclaimer
The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does any mention of trade names, commercial products, or organizations imply endorsement by the US Government. GSK provided AS03 adjuvant, Sanofi provided H7N9 vaccine, seasonal influenza vaccine, and buffered sodium chloride solution.
Appendix A. Supplementary material
Supplementary data to this article can be found online at https://doi.org/10.1016/j.vaccine.2022.03.055.
References
- [1].Centers for Disease Control and Prevention. Asian Lineage Avian Influenza A (H7N9) Virus. Available from: https://www.cdc.gov/flu/avianflu/h7n9-virus.htm. Accessed 17 May 2021.
- [2].World Health Organization Western Pacific Region. Avian Influenza Weekly Update Number 791. Available from: https://www.who.int/docs/default-source/wpro—documents/emergency/surveillance/avian-influenza/ai-20210507.pdf. Accessed 17 May 2021.
- [3].World Health Organization. Influenza at the human-animal interface: Summary and assessment, from 28 February to 8 May 2020. Available from: https://www.who.int/influenza/human_animal_interface/Influenza_Summary_IRA_HA_interface_08_05_2020.pdf. Accessed 17 May 2021.
- [4].World Health Organization. Analysis of recent scientific information on avian influenza A(H7N9) virus. Available from: https://www.who.int/influenza/human_animal_interface/avian_influenza/riskassessment_AH7N9_201702/en/. Accessed 17 May 2021.
- [5].Wang X, Wu P, Pei Y, Tsang TK, Gu D, Wang W, et al. Assessment of human-to-human transmissibility of avian influenza A(H7N9) virus across 5 waves by analyzing clusters of case patients in Mainland China, 2013–2017. Clin Infect Dis 2019;68(4):623–31. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [6].World Health Organization. Influenza at the human-animal interface: Summary and assessment, 13 February to 9 April 2019. Available from: https://www.who.int/influenza/human_animal_interface/Influenza_Summary_IRA_HA_interface_09_04_2019.pdf?ua=1. Accessed 17 May 2021.
- [7].Kile JC, Ren R, Liu L, Greene CM, Roguski K, Iuliano AD, et al. Update: increase in human infections with novel asian lineage avian influenza A(H7N9) viruses during the fifth epidemic - China, October 1, 2016-August 7, 2017. MMWR Morb Mortal Wkly Rep 2017;66(35):928–32. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [8].Centers for Disease Control and Prevention. Summary of Influenza Risk Assessment Tool (IRAT) Results. Available from: https://www.cdc.gov/flu/pandemic-resources/monitoring/irat-virus-summaries.htm. Accessed 17 May 2021.
- [9].Belongia EA, Skowronski DM, McLean HQ, Chambers C, Sundaram ME, De Serres G. Repeated annual influenza vaccination and vaccine effectiveness: review of evidence. Expert Rev Vaccines 2017;16(7):723–36. [DOI] [PubMed] [Google Scholar]
- [10].Keitel WA, Cate TR, Couch RB, Huggins LL, Hess KR. Efficacy of repeated annual immunization with inactivated influenza virus vaccines over a five year period. Vaccine 1997;15(10):1114–22. [DOI] [PubMed] [Google Scholar]
- [11].Ohmit SE, Petrie JG, Malosh RE, Cowling BJ, Thompson MG, Shay DK, et al. Influenza vaccine effectiveness in the community and the household. Clin Infect Dis 2013;56(10):1363–9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [12].Chen WH, Winokur PL, Edwards KM, Jackson LA, Wald A, Walter EB, et al. Phase 2 assessment of the safety and immunogenicity of two inactivated pandemic monovalent H1N1 vaccines in adults as a component of the U.S. pandemic preparedness plan in 2009. Vaccine 2012;30(28):4240–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [13].Uno S, Kimachi K, Kei J, Miyazaki K, Oohama A, Nishimura T, et al. Effect of prior vaccination with a seasonal trivalent influenza vaccine on the antibody response to the influenza pandemic H1N1 2009 vaccine: a randomized controlled trial. Microbiol Immunol 2011;55(11):783–9. [DOI] [PubMed] [Google Scholar]
- [14].Vajo Z, Tamas F, Sinka L, Jankovics I. Safety and immunogenicity of a 2009 pandemic influenza A H1N1 vaccine when administered alone or simultaneously with the seasonal influenza vaccine for the 2009–10 influenza season: a multicentre, randomised controlled trial. Lancet 2010;375(9708):49–55. [DOI] [PubMed] [Google Scholar]
- [15].McLean HQ, Thompson MG, Sundaram ME, Meece JK, McClure DL, Friedrich TC, et al. Impact of repeated vaccination on vaccine effectiveness against influenza A(H3N2) and B during 8 seasons. Clin Infect Dis 2014;59(10):1375–85. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [16].World Health Organization. Recommended composition of influenza virus vaccines for use in the 2017-2018 northern hemisphere influenza season. Available from: https://www.who.int/influenza/vaccines/virus/recommendations/201703_recommendation.pdf. Accessed 7/7/21.
- [17].Keitel WA, Dekker CL, Mink C, Campbell JD, Edwards KM, Patel SM, et al. Safety and immunogenicity of inactivated, Vero cell culture-derived whole virus influenza A/H5N1 vaccine given alone or with aluminum hydroxide adjuvant in healthy adults. Vaccine 2009;27(47):6642–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [18].Mulligan MJ, Bernstein DI, Winokur P, Rupp R, Anderson E, Rouphael N, et al. Serological responses to an avian influenza A/H7N9 vaccine mixed at the point-of-use with MF59 adjuvant: a randomized clinical trial. JAMA 2014;312 (14):1409. 10.1001/jama.2014.12854. [DOI] [PubMed] [Google Scholar]
- [19].Noah DL, Hill H, Hines D, White EL, Wolff MC. Qualification of the hemagglutination inhibition assay in support of pandemic influenza vaccine licensure. Clin Vaccine Immunol 2009;16(4):558–66. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [20].US Food and Drug Agency. Clinical Data Needed to Support the Licensure of Pandemic Influenza Vaccines. Available from: https://www.fda.gov/media/73691/download. Accessed 16 March 2021.
- [21].Jackson LA, Campbell JD, Frey SE, Edwards KM, Keitel WA, Kotloff KL, et al. Effect of varying doses of a monovalent H7N9 influenza vaccine with and without AS03 and MF59 adjuvants on immune response: a randomized clinical trial. JAMA 2015;314(3):237. 10.1001/jama.2015.7916. [DOI] [PubMed] [Google Scholar]
- [22].Couch RB, Patel SM, Wade-Bowers CL, Niño D, Miyaji EN. A randomized clinical trial of an inactivated avian influenza A (H7N7) vaccine. PLoS ONE 2012;7(12): e49704. 10.1371/journal.pone.0049704. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [23].Díez-Domingo J, Garcés-Sanchez M, Baldó J-M, Planelles MV, Ubeda I, JuBert A, et al. Immunogenicity and Safety of H5N1 A/Vietnam/1194/2004 (Clade 1) AS03-adjuvanted prepandemic candidate influenza vaccines in children aged 3 to 9 years: a phase ii, randomized, open, controlled study. Pediatr Infect Dis J 2010;29(6):e35–46. [DOI] [PubMed] [Google Scholar]
- [24].Leroux-Roels I, Borkowski A, Vanwolleghem T, Dramé M, Clement F, Hons E, et al. Antigen sparing and cross-reactive immunity with an adjuvanted rH5N1 prototype pandemic influenza vaccine: a randomised controlled trial. Lancet 2007;370(9587):580–9. [DOI] [PubMed] [Google Scholar]
- [25].Treanor JJ, Campbell JD, Zangwill KM, Rowe T, Wolff M. Safety and immunogenicity of an inactivated subvirion influenza A (H5N1) vaccine. N Engl J Med 2006;354(13):1343–51. [DOI] [PubMed] [Google Scholar]
- [26].Vogel FR, Caillet C, Kusters IC, Haensler J. Emulsion-based adjuvants for influenza vaccines. Expert Rev Vaccines 2009;8(4):483–92. [DOI] [PubMed] [Google Scholar]
- [27].World Health Organization. Human infection with avian influenza A(H7N9) virus – China: Update. Available from: https://www.who.int/csr/don/05-september-2018-ah7n9-china/en/. Accessed 3/16/2021.
- [28].World Health Organization. Human infection with avian influenza A (H5N8) – the Russian Federation. Available from: https://www.who.int/csr/don/26-feb-2021-influenza-a-russian-federation/en/. Accessed 8 March 2021.
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