Neutralizing Antibody Kinetics and Immune Protection Against Herpes Simplex Virus 1 Genital Disease in Vaccinated Women.

BACKGROUND: Previously, our group conducted the Herpevac Trial for Women, a randomized efficacy field trial of type 2 glycoprotein D (gD2) herpes simplex virus (HSV) vaccine adjuvanted with ASO4 in 8323 women. Study participants were selected to be seronegative for HSV-1 and HSV-2. We found that the vaccine was 82% protective against culture-positive HSV-1 genital disease but offered no significant protection against HSV-2 genital disease. Efficacy against HSV-1 was associated with higher levels of antibody to gD2 at enzyme-linked immunosorbent assay (ELISA). METHODS: To better understand the results of the efficacy study, we measured postvaccination concentrations of neutralizing antibody (nAb) to either HSV-1 and HSV-2 from HSV-infected study participants and matched uninfected controls. Statistical modeling was used to determine whether these responses were correlated with protection against HSV. RESULTS: nAbs to either HSV-1 or HSV-2 were correlated with ELISA binding antibodies to gD2. HSV-1 or HSV-2 nAb findings support the observation of protection by higher levels of antibody against HSV-1 infection, but the lack of protection against HSV-2 remains unexplained. CONCLUSIONS: The protection against HSV-1 infection observed in the Herpevac Trial for Women was associated with nAbs directed against the virus, although the power to assess this was lower in the nAb study compared with the ELISA results owing to smaller sample size. CLINICAL TRIALS REGISTRATION: NCT00057330.

Cross-Reactive Antibody Responses to Novel H5Nx Influenza Viruses Following Homologous and Heterologous Prime-Boost Vaccination with a Prepandemic Stockpiled A(H5N1) Vaccine in Humans.

Recently, novel highly pathogenic avian influenza H5Nx viruses (clade 2.3.4.4) caused outbreaks in US poultry. We evaluated the potential of a stockpiled A(H5N1) A/Anhui/1/2005 (clade 2.3.4) vaccine to elicit cross-reactive antibody responses to these emerging viruses. Sera from subjects who received 2 doses of MF59-adjuvanted A/Anhui/1/2005, or 1 dose of MF59-adjuvanted A/Anhui/1/2005 following priming with a clade 1 vaccine were characterized by microneutralization assays and modified hemagglutination inhibition (HI) assays. Only heterologous prime-boost vaccination induced modest cross-reactive HI antibody responses to H5Nx viruses. Heterologous prime-boost may provide a more effective vaccination strategy to broaden the antibody responses to emerging viruses.

Safety and Immunogenicity of a Subvirion Monovalent Unadjuvanted Inactivated Influenza A(H3N2) Variant Vaccine in Healthy Persons ≥18 Years Old.

BACKGROUND: Variant influenza A(H3N2) viruses (H3N2v) have transmitted recently from pigs to humans in the United States. Vaccines strategies are needed. METHODS: Healthy adults received 2 doses of subvirion H3N2v vaccine (15 µg of hemagglutinin/dose) 21 days apart in this open-label trial. Serum hemagglutination inhibition (HAI) and neutralizing (Neut) antibody (Ab) titers were measured before and 8 and 21 days after each dose. Memory B-cell (MBC) responses were assessed. RESULTS: Vaccine was well tolerated. A total of 40% of subjects had an HAI Ab titer of ≥40 before vaccination. Eight-seven percent (95% confidence interval [CI], 79%-93%) and 73% (95% CI, 63%-81%) of subjects 18-64 years old (98 subjects) and ≥65 years old (90 subjects), respectively, had an HAI titer of ≥40 21 days after dose 1 (P = .01); 51% (95% CI, 41%-61%) and 52% (95% CI, 41%-62%) of younger and older subjects, respectively, developed ≥4-fold rises in titer (P = not significant). Neut Ab response patterns were similar. Geometric mean titers were higher in younger subjects. Dose 2 provided no significant enhancement in responses. Cross-reactive MBCs were detected before vaccination and expanded after vaccination. Preexisting H3N2v-specific MBCs positively correlated with early increases in vaccine-induced Ab. CONCLUSIONS: In most healthy adults, one 15-µg dose of vaccine elicited levels of HAI Abs associated with protection. Studies in children and elderly individuals are indicated to define the immunization needs of these groups. CLINICAL TRIALS REGISTRATION: NCT01746082.

Safety and Immunogenicity of a Single Low Dose or High Dose of Clade 2 Influenza A(H5N1) Inactivated Vaccine in Adults Previously Primed With Clade 1 Influenza A(H5N1) Vaccine.

Influenza A(H5N1) vaccination strategies that improve the speed of the immunological response and cross-clade protection are desired. We compared the immunogenicity of a single 15-µg or 90-µg dose of A/H5N1/Indonesia/05/05 (clade 2) vaccine in adults who were previously primed with A/H5N1/Vietnam/1203/2004 (clade 1) vaccine. High-dose vaccine resulted in significantly higher titers to both clade 1 and 2 antigens. Clade 2 titers were unaffected by the previous dose of clade 1 vaccine. Low-dose priming with a mismatched pandemic influenza A(H5N1) vaccine would improve the rapidity, magnitude, and cross-reactivity of the immunological response following a single high-dose, unadjuvanted, pandemic vaccine.

Effect of Varying Doses of a Monovalent H7N9 Influenza Vaccine With and Without AS03 and MF59 Adjuvants on Immune Response: A Randomized Clinical Trial.

IMPORTANCE: Human infections with the avian influenza A(H7N9) virus were first reported in China in 2013 and continue to occur. Hemagglutinin H7 administered alone is a poor immunogen necessitating evaluation of adjuvanted H7N9 vaccines. OBJECTIVE: To evaluate the immunogenicity and safety of an inactivated H7N9 vaccine with and without AS03 adjuvant, as well as mixed vaccine schedules that included sequential administration of AS03- and MF59-containing formulations and of adjuvanted and unadjuvanted formulations. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, phase 2 trial at 5 US sites enrolled 980 adults aged 19 through 64 years from September 2013 through November 2013; safety follow-up was completed in January 2015. INTERVENTIONS: The H7N9 vaccine was given on days 0 and 21 at nominal doses of 3.75 µg, 7.5 µg, 15 µg, and 45 µg of hemagglutinin with or without AS03 or MF59 adjuvant mixed on site. MAIN OUTCOMES AND MEASURES: Proportions achieving a hemagglutination inhibition antibody (HIA) titer of 40 or higher at 21 days after the second vaccination; vaccine-related serious adverse events through 12 months after the first vaccination; and solicited signs and symptoms after vaccination through day 7. RESULTS: Two doses of vaccine were required to induce detectable antibody titers in most participants. After 2 doses of an H7N9 formulation containing 15 µg of hemagglutinin given without adjuvant, with AS03 adjuvant, or with MF59 adjuvant, the proportion achieving an HIA titer of 40 or higher was 2% (95% CI, 0%-7%) without adjuvant (n = 94), 84% (95% CI, 76%-91%) with AS03 adjuvant (n = 96), and 57% (95% CI, 47%-68%) with MF59 adjuvant (n = 92) (P < .001 for comparison of the AS03 and MF59 schedules). The 2 schedules alternating AS03-and MF59-adjuvanted formulations led to lower geometric mean titers (GMTs) of (41.5 [95% CI, 31.7-54.4]; n = 92) and (58.6 [95% CI, 44.3-77.6]; n = 96) than the group induced by 2 AS03-adjuvanted formulations (n = 96) (103.4 [95% CI, 78.7-135.9]; P < .001) but higher GMTs than 2 doses of MF59-adjuvanted formulation (n = 94) (29.0 [95% CI, 22.4-37.6]; P < .001). CONCLUSIONS AND RELEVANCE: The AS03 and MF59 adjuvants augmented the immune responses to 2 doses of an inactivated H7N9 influenza vaccine, with AS03-adjuvanted formulations inducing the highest titers. This study of 2 adjuvants used in influenza vaccine formulations with adjuvant mixed on site provides immunogenicity information that may be informative to influenza pandemic preparedness programs. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01942265.

Correlate of immune protection against HSV-1 genital disease in vaccinated women.

BACKGROUND: Previously we conducted a double-blind controlled, randomized efficacy field trial of gD-2 HSV vaccine adjuvanted with ASO4 in 8323 women. Subjects had been previously selected to be seronegative for HSV-1 and HSV-2. We found that vaccine was 82% protective against HSV-1 genital disease, but offered no significant protection against HSV-2 genital disease. METHODS: To better understand the results of the efficacy study, post-vaccination anti-gD-2 antibody concentrations from all HSV infected subjects and matched uninfected controls were measured. Three models were used to determine whether thes responses correlated with protection against HSV infection or disease. Similarly, cellular immune responses from a subset of subjects and matched controls were evaluated for a correlation with HSV protection. RESULTS: Antibodies to gD-2 correlated with protection against HSV-1 infection with higher antibody concentration associated with higher efficacy. Cellular immune responses to gD-2 did not correlate with protection. CONCLUSIONS: The protection against HSV-1 infection observed in the Herpevac Trial for Women was associated with antibodies directed against the vaccine. Clinical Trials Registration NCT00057330.

HSV-1 and HSV-2 seroprevalence in the united states among asymptomatic women unaware of any herpes simplex virus infection (Herpevac Trial for Women).

OBJECTIVES: Recent evidence suggests that the epidemiology of herpes simplex viruses (HSVs) is changing because fewer HSV-1 infections are acquired in childhood and increased sexual transmission of HSV-1 is reported. The objective of the study was to assess the seroprevalence of type-specific antibodies to HSV-1 and HSV-2 in the United States. METHODS: We used the Western blot antibody screening data from a large phase III vaccine efficacy trial (Herpevac Trial for Women) to assess the seroprevalence of type-specific antibodies to HSV-1 and HSV-2 in the United States. RESULTS: The antibody status of 29,022 women (>31,000 women interviewed and then had their blood drawn for the HSV testing [29,022 women]) between the ages of 18 and 30 years in the United States revealed that increasing age was associated with increasing seroprevalence to HSV. Overall, in asymptomatic women unaware of any HSV infection, HSV-1/-2 status was positive/negative in 45%, negative/positive in 5%, positive/positive in 7%, negative/negative in 38%, and indeterminate in 5%. HSV-1 infections were more common in Hispanic and non-Hispanic black women and in the US northeast and in individuals living in urban areas. HSV-2 was more common in non-Hispanic black women, the US south, and in urban areas. CONCLUSIONS: Seronegative status for both HSV-1 and HSV-2 was the second most common finding after positive antibody to HSV-1 but negative antibody to HSV-2. Despite recent changes in genital herpes epidemiology, most women acquired HSV-1 but not HSV-2 infections before 18 years of age. Among participants screened for study participation and who were unaware of any HSV infection, progressively higher prevalence of the HSV-1 or HSV-2 antibody was observed in older subjects. Many women who test positive for HSV-1 and/or HSV-2 are unaware of their status.

Serological responses to an avian influenza A/H7N9 vaccine mixed at the point-of-use with MF59 adjuvant: a randomized clinical trial.

IMPORTANCE: Human infections with avian influenza A/H7N9 have resulted in high morbidity and mortality in China. OBJECTIVE: To compare safety and immunogenicity of different doses of influenza A/Shanghai/2/13 (H7N9) vaccine mixed with or without the MF59 adjuvant. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized, double-blind, phase 2 trial at 4 US sites enrolled 700 adults aged 19 to 64 years beginning in September 2013; 6-month follow-up was completed in May 2014. INTERVENTIONS: The H7N9 inactivated virus vaccine was administered intramuscularly on days 0 and 21 at nominal doses of 3.75, 7.5, 15, or 45 µg of hemagglutinin (actual doses approximately 50% higher) with or without the MF59 adjuvant. A total 99, 100, or 101 participants were randomized to each group (7 groups; N = 700). MAIN OUTCOMES AND MEASURES: Proportions achieving day 42 antibody titer of 40 or greater or seroconversion (a minimum 4-fold increase to titer ≥40) with the hemagglutination inhibition assay; vaccine-related serious adverse events through month 13; and solicited postvaccination symptoms through day 7. RESULTS: Hemagglutination inhibition antibodies were minimal after participants received an unadjuvanted vaccine. After receiving 2 doses of H7N9 vaccine at a dosage of 3.75 µg plus the MF59 adjuvant, day 42 seroconversion occurred in 58 participants (59%; 95% CI, 48%-68%). The peak seroconversion occurred at day 29 in 62 participants (62%; 95% CI, 52%-72%). The day 42 geometric mean titer was 33.0 (95% CI, 24.7-44.1). Higher antigen doses were not associated with increased response. For the neutralizing antibody assays, after receiving 3.75 µg of H7N9 vaccine plus the MF59 adjuvant, day 42 seroconversion occurred in 81 participants (82%; 95% CI, 73%-89%). The day 42 geometric mean titer was 81.4 (95% CI, 66.6-99.5). There was no statistically significant difference in day 42 hemagglutination inhibition seroconversion after mixing adjuvant with either the first or both 15 µg doses (n = 34 [35%; 95% CI, 25%-45%] vs n = 47 [47%; 95% CI, 37%-58%], respectively; P = .10). Recent receipt of seasonal influenza vaccination and older age were associated with attenuated response. No vaccine-related serious adverse events occurred. Solicited postvaccination symptoms were generally mild with more local symptoms seen in participants who received the adjuvant. CONCLUSIONS AND RELEVANCE: Point-of-use mixing and administration of 2 doses of H7N9 vaccine at the lowest tested antigen dose with MF59 adjuvant produced seroconversion in 59% of participants. Although these findings indicate potential value in this approach, the study is limited by the absence of antibody data beyond 42 days and the absence of clinical outcomes. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01938742.

Immunogenicity of avian influenza A/Anhui/01/2005(H5N1) vaccine with MF59 adjuvant: a randomized clinical trial.

IMPORTANCE: The need to respond quickly to potential influenza pandemics is important. Immunologic priming (initial presentation of an antigen to allow antibody responses on revaccination) with vaccine directed toward an older avian influenza H5 strain might lead to secondary antibody responses to a single dose of more current H5 avian influenza vaccine. OBJECTIVES: To assess priming with the older avian influenza A/Vietnam/1203/2004(H5N1) (Vietnam) vaccine and to conduct dose-response studies with vaccine directed against the more contemporary H5N1 avian influenza virus, influenza A/Anhui/01/2005 (Anhui). DESIGN, SETTING, AND PARTICIPANTS: Multicenter US randomized clinical trial beginning in June 2010 with follow-up continuing through October 2011 enrolling 72 healthy adults who were vaccinated 1 year previously with the Vietnam vaccine and 565 vaccine-naive adults. INTERVENTIONS: Participants who were previously vaccinated with 90 µg of unadjuvanted Vietnam vaccine were randomly assigned to receive 3.75 µg of avian influenza Anhui vaccine with or without MF59 adjuvant, stratified by 1 vs 2 previous doses (1 dose: n = 18 with MF59 and n = 17 without; 2 doses: n = 19 with MF59 and n = 18 without). Vaccine-naive individuals were randomly assigned to receive Ahnui vaccine with or without MF59 adjuvant in 1 of 5 doses (3.75 µg [n = 55 with MF59 and n = 59 without], 7.5 µg [n = 51 with MF59 and n = 57 without], 15 µg [n = 48 with MF59 and n = 44 without], 45 µg [n = 47 with MF59 and n = 47 without], or 90 µg [n = 57 without adjuvant]) or placebo (n = 100) given at days 0 and 28. MAIN OUTCOMES AND MEASURES: The primary immunogenicity outcome was hemagglutination inhibition assay (HAI) titer against each vaccine antigen 1 month (day 28) and 6 months (day 180) after last vaccination. The primary safety outcomes were local and systemic adverse events on days 0 to 7 after each vaccination and serious adverse events. RESULTS: Previously vaccinated participants manifested secondary antibody responses after receipt of low-dose Anhui vaccine ("boosting"); by day 28, 21% to 50% developed HAI responses of 1:40 or greater. Use of adjuvant was not associated with increased HAI responses. Among vaccine-naive participants (n = 565), the optimum dose was 7.5 µg of antigen with adjuvant (geometric mean titer [GMT], 63.3; 95% CI, 43.0-93.1). The greatest response to unadjuvanted antigen was seen at the highest dose, 90 µg (GMT, 28.5; 95% CI, 19.7-41.2). Local or systemic reactions occurred, respectively, in 40 (78%) and 25 (49%) of 51 participants who received 7.5 µg plus adjuvant vs 50 (88%) and 29 (51%) of 57 who received 90 µg of unadjuvanted vaccine. In general, antibodies were short-lived, and by day 180, HAI titers had decreased to less than 1:20 in all treatment groups. CONCLUSIONS AND RELEVANCE: Previous receipt of a single dose of influenza A(H5N1) Vietnam vaccine was associated with sufficient immunologic priming to facilitate antibody response to a different H5N1 antigen using low-dose Anhui (booster) vaccine. In participants who had not previously received H5 vaccine, low-dose Anhui vaccine plus adjuvant was more immunogenic compared with higher doses of unadjuvanted vaccine. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00680069.

Epidemiology, clinical presentation, and antibody response to primary infection with herpes simplex virus type 1 and type 2 in young women.

BACKGROUND: Herpes simplex virus infections type 1 (HSV-1) and type 2 (HSV-2) are common, but the epidemiology of HSV disease is changing. METHODS: HSV-seronegative women, aged 18-30 years, who were in the control arm of the HERPEVAC Trial for Women were followed for 20 months for primary HSV infections. RESULTS: Of the 3438 evaluable participants, 183 became infected with HSV: 127 (3.7%) with HSV-1 and 56 (1.6%) with HSV-2. The rate of infection for HSV-1 (2.5 per 100 person-years) was more than twice that for HSV-2 (1.1 per 100 person-years). Most infections (74% of HSV-1 and 63% of HSV-2) occurred without recognized signs or symptoms of herpes disease. The HSV-2 infection rate was 2.6 times higher in non-Hispanic black participants than in Hispanics and 5.5 times higher than in non-Hispanic whites (P < .001), while the HSV-1 infection rate was 1.7 times higher in non-Hispanic whites than non-Hispanic blacks. Younger participants (18-22 years) were more likely to acquire HSV-1 infections and less likely to develop recognized disease than older participants. Overall, 84% of recognized disease cases were genital. No differences were noted in the clinical manifestations of genital HSV-1 vs genital HSV-2 disease. The clinicians' assessment that cases were caused by HSV was good when they assessed cases as clinically confirmed or unlikely (validated in 83% and 100% of cases, respectively). CONCLUSIONS: HSV-1 is now more common than HSV-2 as a cause of oral and genital mucosal infections in young women, but there are important age and race differences.

An Oil-in-Water adjuvant significantly increased influenza A/H7N9 split virus Vaccine-Induced circulating follicular helper T (cTFH) cells and antibody responses.

BACKGROUND: Unadjuvanted A/H7N9 vaccines are poorly immunogenic. The immune response is improved with the addition of MF59, an oil-in-water adjuvant. However, the cellular immunologic responses of MF59-adjuvanted A/H7N9 vaccine are not fully understood. METHODS: 37 participants were vaccinated with 2 doses of 2013 influenza A/H7N9 vaccine (at Days 1 and 21) with or without MF59 and enrolled in an immunology substudy. Responses were assessed at multiple timepoints (Days 0, 8, 21, 29, and 42) for hemagglutination inhibition (HAI) and neutralizing antibody (Neut) assays, memory B cell responses by enzyme-linked ImmunoSpot; circulating follicular helper T cells (cTFH) and CD4 + T cells by intracellular cytokine staining. RESULTS: MF59-adjuvanted influenza A/H7N9 vaccine induced significantly higher hemagglutination inhibition (HAI) and neutralizing antibody (Neut) responses when compared to unadjuvanted vaccine. The adjuvanted vaccine elicited significantly higher levels of Inducible T-cell Co-Stimulator (ICOS) expression by CXCR3+CXCR5+CD4+ cTFH cells, compared to unadjuvanted vaccine. The magnitude of increase in cTFH cells (from baseline to Day 8) and in IL-21 expressing CD154+CD4+ T cells (from baseline to Days 8 and 21) correlated with HAI (at Day 29) and Neut antibody (at Days 8 and 29) titers. The increase in frequency of IL-21 expressing CD154+CD4+T cells (from baseline to Day 21) correlated with memory B cell frequency (at Day 42). CONCLUSION: cTFH activation is associated with HAI and Neut responses in recipients of MF59-adjuvanted influenza A/H7N9 vaccine relative to unadjuvanted vaccine. Future studies should focus on optimizing the cTFH response and use cTFH as an early biomarker of serological response to vaccination. This trial was registered at clinicaltrials.gov, trial number NCT01938742.

An evaluation of cytokine and cellular immune responses to heterologous prime-boost vaccination with influenza A/H7N7-A/H7N9 inactivated vaccine.

The immunologic mechanisms underlying the improved serologic responses to heterologous prime-boost avian influenza vaccination are unclear. An exploratory analysis of the immune responses following 1 dose of influenza A/H7N9 inactivated vaccine in subjects who received an influenza A/H7N7 inactivated vaccine (N = 17) 8 years earlier or who were influenza A/H7-naïve (10) was performed. Plasma IL-6 and IL-21 concentrations by ELISA, the frequency of A/H7N7-specific memory B cells and antibody secreting cells by ELISpot, the frequency of circulating T follicular helper cells and the frequency of T cells expressing IL-6 and IL-21 by flow cytometry were assessed at baseline (D1), and 8 days (D9) and 28 days (D29) after vaccination. We assessed the correlation between these measurements and the D29 serologic responses to the boost vaccine. Plasma IL-6 concentration on D9 significantly correlated with the H7N7 and H7N9 hemagglutination inhibition (HAI) antibody levels (P = .03 and 0.02 respectively); and the percentage of T cells expressing IL-21 on D9 significantly correlated with H7N9 HAI antibody seroconversion (P < .001). Significant associations with other immunologic markers were not detected. We detected an association between plasma IL-6 and intracellular IL-21 and serologic responses to heterologous prime-boost avian influenza vaccination. A clarification of the role of these and additional immunologic markers requires larger clinical trials.

High dose trivalent influenza vaccine compared to standard dose vaccine in patients with rheumatoid arthritis receiving TNF-alpha inhibitor therapy and healthy controls: Results of the DMID 10-0076 randomized clinical trial.

INTRODUCTION: Subjects with rheumatoid arthritis (RA) receiving tumor necrosis factor-inhibiting (TNFi) therapies are at risk for severe influenza, and may respond less well to influenza vaccine. We examined the safety and immunogenicity of high dose influenza vaccine (HD) compared to standard dose vaccine (SD) in participants with RA receiving stable TNFi. METHODS: A randomized, double-blinded, Phase II study was conducted in adults with RA receiving TNFi, and healthy, gender and age-matched control subjects. Participants were immunized with HD (Sanofi Pasteur Fluzone High Dose [60 mcg × 3 strains]) or SD (Sanofi Pasteur Fluzone® [15 mcg × 3 strains]) intramuscularly (IM). A self-administered memory aid recorded temperature and systemic and local adverse events (AEs) for 8 days, and safety was evaluated and serum obtained to measure HAI activity on days 7, 21 and 180 days following vaccination. RESULTS: A greater proportion of RA subjects who received HD seroconverted at day 21 compared to SD, although this was not statistically significant. GMT antibody responses in RA subjects who received HD compared to SD were greater for all strains on day 21, and this was significant for H1N1. Seroconversion rates and GMT values were not different between RA subjects and control subjects. There were no safety concerns for HD or SD in RA subjects, and RA-related symptoms did not differ between SD and HD recipients by a RA-symptom questionnaire (RAPID 3). CONCLUSIONS: TNF-inhibitor therapy in people with RA did not appear to influence the immunogenicity of either SD or HD. Influenza seroconversion and GMT values were higher among RA subjects receiving HD compared to SD; however, differences were small and a larger study is needed to validate these findings. Given the apparent risk of increased influenza-related morbidity and mortality among immune compromised subjects, the higher GMT values generated by HD may be beneficial.

Baseline Levels of Influenza-Specific B Cells and T Cell Responses Modulate Human Immune Responses to Swine Variant Influenza A/H3N2 Vaccine.

The cellular immune responses elicited by an investigational vaccine against an emergent variant of influenza (H3N2v) are not fully understood. Twenty-five subjects, enrolled in an investigational influenza A/H3N2v vaccine study, who received two doses of vaccine 21 days apart, were included in a sub-study of cellular immune responses. H3N2v-specific plasmablasts were determined by ELISpot 8 days after each vaccine dose and H3N2v specific CD4+ T cells were quantified by intracellular cytokine and CD154 (CD40 ligand) staining before vaccination, 8 and 21 days after each vaccine dose. Results: 95% (19/20) and 96% (24/25) subjects had pre-existing H3N2v specific memory B, and T cell responses, respectively. Plasmablast responses at Day 8 after the first vaccine administration were detected against contemporary H3N2 strains and correlated with hemagglutination inhibition HAI (IgG: p = 0.018; IgA: p < 0.001) and Neut (IgG: p = 0.038; IgA: p = 0.021) titers and with memory B cell frequency at baseline (IgA: r = 0.76, p < 0.001; IgG: r = 0.74, p = 0.0001). The CD4+ T cells at Days 8 and 21 expanded after prime vaccination and this expansion correlated strongly with early post-vaccination HAI and Neut titers (p ≤ 0.002). In an adult population, the rapid serological response observed after initial H3N2v vaccination correlates with post-vaccination plasmablasts and CD4+ T cell responses.

Correlation between herpes simplex virus neutralizing antibody titers determined by ELVIS cell and traditional plaque reduction assays.

Preventive viral vaccine efficacy trials require large-scale sample analysis to quantitate immune responses and their correlation with infection outcomes. Traditional plaque reduction assays measure a functionally important form of humoral immunity, neutralizing antibody titer. These assays, however, are time-consuming and laborious. We previously developed a higher throughput assay of neutralizing antibody to herpes simplex viruses 1 and 2 (Blevins et al., PLOS ONE, 10(12), e0144738) using the enzyme-linked virus inducible system (ELVIS) cell line; this cell line produces ß-galactosidase in response to HSV infection. Here, serum samples from recipients of an investigational vaccine in the Herpevac Trial for Women were used to compare the ELVIS cell assay with the lower throughput, traditional plaque reduction assay. We demonstrate that neutralizing antibody titers to HSV-1 or HSV-2 determined using ELVIS cells positively correlate with neutralizing antibody titers determined by traditional plaque reduction assay, thus validating a higher throughput alternative for large-scale sample analysis.

Safety and immunogenicity of an 8 year interval heterologous prime-boost influenza A/H7N7-H7N9 vaccination.

BACKGROUND: Influenza A/H7N9 viruses are undergoing antigenic drift since their emergence in 2013, and vaccination strategies are needed for pandemic preparedness. Two doses of adjuvanted monovalent inactivated influenza A/H7N9 vaccine (IIV1 A/H7N9) are needed for optimal serological responses. However, administering 2 doses in a pandemic setting might be challenging. We evaluated the immunogenicity of "boosting" with IIV1 A/H7N9 in subjects "primed" 8 years previously with IIV1 A/H7N7. METHODS: We administered 1 booster dose containing 45 mcg of IIV1 A/H7N9 hemagglutinin to 17 recipients of 2 prior doses of IIV1 A/H7N7, and to 10 influenza A/H7-naïve subjects. We tested their post-boosting sera for antibodies (Ab) against homologous influenza A/H7N9 using a hemagglutination inhibition assay; and compared their Ab titers to those in stored sera from recipients of AS03-adjuvanted IIV1 A/H7N9 against 9 strains of influenza A/H7N9 viruses. RESULTS: The percentage of subjects with Ab titers ≥40 on Days 9 and 29 post boosting, respectively, was 65% and 41% in primed subjects and 10% and 0% in unprimed subjects. The Ab titers in recipients of AS03-adjuvanted IIV1 A/H7N9 were higher than those in the prime-boost group against a panel of influenza A/H7N9 viruses, except for 2 highly pathogenic strains. CONCLUSIONS: Priming with IIV1 A/H7 results in serological responses following a delayed boost with 1 dose of unadjuvanted IIV1 A/H7N9, despite lack of antibody response after the prime. Optimizing prime-boost approaches would benefit pandemic preparedness. ClinicalTrials.gov identifier: NCT02586792.

Safety and immunogenicity of unadjuvanted subvirion monovalent inactivated influenza H3N2 variant (H3N2v) vaccine in children and adolescents.

OBJECTIVE: In response to the emergence of influenza viruses with pandemic potential, we evaluated a swine-origin influenza A/H3N2 variant (H3N2v) vaccine in children. STUDY DESIGN: This multicenter phase II open-label study assessed the safety and immunogenicity of two doses, 21 days apart, of investigational unadjuvanted subvirion monovalent inactivated H3N2v vaccine administered via intramuscular injection. Children 6-35 months of age received 7.5mcg or 15mcg of hemagglutinin (HA)/dose; children 3-17 years of age received 15mcg HA/dose. Safety and reactogenicity were assessed by measuring the occurrence of solicited injection site and systemic reactions in the 7 days after each vaccination; adverse events were assessed for 42 days and serious adverse events for 7 months after the first vaccination. Immunogenicity was evaluated by measuring hemagglutination inhibition (HAI) and neutralizing (Neut) antibodies to H3N2v prior to and 21 days after each vaccination. Cross-reactivity against seasonal H3N2 strains was evaluated. RESULTS: The H3N2v vaccine was well tolerated. Transient mild to moderate injection site tenderness, pain and erythema was observed, with the most commonly reported systemic reactogenicity being irritability in children 6-35 months, and headache and fatigue in children 9-17 years old. Children 6-35 months old, whether they received 7.5mcg or 15mcg/dose, had low HAI and Neut antibody responses after two doses compared to older children. Children under 9 years of age required two doses of vaccine to demonstrate a response, while 9-17 year olds responded well after one dose. Previous influenza vaccination and older age were associated with higher immune responses to H3N2v vaccine. Children 9-17 years of age also developed cross-reactive antibodies against recent seasonal H3N2 influenza viruses. CONCLUSION: The H3N2v vaccine was safe and immunogenic in children and adolescents. Age-related increases in immunogenicity against H3N2v and seasonal H3N2 viruses were observed, suggesting prior priming via infection and/or immunization. Clinical trial registry: The trial is registered with clinicaltrial.gov: NCT02100436.

Safety and immunogenicity of investigational seasonal influenza hemagglutinin DNA vaccine followed by trivalent inactivated vaccine administered intradermally or intramuscularly in healthy adults: An open-label randomized phase 1 clinical trial.

BACKGROUND: Seasonal influenza results in significant morbidity and mortality worldwide, but the currently licensed inactivated vaccines generally have low vaccine efficacies and could be improved. In this phase 1 clinical trial, we compared seasonal influenza vaccine regimens with different priming strategies, prime-boost intervals, and administration routes to determine the impact of these variables on the resulting antibody response. METHODS: Between August 17, 2012 and January 25, 2013, four sites enrolled healthy adults 18-70 years of age. Subjects were randomized to receive one of the following vaccination regimens: trivalent hemagglutinin (HA) DNA prime followed by trivalent inactivated influenza vaccine (IIV3) boost with a 3.5 month interval (DNA-IIV3), IIV3 prime followed by IIV3 boost with a 10 month interval (IIV3-IIV3), or concurrent DNA and IIV3 prime followed by IIV3 boost with a 10 month interval (DNA/IIV3-IIV3). Each regimen was additionally stratified by an IIV3 administration route of either intramuscular (IM) or intradermal (ID). DNA vaccines were administered by a needle-free jet injector (Biojector). Study objectives included evaluating the safety and tolerability of each regimen and measuring the antibody response by hemagglutination inhibition (HAI). RESULTS: Three hundred and sixteen subjects enrolled. Local reactogenicity was mild to moderate in severity, with higher frequencies recorded following DNA vaccine administered by Biojector compared to IIV3 by either route (p <0.02 for pain, swelling, and redness) and following IIV3 by ID route compared to IM route (p <0.001 for swelling and redness). Systemic reactogenicity was similar between regimens. Though no overall differences were observed between regimens, the highest titers post boost were observed in the DNA-IIV3 group by ID route and in the IIV3-IIV3 group by IM route. CONCLUSIONS: All vaccination regimens were found to be safe and tolerable. While there were no overall differences between regimens, the DNA-IIV3 group by ID route, and the IIV3-IIV3 group by IM route, showed higher responses compared to the other same-route regimens.

DNA vaccine priming for seasonal influenza vaccine in children and adolescents 6 to 17 years of age: A phase 1 randomized clinical trial.

BACKGROUND: Children are susceptible to severe influenza infections and facilitate community transmission. One potential strategy to improve vaccine immunogenicity in children against seasonal influenza involves a trivalent hemagglutinin DNA prime-trivalent inactivated influenza vaccine (IIV3) boost regimen. METHODS: Sites enrolled adolescents, followed by younger children, to receive DNA prime (1 mg or 4 mg) intramuscularly by needle-free jet injector (Biojector), followed by split virus 2012/13 seasonal IIV3 boost by needle and syringe approximately 18 weeks later. A comparator group received IIV3 prime and boost at similar intervals. Primary study objectives included evaluation of the safety and tolerability of the vaccine regimens, with secondary objectives of measuring antibody responses at four weeks post boost by hemagglutination inhibition (HAI) and neutralization assays. RESULTS: Seventy-five children ≥6 to ≤17 years old enrolled. Local reactogenicity was higher after DNA prime compared to IIV3 prime (p<0.001 for pain/tenderness, redness, or swelling), but symptoms were mild to moderate in severity. Systemic reactogenicity was similar between vaccines. Overall, antibody responses were similar among groups, although HAI antibodies revealed a trend towards higher responses following 4 mg DNA-IIV3 compared to IIV3-IIV3. The fold increase of HAI antibodies to A/California/07/2009 [A(H1N1)pdm09] was significantly greater following 4 mg DNA-IIV3 (10.12 fold, 5.60-18.27 95%CI) compared to IIV3-IIV3 (3.86 fold, 2.32-6.44 95%CI). Similar neutralizing titers were observed between regimens, with a trend towards increased response frequencies in 4 mg DNA-IIV3. However, significant differences in fold increase, reported as geometric mean fold ratios, were detected against the H1N1 viruses within the neutralization panel: A/New Caledonia/20/1999 (1.41 fold, 1.10-1.81 95%CI) and A/South Carolina/1/1918 (1.55 fold, 1.27-1.89 95%CI). CONCLUSIONS: In this first pediatric DNA vaccine study conducted in the U.S., the DNA prime-IIV3 boost regimen was safe and well tolerated. In children, the 4 mg DNA-IIV3 regimen resulted in antibody responses comparable to the IIV3-IIV3 regimen.

Safety and efficacy of a cytomegalovirus glycoprotein B (gB) vaccine in adolescent girls: A randomized clinical trial.

BACKGROUND: Cytomegalovirus (CMV) is a leading cause of congenital infection and an important target for vaccine development. METHODS: CMV seronegative girls between 12 and 17 years of age received CMV glycoprotein B (gB) vaccine with MF59 or saline placebo at 0, 1 and 6 months. Blood and urine were collected throughout the study for evidence of CMV infection based on PCR and/or seroconversion to non-vaccine CMV antigens. RESULTS: 402 CMV seronegative subjects were vaccinated (195 vaccine, 207 placebo). The vaccine was generally well tolerated, although local and systemic adverse events were significantly more common in the vaccine group. The vaccine induced gB antibody in all vaccine recipients with a gB geometric mean titer of 13,400 EU; 95%CI 11,436, 15,700, after 3 doses. Overall, 48 CMV infections were detected (21 vaccine, 27 placebo). In the per protocol population (124 vaccine, 125 placebo) vaccine efficacy was 43%; 95%CI: -36; 76, p=0.20. The most significant difference was after 2 doses, administered as per protocol; vaccine efficacy 45%, 95%CI: -9; 72, p=0.08. CONCLUSION: The vaccine was safe and immunogenic. Although the efficacy did not reach conventional levels of significance, the results are consistent with a previous study in adult women (Pass et al. N Engl J Med 2009;360:1191) using the same formulation.