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

Safety and immunogenicity of influenza A(H3N2) component vaccine in juvenile systemic lupus erythematosus

INTRODUCTION

Seasonal influenza A (H3N2) virus is an important cause of morbidity and mortality in the last 50 years in population that is greater than the impact of H1N1. Data assessing immunogenicity and safety of this virus component in juvenile systemic lupus erythematosus (JSLE) is lacking in the literature.

OBJECTIVE

To evaluate short-term immunogenicity and safety of influenza A/Singapore (H3N2) vaccine in JSLE.

METHODS

24 consecutive JSLE patients and 29 healthy controls (HC) were vaccinated with influenza A/Singapore/INFIMH-16-0019/2016(H3N2)-like virus. Influenza A (H3N2) seroprotection (SP), seroconversion (SC), geometric mean titers (GMT), factor increase in GMT (FI-GMT) titers were assessed before and 4 weeks post-vaccination. Disease activity, therapies and adverse events (AE) were also evaluated.

RESULTS

JSLE patients and controls were comparable in current age [14.5 (10.1-18.3) vs. 14 (9-18.4) years, p = 0.448] and female sex [21 (87.5%) vs. 19 (65.5%), p = 0.108]. Before vaccination, JSLE and HC had comparable SP rates [22 (91.7%) vs. 25 (86.2%), p = 0.678] and GMT titers [102.3 (95% CI 75.0-139.4) vs. 109.6 (95% CI 68.2-176.2), p = 0.231]. At D30, JSLE and HC had similar immune response, since no differences were observed in SP [24 (100%) vs. 28 (96.6%), p = 1.000)], SC [4 (16.7%) vs. 9 (31.0%), p = 0.338), GMT [162.3 (132.9-198.3) vs. 208.1 (150.5-287.8), p = 0.143] and factor increase in GMT [1.6 (1.2-2.1) vs. 1.9 (1.4-2.5), p = 0.574]. SLEDAI-2K scores [2 (0-17) vs. 2 (0-17), p = 0.765] and therapies remained stable throughout the study. Further analysis of possible factors influencing vaccine immune response among JSLE patients demonstrated similar GMT between patients with SLEDAI < 4 compared to SLEDAI ≥ 4 (p = 0.713), as well as between patients with and without current use of prednisone (p = 0.420), azathioprine (p = 1.0), mycophenolate mofetil (p = 0.185), and methotrexate (p = 0.095). No serious AE were reported in both groups and most of them were asymptomatic (58.3% vs. 44.8%, p = 0.958). Local and systemic AE were alike in both groups (p > 0.05).

CONCLUSION

This is the first study that identified adequate immune protection against H3N2-influenza strain with additional vaccine-induced increment of immune response and an adequate safety profile in JSLE. ( www.

CLINICALTRIALS

gov , NCT03540823).

Bridging nanoplatform and vaccine delivery, a landscape of strategy to enhance nasal immunity

Vaccination is an urgently needed and effective option to address epidemic, cancers, allergies, and other diseases. Nasal administration of vaccines offers many benefits over needle-based injection including high compliance and less risk of infection. Inactivated or attenuated vaccines as convention vaccine present potential risks of pathogenic virulence reversal, the focus of nasal vaccine development has shifted to the use of next-generation (subunit and nucleic acid) vaccines. However, subunit and nucleic acid vaccine intranasally have numerous challenges in development and utilization due to mucociliary clearance, mucosal epithelial tight junction, and enzyme/pH degradation. Nanoplatforms as ideal delivery systems, with the ability to enhance the retention, penetration, and uptake of nasal mucosa, shows great potential in improving immunogenic efficacy of nasal vaccine. This review provides an overview of delivery strategies for overcoming nasal barrier, including mucosal adhesion, mucus penetration, targeting of antigen presenting cells (APCs), enhancement of paracellular transportation. We discuss methods of enhancing antigen immunogenicity by nanoplatforms as immune-modulators or multi-antigen co-delivery. Meanwhile, we describe the application status and development prospect of nanoplatforms for nasal vaccine administration. Development of nanoplatforms for vaccine delivery via nasal route will facilitate large-scale and faster global vaccination, helping to address the threat of epidemics.

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.