Intranasal M2SR (M2-Deficient Single Replication) H3N2 Influenza Vaccine Provides Enhanced Mucosal and Serum Antibodies in Adults.
J Infect Dis
; 227(1): 103-112, 2022 12 28.
Article
em En
| MEDLINE
| ID: mdl-36350017
ABSTRACT
BACKGROUND:
We previously demonstrated that an intranasal dose of 108 50% tissue culture infectious dose (TCID50) M2-deficient single replication (M2SR) influenza vaccine protected against highly drifted H3N2 influenza challenge in a subset of subjects who demonstrated ≥2-fold increase in microneutralization (MN) antibodies to Belgium2015 (the challenge strain) after vaccination. Here, we describe a phase 1b, observer-blinded, dose-escalation study demonstrating an increased proportion of responders with this signal of immune protection.METHODS:
Serosusceptible subjects aged 18-49 years were randomized to receive 2 doses (108-109 TCID50) of M2SR or placebo administered 28 days apart. Clinical specimens were collected before and after each dose. The primary objective was to demonstrate safety of M2SR vaccines.RESULTS:
The vaccine was well tolerated at all dose levels. Against Belgium2015, ≥ 2-fold increases in MN antibodies were noted among 40% (95% confidence interval [CI], 24.9%-56.7%) of subjects following a single 108 TCID50 M2SR dose and among 80.6% (95% CI, 61.4%-92.3%) after 109 dose (P < .001). A single 109 TCID50 dose of M2SR generated ≥4-fold hemagglutination inhibition antibody seroconversion against the vaccine strain in 71% (95% CI, 52.0%-85.8%) of recipients. Mucosal and cellular immune responses were also induced.CONCLUSIONS:
These results indicate that M2SR may provide substantial protection against infection with highly drifted strains of H3N2 influenza. CLINICAL TRIALS REGISTRATION NCT03999554.
In recent years, influenza A H3N2 viruses have evolved into multiple cocirculating clades, resulting in low vaccine efficacy and highlighting the need for more effective influenza vaccines. In a previous challenge study, a single intranasal dose of the investigational vaccine M2SR demonstrated protection against a highly drifted H3N2 influenza challenge virus in a subset of vaccine recipients with a signature immune response. Increasing the dose of the M2SR vaccine in this phase1b study demonstrated a statistically significant increase in the proportion of subjects with the signature immune responses seen previously. The vaccine-induced antibodies were cross-reactive with a panel of drifted H3N2 viruses from 2007 to 2019. Additionally, M2SR generated a rise in serum hemagglutination inhibition antibody titer in 71% of subjects. In contrast, the H3N2 seroresponse rate for the licensed intranasal vaccine FluMist is 10% in seronegative adults. Moreover, M2SR elicited mucosal and cell-mediated immune responses. This study demonstrates that the intranasal M2SR generates a multifaceted immune response and has the potential to provide better efficacy against vaccine-matched strains and influenza drift variants reducing the need to update the vaccine on an annual basis. This is a noteworthy step in the development of a broadly protective influenza vaccine.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vacinas contra Influenza
/
Influenza Humana
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Humans
Idioma:
En
Revista:
J Infect Dis
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Estados Unidos