Developments in mucosal influenza virus vaccines

Area of Science:

• Immunology
• Vaccinology
• Virology

Background:

• Influenza virus poses a significant global health burden, necessitating effective vaccination strategies.
• Current influenza vaccines include parenteral inactivated vaccines and live attenuated vaccines, each with limitations.
• Aerosol delivery offers a potential route for mucosal vaccination, aiming for enhanced local and systemic immunity.

Purpose of the Study:

• To evaluate the immunogenicity and efficacy of aerosol-inactivated split influenza virus vaccines.
• To compare these responses with those induced by cold-adapted reassortant live influenza virus vaccines.
• To assess the potential of mucosal inactivated influenza vaccines for infection prevention.

Main Methods:

• Aerosol inactivated split influenza virus vaccines (threefold parenteral strength) and live influenza virus vaccines were administered.
• Mucosal immune response assessed via specific IgA antibody levels in nasal swabs.
• Systemic immune response measured by serum haemagglutination inhibition (HAI) antibody titers.
• Vaccine efficacy determined through challenge tests using live influenza virus.

Main Results:

• Mucosal administration of inactivated influenza virus vaccine elicited stronger systemic and mucosal immune responses than live influenza virus vaccine.
• The inactivated vaccine demonstrated a significantly greater booster effect compared to the live vaccine.
• Efficacy studies confirmed that mucosal inactivated influenza virus vaccine effectively prevented infection by live vaccine virus.

Conclusions:

• Mucosally administered inactivated influenza virus vaccines are highly immunogenic and efficacious.
• This vaccination strategy offers advantages over live influenza vaccines, including enhanced immune stimulation and booster response.
• Aerosol delivery of inactivated influenza vaccines represents a promising approach for influenza prevention.