Adjuvanted influenza vaccine

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Influenza vaccines are crucial for preventing seasonal and pandemic influenza.
• Adjuvanted vaccines, like those with MF59 emulsion, aim to enhance immune responses.
• Assessing the immunogenicity and effectiveness of adjuvanted influenza vaccines is vital, especially in vulnerable populations like the elderly.

Purpose of the Study:

• To evaluate the immunogenicity and effectiveness of an adjuvanted influenza vaccine (MF59-adjuvanted) compared to non-adjuvanted vaccines.
• To assess the duration of immune response and protection against heterovariant strains in elderly vaccinees.
• To analyze the safety profile, including systemic and local adverse events.

Main Methods:

• The study involved elderly vaccinees and younger adults receiving 1 to 3 annual injections of the adjuvanted influenza vaccine.
• Immunogenicity was assessed by measuring antibody responses against influenza strains.
• Effectiveness was evaluated by comparing seroprotection rates and responses to antigenically different strains with non-adjuvanted vaccines (subunit, split virus, virosomal).

Main Results:

• The adjuvanted vaccine demonstrated superior immunogenicity compared to non-adjuvanted subunit, split virus, and virosomal vaccines for 1-3 strains per injection.
• Enhanced and longer-lasting immunogenic effects were observed in elderly recipients compared to non-adjuvanted subunit vaccines.
• Significantly greater 28-day seroprotection rates were achieved with the adjuvanted vaccine, and it showed greater effectiveness against heterovariant strains in the elderly.

Conclusions:

• The MF59-adjuvanted influenza vaccine is immunogenic and provides enhanced, durable protection in elderly individuals.
• It offers improved effectiveness against drifted influenza strains compared to non-adjuvanted vaccines.
• While local reactions were more frequent, they were mild and transient, indicating a favorable safety profile.