Similar to children, adults frequently visit outpatient clinics to get two or more kinds of vaccines at the same time: pneumococcal vaccine, influenza vaccine, Td (diphtheria and tetanus) vaccine, HPV (human papilloma virus) vaccine, meningococcal vaccine, zoster vaccine, etc. This study is intended to evaluate the immunogenicity and safety of concomitant administration of 23-valent pneumococcal polysaccharide vaccine (PPV23, Prodiax) and MF59 adjuvanted trivalent influenza vaccine in the elderly subjects aged ≥65 years.

During influenza season, concomitant influenza and pneumococcal vaccination would be an effective strategy to enhance pneumococcal vaccine coverage rate in high-risk adults. However, the immunogenicity and safety of concomitant vaccination need to be further investigated. There is data on immunogenicity and safety after concomitant administration of pneumococcal polysaccharide vaccine (PPV) and unadjuvanted influenza vaccine; no interference was noted between two vaccines. However, there are no data for MF59 adjuvanted influenza vaccine with pneumococcal vaccine. MF59 only locally reacts for immune response, so immunogenicity should be assessed for both vaccines injected in same arm versus different arms.

This study is intended to evaluate the immunogenicity and safety of concomitant MF59-adjuvanted trivalent influenza vaccine (MF59-aTIV, Fluad) and 23-valent pneumococcal polysaccharide vaccine (PPV23, Prodiax) vaccination in the elderly subjects aged ≥65 years. Healthy elderly subjects (N = 424) are randomized in a 1:1:1:1 ratio to receive MF59-aTIV alone (group 1), MF59-aTIV +PPV23 at different arm (group 2), MF59-aTIV +PPV23 at same arm (group 3) or PPV23 alone (group 4).

Hemagglutination inhibition (HI) assay and multiplex opsono-phagocytic killing assay (MOPA) will be used to compare the immunogenicity of each vaccine after single or concomitant vaccination at pre-vaccination and 1 month post-vaccination. MOPA will be taken for four serotypes (5, 6B, 18C and 19A).

Inclusion Criteria:

• At least 65 years of age who are eligible for the study vaccines;
• Who have given written informed consent at the time of enrollment);
• Those who are available for all the visits scheduled in the study;
• Subjects In good health as determined by medical history, physical examination and clinical judgment of the investigator

Exclusion Criteria:

• History of egg allergy
• History of influenza vaccination in previous 6 months
• History of any pneumococcal vaccination
• Documented S. pneumonia infection in the previous 5 years
• Chemotherapy for malignancy within the past 30 days
• High-dose systemic steroid (prednisone ≥0.5 mg/kg/day) in the past 30 days
• Receipt of blood product within 6 months before enrollment
• Significant acute or chronic infection within the previous 7 days or fever within the previous day
• Any serious chronic or progressive disease
• Any condition that might interfere with the study results.