The present study explores whether a simultaneously given hepatitis A vaccine (Epaxal) will have an impact on the immune response to PCV13 (pneumococcal conjugate vaccine; Prevenar13) vaccine in adults. The immune response to PCV13 is measured as levels of serotype specific serum antibodies and their opsonophagocytic activity. The results of volunteers receiving PCV13 and Epaxal will be compared to that in a control groups of adults receiving either hepatitis A or PCV13 vaccines only.

Inclusion Criteria:

1. Male or female subjects aged ≥50
2. General good health as established by medical history and physical examination
3. Written informed consent
4. Females of childbearing potential must agree to use an efficacious hormonal or barrier method of birth control during the study. Abstinence is acceptable.
5. Available for all visits scheduled in this study.
6. No previous Pnc vaccination
7. No previous hepatitis A vaccine
8. No other vaccines administered 30 days prior to or during the study

Exclusion Criteria:

1. Previous pneumococcal or hepatitis A vaccination
2. Immunization with any other vaccine (oral or parenteral) within 4 weeks prior to study start or planned vaccination during the study
3. Chronic administration of immunosuppressants or other immune-modifying drugs within 6 months before the first dose of vaccine; patients using oral corticosteroids in dosages of ≥0.5 mg/kg/d prednisolone or equivalent are excluded; inhaled or topical steroids are allowed
4. Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection
5. Pregnancy or lactation
6. Acute disease at the time of enrollment (defined as the presence of a moderate or severe illness with or without fever (fever is defined as body temperature of ≥38 °C).
7. Alcohol or drug abuse
8. Suspected non-compliance
9. Use of any investigational drug within 30 days preceding the study vaccine, or planned use during the study period
10. Any clinically significant history of known or suspected anaphylaxis or hypersensitivity reaction based on the judgement of the investigator
11. Employee at the investigational site, relative or spouse of the investigator
12. Any other criteria which, in the investigator's opinion, would compromise the ability of the subject to participate in the study, the subject's well-being, or the outcome of the study