A Phase 2 Study to Evaluate the Safety, Tolerability, and Immune Response of AFX3772 Vaccine in Healthy Infants

Inclusion Criteria:

• Is a full-term infant approximately 2 months of age at time of obtaining the informed consent.

Exclusion Criteria:

• Had prior administration of any pneumococcal vaccine.

• Has a known or suspected hypersensitivity to AFX3772, PCV13, PCV20 or any componentsof the formulations used.

• Has a known or suspected immunodeficiency or other conditions associated withimmunosuppression that may require immunosuppressive drugs. In addition, theparticipant's biological mother has known HIV infection or known to be hepatitis Bsurface antigen positive.

• Has any clinically significant allergic condition or history prior to the firstvaccination for primary immunization series.

• Has a history of microbiologically proven invasive disease caused by S. pneumoniae.

• Has received immunoglobulins.

• Has a bleeding diathesis or condition associated with prolonged bleeding that wouldcontraindicate intramuscular injection.

• Has received systemic corticosteroids for a period of more than 14 days and has notcompleted the treatment for at least 30 days before study vaccine.