Subjects will be randomly assigned to 1 of 3 groups to receive the following vaccines: Group 1: 13-valent pneumococcal conjugate vaccine (13vPnC) and diphtheria, tetanus, and acellular pertussis vaccine (DTaP), Group 2: 7-valent pneumococcal conjugate vaccine (7vPnC) and DTaP, Group 3: DTaP alone. Group 3 subjects will also receive catch-up doses of Prevenar (commercial product of Prevenar in Japan) 13vPnC and 7vPnC will be blinded, and DTaP will be open-label. The main purpose of the study is to determine if the immune responses to 13vPnC are comparable to the immune responses to 7vPnC and if the immune responses to 13vPnC given with DTaP are comparable to those induced by DTaP given alone. In addition, the study aims to evaluate the side effects (safety profile) after vaccination of 13vPnC and 7vPnC when given with DTaP in healthy Japanese infants.