PCV13: What Is the Optimal Primary Immunization Schedule?

Pneumococcal disease is the leading vaccine-preventable cause of death worldwide. The recommended primary vaccine schedule in the U.S. is at ages 2, 4, and 6 months, but vaccine schedules differ worldwide. Studies suggest that immunogenicity might be affected by age at first dose (2 vs. 3 months), duration between doses (1 vs. 2 months), and number of primary doses (2 vs. 3). In a single center study in the Netherlands, investigators compared immune responses of four different primary schedules to 13-valent pneumococcal conjugate vaccine (PCV13) serotypes. They randomized 400 infants to receive PCV13 according to one of the following schedules: (a) ages 2, 4, and 6 months; (b) ages 3 and 5 months; (c) ages 2, 3, and 4 months; or (d) ages 2 …