Researchers Compare the Efficacy of Three PCV13 Vaccination Schedules

After testing several pneumococcal vaccination schedules for preterm infants, researchers found that all the schedules eventually resulted in seroprotective concentrations of antibodies. However, the timing of the primary schedule did affect their immune response. 

Currently, the CDC and the American Academy of Pediatrics recommend pneumococcal vaccination at 2, 4, 6, and 12-15 months. Outside the US, other schedules are in use. 

“Premature infants have a higher risk of invasive pneumococcal disease and are more likely to have lower vaccine responses compared with term infants. Increasingly, immunization schedules are including a reduced, 2-dose, pneumococcal conjugate vaccine priming schedule,” the study’s authors wrote. 

For the study, 210 infants were randomly assigned to receive 13-valent pneumococcal conjugate vaccine (PCV13) on 1 of 3 possible schedules. Those on the reduced schedule received PCV13 at 2 and 4 months. There was also an accelerated schedule of 2, 3, and 4 months, as well as an extended schedule of 2, 4, and 6 months. Regardless of their primary schedule categorization, all infants were administered a booster at 12 months. 

Measurements of serotype-specific pneumococcal immunoglobulin G (IgG) for PCV13 serotypes indicated that about 75% of infants on the reduced schedule showed seroprotection for more than half of the PCV serotypes. Approximately 88% of infants on the accelerated schedule and 97% of those on the extended schedule showed seroprotection for more than half of the PCV serotypes. 

After all the infants were administered the booster, the children on the extended scheduled had lower geometric mean concentrations compared with those on the accelerated and reduced schedules. 

“A reduced priming schedule of PCV13 resulted in higher post-booster IgG concentrations but lower post-primary concentrations. The optimum vaccine schedule for preterm infants will therefore depend on when they are most at risk for invasive pneumococcal disease,” the authors concluded. 

—Lauren LeBano 

Reference

Kent A, Ladhani SN, Andrews NJ. Schedules for Pneumococcal Vaccination of Preterm Infants: An RCT. Pediatrics. 2016 Aug 8. pii: e20153945. [Epub ahead of print].