• Persistence of pneumococcal antibodies after primary immunisation with a polysaccharide-protein conjugate vaccine.

      Zimmermann, Petra; Perrett, Kirsten P; Berbers, Guy; Curtis, Nigel (2019-02-22)
      Despite immunisation, antibiotics and intensive care management, infection with We measured pneumococcal antibody concentrations to all 13 antigens included in the 13-valent pneumococcal conjugate vaccine (PCV13) after immunisation with a 3+0 schedule in 91 infants at 7 months and in 311 infants at 13 months of age. The geometric mean concentrations (GMCs) and the proportion of infants with an antibody concentration above the standard threshold correlate of protection (seroprotection rate) were calculated at both time points. At 7 months of age, GMCs varied between 0.52 µg/mLand 11.52 µg/mL, and seroprotection rates varied between 69% and 100%. At 13 months of age, GMCs had decreased to between 0.22 µg/mLand 3.09 µg/mL, with the lowest responses against serotype 4, followed by 19A, 3, 6B and 23F. Seroprotection rates at 13 months of age were below 90% for most serotypes, with the lowest rates for serotype 4 (23%) followed by 19A (50%), 23F (61%) and 6B (64%). Our study shows that at 13 months of age, many infants vaccinated with a 3+0 schedule have pneumococcal antibody concentrations below the standard threshold correlate of protection. To optimise protection against pneumococcal disease through early childhood and to improve antibody persistence and indirect protective effects, immunisation schedules with booster doses might be necessary.