Pneumococcal carriage and type-specific antibody. Failure of a 14-valent vaccine to reduce carriage in healthy children
R. M. Douglas, D. Hansman, H. B. Miles and J. C. Paton
No consistent effect on nasal carriage rates of Streptococcus pneumoniae
belonging to vaccine types was observed during a randomized, controlled
trial of a 14-valent pneumococcal vaccine, which included 1273 Australian
children aged 6 to 54 months. Nasal carriage of S pneumoniae was associated
with a significantly elevated homotypic serum antibody concentration for
types 18C, 19F, and 23F, but not for types 6A and 14 (these five types are
the most important causes of pneumococcal infections in children). Upper
respiratory tract carriage seems to play an important role in natural
acquisition of antibody to some but not all pneumococcal serotypes. These
findings help to explain why pneumococcal vaccine fails to protect young
children from acute otitis media.
