Streptococcus pneumoniae vaccine (Affinivax)

Streptococcus pneumoniae is a causative agent for community acquired pneumonia, bacteremia, acute otitis media, and meningitis. Recent emergence of multi-drug resistant clinical isolates prompts the need of effective vaccine for the prevention of disease. The licensed polysaccharide-based pneumococcal vaccines only elicit protective antibodies against the infection of serotypes that are included in the vaccine. To broaden the protection, the use of pneumococcal proteins will be a feasible and preferable alternative. This communication provides a review on the biochemical properties of these protein candidates, their immunization results in animal studies, and perspectives on the development of protein-based pneumococcal vaccine.

A double-blind, randomized, controlled trial of a 14-valent Streptococcus pneumoniae polysaccharide vaccine, with saline as placebo, was performed on 1,273 healthy children six to 54 months of age. Different dosage regimens were used for children younger and older than two years of age. The vaccine was well tolerated. Follow-up continued for two years, during which time 95% of mothers submitted diaries of their children's respiratory-tract and otic symptoms. Data from diaries and medical and hospital case notes failed to reveal consistent or significant benefits in those who received the vaccine. In the first 16 months after immunization, recipients of placebo experienced an average of 0.69 episodes of otitis media per child, compared with 0.63 in recipients of vaccine (P = .6). Recipients of vaccine had no consistent reduction in days of respiratory morbidity, antibiotic consumption, hospitalization, or visits to a physician, when compared with recipients of placebo.