The main bacterial pathogens in acute otitis media, which has its greatest prevalence among children less than 2 years old, are Streptococcus pneumoniae and non-typable Haemophilus influenzae. Plain pneumococcal capsular polysaccharide vaccines are not immunogenic in children under the age of 2 years but heptavalent conjugate vaccine is effective against pneumococcal disease due to vaccine serotypes. Now a new vaccine has been developed that contains 11 different pneumococcal polysaccharide serotypes, each conjugated to H influenzae-derived protein D. Protein D is an H influenzae cell surface lipoprotein that is highly conserved in both encapsulated and non-encapsulated strains of the organism and has proved effective in inducing protection against non-typable H influenzae in animal studies. The new vaccine has been assessed in the Czech Republic (

) .

A total of 4968 infants were randomised to receive either pneumococcal protein D conjugate vaccine or hepatitis A vaccine (controls) at 3, 4, 5, and 12–15 months of age and followed up to age 2 years. Data were analysed for 4907 infants. In the novel vaccine group there were 333 clinical episodes of acute otitis media and in the control group 499, a significant 34% reduction in the experimental group. Vaccine efficacy was 58% against acute otitis media due to vaccine serotype pneumococci and 35% against acute otitis media due to non-typable H influenzae.

The new vaccine provides protection against acute otitis media in children under the age of 2 years due to either of the two main bacterial pathogens. Its effectiveness against lower respiratory tract infections remains to be determined.