Receipt of PncCRM vaccine at infancy was associated with a reduction in tympanostomy tube placement from 2 to 4-5 years of age.

The licensure of new pneumococcal conjugate vaccines (PCVs) relies on immunogenicity data. When defining correlates of protection, vaccine efficacy data must be included. In the FinOM Vaccine Efficacy Trial, the PncOMPC vaccine showed an efficacy profile similar to that of the licensed PncCRM vaccine despite different antibody responses after primary and booster vaccinations. We determined antibody kinetics and avidities in a subgroup of infants participating in the FinOM trial. A total of 166 infants in three vaccine groups were immunized at 2, 4, 6, and 12 months of age with 7-valent PCV, PncCRM or PncOMPC, or hepatitis B vaccine. Concentrations of serum immunoglobulin G (IgG) against pneumococcal capsular polysaccharides were determined at 2, 4, 6, 7, 12, 13, and 24 months of age, and the avidity index (AI) to serotypes 6B, 19F, and 23F were determined at 7, 12, 13, and 24 months of age by enzyme immunoassay. Both PCVs were highly immunogenic, but they demonstrated different kinetics of antibody response; the concentration of IgG against serotypes 6B, 19F, and 23F declined faster after the third and fourth doses of vaccine in the PncCRM group than in the PncOMPC group. For both PCVs, the mean AI of anti-6B and -23F, but not of anti-19F, increased during the follow-up, which is in line with serotype-specific protection in the FinOM trial. Our data suggest that the kinetics and avidities of antibodies should be considered, in addition to antibody responses, when defining correlates of protection.

In the Finnish Otitis Media Vaccine Trial, the now-licensed pneumococcal conjugate vaccine containing polysaccharides conjugated to protein CRM 197 (PncCRM) and the experimental pneumococcal polysaccharide-meningococcal outer membrane protein complex conjugate vaccine (PncOMPC), showed similar efficacy profiles against acute otitis media despite different antibody concentrations in sera. We now report the opsonophagocytic activities (OPA) in these sera. OPA, antibody concentration, and avidity for serotypes 6B, 19F, and 23F were determined in sera of infants who received either pneumococcal conjugate (PCV) or control vaccine at 2, 4, and 6 months of age and either the homologous or pneumococcal polysaccharide vaccine at 12 months of age. OPA varied by vaccine and serotype. The majority of PCV recipients had positive OPA after the fourth dose, while OPA was undetectable in the control group. Coinciding with the efficacy data, the concentration of antibodies required for 50% killing was low for 6B and high for 19F for both PCVs. Contradictory to the efficacy data, PncOMPC induced lower functional capacity to 23F than PncCRM. OPA correlated with antibody concentration, while avidity and functional capacity of antibodies showed no correlation. The OPA data provide valuable additional information for serotype-specific differences in protection and when evaluating serotype-specific immunogenicity and should thus be considered when defining serological correlates of protection.

The aim of this study was to evaluate cost-effectiveness of pneumococcal conjugate vaccine (PCV7) in children <5 y of age. A Markov simulation model was used to compare the cost-effectiveness of 4 doses (assumed 50.5 euros per dose) of PCV7 with no intervention. Only direct effects of the vaccine were taken into account. In Finland, vaccination of a birth cohort of 57,500 healthy infants would potentially prevent annually 60 cases of invasive PD, 1,400 cases of pneumococcal pneumonia, 15,000 episodes of acute otitis media, 3,000 otological surgery procedures and 0.9 deaths in children aged <5 y. Investing 12.0 million euros to vaccinate a birth cohort would save annually 6.3 million euros in medical, and 2.0 million euros in productivity and other, costs. Therefore, investing 1 euros in a vaccination programme would return 0.53 euros in medical costs and 0.70 euros in societal costs. In the base case, vaccination would cost society 139,986 euros per life y gained. To achieve cost savings from a health care provider (societal) perspective, without considering herd effects or replacement phenomenon, the price of PCV7 should be 50% (70%) of the price used in the base case.