Antibody persistence and immunologic memory in children vaccinated with 4 doses of pneumococcal conjugate vaccines: Results from 2 long-term follow-up studies.

To investigate long-term antibody persistence following the administration of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV), we present results of 2 follow-up studies assessing antibody persistence following 2 3+1 schedules up to 4 (NCT00624819 - Study A) and 5 years (NCT00891176 - Study B) post-booster vaccination. In Study A, antibody persistence was measured one, 2 and 4 years post-booster in children previously primed and boosted with PHiD-CV, or primed with the 7-valent pneumococcal conjugate vaccine (7vCRM) and boosted with either PHiD-CV or 7vCRM. In Study B, PHiD-CV was co-administered with meningococcal vaccines, and pneumococcal antibody persistence was measured 2, 3 and 5 years post-booster. An age-matched control group, unvaccinated against Streptococcus pneumoniae, was enrolled in Study A, allowing assessment of immunologic memory by administration of one dose of PHiD-CV to both primed (4 years post-booster) and unprimed 6-year-old children. Four years post-booster (Study A), antibody concentrations and opsonophagocytic activity (OPA) titers remained higher compared to the pre-booster timepoint, with no major differences between the 3 primed groups. Antibody persistence was also observed in Study B, with minimal differences between groups. The additional PHiD-CV dose administered 4 years post-booster in Study A elicited more robust immune responses in primed children than in unprimed children. Long-term serotype-specific antibody persistence and robust immunologic memory responses observed in these 2 studies suggest induction of long-term protection against pneumococcal disease after PHiD-CV vaccination.

Impact of rotavirus vaccination on childhood deaths from diarrhea in Brazil.

OBJECTIVES: Rotavirus vaccination was introduced in Brazil in March 2006, targeting an annual birth cohort of approximately 3.5 million. We analyzed trends in all-cause gastroenteritis-related deaths in children <5 years of age during the pre- and post-vaccination periods. METHODS: Data from the National Immunization Program and the Mortality Information System were used to calculate vaccine coverage and mortality rates related to gastroenteritis in children <1 year and 1-4 years of age, using population estimates from the census as the denominator. Relative reductions in mortality rates were calculated for 2007 and 2008, using the 2004-2005 mean as baseline before vaccine introduction. RESULTS: Coverage of two doses of human rotavirus vaccine was 39% in 2006, increasing to 72% in 2007 and 77% in 2008. During 2004-2005, the gastroenteritis mortality rate in children <1 year of age was 56.9 per 100 000, decreasing by 30% (95% confidence interval (CI) 19-41) in 2007 and by 39% (95% CI 29-49) in 2008. In children 1-4 years of age, the mortality rate was 4.5 per 100 000 during 2004-2005, decreasing by 29% (95% CI 10-49) in 2007 and by 33% (95% CI 15-52) in 2008. CONCLUSIONS: The decreased rates of childhood gastroenteritis-related deaths in Brazil following rotavirus vaccine introduction, particularly among children <1 year of age, suggest the potential benefit of vaccination.