Universal childhood immunisation against Streptococcus pneumoniae: the five-year experience of Liguria, Italy

Liguria was the first Italian Administrative Region, since 2003, to actively recommend free-of-charge immunisation, of all infants, with heptavalent Pneumococcal Conjugate Vaccine (PCV-7), within a research pilot-project. Vaccination coverage among infants rapidly increased from 42.8% in 2003 to 83.3% in 2004, progressively reaching levels of 93.4% in 2007. Two scientific projects have been carried out, aimed: (i) to assess the immunogenicity of PCV-7 and of a hexavalent vaccine Diphtheria-Tetanus-Trivalent Acellular Pertussis-Hepatitis B-Inactivated Polio Virus-Haemophilus influenzae type B (DTaP-HBV-IPV-Hib) when co-administered to healthy infants at 3, 5 and 11-12 months of age (routine schedule), and (ii) to evaluate the effect of the immunisation campaign in preventing pneumococcal-associated hospitalisations. Results in 151 infants showed the high immunogenicity of the vaccines, seroprotection rates, measured 1 month after the third dose, ranging between 97.3% (serotype 6 B) and 100% (serotypes 4 and 9 V) for PCV-7 and between 99.3% and 100% against common antigens of hexavalent vaccine. Monitoring nearly 70,000 children, aged 0-24 months, during the period 2000-2007, and comparing hospitalisation rates occurred in subjects belonging to birth cohorts before and after the introduction of widespread immunisation, a significant decline for all-cause and pneumococcal pneumonia and for acute otitis media was observed, with preventive fractions of 15.2%, 70.5% and 36.4%, respectively.