Effectiveness of 23-valent pneumococcal polysaccharide vaccine in adults aged 60 years and over in the Region of Madrid, Spain, 2008-2011.

Invasive pneumococcal disease (IPD) is a notifiable disease in the Region of Madrid. The 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for children and adults aged two years or over with a high risk of disease, and for all adults aged 60 and over. We describe the evolution of IPD incidence from 2008 to 2011 in people aged 60 years and over and PPV23 vaccine effectiveness (VE). VE is estimated using both the screening method and indirect cohort method. The incidence of IPD varied from 20.0 in 2008 to 15.2 per 100,000 inhabitants in 2011 (RR: 0.8; 95% CI: 0.6­0.9). Adjusted VE estimated with the screening method was 68.2% (95% CI: 56.2­76.9). VE with the Broome method was 44.5% (95% CI: 23.8­59.6) for all PPV23 serotypes, and 64.4% (95% CI: 45.2­76.8) for PPV23 serotypes not included in conjugate vaccines. VE was lower in patients aged 80 years and older (25.5%; 95% CI:-23.2 to 55.0) and those with highrisk medical conditions (31.7%; 95% CI: -2.2 to -54.4). Adjusted VE was 44.5% (95% CI: 19.4-61.8) within 5 years of vaccination and 32.5% (95% CI: -5.6 to 56.9) after 5 years. These results are compatible with current recommendations for PPV23.

[Evolution of meningococcal disease in the community of Madrid. Effectiveness of antimeningococcal A+C vaccination]. / Evolución de la enfermedad meningocócica en la Comunidad de Madrid. Efectividad de la vacunación antimeningocócica A + C.

BACKGROUND: In 1997 (between 22 September and 14 November) an A + C meningococcal mass vaccination campaign was carried out in Madrid, targeting the age group of from 18 months to 19 years of age, in the face of an increase in the number of cases of meningococcal disease caused by serogroup C occurring in the 1996-97 season. This study forms a part of the impact assessment of that campaign. METHODS: The evolution of the meningococcal disease, by means of the comparison of rates of incidence; and the efficacy of the vaccination campaign was determined after one year (1997-98 season) and after two years (1997-98 and 1998-99 seasons) of monitoring. The vaccine efficacy has been calculated as [1-(Incidence rate in vaccinated/Incidence rate in unvaccinated)]* 100. RESULTS: A significant drop was registered in the incidence of serogroup C meningococcal disease on comparing the 1997-98 and 1998-99 seasons with the epidemic season (1996-97). The vaccine efficacy after two years of monitoring subsequent to the vaccination campaign was 76.9% for the global population between 18 months and 19 years of age and 88.5% in the group of vaccinated individuals between 15 and 19 years of age. CONCLUSIONS: The vaccine efficacy obtained is compatible with that described in the relevant literature. The significant reduction in the incidence of meningococcal disease caused by serogroup C was due to the vaccine efficacy obtained.