Childhood pneumococcal vaccination in Europe.

Abstract

Invasive diseases caused by Streptococcus pneumoniae (pneumococcus) are a major public health issue in Europe as well as worldwide. Severe diseases caused by pneumococci are pneumonia, meningitis and febrile bacteraemia; otitis media is a more common, but less serious manifestation of pneumococcal infection. Pneumococcus can affect all age groups but the bigger burden of disease is among children, elderly and other vulnerable people, like those with conditions associated with immune deficiency. The World Health organisation (WHo) estimated in 2005 that 0.7-1 million children below 5 years of age died of pneumococcal disease. Most of those deaths are in the developing countries [1]. In the industrialised world pneumococcal meningitis still shows fatality rates of 5-10% (much higher in those with underlying serious conditions); fatality rates of pneumococcal pneumonia are generally age-related and can range between 10 and 30% [2]. S. pneumoniae is showing a growing resistance to commonly used antibiotics. This highlights the urgent need for effective vaccines against pneumococcal infection. Specific protection against capsular polysaccharide antigens is needed to prevent pneumococcal infections and invasive disease. Pneumococcal vaccines have been developed to cover the serotypes that are most frequently cause of invasive disease in different age groups. Currently a 7-valent protein-conjugated (PCV7) and an unconjugated 23-valent vaccine are available worldwide. The 23-valent is licensed for use after 2 years of age and is designed for use in older children and adults. PCV7 is licensed for use under 5 years of age and can be easily integrated in most of the childhood vaccination schedules. PCV7 has been licensed in the US in February 2000. In october 2000 the Advisory Committee for Immunisation Practice (ACIP) recommended the use of PCV7 for all American children aged 2-23 months and for those aged 24-59 months that are at higher risk of pneumococcal invasive disease [3]. The first evaluation carried out during the following years indicated substantial declines in invasive pneumococcal disease (IPD) in children and adults compared with pre-vaccine years; surprisingly the vaccine prevented more than twice as many IPD cases in 2003 through indirect effects on pneumococcal transmission (i.e., herd immunity) than through its direct effect of protecting vaccinated children [4].