We reviewed the evidence about the effect of vaccination against pneumococcus (a type of bacterium) on preventing middle ear infections in children.
Middle ear infection, or otitis media, is one of the most common respiratory infections in childhood. Infection with Streptococcus pneumoniae (pneumococcus) is a frequent cause of middle ear infection. Vaccination against pneumococcus with pneumococcal conjugate vaccines (PCVs) is primarily introduced to protect young children against severe pneumococcal infections, such as meningitis and pneumonia. We wanted to discover whether vaccination with PCV also leads to fewer middle ear infections in children.
This review included evidence up to 3 December 2013. Nine trials with a total of 48,426 children were included; five trials included 47,108 infants, while four trials included 1318 children at a later age, i.e. aged one to seven years, who were either healthy (one trial, 264 children) or had previous upper respiratory tract infections, including middle ear infections. All trials had a long follow-up, varying from 6 to 40 months.
When vaccinating against seven different serotypes of pneumococcus (7-valent PCV) during early infancy, the occurrence of middle ear infections either increased by 5% or decreased by 6% to 7%. One study in infants used 11 serotypes of pneumococcus together with a carrier protein from another bacterium (Haemophilus influenzae); this decreased the occurrence of middle ear infections by 34%.
Children with a history of middle ear infections do not seem to benefit from 7-valent PCV when immunised at an older age (after infancy).
Quality of the evidence
We judged the quality of the evidence for 7-valent PCV in early infancy to be high (further research is very unlikely to change our confidence in the estimate of effect), while we judged the quality of the evidence for multivalent (more than seven different serotypes) PCV to be moderate (further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate), as this evidence is derived from only one trial. We judged the quality of the evidence for 7-valent PCV in older children with a history of middle ear infections to be high.
Future studies on the effects of PCV in infants, with broader serotype coverage (more than seven different serotypes), are likely to provide more understanding of the role of PCV in preventing middle ear infections.