Respiratory infections are major triggers of exacerbations in preschool asthma. Many countries' guidelines recommend immunization against pneumococci for patients suffering from chronic airway disease. Also the interval between priming and booster is a matter of debate.
We immunize a large group of preschool asthmatics (2-5 years old) sequentially: one dose of seven-valent pneumococcal conjugate vaccine (PCV-7) followed by a single dose of 23-valent pneumococcal polysaccharide vaccine (PPV-23). We randomly assign half of the vaccinees to receive PPV-23 eight weeks after PCV-7 (group A), and the rest to a 10-month interval (group B). Pneumococcal antibody concentrations to serotype 4, 5, 6B, 7, 9V, 14, 18c, 19F, and 23F are determined initially, after two, and 12 months after PCV-7. Local and systemic reactions to each vaccine are recorded.
