Safety and immunogenicity of sequential pneumococcal immunization in preschool asthmatics.
OBJECTIVE
Respiratory infections are major triggers of exacerbations in preschool asthma. Many countries' guidelines recommend immunization against pneumococci for patients suffering from chronic airway disease. Beyond infancy, however, data on the immunogenicity and safety are scarce. Also, the interval between priming and booster is a matter of debate.


METHODS
Seventy preschool asthmatics (2-5-year-old; mild to moderate asthma) underwent sequential immunization: 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 assigned 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 were determined initially, after two and 12 months after PCV-7. Local and systemic reactions to each vaccine were recorded.


RESULTS
Initially, depending on the serotype, up to 79.4% (group A) or 80.4% (group B) individuals did not reach the protective antibody threshold of 0.35 microg/ml. Sequential pneumococcal immunization was immunogenic in preschool asthmatics, inducing protection in the majority of our children. Subjects boostered after eight weeks had significantly lower antibody levels than those boostered after 10 months. Local and systemic adverse events were mild in character and self-limiting.


CONCLUSIONS
Although both sequential pneumococcal vaccine regimens were safe and immunogenic among preschool asthmatics, immunogenicity was higher when the booster was given after 10 months.
Rose
Markus A
MA
Children's Hospital, University of Frankfurt, Theodor-Stern Kai 7, 60590 Frankfurt/M, Germany. Markus.Rose@kgu.de
Gruendler
Matthias
M
Schubert
Ralf
R
Kitz
Richard
R
Schulze
Johannes
J
Zielen
Stefan
S
D000907:Antibodies, Bacterial / Q000097:blood; D001249:Asthma / Q000276:immunology*; D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D008297:Male; D011008:Pneumococcal Infections / Q000276:immunology / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D011446:Prospective Studies
C414006:23-valent pneumococcal capsular polysaccharide vaccine; D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D022242:Pneumococcal Vaccines