Safety and immunogenicity of a purified haemagglutinin antigen in very young high-risk children.
Forty-three high-risk preterm children received either one of three doses of purified hemagglutinin antigen (HA) (7.5 micrograms/0.25 ml, 22.5 micrograms/0.25 ml or 67.5 micrograms/0.25 ml) or standard split product vaccine (ST) (22.5 micrograms/ml dose) over the 1990-1991 influenza season. Components for all vaccines included A/Shanghai 16/89, A/Taiwan 1/86 and B/Yamagata 16.88. Sera for antibody was drawn before, 6 weeks and 4 months after the first vaccine dose. The study was randomized and blinded. All children received two 0.25 ml doses of vaccine 4 weeks apart. No significant local or systemic reactions occurred. Six weeks after the first dose, children receiving ST vaccine had significantly higher seroconversion rates to A/Shanghai (p = 0.03) and to A/Taiwan (p = 0.01) than did those receiving equivalent HA vaccine. However, seroconversion rates were significantly higher for those children receiving the highest HA dose. All four vaccine groups responded poorly to B/Yamagata. Geometric mean titres were low for all groups and declined over 4 months. These results suggest that the equivalent dose of HA vaccine offers no advantage over ST vaccine in the immunization of high-risk preterm children.
Groothuis
J R
JR
Department of Pediatrics, Children's Hospital and University of Colorado School of Medicine, Denver 80218.
Lehr
M V
MV
Levin
M J
MJ
D000914:Antibodies, Viral / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000008:administration & dosage / Q000009:adverse effects / Q000302:isolation & purification*; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D009980:Influenza A virus / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000302:isolation & purification*; D007251:Influenza, Human / Q000517:prevention & control; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012449:Safety
D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D007252:Influenza Vaccines