IMMUNOGENICITY AND SAFETY OF INTRADERMAL INFLUENZA VACCINES WITH DIFFERENT AMOUNT OF ANTIGENS IN OTHERWISE HEALTHY CHILDREN
Assoc. Prof. Susanna Esposito
11 slide(s) – English – 2011-06-07
In order to explore the immunogenicity and safety of different doses of trivalent influenza vaccine (TIV) administered by intradermal (ID) route by means of a microinjection system in comparison with those evoked by a full-dose of intramuscular (IM) virosomal adjuvanted influenza vaccine (VA-TIV), 112 previously primed healthy children aged >3 years were randomized 1:1:1 to receive 9 µg or 15 µg of each strain of ID-TIV (Intanza, Sanofi Pasteur, France) delivered by a microinjection system, or a full IM dose (15 µg of each strain) of VA-TIV (Inflexal V, Crucell, Switzerland). Blood samples were drawn at enrolment and after 28 ± 2 days to assay hemagglutination-inhibiting antibodies, and systemic and local adverse events were monitored for 14 days after administration. The A/H1N1 and A/H3N2 seroconversion and seroprotection rates were >90% and geometric mean titers (GMT) increased 3.2-14.9 times without any statistically significant between-group differences; however, seroconversion and seroprotection rates against the B strain were significantly higher in the children receiving either ID-TIV dose (p<0.05), and the GMT was significantly higher in the children receiving ID-TIV 15 µg (p<0.05). Local reactions were significantly more common among the children receiving either ID-TIV dose (p<0.05), but systemic reactions were relatively uncommon in all three groups. Our findings suggest that ID TIV with 15 µg of each viral antigen administered by means of new microinjection systems represents an highly immunogenic influenza vaccine with an acceptable safety profile for already primed children aged 3 or more years.