Mucosal immune response to trivalent live attenuated intranasal influenza vaccine in children.

Publication Type
Journal Article
Year of Publication
Boyce, T G; Gruber, W C; Coleman-Dockery, S D; Sannella, E C; Reed, G W; Wolff, M; Wright, P F
Date Published
1999 Aug 20
Administration, Intranasal; Antibodies, Viral; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Hemagglutination Inhibition Tests; Humans; Immunity, Mucosal; Immunoglobulin A, Secretory; Infant; Influenza Vaccines; Orthomyxoviridae; Sensitivity and Specificity; Vaccines, Attenuated

Intranasal trivalent, cold-adapted, live attenuated influenza vaccine (CAIV-T) is a promising alternative to inactivated vaccine for protection against influenza in children. However, correlates of immunity are not well defined. To determine the mucosal immune response to CAIV-T, 19 children ages 15-55 months were randomized to receive two doses of CAIV-T or placebo. Influenza-specific IgA to the haemagglutinin of each of three contemporary strains was measured in nasal washes collected pre- and postvaccination using a kinetic enzyme-linked immunosorbent assay. After two doses of study drug, 62, 69 and 85% of CAIV-T recipients demonstrated a mucosal IgA response to influenza A/H1N1, A/H3N2, and B strains respectively; in comparison, 33, 0 and 17% of placebo recipients demonstrated an IgA response to the same strains (p = 0.35, 0.01 and 0.01). Overall, seropositive vaccinees were 4.5 times more likely to develop a mucosal immune response than an HAI response (p = 0.015). Two doses of CAIV-T induce a mucosal IgA response to all three influenza vaccine antigens in the majority of children. In addition, a mucosal antibody response may be the only indication of a vaccine take in a seropositive child.