WESTPORT, CT (Reuters Health) – A new inactivated, intranasal anti-influenza vaccine prompts antibody responses in children, according to results of a small study by Israeli researchers.
In the August issue of the Journal of Medical Virology, Dr. Zichria Zakay-Rones of the Hebrew University-Hadassah Medical School, Jerusalem, and colleagues note that children may be the main vector for the spread of influenza, and that intranasal immunization is a "painless, side effect-free" method of vaccination.
To evaluate this approach, the researchers studied children who were given a trivalent whole virus vaccine containing 20 µg of three recommended seasonal viral strains. Nine were enrolled during the 1997-1998 flu season and a further 19 during the 1998-1999 season.
Of nonimmune children, 50% to 87.5% became immune following the vaccination. Local antibody response to the viral strains was seen in 50% to 55% of the children. Furthermore, 83.3% showed mucosal and/or serum antibody responses to the A/Beijing strain. Corresponding figures for A/Sydney and B/Harbin strains were 73.3% and 61.1%.
In the nine children enrolled during the earlier study period, the research team observed a significant reduction in the number of sick days compared to a placebo group.
The researchers, who characterize their results as "encouraging," suggest that the mucosal response "may forestall influenza development in its early stages, thereby contributing significantly to the reduction of influenza spread in the community."
In e-mail comments to Reuters Health, Dr. Zakay-Rones said that "intranasal, inactivated, aqueous whole virus vaccine induces both mucosal (SIgA) and serum antibody response following one dose in children." The vaccine is "easy to administer and no side effects were recorded."
In other studies, similar findings were made after one dose in adults and two doses in the elderly, Dr. Zakay-Rones said.