Full-dose trivalent flu vaccine seems safe for children 6 to 35 months of age
By Reuters Staff
NEW YORK (Reuters Health) - Children six to 35 months old can safely be given a full dose of seasonal trivalent inactivated influenza vaccine (TIV), a new study suggests.
Currently in the US, health officials recommend that children six to 35 months old be given half the dose of TIV (0.25 mL) rather than the full dose (0.5 mL).
"One advantage of using the same dose of influenza vaccine for all children would be the simplification of the production, purchase, storage, and administration of influenza vaccines," Dr. Natasha Halasa from the Vanderbilt Vaccine Research Program at Vanderbilt University in Nashville, Tennessee and colleagues say.
They compared the safety and immunogenicity of full-dose versus half-dose TIV in 243 children six to 35 months old in a multicenter, randomized double-blind trial over two influenza seasons (2010-2011 and 2011-2012).
In the first year only, among 32 children with prior influenza immunization (the primed group), 23 received full-dose and nine received half-dose TIV.
Among the 211 children in the vaccine naive group, 140 received the full dose and 71 received the half dose: 67 in the first year (44 full dose and 23 half dose) and 144 in the second year (96 full dose and 48 half dose).
In a June 27 online paper in the Journal of the Pediatric Infectious Diseases Society, the researchers say, "No safety differences between the full-dose or half-dose groups were noted for either the fully primed or naive cohorts for systemic reactions and local reactions when both seasons were combined."
In addition they noted few significant differences in immunogenicity to the three vaccine antigens - A/California/7/09 (H1N1)-like virus, A/Perth/16/2009 (H3N2)-like virus, and B/Brisbane/60/2008-like virus.
They say the immune response to H1N1 was significantly higher in the full-dose group among primed subjects. And in the naive cohort, the geometric mean titers for all three antigens after two doses of TIV were significantly higher in children 12 to 35 months old compared to those six to 11 months old.
The researchers conclude, "Our study confirms the safety of full-dose TIV given to children 6 through 35 months of age. An increase in antibody responses after full- versus half-dose TIV was not observed, except for H1N1 in the primed group."
"Larger studies," they say, "are needed to clarify the potential for improved immunogenicity with higher vaccine doses."
The authors did not respond to request for comment by press time.
SOURCE: http://bit.ly/1l8ut7d
J Ped Infect Dis 2014.
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