May 5, 2006

Nasal flu vaccine beats shots for young children

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - A new vaccine called CAIV-T
that is squirted into the nose offers greater protection
against influenza infection in children than does the current
FDA-approved injectable vaccine, according to study findings
presented this week at the Pediatric Academic Societies meeting
in San Francisco.

CAIV-T, short for Cold Adapted Influenza Vaccine Trivalent,
is closely related to the already approved nasal vaccine
FluMist. The major difference is that the newer vaccine is now
refrigerator stable and capable of being easily stored.

In the largest head-to-head flu vaccine study ever
conducted, 8457 children, between 6 months and 5 years of age,
were randomly assigned to receive CAIV-T or injectable flu
vaccine. The bulk of subjects had never been vaccinated before.

"CAIV-T was dramatically more effective than the injectable
vaccine," lead researcher, Dr. Robert Belshe, from St. Louis
University, told Reuters Health. The number of confirmed flu
cases in the CAIV-T group was less than half that seen in the
injectable vaccine group, he added.

Compared with the injectable vaccine, CAIV-T provided
better protection against circulating flu strains that matched,
as well as those that did not match the recommended vaccine
strain. CAIV-T was particularly effective against these latter
"mismatched" flu stains, Belshe noted.

Given its close similarity to FluMist, the approval process
for CAIV-T could be accelerated, Dr. Belshe said. FluMist is
currently approved for use in people between 5 and 49 years of
age, whereas the application for CAIV-T will seek an indication
for use in children under 5, he added.