* Vaccine has double dose of viral protection
* Study found no safety problems
By Julie Steenhuysen
CHICAGO, Dec 21 Australian vaccine maker CSL
Ltd (CSL.AX) said on Monday its pandemic H1N1 swine flu vaccine
delivered a strong immune response after just one dose in
children as young as 6 months.
Global health authorities recommend children get two swine
flu shots for full protection, but the CSL vaccine showed
strong response with just one shot.
"This is great news that kids, including the very youngest
kids, responded with a single dose. It really is as good as we
would have hoped," said Dr. Anthony Fiore of the U.S. Centers
for Disease Control and Prevention, who wrote a commentary that
accompanied the study in the Journal of the American Medical
The findings suggest a single shot of the vaccine could
protect infants and children, a group that has been especially
vulnerable to pandemic H1N1 influenza.
In the study, a single 15-microgram dose produced
protective antibody levels in 92 percent of children aged 6 to
36 months, and 92.9 percent in children aged 3 to 9.
After a second dose, 100 percent of children in both age
groups were protected. No serious safety concerns were reported
with the vaccine.
"The key finding is really that one dose of the swine flu
vaccine appears to be highly effective in children as young as
six months of age," Dr. Michael Greenberg, director of vaccines
clinical development with CSL, said in a telephone interview.
"While we've seen similar responses in adults, the fact
that we were able to achieve protective antibodies in the
majority of children even after one dose of the vaccine is what
makes these findings unique."
Currently, all H1N1 vaccines in the United States for
children 3 and over are given in a 15 microgram dose, while
children 6 months to three years get a 7.5 microgram dose of
vaccine, Fiore said in a telephone interview.
The CSL study also tested the higher 15-microgram dose in
the youngest children, and found no significant side effects.
"They were testing a double dose of vaccine in those younger
kids -- more than is currently approved," Fiore said.
Fiore said it is not clear exactly why children in the
study did so well on a single dose of the vaccine. He said it
may be that some had unknowingly been exposed to swine flu and
their immune systems were already primed, or it may be the way
they were tested in the lab. Or, he said, it may be that the
CSL vaccine simply produces a better immune response.
Fiore said the findings do not suggest that all swine flu
vaccines approved for children require only dose. Tests of
other vaccines show children need two doses for good
"It's one vaccine, one study, one year, and it's in the
context of fairly long experience with young children who have
never before been vaccinated needing two doses," he said.
The CDC estimates that swine flu has killed 10,000
Americans, including 1,100 children, and put 200,000 into the
hospital since it emerged in March.
The U.S. government has been struggling to vaccinate 160
million Americans considered in most need of H1N1 vaccination
but had 100 million doses of H1N1 vaccine as of last week. CSL
is contracted to provide 36 million doses of vaccine, and
Greenberg said so far the company has delivered everything the
government has asked for.
(Reporting by Julie Steenhuysen; Editing by Maggie Fox,
Editing by Gary Hill)