The finding -- early results from clinical trials of the Sanofi Pasteur version of the swine flu vaccine -- is no surprise. The CDC bases its swine flu vaccination plan on the need for two shots in younger kids.
In kids over age 10, the H1N1 swine flu vaccine works just as well as it does in adults. These older children will need just one dose of the swine flu vaccine and can expect protection in eight to 10 days.
One shot of the vaccine raised protective antibodies in 76% of older children, a level of protection considered very good for flu vaccines. But a single dose of the vaccine protects only 36% of 3- to 9-year-olds, and only 25% of children age 6 months to 35 months.
"These two younger groups may require two doses of the vaccine," National Institute of Allergy and Infectious Diseases director Anthony Fauci, MD, said in a news conference held to announce the findings. "This is not an unexpected finding and is quite similar to what we see with seasonal flu vaccine."
H1N1 swine flu vaccine from other manufacturers -- including the inhaled FluMist version -- is expected to act in much the same way as the Sanofi product.
More clinical trial data are expected soon. But so far, experts are relieved to see that the H1N1 swine flu vaccines act very much like seasonal flu vaccines. There's been no sign of unusual side effects in children or adults given the H1N1 swine flu vaccine.
It's likely that kids will be able to get their seasonal flu shots and their H1N1 swine flu shots on the same day, although clinical trials are still looking at the issue. However, the CDC urges parents to get their kids the seasonal flu vaccine right away and not wait for the swine flu vaccine to become available.
The inhaled FluMist version of the swine flu vaccine cannot be given on the same day a kid gets the FluMist version of the seasonal vaccine. That's because FluMist contains a live, weakened flu virus and stimulates the immune system in a different way than flu shots, which contain inactivated virus particles.
The first 3.4 million doses of swine flu vaccine to be distributed in the U.S. will be FluMist, although millions more doses of the injectable vaccine will start arriving in mid-October. FluMist is recommended only for kids over age 2 (and adults under age 50) who do not suffer respiratory problems.
Since the H1N1 swine flu first appeared, 47 U.S. children and teens have died of the disease.