TORONTO - U.S. government studies have also found a strong response to one dose of swine flu in adults and seniors.
The National Institutes of Health say clinical trials conducted on vaccine produced by Sanofi Pasteur and CSL Limited showed a strong response to one standard-size dose of vaccine without an adjuvant, an additive that boosts the impact of the vaccine.
The response was seen within eight to 10 days of the first shot, which is quick for vaccine.
The trials involved more than 2,800 people.
The NIH says the response in adults over 65 was lower than seen in younger adults but was within the same range as what is seen with seasonal flu.
On Thursday, studies published in the New England Journal of Medicine also showed a single dose of vaccine is likely to be enough to protect adults against swine flu.
