TORONTO -- Mass vaccination programs against swine flu are going to be a lot easier to mount than first thought, experts said Thursday after the fast-tracked publication of studies showing one dose should be enough to protect most people. Two vaccine makers, CSL of Australia and Novartis, reported that a single dose of vaccine -- the first a standard size, the second a half-dose with a boosting additive -- induced a protective response in a high proportion of adults tested.
The findings will be backed by results to be released Friday by the U.S. National Institutes of Health, said Dr. Anthony Fauci, director of the NIH's National Institute of Allergy and Infectious Diseases. "The data from the NIH clinical trial on unadjuvanted H1N1 pandemic vaccine verifies and corroborates the exciting data that have come out on the unadjuvanted vaccine in the New England Journal of Medicine," Fauci said in an interview from Bethesda, Md.Fauci added that the NIH study saw a similarly strong response at eight to 10 days after a single dose, which is very quick by vaccine terms. The findings suggest the limited global supplies of pandemic vaccine can be stretched to cover double the number of people who could have been vaccinated if two doses were required.
And the NIH data suggest people will be protected in less than two weeks of having received one shot. "Looks good," said influenza vaccine expert Dr. John Treanor of the University of Rochester in northwestern New York state. The Public Health Agency of Canada is buying vaccine with adjuvant, an additive that boosts the immune system's response to vaccine. And all along Chief Public Health Officer Dr. David Butler-Jones has said one dose with adjuvant might be sufficient to protect against infection.
Earlier, two Chinese vaccine manufacturers said their vaccines induced a protective response after a single dose without adjuvant. But those findings haven't yet been reported in a journal. The fact so many trials are seeing a strong response to one dose is very promising, Fauci said. "You put them all together, it's real." There's no data yet on how the vaccine works in children who have had less cumulative exposure to flu viruses and vaccine. Even with seasonal flu shots, it's recommended that children under nine who have never been vaccinated before should get two shots. Fauci, who is a leading immunologist, said it is likely that one shot could work for children aged nine to 18, but that children under nine may need two doses.
No comments:
Post a Comment