The U.S. government has bought 195 million doses of H1N1 swine flu vaccine for a possible autumn vaccination campaign, a U.S. federal official said Thursday.
The U.S. Health and Human Services Department has also contracted for 120 million doses of adjuvant, a compound to stretch the number of doses of vaccine needed, the department's Dr. Robin Robinson told a meeting of Food and Drug Administration advisers.
Five companies are making H1N1 vaccine for the U.S. market — AstraZeneca's MedImmune unit, Australia's CSL Ltd, GlaxoSmithKline Plc, Novartis AG and Sanofi-Aventis SA.
Robinson said HHS had accounted for this in planning for a possible influenza pandemic.
"We thought manufacturers would probably get a low or poor yield. That has been borne out," Robinson told the meeting.
He said HHS had planned to have 160 million doses available right away, and then 80 million a month afterward. It would take until March at this rate to vaccinate the full U.S. population of 300 million people with two doses each, Robinson said.
The five vaccine-making companies will tell the FDA committee later Thursday about what they have learned as they work with the virus, which spread globally in less than two months.
No signs of mutation
On Thursday, federal health officials said the new swine flu isn't yet mutating to become more dangerous, but they're closely tracking that as the virus continues to circle the globe.
Dr. Nancy Cox of the Centers for Disease Control and Prevention calls it "quite surprising" that more genetic variation hasn't emerged given the virus' quick spread — sickening more than an estimated million people in the U.S. alone since April.
Earlier, an FDA official said vaccine makers were only getting about 30 percent as much vaccine from eggs as they usually get with seasonal influenza vaccine.
World Health Organization and U.S. health officials have said they want to start vaccinating people against H1N1, alongside regular seasonal flu, in October. The FDA has to approve this vaccine before it can be used but FDA officials indicated earlier Thursday they would like to speed this process.
People under 25 get sick most often, although most of the 263 deaths recorded in the U.S. so far have been in 25- to 49-year-olds. People older than 65 have far lower risk of getting sick — perhaps because of years of exposure to viruses in the same influenza family.
Government-directed studies — and more that manufacturers will run — are key as the government decides whether to offer swine flu vaccine to millions of Americans starting in mid-October, besides vaccinating against the regular winter flu. Health authorities in other countries are looking to the U.S. studies, too, as they make their own plans.
Assuming studies show the vaccine is OK, a big question is how much will be available and when. Last week, the World Health Organization warned that production is going slower than predicted, with the strains now in use yielding only about half as much of the main vaccine ingredient as is usual.
Wednesday, London-based GlaxoSmithKline echoed that caution, saying it is "working as quickly as possible" but being hindered by those low yields.
"Some of us are skeptical that very much will be available by mid-October," said Dr. William Schaffner, a vaccine specialist at Vanderbilt University.
And the government has warned that any vaccination campaign will put higher-risk people in line for the first batches, as supplies gradually increase over time.
Manufacturers' vaccine studies are expected to largely mirror the NIH's plans: Volunteers will get two vaccinations, 21 days apart. By early September, the NIH should have blood tests showing how much immune protection the initial inoculation triggered, and if a low-dose or higher-dose version was needed. It will take another month to get information on the second inoculation.
Concerns about safety
Complicating the question: If plain vaccine doesn't spur enough protection or there isn't enough supply, manufacturers could add immune-system boosters called adjuvants. That will pose a dilemma as the U.S. has never approved a flu vaccine containing those ingredients, although they are widely used in vaccine given to older adults in Europe.
But there's little information on their safety in children and pregnant women. Dr. Anthony Fauci, the NIH's infectious disease chief, said it's highly unlikely that flu vaccine with an adjuvant would be part of a children's immunization campaign. Part of FDA's debate Thursday, however, is how to do additional testing of that combination in various age groups.
The NIH's first studies will use flu shots made by France-based Sanofi-Pasteur and CSL Ltd., which on Wednesday began a much smaller study of its vaccine in its home country of Australia.
Also yet to be studied are shots made by Glaxo and Swiss-based Novartis, and a nasal-spray flu vaccine from Maryland-based MedImmune.
MedImmune told the government Thursday it will only have about 14 million doses of nasal-spray vaccine bottled and ready to use in October — but that's because it can't keep up with putting the vaccine into the special sprayer. MedImmune says it will have tens of millions more doses sitting in bulk and ready to bottle. The drug maker will begin studies next month to make sure the swine flu version of its nasal spray causes no more side effects that its regular flu vaccine.