Canadian health officials expect the first doses of swine flu vaccine will be ready in mid-November. (Greg Baker/Associated Press)

American health officials should help drug companies speed up production of a swine flu vaccine so that some shots are available by mid-September, presidential science advisers urged Monday.

The report by the President's Council of Advisors on Science and Technology calls the H1N1 pandemic strain "poses a serious health threat" to the U.S. — not as serious as the 1918 Spanish flu pandemic but worse than the swine flu outbreak of 1976.

It's not that the new H1N1 pandemic strain is more deadly than previous flu threats, but that it is likely to infect more people than usual because so few people have immunity, the White House advisers said. That could mean that doctors' offices and hospitals could get filled to capacity.

The panel wants the U.S. Department of Health and Human Services to tell drug manufacturers to start putting the H1N1 flu vaccines into vials for shipment right away, accelerating production of the vaccine for people at high risk.

"Such a decision would need to be taken almost immediately," the group said, so it's ready to go by mid-September.

Drawing up vaccine priority lists

Even if vaccine production is not sped up in the U.S., it should be ready by mid-October. Last week, Canada's chief public health officer, Dr. David Butler-Jones, said the goal is to have the vaccine ready for Canadians by mid-November.

The first doses of swine flu vaccine in Canada would also be reserved for segments of the population considered at greatest risk, a list Canadian health officials expect will be ready in September. Since it's likely that two doses of the vaccine will be needed, it could be well into the new year before Canadians who want to be vaccinated are fully inoculated.

Finding enough health-care workers to get the vaccine into Canadians' arms while leaving enough to deliver essential health services is another challenge. Butler-Jones said 3.5 million doses a week is about as fast as the vaccine could be given to people.

National leaders are looking to the World Health Organization and other international health authorities for guidance on how best to distribute swine flu vaccines. Countries will have to decide on their priority groups based on whether the goal is to stop transmission, protect essential infrastructure or reduce deaths and illness, according to the UN health agency.

Social networking spreads the word

"We need to gather advice on priority groups for initial protection," WHO head Margaret Chan said Friday. "This is one of the most difficult decisions governments around the world will need to make, especially as we know that supplies will be extremely limited for some months to come."

The United Kingdom expects to get its first supplies of swine flu vaccine in late August or early September and available to give to people at the beginning of October after licensing, Britain's Chief Medical Officer Sir Liam Donaldson said Monday.

U.S. authorities were also advised to step up their communications about swine flu. Instead of relying on traditional media ads in newspapers or on TV for example, they suggested sending the message out online on social networking tools like Twitter and Facebook as well, to help reach young people who seem to be more susceptible to severe cases of swine flu compared with seniors.

The U.S. panel also urged the U.S. Food and Drug Administration to quickly decide on new intravenous forms of flu drugs for people who are seriously ill and can only be given the drugs intravenously.

Other recommendations included:

• Clarify guidelines on using antiviral medicines.
• Upgrade the current system for tracking the pandemic.
• Identify a White House point person to co-ordinate key decisions across the government as the pandemic evolves.

With files from The Associated Press