The first doses of a swine flu vaccine will be available in as soon as two weeks, providing health authorities a better chance of controlling the first pandemic in 41 years, U.S. officials said today, according to Bloomberg.

Shots made by four manufacturers were approved today in the U.S., and the first doses may be available at the beginning of October, earlier than previous estimates, said Kathleen Sebelius, U.S. health and human services secretary. Speedier- than-expected delivery of a swine flu vaccine is raising hopes of protecting almost half the world’s population.

The shots may come in time to bring relief to an “unprecedented” fall outbreak, said Nancy Cox, director for the flu division of the U.S. Centers for Disease Control and Prevention. Last week, the first U.S.-sponsored studies found a single shot was effective in 8 to 10 days. Health officials had anticipated it would take two shots and five weeks for immunity. The next challenge is getting the vaccine to people and convincing them to take it, Cox said.

The vaccine success is “the best news we’ve had in a very long time,” Cox said in an interview. The campaign is “going to take a lot of education and a lot of discussion. There is reluctance among some parents to have their children immunized and they perceive this vaccine to be in some way experimental.”

Four Approved

Vaccines made by Melbourne-based CSL Ltd.,Sanofi-Aventis SA, based in Paris, London-based AstraZeneca Plc and Novartis AG based in Basel, Switzerland, were approved today by the U.S. Food and Drug Administration, said Peper Long, a spokeswoman for the agency, in an e-mail. GlaxoSmithKline Plc also contracts with the U.S., though its shot wasn’t mentioned.

“We will have enough vaccine for everyone,” Sebelius today told the U.S. House Energy and Commerce Committee. A small number of doses is expected to be available at the start of October with mid-October being the target release date for most of the supply, Sebelius said.

Glaxo initially concentrated on development of its vaccine with an adjuvant, said Sarah Alspach, a Glaxo spokeswoman, in an e-mail. Adjuvants are ingredients used by some countries in vaccine formulations to boost effectiveness. U.S. health officials said they favored a swine flu shot that didn’t use the extra ingredient and their clinical tests are being conducted on vaccines without adjuvants.

Glaxo earlier this month submitted a request to the FDA for approval of the company’s non-adjuvanted vaccine, Alspach said.

“We are working with the FDA and HHS to support the government’s plans for vaccination in the U.S.,” she said in the e-mail.

Enough for Billions

Manufacturing improvements and a single-dose vaccine may allow drugmakers to make enough vaccine to inoculate 3 billion people, said Marie-Paule Kieny, director of the World Health Organization’s Initiative for Vaccine Research, in an e-mail.

“The really good news is that for everybody in the world, we will have more people protected earlier in both developing and developed countries,” Cox said at the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Francisco.

Influenza outbreaks don’t typically occur in September in the Northern Hemisphere. Yet, cases in the U.S. spiked in the last few weeks to rates greater than last winter’s peak, the CDC reported on its Web site. In Memphis, 12 children with the H1N1 swine flu have been admitted to intensive care units in the past two weeks, said Jonathan McCullers, an infectious diseases doctor at the city’s St. Jude Children’s Research Hospital.

Swine flu outbreaks have rippled across U.S. schools and universities after pupils returned to classes this month. Washington State University in Seattle reported more than 2,500 cases, and a student at Cornell University in New York died after 291 students fell ill.

Unprecedented Outbreak

“Seeing this much influenza activity this early is unprecedented,” Cox said. “One really can’t predict who is going to have a severe infection, who is going to be hospitalized and who might die in advance. The best way to prevent infection by this new virus is to get the vaccine.”

A separate vaccination will be needed to protect against seasonal flu. Once the pandemic shots are available, the two shots can be given at the same time, Cox said. That will make administering the voluntary vaccine easier for doctors and school-based vaccination programs.

Setting up those programs and delivering the vaccines remain significant hurdles, she said.

The first challenge will be to persuade the highest priority people, including children, pregnant women and health- care workers, that getting the shot is safer than risking infection.

Vaccine ‘Myths’

“Myths” about vaccine side effects are circulating on the Internet, Cox said. The U.S. Department of Health and Human Services is distributing an online kit that includes scientific studies and fact sheets.

“I subscribe to an online newsletter that is very anti-flu shot,” said Gail Caswell, a 62-year-old San Francisco resident. “I don’t know if I feel this way or not, but they even feel that some people are going to die from the shot and it’s almost population control.”

The Atlanta-based CDC is creating video and print advertisements for buses and Web sites including YouTube, Facebook and Twitter, to teach people about the safety of the vaccine and the risks of infection.

Safety Data

“Preliminary data indicated that the vaccines are safe,” Sebelius told U.S. lawmakers today. “The vaccines are being manufactured by the same methods used for the production of seasonal flu vaccines administered every year.”

Getting people most likely to benefit to use the vaccine is “challenging, especially when a lot of the messaging in the past has been about how this is a relatively mild disease with an overall impact that’s not a lot different to seasonal flu,” said Frederick Hayden, professor of clinical virology at the University of Virginia School of Medicine in Charlottesville. “I don’t agree with that perspective.”

Health-care workers, who make up 1 percent to 2 percent of the global population, should get the vaccine first, according to the Geneva-based WHO. More than half of health-care workers surveyed in Hong Kong last month said they would refuse the shot after drugmakers expedited tests. A poll shows a third of U.K. nurses would do the same.

“This isn’t the kind of disease that makes you think you’re going to stand in line all night for the vaccine,” said Jody Lanard, a physician and risk-communication consultant in Princeton, New Jersey.

Fort Dix

Lanard was in her first year of medical school in 1976 when 13 soldiers at Fort Dix, New Jersey, fell ill from swine flu and one died, prompting concern a pandemic would erupt. Even though the disease didn’t spread, a vaccine developed to prevent it was given to 45 million Americans in 10 weeks. The shot was later linked to Guillain-Barre syndrome, which can cause paralysis and death, in more than 1,000 people.

Unlike the Fort Dix outbreak, the 2009 swine flu pandemic has spread widely, sickening millions in 177 countries and causing unusually high numbers of severe illness and death in children, said Anne Schuchat, director of the CDC’s Center for Immunization and Respiratory Diseases, in an Aug. 24 interview.

The CDC plans close monitoring for Guillain-Barre, a rare syndrome that occurs even in unvaccinated seasonal flu patients. While scientists haven’t identified what went wrong in 1976, there’s no reason to expect a repeat, Schuchat said.

Trial Results

Last week, the U.S. released results from five government- sponsored trials initiated July 22 that found a single shot of H1N1 vaccine was sufficient to protect most healthy adults, according to Anthony Fauci, director of the National Institute of Allergy and Infectious Disease in Bethesda, Maryland. Results aren’t ready yet for children, pregnant women or the elderly.

The healthy adult results bolstered similar findings from a separate study from CSL, which found that more than 95 percent of 240 patients given a single shot had protective antibodies three weeks later. The vaccinations had similar side effects to regular flu shots, the most common being headache and pain at the injection site.

“The H1N1 vaccines approved today undergo the same rigorous FDA manufacturing oversight, product quality testing and lot release procedures that apply to seasonal influenza vaccines,” said Jesse Goodman, the agency’s acting chief scientist, in a statement.

The success with a single shot, instead of the two shots that scientists previously thought would be needed, may effectively double anticipated stockpiles of the vaccine and make more shots available in developing countries, Cox said.

‘Active Discussions’

The U.S. is in “very active discussions” about donating some of its supply to countries that need it, she said.

CSL said it plans to donate the vaccine to developing nations in Asia and the South Pacific and is discussing a pilot program with the World Health Organization to start by providing as many as 100,000 doses.

About 25 percent to 50 percent of severe cases worldwide involve healthy young and middle-aged people, according to WHO Director-General Margaret Chan. Underlying conditions that can intensify the effects of flu include respiratory illnesses, especially asthma, cardiovascular disease, diabetes, a suppressed immune system, and pregnancy.

As many as 2 billion people, or 30 percent of the world’s population, may become infected by the new virus as it spreads globally, according to the WHO. While fewer than 0.5 percent of sufferers may need hospitalization, those who do may require critical care for up to three weeks, overwhelming intensive-care units.

By Tom Randall and Catherine Larkin, Bloomberg