As swine flu takes its toll in the Southern Hemisphere, six young people are on life support in a Sydney, Australia hospital. Their lungs aren't responding to regular ventilation.

The Medical Journal of Australia has detailed the cases of five people in Melbourne whose conditions point out the small but serious risk of swine flu causing life-threatening respiratory failure.

Meanwhile, at a WHO meeting last week, Dr. Marie-Paule Kieny, director of the Initiative for Vaccine Research recognized that the H1N1 pandemic "is unstoppable and therefore, that all countries need access to vaccine."

Last week, WHO reported nearly 95,000 cases of swine flu worldwide including 429 deaths. Most people who get the virus only experience mild symptoms and don't need medical attention.

Obesity a Factor

Obesity has been observed to be one of the risk factors for more severe reaction to H1N1--something never before seen, Kieny said. It's not clear whether obese people may have undiagnosed health problems that make them vulnerable to this stain of flu, or if obesity is a risk factor in and of itself.

On Friday, a team at the CDC and the University of Michigan reported that nine out of 10 patients treated in an intensive care unit there were obese. They also had unusual symptoms, such as pulmonary embolisms and organ failure. None of the patients has recovered and three have died.

Half as Much "Yield"

Kieny told experts at the WHO meeting that officials would also try to get more robust viral strains to companies making vaccines. She said the strains that had been given to vaccine makers did not grow well in the chicken eggs used to cultivate them.

One exception, she said, is AstraZeneca's MedImmune unit, which manufactures a live virus that is squirted into the nose and is easier to produce.

Because the viral strains are weak, a vaccine might not be available until the end of the year, Kieny said. So far, the swine flu viruses being used are only producing about half as much "yield" as regular flu viruses, she noted.

U.S. Update

The Obama Administration's campaign to start vaccinating as many people as possible--beginning with health care workers--might be risky, she added. Until millions of people start getting the medicine, experts will not know if the vaccine causes potentially dangerous side effects.

To boost the vaccine's potency, several vaccine makers are considering using adjuvants. But little or no data exists on the safety of vaccines with adjuvants. Certain populations, including children and pregnant women, would be most vulnerable to the revved-up shots. In the U.S., there are no flu vaccines that use adjuvants.

Dr. Anthony Fauci, who heads research on infectious diseases at the National Institutes of Health, is more sanguine than his counterparts at WHO.

"I can say with confidence that we will have a vaccine that we will be making a decision on in the fall," he said.

Dr. Fauci said no vaccine will be released to the public unless it is proven safe. Clinical trials could begin in August. Researchers will then decide how much medicine is needed, he said.

People Must Take Responsibility

Officials say there is only so much they can do, even with the best vaccine and antiviral medicines. They say people must take responsibility for their own health by washing their hands, coughing into their sleeves, and throwing away tissues after sneezing into them.

Meanwhile, the U.S. has stockpiled 50 million courses of a broad flu-fighting medication for Federal distribution and another 22 million courses to give to states.

"We want to make sure we're not promoting panic, but we are promoting vigilance and preparation," President Obama said.

Secretary of Health and Human Services Kathleen Sebelius said government agencies at every level are preparing a defense against the H1N1 flu as well as the seasonal flu.

The U.S. government has allocated $350 million to help the country prepare for the H1N1 flu virus as well as the seasonal flu. Disputing WHO's prediction that a vaccine could be delayed until year's end, U.S. officials say a vaccine for the H1N1 flu could be available by October before the flu season starts in the Northern Hemisphere.

Hospitals Taking Measures

When it first arrived on the scene, H1N1 was a big concern, because it was thought to have an airborne method of transmission, said Dr. Katie Passaretti, assistant professor of infectious diseases and hospital epidemiologist at Johns Hopkins, Bayview, in Baltimore. Johns Hopkins immediately began using N95 masks, which were thought to be able to prevent airborne transmission if the virus was in fact able to hang in the air.

"The epidemiology of the disease has since presented itself more and the
worry that there was airborne transmission involved has subsided," Dr. Passaretti told DOTmed News.

Stephen Streed, member of the board of the Association for Professionals
in Infection Control and system director of infection control at Lee Memorial Health System, Ft. Myers, FL, said that preventionists have a better understanding that H1N1 is very similar to the seasonal flu, in that it is spread by droplet contact from the respiratory tract, from hands and close contact. In order to prevent in-hospital transmission, Johns Hopkins and Lee Memorial emergency rooms screen all patients upon entry for signs of the flu, and then immediately mask and triage those patients. The same goes for Children's Healthcare of Atlanta, said J. Renee Watson, infection control manager at the pediatric hospital. Infection preventionists at these hospitals say that they were able to mobilize quickly because they already had robust pandemic plans in place.

"Our policies with regard to N1H1 are constantly evolving as the situation
changes," said Dr. Passaretti. "We've seen a number of cases here now and
admitted a number, and we're still perfecting what we're going to do to deal with it, should it turn into a local pandemic issue in the fall. Supposedly no one in the population has a significant degree of immunity, like we do, to the seasonal flu, and no one has been vaccinated. Basically everyone is susceptible."

Kathy Mahdoubi contributed to this report.