The World Health Organization says the H1N1 swine flu virus should be part of next year's seasonal flu vaccine. The WHO says the H1N1 pandemic could affect up to one third of the world's nearly seven billion people. There will only be enough vaccine this year for one sixth.
As swine flu spreads, hospitals are putting plans in place to cope with a crush of patients, many of them children.
Some U.S. hospitals are setting up screening centers in outdoor tents.
Dr. Pat Crocker evaluates sick children at a Texas hospital.
"In some cases, it will be possible for the patient to be seen, registered, see the physician, discharged, right from the tent and never even have to come into the hospital," he said.
The practice also helps protect other patients and hospital staff from exposure to H1N1 swine flu.
"Of the patients who come in with flu symptoms, almost 70 percent are testing positive for influenza A," Dr. Crocker says, "And right now, that means H1N1."
The symptoms for the swine flu are the same for seasonal flu: cough, sore throat and fever.
Tiasha Brown suspects her daughter has the virus. "My child has been having 101 [Fahrenheit] plus fever, runny nose, flu like symptoms because she has come in contact with someone who does have the swine flu," Brown said.
Seasonal flu viruses change slowly so many people develop some resistance.
Dan Rutz, a spokesman for the U.S. Centers for Disease Control, says this is where H1N1 and the seasonal flu viruses differ. "In the case of a pandemic strain, the population has no protection at all because the immune system has never been exposed to that insult before," he explains.
However, health officials have noted that older people might have some immunity
because they were exposed to a similar virus in the 1950s.
Most cases of H1N1 are mild. But the virus can be deadly for some patients.
Those with chronic disease and pregnant women are most vulnerable.
"I'm pregnant, too. And if my child has the swine flu, I would really like to know," Brown said.
A vaccine is the best way to prevent the flu, but there will be only enough H1N1 vaccine to inoculate one sixth of the world's population.
Health officials are counting on the public to keep the pandemic under control.
They have been stressing sanitation.
And keeping fingers away from your nose, eyes or mouth.
Coughing into your elbow and frequent hand washing.
The World Health Organization recommends that next year's seasonal flu vaccine also protect against the swine flu.