As public health officials around the world try to contain the spread of the swine flu, scientists are working overtime to develop a vaccine against this new strain of the virus.  

According to molecular biologist Andrew Pekosz of The Johns Hopkins University School of Public Health, little is known about the H1N1 swine flu virus that has emerged in several countries.  The speed of the swine flu expansion from country to country has caused alarm that the disease could become an international pandemic.

The virus is a type A influenza virus that causes mild to severe respiratory symptoms that, if bad enough, can result in death.  The virus is spread easily from person to person.

Pekosz says no one has immunity against the virus, which is made up of bits of genetic material from pigs, humans and birds.

"It's a new virus whose biological properties we're still not sure of," said Andrew Pekosz. "And with influenza, it's been documented that different strains have a differential ability to cause disease in animals and in humans.  And right now, we're getting mixed signals about this virus' ability to cause disease."

But the good news is that molecular analysis of the swine virus shows it is the same pathogen all over the world, according to Kathy Neuzil of PATH, an international non-profit organization that promotes vaccine development.

"So we're not seeing a changing virus; we're seeing the same virus being isolated in Mexico and various places in the United States," said Kathy Neuzil.

Neuzil, who heads PATH's Influenza Vaccine Project, says that because the swine flu virus does not appear to be mutating, it should be easier to develop a vaccine.

She says the U.S. Centers for Disease Control and Prevention, or CDC, has started preparing swine flu virus strains that can be sent to drug companies for vaccine production.
Experts say the challenge now will be trying to decide how to distribute a swine flu vaccine.
Since the seasonal flu virus vaccine that is in production for the coming flu season is not effective against H1N1, Andrew Pekosz of The Johns Hopkins University says public health officials will need to decide whether to incorporate it into the existing vaccine or make a stand alone inoculation.

"So if we're going to make an influenza virus vaccine that's based on H1N1 swine that will be used during the next flu season, we have to make a decision as to how much effort is going to be put toward that relatively soon," he said. "Otherwise, we will just simply run out of time to generate enough of the vaccine to really help us."

The World Health Organization and the CDC are  working with drug companies to manufacture a vaccine.