"We have had requests for diagnostic kits from around the world and we feel it is an important role of the CDC to meet some of that demand," said Dr. Richard Besser.
Swine flu vigilance doesn't stop when the flu season ends because the H1N1 virus is always on the move.
"The flu season is about to start in the southern hemisphere," said Dr. Leslie Weiner.
USC immunology expert Dr. Leslie Weiner says it won't take long for the virus to make its rounds. The biggest fear: it could get stronger.
"Our spring flu is very mild, but if there's a flu in Australia or if there's a flu in South America this virus will mutate. If 100,000 people get this virus it will mutate," said Dr. Weiner.
One plane ride to the U.S. and experts say the newly mutated flu could be back with a vengeance. Scientists cite what happened during the Spanish Flu of 1918.
"The first spring flu was not too bad just like this is not too bad. Then there was the summer. Then all hell broke out when the flu season came," said Dr. Weiner.
That's why researchers are working on a vaccine. Dr. Weiner says it needs to contain components against the swine, bird and human segments of the H1N1 virus.
"These vaccines are never more than 60 to 70 percent effective because of immune response because the virus is constantly changing," said Dr. Weiner.
And that's why it's too difficult to predict what will happen next. When the swine flu vaccine becomes available, Dr. Weiner says he expects it will be offered alone separate of the traditional flu shot.