The likelihood of a third wave of pandemic H1N1 influenza appears to be declining as all indicators of swine flu activity remain low throughout the bulk of the country, according to data released Friday by the Centers for Disease Control and Prevention.
"Nobody can say for sure that we are totally out of the woods, but the further we go into spring and summer, the less likely we are to see another wave," said CDC spokesman Tom Skinner. It would not surprise the agency to see some local activity of the virus "continue to percolate along," he added.
Right now, the only U.S. region seeing any significant activity is the Southeast. Although the nation's second wave of swine flu emerged there last fall, experts attributed that to the region's early opening of schools. There is nothing to point at now as a cause of the increased activity, Skinner said.
The traditional flu season ends in four to six weeks, and there is little evidence of an outbreak of other flu viruses.
According to the latest CDC estimates, released a week ago, about 59 million Americans contracted swine flu, 265,000 were hospitalized as a result, and 12,000 died.
With things remaining calm in most of the Northern Hemisphere, attention is now turning to the Southern Hemisphere, where the beginning of fall marks the onset of the traditional flu season. Most authorities believe that swine flu will be the predominant form of seasonal flu this year, and the vaccine against it is being incorporated in seasonal flu vaccines.
Increased flu activity is being noted in West Africa and in South and Southeast Asia, particularly Thailand, according to the World Health Organization. Pandemic flu activity may also be increasing in parts of Central America and the Caribbean, the agency said.
The WHO said it sent 1.1 million doses of swine flu vaccine to Cuba on Wednesday and that shipments are underway to Honduras and El Salvador. Shipments will also be sent to 10 to 15 African countries in the next few weeks. Nigeria alone will receive 2.8 million doses.
Extra doses of vaccine have become available because many countries purchased extra supplies on the assumption that two doses of vaccine would be required.
While the swine flu virus continues to be the primary circulating influenza virus in most of the world, influenza B -- one of the seasonal flu viruses -- is spreading more rapidly in Asia, the WHO said. Influenza B is also beginning to circulate more widely in Russia and Sweden, the WHO said.