GENEVA - The World Health Organization says manufacturers will be able to produce about 3 billion doses of swine flu vaccine a year.
The estimate is significantly lower than the 5 billion doses WHO previously predicted. The global population is 6.8 billion.
WHO says early data from clinical trials suggests a single dose of vaccine will be sufficient for healthy adults and older children.
The U.N. health agency says Australia, China, Hungary and the United States have already licensed vaccines for the pandemic strain of H1N1.
WHO says Japan and several countries in Europe will shortly follow.
WHO chief Margaret Chan urged countries Thursday to keep up their guard against the pandemic through increased surveillance.
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