World Health Organization chief Margaret Chan said on Friday that countries should be ready for more serious H1N1 flu infections and more deaths, according to Reuters.

Chan cautioned the audience at the closing session of her United Nations agency's annual congress that the highly contagious strain of influenza must be closely monitored in parts of Asia, Africa and South America.  "This is a subtle, sneaky virus," she said. "We have clues, many clues, but very few firm conclusions."

In the WHO's latest tally, the strain has infected more than 11,000 people in 42 countries and killed 86. The current flu alert stands at 5, on a scale of 6, meaning a pandemic is imminent. WHO is reconsidering its criteria necessary for declaring a full level 6 pandemic.

Meanwhile, the U.S. government said on Friday it is setting aside $1 billion to help in development of a vaccine against the new strain of H1N1 influenza that is still spreading, according to Reuters.

The money will be used for clinical studies over the summer and for commercial-scale production of vaccine according to U.S. Health and Human Services Secretary Kathleen Sebelius.

"The actions we are taking today will help us be prepared if a vaccine is needed," Sebelius said in a statement. See more H1N1 information.

For more information about the H1N1 outbreak, visit Pork's H1N1 Special Section.

Source: Reuters