The news out of Mexico appears brighter. Mexican officials are saying the number of new swine flu cases seem to be leveling off.
Still, Mexico braced for a shutdown of all non-essential services, including all schools, through Tuesday as authorities sought to limit further infections in that country.
On Monday, a 23-month-old Mexican boy who had traveled to Houston for medical treatment died, becoming the first -- and so far, only -- fatality in the United States.
Speaking at a press conference on Thursday, CDC Acting Director Dr. Richard Besser said that while most cases appear to be mild, "six of the cases have been hospitalized, including the unfortunate case we reported yesterday of the child in Texas who passed away."
And scientists were racing to produce a vaccine against the new flu strain, but the shots -- if needed at all -- wouldn't be available until fall at the earliest, U.S. health officials said Thursday.
"We think 600 million doses is achievable in a six-month timeframe" from that fall start, Health and Human Services Assistant Secretary Craig Vanderwagen told lawmakers.
On Friday, U.S. health officials told reporters that six countries -- the United States, Canada, the Netherlands, Mexico, Germany and New Zealand -- have all shared samples of the virus for testing to further the vaccine effort.
"The good news is that the genes of all of the viruses we have examined to date are 99 to 100 percent identical," Cox said. "This means that it will be somewhat easier for us to produce an influenza vaccine."
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