Although Swine Flu Cases Are Up, U.S. Officials Are Guardedly Optimistic

May 4 -- MONDAY, May 4 (HealthDay News) -- The number of confirmed swine flu cases in the United States climbed late Sunday to 245 in 35 states, according to federal health officials. But, the revised numbers reflected catching up on a backlog of lab tests, and not a sudden rise in new infections, according to published reports.

The new count reflects streamlining in federal procedures and the results of tests by states, which have only recently begun confirming cases, said Dr. Anne Schuchat, of the U.S. Centers for Disease Control and Prevention, the Associated Press reported.

Also Sunday, federal officials said they were guardedly optimistic that the swine flu isn't as dangerous as first feared. Still, they urged people to keep taking commonsense precautions to protect themselves, such as frequent handwashing and staying home if sick.

"The good news is when we look at this virus right now, we're not seeing some of the things in the virus that have been associated in the past with more severe flu. That's encouraging, but it doesn't mean we're out of the woods yet," said Dr. Richard Besser, acting head of the CDC, the AP reported.

What officials don't know is whether the never-before-seen virus -- a genetic mix of pig, bird and human flu strains -- will return, perhaps in a more dangerous form, when the regular flu season begins again late this year. Flu season in the Southern Hemisphere is about to begin, and U.S. authorities will watch how the swine flu circulates there over the coming months as they prepare the first vaccine and then decide whether to order large-scale production in the fall, the news service said.

The World Health Organization reported Monday that the disease continues to spread around the globe, with 20 countries reporting 985 confirmed cases. Mexico -- believed to be the source of the outbreak -- heads the list of countries with 590 laboratory-confirmed cases of infection, including 25 deaths. The United States is next on the list with 226 confirmed human cases, including one death -- a 23-month-old Mexican boy who had traveled to Houston last month for medical treatment.

Currently, the WHO has labeled the outbreak a Phase 5 outbreak, meaning the disease is spreading throughout communities in at least two countries in one of WHO's six regions -- in this case the United States and Mexico. To reach Phase 6, the geographic spread of the disease would have to occur in at least one other country in another region.

The AP reported that Mexico's health secretary said on Sunday that the swine flu epidemic in his country apparently was waning, although global health officials said it was too soon to make such an assessment.

"The evolution of the epidemic is now in its declining phase," Jose Angel Cordova said during a news conference.

As with the previously tested strains of the swine flu virus, new testing has found that the pathogen remains susceptible to the two common antiviral drugs Tamiflu and Relenza, according to the CDC.

U.S. health officials were also cautiously optimistic on Sunday as they learned more about the outbreak of swine flu, officially designated H1N1 flu.

"There are several encouraging signs," Schuchat, interim deputy director for the CDC's science and public health program, said during a teleconference. "We heard reports that the H1N1 activity might be leveling off in Mexico -- it's too soon to be certain that that's the case."

"Today, I do think we do see some encouraging signs, but we are remaining cautious," Schuchat added. "We have a novel infectious disease -- a new H1N1 virus -- and it's too soon for us to know exactly how this is going to evolve or play out. We can't predict with certainty what the weeks and months ahead will look like. I don't think we are out of the woods yet.

"It's good news that we've only confirmed one death and we have 30 hospitalizations, but it's too soon to say the extent of this disease," she said. "But from what I know about influenza, I do expect more cases, more severe cases, and I do expect more deaths, and I am particularly concerned about what will happen in the fall."

Schuchat noted that the United States needs to be ready for next year's seasonal flu, as well as be prepared for what this new virus might do in the fall. "We are working actively and aggressively to be one step ahead," she said. "We don't know if the virus will come back in the fall harder than it did right now."

There are 30 hospitalizations so far, and some of the cases are severe, Schuchat said. Most of those hospitalized are adolescents and young adults, she noted.

Since schools are the focus of many of the outbreaks, the CDC has issued new recommendations for school closings.

Because children may shed the virus longer than adults, the agency is now recommending that affected schools remain closed for two weeks instead of one, Schuchat said during a teleconference on Saturday.

The U.S. Education Department has said that more than 430 schools had closed, affecting about 245,000 children.

Nancy Cox, chief of the influenza division of the National Center for Immunization and Respiratory Diseases at the CDC, did deliver some welcome news on the nature of the virus itself on Friday. She said that a preliminary analysis of the H1N1 strain found that it lacks certain "virulent characteristics" that made the 1918 flu pandemic strain so deadly.

(As of May 3, 2009, 11:00 AM ET)