April 28 (Bloomberg) -- Swine flu will kill people in the U.S., and businesses and citizens should plan in case the outbreak worsens, the acting head of the Centers for Disease Control and Prevention said.

It’s too soon to say whether the virus will spark a pandemic, a global outbreak that spreads easily and causes serious illness, Richard Besser, the Atlanta-based agency’s acting head, said in an interview today. Businesses should review plans and be ready to act, he said.

The CDC today raised the number of confirmed cases in the U.S. to 64, with 45 of them in New York. No deaths have been confirmed in the U.S. That will change, Besser said.

“Given the situation in Mexico, where they’re seeing much more severe disease, I would expect that as we continue to look we’re going to find hospitalized individuals and, unfortunately, I expect that we will see deaths in this country,” Besser said.

Laboratory tests have confirmed 79 cases of the flu worldwide, prompting the World Health Organization yesterday to raise its global alert to the highest level ever. The U.S. has sent investigators to Mexico, where as many as 152 people may have died from the illness, Besser said.

Pre-Pandemic Phase

“We’re in a pre-pandemic phase and it’s going to be hard to know until we’re much further along what we think this is going to progress to,” Besser said.

Ernst & Young LLP, one of the so-called Big Four accounting firms, retracted a statement from earlier today that an employee at its Times Square building in New York had been diagnosed with swine flu. The company acted “out of an abundance of caution,” but couldn’t confirm the infection “based on new information,” Charlie Perkins, an Ernst & Young spokesman, said in an e-mail.

Americans should be thinking about “what they might do if their school is not open tomorrow or if their business is not open tomorrow,” Besser said.

The CDC says people can reduce their risk by washing hands often with soap and water or alcohol-based cleaners. Those who are sick should sneeze or cough into a tissue or an arm or elbow, and stay home from work or school, Besser said. The CDC recommends avoiding close contact with people sick with the flu.

Roche, Glaxo Drugs

Tests show the new strain can be treated with Tamiflu, the anti-viral medication sold by Swiss drugmaker Roche Holding AG, and Relenza, from London-based GlaxoSmithKline Plc., Besser said. The U.S. has distributed millions of doses of the drugs to state authorities who “have what they need” to care for the sick if the disease spreads, he said.

U.S. officials yesterday recommended people avoid nonessential trips to Mexico. The European Union told travelers to avoid outbreak areas. Japan said today it will suspend visa- free entry for Mexican nationals. Asian countries including Singapore and South Korea are screening air passengers. The Geneva-based World Health Organization isn’t recommending travel restrictions.

The number of confirmed cases in Mexico is 26, WHO spokesman Gregory Hartl said on a conference call yesterday. Scientists are trying to determine why swine flu, a respiratory disease caused by a type-A influenza virus, has been more severe in Mexico. In the U.S., one person has been hospitalized, Besser said yesterday.

Pandemics occur when a new influenza A virus, to which almost no one has natural immunity, emerges and spreads internationally. The World Bank, in a worst-case scenario published in October, said a flu pandemic that’s similar in scope to the 1918 outbreak known as the Spanish flu could kill 71 million people worldwide and push the economy into a “major global recession” costing more than $3 trillion.

To contact the reporters on this story: Alex Nussbaum in New York anussbaum1@bloomberg.net.

Last Updated: April 28, 2009 12:22 EDT