Federal officials said Monday small business owners should be prepared to operate with fewer employees this fall as swine flu spreads across the country.

The Department of Homeland Security is issuing guidelines on combating swine flu to small businesses, which employ about half the workers in the U.S. private sector.

"They play a key role in protecting the health and safety of the country but also their own employees and also helping us limit impact of an H1N1 pandemic on our economy and our country," Homeland Security chief Janet Napolitano told reporters.

A guidebook released by the Department of Homeland Security recommends small businesses identify their essential operations and have plans for operating with reduced staffing. The government also says businesses should consider letting employees work from home if they get sick.

Napolitano said small businesses could be particularly vulnerable to a pandemic because they often "have fewer resources, they work with leaner staffs and absenteeism can be a particular issue."

Monday's announcement is the latest in a series of recommendations as the federal government braces for a potentially virulent outbreak this fall, which could hurt businesses by keeping workers at home.

The swine flu virus has caused at least 3,205 deaths since it emerged in Mexico and the U.S. this year and became a global epidemic, according to the World Health Organization. Most deaths have been in the Western Hemisphere.

About 45 million doses of swine flu vaccine from GlaxoSmithKline, Novartis and several other companies are expected to be available by mid-October. First in line to receive the vaccine are pregnant women, health care workers and younger adults with conditions such as asthma.