The worst case scenario? H1N1 (inaccurately and formerly known as swine flu) could sicken up to 40 percent of Americans over the next two years if a vaccine campaign and other measures aren't successful. But that scenario might be avoided if everyone takes responsibility. Here, the experts at Mount Sinai Queens encourage you to:

• Get vaccinated. Many of us will need anywhere from one to three shots this year. In September, the yearly seasonal flu vaccine will become available. Almost anyone can take it, but it should especially be taken by children six months to 19 years old, pregnant women, people 50 years and older, anyone with chronic medical conditions, anyone in a long-term care facility, anyone who lives with or cares for those at risk for complications from flu, healthcare workers and anyone who cares for a child less than six months of age.

Then, probably in mid- October, the first of TWO shots will become available for the H1N1 flu. Three to four weeks later, a second shot will probably be needed.

Those who should get the H1N1 vaccines include pregnant women, anyone who cares for a child less than six months of age, healthcare workers, everyone from six months to 24 years old, and people from 25 through 65 years old who have chronic medical conditions.

It's not yet clear where the H1N1 shots will be administered. Call Mount Sinai Hospital of Queens at 718-267-4333 or New York City's 311 centers (dial 311) for updated information on nearby vaccination centers.

• Wash your hands frequently, especially after sneezing, coughing or blowing your nose. It's one of those most effective defenses! Use warm water and soap, rub hands vigorously for 20 seconds and rinse thoroughly. Use alcoholbased hand cleaners when you can't get to water and soap.

• Cover your coughs and sneezes. Carry tissues and make tissue boxes accessible at home and at work.

• Ask about sick-time policy. It will not be practical to test every person with symptoms, so those who appear to have the flu may be treated for the flu and, at the very least, should be encouraged to stay home. Parents will be asked to keep sick children home, too.

Ask your boss to brainstorm with staff solutions for increased absenteeism, such as employees working from home or via the Internet, the use of temporary workers, staggered shifts or crosstraining everyone to perform essential functions.

• Stay informed. Read local newspapers, where Mount Sinai Hospital of Queens will regularly inform the community of any changing developments. You can also get updates through www.flu.gov.