Smithfield, N.C. — Twelve new cases of the H1N1 virus were confirmed in North Carolina Tuesday, with two new cases in Wake County.

Johnston County health officials said Tuesday that three elementary school children have been diagnosed with the illness, which is also called swine flu.

The students attend Cooper and Wilson's Mills elementary schools, and the other child does not attend school. Health officials are working to determine whether other students or staff at the schools might have been exposed before the infected children showed flu-like symptoms.

To help prevent the transmission of the H1N1 virus:

• Wash your hands frequently with soap and water or alcohol-based hand rub
• Cover your mouth and nose when coughing or sneezing
• Avoid close contact with those who are sick
• Stay at home if you are sick

Influenza-like symptoms include fever, cough, sore throat, body aches, headache, chills and fatigue. Some people have reported diarrhea or vomiting associated with this virus.

Like seasonal flu, the H1N1 virus can vary in severity from mild to severe. This strain of influenza appears to be milder than the seasonal influenza.

Certain people might be more likely to develop a severe illness from novel H1N1 infection such as persons with diabetes, heart disease, asthma or emphysema. Pregnant women are also at risk for complications from the virus. Those who feel sick should check with their health care provider.

North Carolina has 51 confirmed cases of swine flu. Two counties without previous cases were added Tuesday: Alamance and Granville. New Hanover and Rockingham counties reported two new H1N1 cases each Tuesday.

Officials with the federal Centers for Disease Control said that there have been more than 11,000 probable and confirmed swine flu cases in the U.S., including more than 750 hospitalizations and 19 deaths.