The flu is affecting many parts of the United States. Widespread activity has been reported in Arizona, California, Connecticut, Iowa, Kentucky, Maryland, Massachusetts, New Mexico, New York, Pennsylvania, Texas, Vermont, and Puerto Rico.

This flu season, 13 children have died from the illness. The Centers for Disease Control and Prevention does not track the number of adults who die from the flu.

The most common flu strain this season is H1N1, which caused a pandemic in 2009. Vaccines have included H1N1 since 2010.

Most people with the flu do not need to go to the emergency room because they would probably just be sent home. It is common to have a fever as high as 103 degrees Fahrenheit caused by the flu. If you have the flu, you should get plenty of rest and take painkillers for muscle aches. In five to seven days, you should feel healthy again.

In some cases, seeking emergency medical treatment is warranted. If you are short of breath, you should go to the hospital. If you cannot keep fluids down because of nausea or are sweating excessively, you should seek medical attention to avoid becoming dehydrated. This season, 3.1 percent of people with the flu have seen a healthcare provider for treatment.

If you get the flu, you can take antiviral medication such as Tamiflu or Relenza to reduce the length of your illness and the severity of your symptoms. These medications are most effective when taken within the first 48 hours of the illness. Antiviral treatment is mostly recommended for people at high risk for complications, such as young children, the elderly, and people with weakened immune systems.

Antiviral medications will not prevent the flu in healthy people. A flu shot can do that in many cases. It is not too late to get a flu shot if you have not gotten one already.

When a child gets the flu, it is usually enough to treat the symptoms and keep him or her as comfortable as possible. However, if your child has fast or labored breathing or has numb or blue fingers or toes, seek medical treatment. If your child cannot touch his or her chin to chest, that could be a sign of meningitis, a complication of the flu. If your child’s symptoms improve then return, it could be a sign of a secondary infection. You should also seek medical treatment if your child’s behavior is unusual.