ST. LOUIS - Both Missouri and Illinois have made the weekly list tracking this year's flu outbreak.

The Centers for Disease Controls' weekly FluView report, tracks seasonal influenza activity in the United States and both states are listed as seeing moderate increases in local flu activity.

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Overall, the number of states reporting widespread flu activity jumped from 12 to 23, the proportion of samples testing positive for influenza at clinical laboratories went from 8.4% to 14.0%, and the percentage of people seeking outpatient care for influenza-like illness increased from 2.7% to 3.5% over last week's report.

Video: Missouri and Illinois seeing increases in flu activity

While flu vaccination is still recommended for people who have not yet gotten vaccinated, antiviral drugs are an important second line of defense that can be used to treat flu illness.

CDC recommends the use of antiviral drugs as early as possible to treat flu illness in people who are very sick with flu and those at high risk of serious flu complications.

Cases of flu tend to ramp up mid- to late-December and peak in January or February, according to Paul Sax, an infectious disease physician at Brigham and Women's Hospital in Boston.

According to the Illinois Department of Health, Edwardsville is being hit hard, ranking it third on its list of most flu reports in that state.

Video: How you can fight back against flu?

People who have the flu often feel some or all of these symptoms:

  • Fever* or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may have vomiting and diarrhea, though this is more common in children than adults.

Other states reporting 'widespread' flu status include:

  • Alabama
  • Arizona
  • Arkansas
  • Connecticut
  • Idaho
  • Illinois
  • Indiana
  • Kentucky
  • Louisiana
  • Maryland
  • Massachusetts
  • Mississippi
  • Missouri
  • New York
  • North Dakota
  • Ohio
  • Oklahoma
  • Oregon
  • South Carolina
  • Texas
  • Virginia
  • Wisconsin