DENVER -- The flu virus that has killed four children in the state is spreading rapidly. There are 4,687 confirmed cases of the flu reported to the state, the Colorado Department of Public Health and Environment said Monday.

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That number is 730 more cases than the 3,957 confirmed flu cases reported by the department on the Wednesday before Thanksgiving.

Many hope that the long holiday weekend out of the classroom kept some of the flu from spreading. Some schools in the state report a 30 percent absenteeism rate because of the flu. Flu shots are being administered in record numbers around the state. Even during the rush of the holiday shopping, more than 200 people lined up for a flu shot at a K-mart on Federal. Unfortunately, the vaccine does not target the exact strain of this year's virus but doctors say it's still a person's best defense against the flu.

The latest number is almost double the number of cases the state had all of last year. Colorado had 2,681 confirmed flu cases last flu season; 3,558 cases the year before that and 1,518 cases during the 2000-2001 flu season. There were only 1,210 reported flu cases during the 1999-2000 flu season.

The department first reported 694 confirmed flu cases on Monday, Nov. 17; 1,525 confirmed flu cases on Wednesday, Nov. 19; and 2,648 on Monday, Nov. 24.

Doctors fear the recent outbreak in the state is the worst in 20 years. State health officials say parents should bring their child to the doctor if a high fever persists or the child is listless and can't keep fluids down.