Health officials are reporting that influenza cases are "widespread" in Texas.
The Center for Disease Control said positive cases jumped five-percent in the last week.
County health groups are seeing similar increases with Tarrant County Public Health reporting a nearly three-percent increase. Denton health department workers said they're treating hundreds of new flu cases, with most being the H1N1 strain of the virus.
The Dallas County Health and Human Services department said they continue to see an increase in the number of people getting sick from the flu. New figures are expected to be released by the department on Friday afternoon.
But DCHHS Director Zach Thompson said now is the time to get a flu shot -- before the supplies run out.
"As we go into January, as we going to February, it's going to be difficult to find flu shots. That's why we're clear, you need to get your flu shots now," Thompson said. The DCHHS said they have less than 2,000 shots left -- and the season hasn't peaked.
Healthcare workers said they aren't sure when the flu season will peak, but they do believe they know why the disease is on the rise.
"With the cold spells we've been experiencing, most people come back sick and go into workplaces and schools and pass it on," Jose Aguillar with the Tarrant County Public Health department said.
Similarily, Thompson worries that with children back in class after the holidays, the highly contagious illness may spread.
"That is a concern," Thompson said. "We're asking everyone to pay attention to your children. If they have flu-like illnesses, contact your primary care physician immediately."
The CDC's FluView tool, which tracks Influenza and influenza-like illnesses, shows four states in the highest level of activity -- Mississippi, Alabama, Iowa, and Texas. Other Texas-neighboring states like Oklahoma and Louisiana are shown as having Moderate to High levels of influenza-like illnesses.
NBC 5's Kendra Lyn contributed to this report.