The flu continues to make its rounds in San Antonio and it's taking a toll on children.

For the second time, Texas ranked No. 1 for flu activity across the U.S. and San Antonio jumped to the eighth spot from the ninth in the state, according to a map released by Walgreen's.

In just the last few weeks, a spokesperson with The Children's Hospital of San Antonio says that hundreds of sick children have visited the hospital, many with flu-like symptoms.

Pediatrician Mark Gilger with The Children's Hospital of San Antonio says that the number of cases are significantly higher this year.

“Terribly, terribly busy for the past, pretty much, the month of December. So busy as a matter of fact, our intensive care unit has literally been full," Dr. Gilger said.

It's an illness that can take a significant toll on children. Making it worse here, Bexar County has confirmed cases of both type A and type B flu.

Dr. Gilger says that more young children have also been diagnosed with RSV, a harsh respiratory virus.

"It causes a problem called bronchiolitis, and we're seeing a lot of it and we are seeing some very ill children that are needing some intensive care,” Dr. Gilger noted.

Over the last few weeks, the hospital beefed up staff to keep up with the increasing number of patients. With some schools back in session, the hospital is expecting another spike and doctors want everyone to take action.

"This year, for example, the flu vaccine has not been quite as effective as we like [but] it still lessens the symptoms of the disease, so I think always a good idea to get it. It's not too late even now," Dr. Gilger said.

Doctors stress that parents should keep children home from school or daycare if they are sick to keep the virus from spreading.