THURSDAY, Feb. 17 (HealthDay News) -- The flu season got off to a slow start in the United States last fall, but is now circulating in all 50 states and widespread in 37, health officials report.

Pediatric deaths from flu tripled in the past month, jumping from 10 early in January to 30 by Feb. 5, according to the U.S. Centers for Disease Control and Prevention.

"We still have a lot of flu out there," said CDC spokesman Tom Skinner. "We saw activity really start to pick up in December, and it has continued through January into February, which is normal," he said.

Outpatient doctor visits because of flu increased steadily from January to February, according to the report in the Feb. 18 issue of the CDC's Morbidity and Mortality Weekly Report. The report covers the period from Oct. 3, 2010, to Feb. 5, 2011.

While it's too early for exact numbers, the flu, which usually peaks in February, contributed to 8 percent of adult deaths in 122 cities that report this data to the CDC. This is considered an epidemic level.

"This year we are seeing a very typical flu season," noted one expert, Dr. Marc Siegel, an associate professor of medicine at New York University, New York City. "The time is right on target. This is when you see the peak of flu season."

He added that "the number of hospitalizations and deaths are right on course for a typical flu season." Each year about 200,000 Americans are hospitalized and 37,000 will die from flu, Siegel said.

Skinner stressed that it's not too late to get a flu shot. "Flu activity is going to continue into March," he said. "There is plenty of vaccine out there, and we encourage vaccination throughout the season."

Of the three confirmed flu viruses -- influenza A H1N1, influenza A H3N2 and influenza B -- the H3N2 strain has predominated, but all three are circulating, according to the CDC report. The relative proportions have varied by time period and region this flu season.

Unlike last year, when the H1N1 flu swept the globe, there is no pandemic. All flu seasons are unique, Skinner said, but there is "nothing extraordinary going on when it comes to our flu season."

Siegel was somewhat surprised that H1N1 flu is not as predominant as he thought it would be. "It looks like it got enough out into the population, so that a great deal of resistance developed quickly," he said.

Children's deaths have been reported from 18 states, with more than a third of those deaths from influenza B. By contrast, from April 2009 through late January 2010, the CDC said 329 children died of the pandemic flu.

"A lot of people get sick from flu and, unfortunately, people die from flu," Skinner said.

The good news is the current flu vaccine contains the strains of flu that are currently circulating, Skinner said. "The vaccine is a good match," he said.

Vaccination is recommended after 6 months of age. The CDC recommends discussing vaccination with your doctor.

More information

For more information on flu, visit the U.S. Centers for Disease Control and Prevention.