Seasonal flu activity is on the rise at the local and state levels. It's also increasing in other parts of the country.

There were 18 positive rapid antigen tests for the illness reported in Aiken County for the week of Dec. 15-21, according to the South Carolina Department of Health and Environmental Control.

The previous week, there were no reports of positive tests.

Statewide, 2,422 positive rapid antigen tests were reported during the week of Dec. 15-21, compared to 2,206 the prior week. There were 1,976 reported Dec. 1-7. The total for Nov. 24-30 was 1,077.

Since Sept. 29, 9,843 positive tests have been reported.

At least six people in South Carolina have died of the flu so far this season. The deaths occurred in Berkeley, Charleston, Dorchester and Richland counties.

“Influenza is here, and the number of cases do appear to be growing for us,” said Jim Beasley, the Department of Health and Environmental Control's public information director. “Therefore, best thing you can possibly do to protect yourself is to get vaccinated. The sooner you do it, the better, because it takes a couple of weeks for your body to build up the full complement of antibodies against the virus.”

The vaccine is still available at a number of locations, according to Beasley.

“I know we have it at all of our DHEC health departments,” he said. “There are certainly other locations that carry the vaccine as well, such as pharmacies and the mini clinics at some grocery stores.”

However, at Aiken's Ingate Professional Pharmacy on Laurens Street, the remaining supply is limited.

“We've still got some left, but not a lot,” said Breck Klein, a pharmacist who is Ingate's founder and co-owner. “The demand has been steady. I think people are becoming more conscious about being vaccinated for the flu. It's being promoted much more throughout all types of media.”

The Centers for Disease Control and Prevention announced on Friday that the number of states reporting widespread seasonal flu activity grew from four to 10 during the week ending Dec. 21.

The states with widespread activity were Alabama, Alaska, Kansas, Louisiana, Massachusetts, New York, Pennsylvania, Texas, Virginia and Wyoming.

The previous week, only Alabama, Louisiana, New York and Texas reported widespread flu.

“Widespread” means that more than 50 percent of the geographic regions in a state are reporting flu activity.

The most common strain of flu so far this year has been H1N1, which also is known as swine flu, according to the Centers for Disease Control and Prevention.

H1N1 is known for causing somewhat more severe complications in younger, otherwise healthy people than other strains. In the elderly, H1N1 is somewhat less serious.

In general, the Centers for Disease Control and Prevention recommends that everyone over the age of six months get vaccinated against the flu annually.

It is especially important for some people to get vaccinated, including pregnant women, children younger than 5 years of age, adults who are 65 and older and anyone who has chronic lung disease or another persistent medical problem, such as asthma or diabetes.

Dede Biles is a general assignment reporter for the Aiken Standard and has been with the newspaper since January 2013. A native of Concord, N.C., she graduated from the University of North Carolina at Chapel Hill.