The flu season is now considered an epidemic, and it continues to spread throughout the U.S., according to federal health officials.

The seasonal viral spread is the worst it’s been since the 2009 swine flu outbreak, the Center for Disease Control and Prevention said in updates today.

“We may be on track to break some recent records,” said Anne Schuchat, acting CDC director.

Ten additional children died in the latest weekly update, bringing the total death toll to 63.

The dominant strain for the season is the Influenza A H3N2 strain, which jumpstarted the season in the final weeks of 2017 – and continues to drive most of the cases seen by doctors.

About 60 hospitalizations for flu-like illnesses per 100,000 people were reported in the latest numbers, according to the CDC. Hospitalization rates due to influenza-suspected symptoms continue to climb to roughly 8 percent, about six weeks into the new year. By comparison, the 2009 H1N1 swine flu outbreak peaked around Jan. 1, just short of 6 percent.

More weeks of viral spread could be coming. While the flu season, now in its 11th week, generally ends about now, it can last into a 20th week, according to health officials.

The H3N2 strain was first isolated and identified as the germ culprit behind the Hong Kong flu epidemic of 1968, which left 1 million dead.

This year’s trivalent vaccine mixture in North America was aimed at covering H3N2. But as was the case in Australia, the targeted vaccine could not stop the strain. (Two other strains are also currently in circulation at lower levels: some Influenza B varieties, and Influenza A H1N1 strains).

However, the H3N2 family has proven to be a particularly difficult and diverse target. For instance, scientists reported attempts to make a “universal” vaccine covering all the different varieties within that family – but their new coverage was only recently unveiled in experimental mice and ferret models.

Influenza kills an average of 36,000 people in the United States each year. Researchers continue to look for ways to attack the viruses – even through proteins long-lost in the process of evolution.