The flu is rampant in most of the country, and health officials say the season could peak soon.

Flu was widespread in 43 states and flu activity was intense in most of them during the week of Christmas, according to the latest figures issued Monday by the Centers for Disease Control and Prevention.

Those trends are expected to continue, said the CDC’s Dr. Michael Jhung.

It’s been an early and forceful start to the flu season, and it’s possible the worst could be over soon. But then again, maybe not — flu has yet to rev up to high levels in large states like New York and California, Jhung said.

More on the flu situation:

HOW BAD IS THIS FLU SEASON?

It’s not clear yet. Experts worry this winter will be unusually bad because the nasty bug that’s making most people sick isn’t included in this year’s vaccine. Preliminary data on how well the vaccine is working is still weeks away. Among infectious diseases, flu is considered one of the nation’s leading causes of death, killing roughly 24,000 a year, on average.

HOW UNUSUAL IS FLU THIS YEAR?

The different flu strain makes predictions more difficult. The current season hit hard in December — earlier than usual. But the last two flu seasons hit early, too. So far, flu hospitalization rates are similar to the harsh season two years ago, which was dominated by a similar flu virus. Especially this year, health officials this year are urging doctors to treat flu patients promptly with antiviral medications.

HAS FLU BECOME EPIDEMIC?

Yes, but that’s not unusual. “It’s safe to say we have a flu epidemic every year,“Jhung said Monday. Epidemics occur when a virus spreads quickly and affects many people at the same time. According to one CDC definition, flu is epidemic when a certain percentage of deaths in a given week are due to flu and pneumonia. By that measure, flu epidemics occurred in nine of the last dozen winters, including this one. Flu-related deaths surpassed the epidemic threshold three weeks ago, then dropped below that level the next week. But other measures indicate flu still is epidemic.

IS IT TOO LATE TO GET A FLU SHOT?

CDC officials say no. The flu season appears to be on track to peak this month, but even if it does, the flu will still be around for months. Despite the new flu strain, the vaccine has been well matched in roughly a third of the flu cases seen so far. And it is considered to be effective against some other flu viruses that could surge in the late winter or spring. About 40 percent of the public was vaccinated against flu as of November, which is about normal in recent years, Jhung said.

(AP)