The Maine Center for Disease Control on Wednesday reported 531 new cases for the week ending Jan. 20, with 1,749 total cases for this flu season. The previous week, through Jan. 13, there were 391 new cases.

Flu season runs from October through May, and nationally, U.S. Centers for Disease Control has reported widespread flu in every state except Hawaii.

The flu strain is still predominantly influenza A H3N2, which is a more virulent form of the disease and more likely to result in hospitalizations, especially for seniors.

Maine had 429 hospitalizations so far this season, and the mean age of a hospitalized patient was 63.

Confirmed flu cases were most prevalent in York and Penobscot counties, with 394 cases in York and 257 in Penobscot. Cumberland County had a reported 253 cases.

The actual number of flu cases is much higher than confirmed cases, because many people recover at home and are not tested.

There were 5,830 confirmed flu cases in Maine in 2016-17, although the flu strain was less virulent, and there were fewer hospitalizations.

Health experts say people should still get vaccinated if they haven’t yet done so, even though flu shot clinics are typically held in the fall. The flu shot is available at primary care practices, drug stores and some employers.

It’s still not clear how effective the flu vaccine is this year. Every year, scientists attempt to predict the predominant flu strains that will be circulated, and the vaccine is never 100 percent effective.

The vaccine was 48 percent effective in 2016-17 and 59 percent effective in 2015-16, according to the CDC.

For those who get vaccinated, if they do still contract the flu, it will most likely be a milder version than those who do not get immunized, according to the CDC.

This story will be updated