Cases of the flu are surging in Maine, with outpatient and emergency room visits as well as hospitalizations all spiking as the new year kicks in.

The U.S. Centers for Disease Control and Prevention now lists Maine as one of 30 states with “very high” flu activity in new data released Monday.

The state had low activity back in mid-December.

The rapid rise in Maine and across the country is largely being driven by a new variant of the flu virus known as “subclade K,” or Super K.

According to Scientific American, experts think the current flu vaccine may be less effective at preventing infection from the subclade K variant because the virus has mutated since the vaccine strains were selected.

Speaking with the WGAN Morning News on Thursday, Dr. Dora Mills, Chief Health Improvement Officer for MaineHealth, said there were well over 100 people hospitalized with flu in the state as of Thursday.

The spike is far ahead of last year’s peak of influenza in the state in February.

The Hill reports that experts fear low vaccination rates in the U.S. could lead to a historically bad flu season, although there’s hope that more people will choose to get vaccinated.

In addition to getting vaccinated, Dr. Mills offered basic steps you can take to keep yourself and others healthy.

She recommends staying home if you’re sick, washing you hands vigilantly, opening windows when possible, and wearing a mask if you’re around others who are sick or are at high risk of severe illness.