Alabama closed 2021 with a surge of COVID-19 cases as the extremely contagious omicron variant of the coronavirus continues to sweep the nation.

Alabama on Thursday hit a new high for the seven-day average positivity rate— the percentage of COVID tests coming back positive — at 31.4%. It is the first time the seven-day average is over 30%.

All 67 counties in the state are now considered to have high levels of community transmission. The seven-day rolling average of daily new cases in Alabama has jumped over the past two weeks from 682 new cases per day on Dec. 14 to 2,742 new cases per day on Dec. 28, according to researchers at Johns Hopkins University.

Dr. Bert Eichold, the health officer for Mobile County, said Thursday that the highly contagious omicron variant is driving a rise in cases and hospitalizations there. He said over 50% of recently sequenced samples from COVID-19 patients came back as the omicron variant.

“What we are really trying to do is avoid people getting sick, so the mask is extremely important. You need to get vaccinated. You need to get your booster shot,” Eichold said in a briefing.

While early indications show that the omicron variant does not cause as severe illness as earlier variants, officials cautioned that the highly contagious variant will mean more people getting sick and some of those will get severely ill.

“Even though it is less severe we will likely see many hospitalizations and deaths,” Dr. Rendi Murphree, an epidemiologist with the Mobile County Public Health Department, said Thursday.

The number of people with COVID-19 in state hospitals doubled over the last two weeks, growing to 791 on Thursday. While hospitalization numbers are still well below what they were during the previous two surges — when more than 3,000 COVID-19 patients were in state hospitals — health officials have expressed concern over the rapid increase.

Officials with the University of Alabama at Birmingham Hospital said emergency rooms are seeing a surge in COVID-19 patients although some people are coming in with only mild symptoms.

“All of these emergency departments — not just ours but everyone around the city — is experiencing record numbers of patients presenting with COVID and all of the other complaints we see on a day-to-day basis,” Dr. Bobby Lewis, vice chair for clinical operations at UAB’s Department of Emergency Medicine, said in a briefing this week.

Lewis urged patients with mild symptoms, as well as people simply needing a COVID test, to go to their local doctor or clinic instead of the emergency room.

Auburn University announced this week that masks will be required on campus beginning Jan. 3 regardless of vaccination status.