State health officials are expecting a typical flu season this year, with a mix of influenza strains including the once-dreaded H1N1.

The first laboratory case of influenza was confirmed by the Maine Center for Disease Control two weeks ago, when an adult from Sagadahoc County tested positive for influenza B.

Stephen Sears, state epidemiologist, said last year was unusual because the season started earlier, in the summer months, with a totally new strain: the H1N1 pandemic strain.

The strains circulating this season include H1N1 — which Sears said is no longer referred to as “swine flu” — as well as influenza B and influenza A, also known as H3N2.

“That one (H3N2) circulated last year, but we didn’t see it because the pandemic strain pretty much took over,” Sears said Wednesday.

“We never know exactly how severe a season will likely be. This year, we’ll have our usual influenza outbreaks with a couple of different strains circulating, including H1N1. That’s going to be with us for years now because it’s in the population, but I think we will have less cases.”

Sears said that 75 million to 80 million people got H1N1 last year, and between 70 and 80 million were vaccinated, which decreased the risk pool.

About 20,000 people die each year from influenza in the United States, he said. It was about the same last flu season — with 18,000 deaths, many of whom were younger people.

“They’re usually older individuals with chronic, underlying illnesses,” he said. “With H1N1 we saw a different pattern: Young people and pregnant women were especially affected.

“That was because the younger individuals had never been exposed to anything like it before, so they had no immunity. Older individuals have some protection against it because a similar strain circulated about 20 years ago.”

He said it’s easy to be vaccinated now, after severe shortages of vaccine last year. He said vaccine is available at multiple places including most doctor offices and clinics. H1N1 appeared last year before the country had enough vaccine, so it became a challenge to deliver vaccine to the public.

“The thing different this year is (the Advisory Committee on Immunization Practices), the advisory group to the federal CDC, is recommending everyone over 6 months, especially people (at) high risk, receive the vaccination,” he said. “We had 2,235 confirmed swine flu cases (last season). Clearly there were more than that.”

He said 88 percent of those infected with H1N1 in Maine were under the age of 50.

Dora Anne Mills, director of the Maine CDC, said it is important to try to limit the spread, since even in a mild year influenza is a major cause of severe illness.

“The best way to prevent influenza is by getting vaccinated,” Mills said. “The U.S. CDC recommends all individuals older than 6 months be immunized All high-risk individuals should be vaccinated as soon as possible.

“Besides getting vaccinated, it is important to also remember the other basics guidelines of preventing illness, including: washing hands; covering coughs with sleeves or tissue; and staying home when sick.”