Flu season normally peaks around February — but at USC, it hasn’t this year.

The Thomson Student Health Center has only reported one positive flu case on campus so far this flu season, and that was just in the last week, according to Nicole Carrico, a Student Health Services administrator.

The health center usually sees positive flu cases as soon as students return to campus after fall break, Carrico said.

“This year has been quite unusual, not only for our campus, but also the larger community in terms of flu spread, and we’re not exactly sure why,” Carrico said.

Richland and Lexington counties have seen a similarly inactive flu season so far, Carrico said. Data from the Centers for Disease Control show that the number of flu cases has been below average across the country.

There have been only 12 positively confirmed flu test results reported in South Carolina in the past four months, including six in the last week, according to weekly flu surveillance reports from the South Carolina Department of Health and Environmental Control.

The CDC monitors flu activity in the U.S. year-round and releases weekly reports of flu data during the official flu season. The most recently released CDC data from the week of Jan. 15 to 21 reported that “influenza activity in the United States remained relatively low.” There were 175 positive cases of the flu aroundthe nation for the week.

“We’re not in the clear yet with flu this year on campus,” Carrico said.

She added that two years ago the outbreak of the H1N1 virus caused two peaks in one flu season.

“[A peak] could hit us later this spring or even this summer, which is why we’re encouraging everyone to come in the health center and get the flu vaccine,” Carrico said.

The best way to prevent the flu is to be vaccinated, Carrico said. she added that almost 2,000 students, faculty and staff have received flu vaccines from the health center so far this academic year, and the health center has access to an unlimited supply of the vaccine.

Carrico described a concept called “herd immunity,” which states that if a certain percentage of a population is vaccinated against a particular contagion, then members who are not immune are less likely to become infected because the vaccinated members act like firewalls to the disease.

“So it really is true that if one person is vaccinated against the flu, it can end up protecting many, many more people,” she said.

Common flu symptoms may include high fever, headache, muscle aches, sore throat, cough and dizziness or fatigue. The virus usually lasts one to two weeks, and patients are able to spread the virus one day before symptoms develop and five to seven days after symptoms appear, according to the CDC.

Carrico said the flu is more contagious when people live in close proximity to other people, sit in classrooms shared by thousands of students and share facilities with a campus community of around 30,000 people.

“It’s tough to avoid touching a contaminated surface,” Carrico said.

Students experiencing flu-like symptoms are encouraged to make an appointment with Student Health Services. Health Services also recommends that students with symptoms isolate themselves, except to receive medical attention, until at least 24 hours after fever subsides.