The flu is spreading quickly in Nebraska, and many reported cases were caused by strains of the virus not directly covered by this flu season’s vaccine.

Those factors, coupled together, are enough to worry state Epidemiologist Dr. Thomas Safranek of the Nebraska Department of Health and Human Services.

“We’re right in the middle of a pretty serious flu season,” he said.

Flu cases reported by a sample of 80 labs across the state have climbed dramatically and are higher than normal, he said.

In Lincoln, the news is better: Flu rates are typical for this time of year, and most cases are of a type prevented by the vaccine, said Tim Timmons of the Lincoln-Lancaster County Health Department.

Lincoln Public Schools also has experienced only moderate numbers of confirmed flu cases.

“Things can change. We are still seeing an increase in activity,” Timmons said.

However, “What we’re seeing locally is predominantly Influenza Type A, which is well covered by the vaccine,” he said.

Statewide, at least one school closed this week because of illness. Crawford Elementary was closed for three days after 40 percent of its students became ill, Principal Kathy Griesse said. On Friday, the middle and high schools also closed.

The state also has seen significant cases of Influenza B, with strains that differ from the one included in this season’s flu shot formula. The less similar the strain, the less effective the vaccine.

That’s caused Safranek to be more concerned than usual.

The flu is probably still on the rise, he said, and is present in all areas of Nebraska.

“The critical message here is that everyone should be using nonpharmaceutical methods of prevention,” he said.

That includes washing your hands often, using a hand sanitizer and covering your mouth, preferably with a tissue or a sleeve, when coughing and sneezing.

Flu symptoms include fever, sore throat, coughing, achiness, chills and extreme fatigue.

Those who come down with the bug can lessen its severity by taking a prescription antiviral medication, Tamiflu, within 48 hours of the start of symptoms. The series of pills can cost $50 to $100 per treatment, Safranek said. It is not effective for those who’ve had the flu longer than 48 hours.

Those who did get a flu shot may be more protected and may suffer less than those who didn’t, Safranek said.

“Normally I’m a big promoter of the flu shot,” he said, though the public health experts miscalculated which strains to include in this season’s formulation.

Each season’s vaccine needs to be planned months in advance, before the virus starts circulating, to allow enough supply.

This year, “their crystal ball wasn’t very good,” Safranek said.

Reach Kendra Waltke at (402) 473-7303 or kwaltke@journalstar.com.