Raleigh, N.C. — The number of flu cases statewide has continued to rise, in part, because the flu vaccine distributed this year cannot handle some new strains of the virus, public health officials said Thursday.

For the week ending Feb. 15, health-care providers reported 5.66 percent of patients seen had influenza-like illness. The figure is higher than the peaks for the four previous flu seasons.

The record flu season was recorded in mid-December 2003, when 7.7 percent of the patients reported influenza-like illness.

Seventy-six health-care providers report the number of people they see with influenza-like symptoms – a temperature of 100 degrees or greater and cough or sore throat – to help officials determine how the flu is progressing across North Carolina.

Sal Frances Hargrave said she was "shocked" when doctors at WakeMed diagnosed her husband, 84-year-old Edwin, with flu. The couple had gotten the vaccine months earlier.

"I thought pneumonia was enough. I didn't know that the flu had gotten him," Hargrave said.

Two of the three strains in the flu vaccine distributed this year are ineffective against the virus circulating through the state, health officials said. Nationwide, the vaccine protects against 40 percent of the virus strains out this year, according to the Centers for Disease Control and Prevention.

The formula for each year's flu vaccine is set eight months before the doses are shipped, so that manufacturers will have time to produce large  quantities of the vaccine.

"Sometimes, they match up pretty well to what comes, and sometimes they miss the mark," Dr. Gay Benevides, with WakeMed Cary Emergency Medicine, said. This year's vaccine does provide some partial protection, she added.

Federal officials said the vaccine will be overhauled and the two ineffective strains replaced for the next round of the vaccine, set to be distributed in the fall.

Until then, doctors urge people to take precautions to prevent the spread of the flu: Wash your hands, cover your coughs and sneezes, and wipe off community surfaces in the home and workplace.

The elderly, young and those with underlying medical conditions who contract the flu should seek emergency medical care.

People in normal health should seek their primary care physician or simply stay home from work. Rest, drink plenty of fluids, and take fever-reducing medications.

Sal Frances Hargrave said she hopes people follow those precautions to help stop the spread of flu. She wears a face mask around her husband to avoid getting the virus.

"You don't like to see your partner sick," Sal Frances Hargrave said.