Flu season comes on strong
Davis Hubb tries to resist the flu shot while his mother Jeanie and friend Tanner Johnson hold him in Whitefish, Montana.
Children are crowding emergency rooms with complications from flu.
This year's flu strain a tough one.
(CNN) -- Widespread outbreaks have been reported in at least 13 states -- mostly in the West -- but federal health officials say this year's flu season has not yet peaked -- and vaccine supplies are running low.
"It hasn't reached what we call the epidemic threshold status yet, in terms of deaths from influenza-like illness," said Dr. Julie Gerberding, director of the Centers for Disease Control and Prevention in Atlanta, Georgia. "But we won't be surprised if that happens given the pattern emerging right now."
The season began early, with about 5 percent of patients visiting the doctor or clinic for flu-like illnesses at the end of November, the CDC reported -- that's twice the percentage of patients expected at this time of year. Only the District of Columbia and Massachusetts have not reported cases.
The especially virulent strain of the virus that is predominant this season was not included in this year's flu vaccine. Health officials are investigating whether this strain might be particularly harmful to kids.
"[That is] something that we're evaluating very carefully to determine whether or not there's anything about this particular flu strain that's preferentially affecting children or causing more severe disease in children," Gerberding said Tuesday. "We don't know the answer to the question yet. It is common for children to develop severe influenza and for deaths to occur in every flu season, unfortunately, so it will take us some time to figure that out."
That the flu can be fatal never occurred to Vera Cover and her husband, of Colorado. Then, their 23-month-old daughter Elizabeth caught the illness and died.
"We were concerned the flu was going around, but we never imagined it would lead to anything like this," she said to CNN affiliate KCNC in Denver, Colorado. Health authorities in Colorado report that nine children have died of flu-like illnesses already as of Wednesday in their state.
Other states also have reported children's deaths from flu-like illnesses. In the past, the CDC hasn't kept track of children's deaths from the flu.
Schools, hospitals close
Schools across the nation report high absentee rates -- and some have temporarily suspended classes because so many students were out with the flu.
Mio AuSable schools in Michigan closed doors on Tuesday after more than 25 percent of its 802 students and some staff were absent Monday afternoon, said superintendent Patrick Bootz. Schools reopened Wednesday.
Trousdale County schools near Nashville, Tennesee, were forced to close. The district of 1,300 students had so many children and some staff out with the flu that it cancelled classes Tuesday and planned on staying closed until Monday, school official David Freeman said.
A hospital in Liberty, Missouri, temporarily shut its emergency room doors to ambulance traffic because of the crowd of new patients. Dr. Steve Price, an emergency room doctor, said the doors were shut Monday night to Tuesday afternoon because of the upswing of flu patients.
Searching for flu shots
Because of the increased public concern, demand for flu vaccines is surging upward after makers of the vaccine have finished shipping for the season to health care providers.
The CDC is working to redistribute what remains in American stock and are asking European drug companies to send over any doses they can spare.
But will the vaccine be effective?
The vaccine now in use was designed to protect against three different strains, but the predominant strain detected this season -- Type A-Fujian -- was not expected. This makes the vaccine's effectiveness uncertain.
"Twice a year, flu experts meet and try to decide what's going to be the strain that circulates that year because we have to make the vaccine four to six months in advance in order to give it to everyone," explained Dr. Jon McCullers, infectious disease expert at St. Jude Children's Research Hospital.
"The Panama strain is in the vaccine this year because it was thought to be the predominant strain to come around. As it turns out, it only counts for a third of the flu that's out there and two-thirds is the Fujian strain," McCullers said.
An alternative to the flu shot is FluMist, a more expensive inhaled version of the vaccine, which is recommended for healthy people between the ages of 5 and 49. There are about 4 million doses available of FluMist, health officials said.
Each year, more than 36,000 Americans die of complications from influenza, according to the CDC. Flu symptoms include fever above 100 degrees, extreme fatigue, body aches, dry cough, sore throat and nasal congestion.
In a typical year, 70 million to 75 million Americans receive a flu shot, and the United States has never used more than 80 million doses of the vaccine, according to the CDC.
CDC guidelines suggest that everyone over the age of 50 get the flu vaccine. It also recommends a shot for children and adults with respiratory ailments, infants ages 6 to 23 months, and pregnant women who will be in their second or third trimester during flu season.
CNN.com producer Amy Cox contributed to this report.