Flu outbreak worsens - 26 children have been killed

© Charles Krupa, AP

Flu is now widespread in 46 states and has killed 26 children, health officials said today.

"This year is shaping up to be a bad one, particularly for people 65 and older," says Thomas Frieden, director of the Centers for Disease Control and Prevention. Children younger than 5 are also at high risk of hospitalization, particularly babies under 6 months, who are too young to be vaccinated.

Flu is hitting the USA especially hard this year for two reasons.

First, the dominant flu strain in circulation is H3N2, a type that tends to cause twice as many hospitalizations and deaths as other strains of flu, Frieden says. Hospitalization rates have risen to 92 per 100,000 people, compared with 52 hospitalizations per 100,000 in a typical year.

"H3N2 is a nastier flu virus than other flu viruses," Frieden says. "Hospitalization rates in the over-65 age group are rising."

Second, the H3N2 viruses used to make this year's influenza vaccines aren't a good match to those spreading throughout the country, the CDC says. That's because about two-thirds of the H3N2 viruses in circulation have mutated significantly since vaccine production began last spring. Drugmakers tend to start making flu vaccines in the spring, in order to produce enough for the fall flu season.

"Even in a good year, the flu vaccine is not as effective as our other vaccines," Frieden says, noting that flu efficacy rates are about 60% to 65%.

Frieden says there are several ways for people to protect themselves.

Flu vaccines. While the flu shot this year may be less effective than usual, Frieden says it's not too late to get a shot. About one-third of the H3N2 viruses in circulation are a good match for those in the vaccine. And vaccines protect against three or four strains of flu. So flu shots may still protect people from other types of flu, such as strains of influenza B, which often show up later in the flu season.

The CDC recommends flu shots for everyone over the age of 6 months.

Only about half of Americans get flu vaccines, the CDC says. Doctors recommend that pregnant women get vaccinated, to provide immunity to babies in the first few months of life.

Antiviral drugs. Frieden also urged patients and doctors to make more use of antiviral drugs, such as Tamiflu and Relenza, which can reduce the risk of complications, hospitalizations and death. While the drugs are most effective if given in the first 24 hours after symptoms appear, Frieden says they may still offer some benefit after that point, especially for elderly people and others at high risk of complications.

Surveys show most Americans don't know there are prescription medicines to treat the flu, Frieden says.

"They work, but they aren't being used nearly enough," Frieden says. A study found that "fewer than one out of five high-risk outpatients who clearly should have gotten treated with antivirals, actually did."

Frieden encouraged doctors to prescribe antivirals immediately when patients have symptoms of the flu - such as fever, headache and body ache - rather than wait for definitive results from tests, which may unnecessarily delay treatment.

Some pharmacies are running short of the drugs, although manufacturers say the overall supply of antivirals is good, Frieden says.

"You may have to call around" to more than one pharmacy, Frieden says.

Pneumococcal shots. This fall, the CDC began encouraging people over age 65 to get two different vaccines against pneumococcus, a bacteria that causes pneumonia. The flu increases the risk of pneumonia, especially in the elderly.

The flu sickens millions of Americans every year, says the CDC's Joseph Bresee, which leads to hundreds of thousands of hospitalizations. Deaths from the flu can range from 5,000 to 50,000 every year, says the CDC.

The USA is about halfway through the flu season now.

Good hygiene. People should wash their hands frequently and cover their coughs, Frieden says. People who are sick should stay home and not go to work or school.