Nearly half of the states in the nation are reporting outbreaks of flu, in part because supplies of the vaccine are running thin in many places, and are non-existent in some.
That may be due, in part, to higher demand for the vaccine this year over last year, when too much supply left companies hesitant to make more than they could distribute.
"You have to have reserves when you don't know how much of a life-saving, vital product you're going to need," said Dr. Bernadine Healy, former head of the National Institutes of Health (search). "A lot of people, whether it be the government — whether it be manufacturers — don't want to invest in reserves because it often means throwing them out."
Last year, three manufacturers made 95 million doses of the flu vaccine. Eighty million doses were used, and companies were forced to eat the cost of the unused portions. The outcome was costly — with pharmaceutical giant Wyeth (search) dropping out of producing vaccines this year, and the remaining two companies — Aventis Pasteur (search) and Chiron Corp. (search) — hoping not to make the same mistake.
The government does not pay for the extra doses of flu vaccine. It works with drug companies to guess yearly demand based on the previous year's use.
"You have to have reserves and you don't know how much of a vital life-saving product you're going to need. The unexpected is what preparedness is about," Healy said.
Even over the summer, experts were not expecting increased demand. In June, Dr. Roland Levandowski, of the Food and Drug Administration's Division of Viral Products, told the American Medical News that supplies and distribution were "on schedule." Top American health officials suggested that vaccine supplies were sufficient and said they were more worried about not having enough demand.
But this year's flu is traveling at a faster pace than it was last year — hitting 11 states in just the last week. Though the strain doesn't appear to be any more virulent than in previous years, more people are getting sicker.
"It got off to an early start, starting as early in October is unusual ... In addition, we saw widespread activity ... much earlier in the flu season than is average," said Dr. Julie Gerberding (search), director of the Centers for Disease Control and Prevention (search).
"It comes all of the sudden, you don't know what it is," said one patient, who with her mother, is under observation at Inova Fairfax Hospital in Virginia.
On Thursday, the federal government agreed to buy an extra 250,000 doses of the vaccine from Aventis Pasteur. About 100,000 doses are available of the adult vaccine, while 150,000 doses are for children. Distribution will be limited, but even with the newly-located vaccine, it is not nearly enough to cover the 85 million or more Americans expected to seek the vaccination. No other vaccine is in reserve.
"It's a very spotty picture right now, but we don't have any information to suggest that there's a big reserve hidden away somewhere that we would be able to tap into," Gerberding said.
Each year, the government encourages 185 million Americans to get a flu shot, but it never sees to it that a supply that large is available. Healy said the government should be the purchaser and should be prepared. But Congress has not wanted to set aside millions of dollars each year that may never be used.
Each year on average, 36,000 Americans die from the flu and 114,000 are hospitalized, the CDC reports. Occupational health experts say a case of the flu costs workers an average of three lost work days and $400 in lost wages. The estimated losses in productivity for American businesses totals $12 billion annually.
Workers who are not vaccinated are more vulnerable to the flu and could drive up wage and productivity losses throughout the economy. That has some lawmakers rethinking congressional policy.
The effects of this year's flu are also being felt in other areas — schools in Missouri and Ohio are closed. Twenty-three school-age children have lost their lives in Colorado and other western states, and on Wednesday, news reports revealed that a college student in Massachusetts had died from the virus.
Hospitals are now being overrun with panicky parents bringing their children to the emergency rooms. One doctor said the effort may not be worth it.
"If he doesn't have respiratory distress, if he's not dehydrated, if he's not lethargic and has mental status changes, there's really not a reason that you need to be seen, because there's not anything we can really do for you," said Dr. Michael Altieri, chairman of pediatrics at Inova Fairfax Hospital.
Jim Young, president of research and development of Medimmune Inc. (search), said his company has produced an inhaled vaccine called Flumist (search). The product is costlier, and not meant for children under 5-years-old or seniors, but Young said his company has made about 4 million to 5 million doses of the vaccine.
"It's the first new flu vaccine in 50 years, and it's extremely safe, extremely effective in protecting children and adults against the flu virus," Young said.
States with widespread flu activity, according to the CDC: Alaska, Arizona, Arkansas, Colorado, Idaho, Indiana, Iowa, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas, Utah, Washington, West Virginia and Wyoming.
Fox News' Major Garrett and Doug Luzader contributed to this report.