Two months after the government recommended that scarce flu shots (search) be reserved for people most at risk, health officials are now worried that tens of thousands of doses could go to waste, and they are considering easing the restrictions.

It turns out that the furor over the vaccine shortage (search) and the government's response have had an unintended effect: More than half of all elderly or chronically ill adults have not even tried to get flu shots because they figured they would not be able to get one, the Centers for Disease Control and Prevention said Thursday.

The CDC's Advisory Committee on Immunization Practices is expected to hold an emergency conference call Friday to discuss whether to amend its earlier response to the vaccine shortage and recommend that more people be allowed to get shots.

"Many of us are now concerned we will not use vaccine supplies. The only sin this season is to leave vaccine on the shelf," said Dr. William Schaffner, an influenza vaccine expert and head of preventive medicine at Vanderbilt University Medical Center in Nashville, Tenn.

The problem is that a flu shot is only good for the flu season it is made for. Any excess must be disposed of at the end of the season. The flu season begins in the fall and can last through April.

The medical center at Vanderbilt said it has vaccinated most of its high-risk patients and still has 3,000 doses left over. Health officials in California, Colorado and Washington have expressed concerns similar to Schaffner's.

The surplus already has prompted some states to loosen their immunization restrictions, allowing people as young as 50 to get a shot. Others are considering allowing flu shots for anyone who has close contact with those in a high-risk group.

"That almost opens it up to everybody," Schaffner said.

The government in October recommended that healthy adults delay or skip a flu shot this season to save vaccine for the estimated 98 million people in the country who need it most -- the elderly, infants or those with chronic conditions. Those people are at highest risk of severe complications or death from the flu, which kills on average 36,000 people and hospitalizes 200,000 each year in the country.

The recommendation was made after health officials learned that nearly half of the country's flu shot supply would be cut off because of contamination at vaccine maker Chiron Corp.'s plant in Liverpool, England.

Only about 65 million doses of vaccine will be available this season in the United States, including a nasal vaccine that is safe for only healthy people.

The CDC study found that as of last month, only about 35 percent of high-risk adults, mainly senior citizens, had gotten a flu shot. Another CDC study released Thursday found that people at high risk often do not get vaccinated for various reasons, including a misperception that the shot causes influenza and the belief that it would not be easy for them to get the vaccine.

As a result, health officials have been scrambling to find a way to make use of the remaining supply of flu shots -- before they go to waste.

"Everybody should have it who wants it," said Dr. Paul Glezen with the Baylor College of Medicine in Houston.

Schaffner said: "We really have to work hard to get rid of it."