Federal health officials say they expect a record 100 million vaccine doses to be available in the U.S. this flu season, eliminating worries of a shortage.

Officials stressed that the numbers are based on manufacturers’ estimates and that final numbers could fluctuate.

But public health authorities and companies now expect large supplies this fall and winter, a welcome relief from shortages and other supply problems that marked the last two flu seasons.

“If the manufacturers' estimates hold, more people than ever before will be able to protect themselves and their loved ones from influenza this year," CDC director Julie M. Gerberding, MD, MPH, said in a statement.

Safety problems at a vaccine plant in England caused widespread shortages that sent authorities scrambling to find adequate supplies in 2004. The plant, owned by Chiron Corp., also produced less vaccine than expected last year, forcing officials to establish priority groups so high-risk patients could be vaccinated first.

“The problems are resolved” now at the Liverpool plant, says Alison Marquiss, a spokeswoman for Novartis, which owns Chiron Corp.

The 2004 and 2005 shortages exposed gaps in the U.S. vaccine supply and have led to calls for more incentives to entice firms to produce flu shots.

Expanded Recommendations

The CDC, in Atlanta, expanded recommendations for who should receive flu vaccinations this year. The new policy aims to prevent flu in more Americans while also expanding market size as an incentive for vaccine companies.

The recommendations this year call for vaccination of all adults 50 and older. In some previous years, the recommendation for vaccinating healthy adults was set at age 65 and older because of shortages.

The CDC also recommends vaccination for children between the ages of 6 months and 5 years, a larger age group than in the past.

Pregnant women, those with chronic medical conditions, and those who live with or care for high-risk people -- such as infants or those with certain medical conditions -- are also recommended for vaccination.

“The more of the vaccine that gets used, two good things happen: The more individuals will be protected … and the manufacturers’ decisions each year on how many doses they will make are affected,” Lance Rodewald, who heads the CDC’s vaccination programs, tells WebMD.

Rodewald says 75 million doses are expected in doctors’ offices and clinics by the end of October, meaning prioritizations that prevented some people from being vaccinated over the last two years should not be needed this fall.

Companies estimated their overall supplies could top 100 million doses. Marquiss says Novartis expects to produce “north of 30 million, possibly 40 million” doses. Sanofi Pasteur expects to produce 50 million doses, says spokeswoman Patty Tomsky.

Meanwhile GlaxoSmithKline could market 25 million or more doses if they receive expected FDA approval for a Canadian-made vaccine, the company said.

GlaxoSmithKline and Novartis are WebMD sponsors.

As many as 200,000 Americans are hospitalized because of influenza each year, and 36,000 die from it.

By Todd Zwillich, reviewed by Louise Chang, MD

SOURCES: Julie M. Gerberding, MD, MPH director, CDC. Alison Marquiss, spokeswoman, Novartis. Patty Tomsky, spokeswoman, Sanofi Pasteur. Lance Rodewald, MD, director, immunization services, CDC.