With the first season of H1N1 swine flu vaccinations winding down, government officials are encouraging continued vigilance but vaccination are also revealing that as many as 71 million doses of unused vaccine may expire in the coming months.
A CDC briefing on how many people had received vaccinations against H1N1 was punctuated by a number of questions about a report in today's Washington Post that says 71.5 million doses would be thrown away because they would soon expire.
Dr. Anne Schuchat, director of the CDC's National Center for Immunization, said that while some expired vaccine would need to be discarded, "we made a conscious decision to have more than enough vaccine instead of less than enough vaccine."
But Schuchat said that the number of doses of vaccine that would be discarded remains unclear, because some might be reused next year, as the strain of the virus has not mutated and is still circulating. She said some of the ingredients from this year's vaccine might be used in next year's batch.
"Virtually every year, of course, we have influenza vaccine that goes unused," Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt University and president of the National Foundation for Infectious Diseases told ABCNews.com. "This year we had a special challenge, because we decided to make a vaccine much later than the annual routine was."
He also noted that the virus picked up very quickly in the fall, while the vaccine took longer to manufacture than expected, contributing to the overage in supply.
"We had a very odd H1N1 season, it occurred in the fall, rather than later in the winter," said Schaffner. "By the time the vaccine came out where it could be used, we were already at the down-slope of the occurrence of illness."
Last spring, after the virus initially surfaced, $1.6 billion was pledged to develop a vaccine for the novel strain of influenza.
While the first doses of vaccine arrived before the onset of traditional flu season, H1N1 had already returned, hitting the southern states especially hard.
Schuchat said that may help explain why Georgia has seen a return of the virus in recent weeks.
"I think it's still a puzzle," she said. "It is important to say that Georgia experienced disease earlier than a lot of the country. And so by the time that the vaccine became available, I think there was less public interest in vaccination and in the flu than there was back in August or September."
A representative for the Department of Health and Human Services said it would be difficult to give an exact figure for the cost of the doses to be discarded, since the money allocated goes into manufacturing, distributing and researching the vaccine.
But it does seem unlikely that the current model of government contracting private vaccine manufacturers will go away.
"We always want a number of different companies that supply influenza vaccine to the United States," said Schaffner, explaining that it allows other manufacturers to make up for shortfalls by another. You don't like to have all your vaccine, or all your eggs in one basket."
But he said that some encouraging changes for the future involved a new plant being constructed in a joint venture by the U.S. government and a vaccine manufacturer (Novartis). This brings two benefits, he said.
First, the new plant will use the newer "cell line technology" to create vaccines in place of the slower traditional method that uses chicken eggs, still emplyued for makuing seasonal flu vaccines.
Second, having this new plant puts the vaccine manufacturing back on U.S. soil, which allayed concerns that a pandemic outbreak in a country that makes U.S. vaccine might delay delivery.
"One of the things this pandemic pointed out to people beyond public health," said Schaffner, "is a lot of the vaccine we use in the United States is manufactured abroad."
ABC News' Brian Hartman contributed reporting.