Flu experts try to ensure record vaccine doses get used

May 13, 2008 – ATLANTA (CIDRAP News) – Manufacturers of influenza vaccine are poised to deliver record quantities of flu shots for the coming season. But unless medicine and public health officials find new methods and venues for getting those shots into the arms of Americans, another record may also fall: the number of influenza-vaccine doses that go unused.

The need to expand flu-vaccine use—to protect Americans' health, and also to preserve vaccine manufacturing capacity that would be needed during an influenza pandemic—topped the agenda yesterday at the start of the National Influenza Vaccine Summit.

The little-known 2-day meeting, which is sponsored each year by the American Medical Association and the Centers for Disease Control and Prevention (CDC), has drawn record attendance of 230 this year. It comes on the heels of a microbiological double-whammy: midseason strain changes that created one of the harshest flu seasons in recent memory, coupled with a vaccine that, because of those viral changes, protected only 44% of recipients against the flu.

The possibility that the vaccine mismatch impaired public trust in the flu shot is much on the minds of summit participants. In the just-concluded season, manufacturers made a record 140 million doses, but only 113 million were used, leaving 27 million—also a record—unbought or returned to manufacturers.

Representatives of the five companies now selling flu vaccine in the United States said Monday evening that they collectively expect to deliver from 143 million to 146 million doses next flu season, the largest amount ever brought to market here. But health authorities are concerned that consumer distrust might cause a largest-ever amount to go unused as well.

The quandary of unused vaccine
That flu vaccine goes unused is not news; it has happened in most years for which public health has records, including years when midseason shortages caused long lines and public unrest.

Research unveiled at the summit explains why: The timing of flu-vaccine use and delivery do not match up. Flu-shot use peaks around Oct 1 and falls off to almost zero by Thanksgiving, but by October, manufacturers have delivered only two thirds of what they have made.

"If this distribution pattern prevails, and all indications are that it will, we will continue to receive 30% of our vaccine in the period after which people seek to use it," said Dr. William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt University School of Medicine. "This is a discontinuity."

The pattern makes even less sense when it is graphed against influenza incidence. In most years, flu cases do not appear until the end of January, meaning that influenza vaccination virtually ends before the disease it is meant to prevent begins.

Americans have seemed to have no interest in end-of-year flu shots. Last year, for instance, the CDC and a number of other health organizations conducted public-information campaigns, including a post-Thanksgiving "National Influenza Vaccination Week," that urged late-season vaccination but did not affect shot use.

Part of the problem may be simply that no one is asking patients about flu vaccination. That is what manufacturer Sanofi-Pasteur Inc. discovered after analyzing insurance-claims data from approximately 25% of US physician practices during the second half of the flu season.

Over "about a 16-week period . . . about 25 million individuals come into their physicians' offices for about 55 million visits and are not immunized against influenza," said Dr. David Greenberg, Sanofi's director of medical and scientific affairs.

The patients were not offered vaccination, he said, because their doctors had nothing to vaccinate them with: They had ordered a certain amount of flu vaccine, administered it early in the season, and then had not ordered more for fear it would not be used.

But several summit participants said that self-fulfilling situation is unlikely to change until physicians can be persuaded that placing larger vaccine orders at the start of the season will not cause them a financial loss at the end.

"Family physicians are trying to stay on the conservative side, because no one wants to get stuck with too much vaccine," said Dr. Herbert Young, director of scientific activities with the American Academy of Family Physicians.

Covering more of the population
Part of the problem, according to some attendees, is the now-lengthy list of groups for whom the vaccine is recommended because the federal government judges them to be at "high risk" of life-threatening flu complications. Currently they include children from 6 to 59 months old, all people 50 and older, younger people with some chronic medical conditions, nursing home residents, pregnant women, healthcare workers, and households and caregivers of all of those groups as well.

"That list is long," said Dr. Andrew Eisenberg, a family physician attending the conference who works in Sarasota, Fla., and rural Texas. "It has 20 items on it, it takes a while to go through it, and that is time the doctor is not being paid for."

In his own office, Eisenberg said, he focuses instead on the much shorter list of people for whom the shot is not advised, and strongly recommends the vaccine for everyone else: "When the patient signs in, the lady who is taking their information asks, 'Have you had the flu vaccine this year?,' and if the answer is 'No," we say, 'Well, today you are getting it.'"

The question of reaching and vaccinating the recommended groups is about to become more complicated: This fall, a new recommendation that covers all school-aged children will go into effect. (The change, voted in by a federal panel last February, becomes mandatory in the 2009-2010 season but is optional this year.) Up to 30 million children could be covered by that recommendation, though few experts expect them all to step up.

Health authorities are just beginning to grapple with the practicalities of getting even a fraction of those children into healthcare offices in the narrow window during which most Americans take flu shots. The task is compounded by the fact that these children need two shots administered 2 months apart to establish immunity.

Some of these complexities are being explored as the summit continues today.

See also:

Apr 17 CIDRAP News story "CDC: Imperfect flu vaccine was of help in tough season"

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