WEDNESDAY, Oct. 6, 2004 (HealthDayNews) -- One day after the stunning news that the United States would receive only half its expected 100 million flu vaccine doses this year, federal health officials are urging healthy people to wait or even forgo a shot this season.
They're also advocating a low-tech approach to preventing infection: frequent hand-washing.
Meanwhile, top flu experts are proposing that available vaccines could potentially be diluted to partially meet the needs of healthy Americans, with the thinking that a weakened vaccine is better than none at all.
The scramble for solutions followed Tuesday's announcement that British health officials had suspended the license for a Chiron Corp. factory outside Liverpool that makes all the company's vaccine for the U.S. market. Chiron was expected to ship as many as 48 million doses here, beginning this month. A second company, Aventis Pasteur, makes another 54 million doses, and has reported no problems.
As the news broke, Dr. Julie Gerberding, director of the federal Centers for Disease Control and Prevention, asked healthy individuals to forgo the vaccine this year.
Instead, she recommended frequent and thorough hand-washing to protect against the flu. "One of the most important things is good hand hygiene," she said.
Other infectious disease experts agreed with that advice.
"Hand-washing is very effective," said Dr. Pascal James Imperato, director of the Master of Public Health Program at SUNY Downstate Medical Center in New York City. "It's such a simple prophylactic measure that people didn't attach great significance to it for many years. We now know that hand-washing does indeed have a very major impact on preventing the spread of a variety of pathogens."
So, who should get the vaccines that are available?
The CDC said high-risk groups should be the first in line to get a shot, and considers each group to be of equal importance. The groups are: infants aged 6 months to 23 months; adults 65 years and older; those aged 2 to 64 who have underlying chronic medical conditions; children 6 months to 18 years who are on chronic aspirin therapy; all women who will be pregnant during the flu season; residents of nursing homes and long-term care facilities; health-care workers involved in direct patient care; and out-of-home caregivers and household contacts of children under the age of 6 months.
About 1.1 million doses of MedImmune's nasal spray version of the vaccine will also be available, and those are encouraged for healthy persons aged 5 to 49 who are not pregnant, including health-care workers and persons caring for children under the age of 6 months.
As for healthy Americans, the possibility of dilution to stretch the existing supply is now being explored.
The Food and Drug Administration and the National Institutes of Health are studying whether Aventis' vaccine could be diluted to get two doses out of each original shot, according to Dr. Anthony Fauci, the NIH infectious disease chief. Fauci, according to an Associated Press report, said a small NIH study several years ago suggested doing so could provide enough protection for healthy people.
And the scientist who for many years made the annual prototype flu vaccine agreed.
"I think it is a logical step," Dr. Edwin D. Kilbourne told HealthDay.
"You could probably use half a dose and stimulate immunity in most people," continued Kilbourne, who is now emeritus professor of microbiology and immunology at New York Medical College in Valhalla, N.Y.
"What should have been done, or what should be launched right now, is a short clinical trial in which they tried half the dosage, and in a few days they would have the answer as to whether it stimulated antibodies," Kilbourne said.
While this option seems to have been mentioned most often in relation to healthy adults, Kilbourne thought there was also a possibility it would work in higher-risk groups. But, he added, "it is riskier to take that chance."
The case for dilution was also backed by microbiologist Doris Bucher, who now produces the prototype flu vaccine that is sent to the manufacturers for mass production.
"If you've got people who are healthy and younger, it would probably have quite a good response," said Bucher, an associate professor in microbiology and immunology at New York Medical College.
Others are skeptical of that approach, however. "The difficulty in diluting the vaccine is that we have no experience whatsoever with diluting influenza vaccines," Imperato said. "We don't know whether a diluted vaccine will protect people the way an undiluted vaccine will. It's untested at this point."
Another potential problem, Imperato said, is that some people who may be able to skip a flu shot will insist on one.
"How does one now tell people who wanted to be vaccinated?" he wondered. "This creates a public health education issue for public health departments, and for all of us in preventive medicine, because we have been telling people to do this for the last several years -- and now we're saying we don't have enough vaccine to go around, therefore you can't get immunized."
Part of the problem is the concentration of manufacturing with just a few firms. "We have too few manufacturers making flu vaccine," Kilbourne said. "Only 10 years ago we probably had five or six."
Manufacturers shy away from the business of making flu vaccines, Kilbourne explained, because demand is unpredictable, varying widely from year to year, depending on public health announcements and how scared people are.
Looking ahead, many experts feel that the current egg-based system of producing vaccines should cede to a cell culture system. Since the 1970s, the influenza virus used in vaccines has been grown in eggs, a very slow process and one that requires millions of eggs (three per dose), according to the National Institutes of Health. Researchers have been experimenting with faster cell-culture methods, but none are in place yet.
"That's not for next year. That's for maybe five or six years ahead," Kilbourne said. "In the meantime, we'd better catch up on our production techniques for regular egg vaccines or we might very well be caught in a pandemic situation."
More information
The U.S. Centers for Disease Control and Prevention has more on the flu and flu vaccine.
