Jul 2, 2004 (CIDRAP News) – More Americans are being told to seek flu vaccination and more vaccine will be available in the coming influenza season, as authorities try to improve people's odds against the persistent and sometimes deadly influenza virus.
Experts have cast a wider net by recommending that 6- to 23-month-old children be vaccinated (see Apr 30 CIDRAP News story). In addition, healthcare workers will be more strongly advised than before to get their flu shots, and vaccine manufacturers are planning to make about 13 million more doses this year than they did last year.
Young children suffer complications from flu nearly comparable to those endured by seniors, Curtis Allen, a spokesman for the National Immunization Program at the Centers for Disease Control and Prevention (CDC), told CIDRAP News. He is hopeful more parents will make the two clinic visits necessary to develop immunity in small children.
Only about 35% of healthcare workers get vaccinated, Allen said. In answer to this situation, the Advisory Committee on Immunization Practices and the Hospital Infection Control Practices Advisory Committee plan to issue a joint recommendation "which uses stronger language than either has ever used before affirming the importance of healthcare workers getting vaccinated," a Jun 24 Reuters story quotes ACIP liaison member Dr. William Schaffner of Vanderbilt University as saying.
The vaccine is also recommended for people older than 50 and people with certain conditions that affect their immune systems, as well as those in close contact with such people.
In a bid to avoid a repeat of last year's flu-shot shortage, drug companies are making more than 100 million doses of vaccine. As announced by the Department of Health and Human Services early this year, the agency will spend about $80 million in the next 2 years to stockpile another 4 million or 5 million doses a year for uninsured and underinsured children eligible for the Vaccines for Children Program.
Those stockpiled doses will be free of the controversial preservative thimerosal, according to Allen. Although a safety review by the Institute of Medicine found that the bulk of evidence favors rejection of a causal relationship between thimerosal-containing vaccines and autism, some public concern lingers. The product is still used in injectable influenza vaccine, but thimerosal-free flu vaccine is available.
"We continue to work with manufacturers to remove thimerosal from the vaccine," Allen said. "It's a matter of prudence even though there's no evidence it causes harm." He recommends that parents who want a thimerosal-free vaccine ask their healthcare provider how to find it.
Those who assess supply and demand anticipate that not everyone who ought to get the vaccine actually will. Compliance usually isn't higher than 40%, Allen said. Last year, however, saw vaccine shortages in some places as manufacturers dropped production to 86.9 million doses, down from 95 million doses in 2002.
It's a delicate balance, acknowledged Dr. Raymond Strikas, associate director for adult immunization in the Immunization Services Division of the National Immunization Program.
"There are many more people who actually should be vaccinated who haven't asked for vaccine," he said, estimating that 185 million people should be immunized.
A final variable in the flu fight is predicting which three virus strains to include in the vaccine, a decision that must be made well in advance to allow time for vaccine production.
Last year's vaccine benefited people, although it lacked the strain that dominated the flu season, Strikas said. On average, the experts who conduct surveillance correctly predict the circulating virus 9 of every 10 years, Strikas said.
It's too soon to know if this year's trivalent vaccine—with an H1N1 (A/New Caledonia), an H3N2 (A/Fujian), and a new B/Shanghai strain—will hit the immunization trifecta.
"It's the Yogi Berra story," Strikas said. "Predictions are difficult when they involve the future."
CDC overview of last year's flu season and preview for 2004-05
Current ACIP influenza vaccine recommendations, released Apr 30
Amy Becker is a full-time reporter at the St. Paul Pioneer Press and a freelance reporter for CIDRAP. She will enter the University of Minnesota's graduate program in public health administration and policy in fall 2004.