Feb 25, 2009 (CIDRAP News) – Americans who receive anthrax shots—mainly members of the military—are likely to get five injections into muscle tissue instead of six subcutaneous injections, as a result of action today by the federal Advisory Committee on Immunization Practices (ACIP).
The ACIP voted unanimously to make the changes in the schedule and route of administration for BioThrax, also known as anthrax vaccine adsorbed, according to Tom Skinner, a spokesman for the Centers for Disease Control and Prevention (CDC). BioThrax is the only anthrax vaccine currently licensed in the United States.
Also, in making its annual recommendations for influenza prevention and control, the ACIP did not add any new age or risk groups to those already targeted for annual flu immunizations, Skinner reported.
The ACIP sets the government's immunization guidelines, making recommendations that are routinely approved by the CDC director and health and human services secretary.
Change in anthrax regimen
The ACIP endorsed an anthrax vaccination schedule of intramuscular injections at 0 and 4 weeks and 6, 12, and 18 months, replacing the old regimen of subcutaneous injections at 0, 2, and 4 weeks and 6, 12, and 18 months, according to Skinner. Annual booster shots are also recommended after the initial series.
"Subcutaneous administration is allowable only when medically indicated such as in persons with coagulation disorders," Skinner reported in a written statement.
The revised schedule and administration route stem from a large, ongoing clinical trial to determine if the long series of shots and resulting side effects can be reduced. The immunizations are required for US military personnel deployed in high-risk areas, mainly the Middle East, and some service members have objected to the shots because of side effects.
In interim trial results reported last October, volunteers who received either three or four intramuscular doses over 6 months had about the same antibody responses at 7 months as did volunteers who received the standard regimen, involving four subcutaneous doses in the first 6 months. In addition, those who received intramuscular doses had fewer side effects at the injection site than those who received subcutaneous doses.
As a result of those findings, in December the Food and Drug Administration (FDA) approved the five-dose intramuscular injection schedule. Emergent BioSolutions, manufacturer of BioThrax, had asked the FDA to authorize the new schedule.
Emergent has said it may ask for FDA clearance to shorten the immunization series further, depending on future findings from the ongoing clinical trial.
In approving its annual recommendations for flu immunization, the ACIP did not expand the recommendations to any new segments of the population. A year ago, the committee recommended flu immunizations for school-age children, adding about 30 million people to the millions already targeted for flu vaccination.
"No new age or risk groups are being recommended to receive annual influenza vaccination," Skinner said.
He said no information on current flu immunization coverage among school children was presented at the meeting, adding, "We won't know that for some time."
In addition to school children, the CDC recommends flu shots for children from 6 to 59 months old, people aged 50 and older, those with certain chronic medical conditions, people in nursing homes, pregnant women, healthcare workers, and other close contacts and caregivers of those who run an increased risk of flu complications.
In line with previous recommendations by the World Health Organization and FDA, the ACIP also voted today to change the influenza B strain in the flu vaccine for next winter but to keep the two influenza A strains used in this year's vaccine, according to Skinner.
Dec 22, 2008, CIDRAP News story "FDA approves shortened anthrax-vaccine course"
Oct 6, 2008, CIDRAP News story "Trial offers hope for shortening anthrax-shot series"
Feb 27, 2008, CIDRAP News story on ACIP meeting