Anthrax: Federal Agencies Have Taken Some Steps to Validate Sampling Methods and to Develop a Next-Generation Anthrax Vaccine
http://www.gao.gov/new.items/d06756t.pdf
GAO-06-756T
EXCERPTS relating to BioPort anthrax vaccine absorbed (AVA):
GAO report, page 5:
"...With regard to the licensed anthrax vaccine, we identified a number of problems, including, among others, greater understanding of 1. the need for a six-shot regimen and annual booster shots; 2. the long-term and short-term safety of the vaccine, including gender differences; and 3. the vaccine's efficacy. In addition, we provided information on the disadvantages of the licensed anthrax vaccine and the status of federal efforts to develop an improved vaccine.
Given these problems, and taking into account promising early DOD research into an alternative, recombinant protective antigen (rPA) vaccine for anthrax, we recommended the development of a second-generation vaccine, based on this technology..."
GAO report, page 15:
The Licensed Anthrax Vaccine Had Several Limitations
Starting in 1999, we identified a number of problems with the licensed anthrax vaccine. These included, among others, (1) the need for a six-shot regimen and annual booster shots; (2) questions about the long-term and short-term safety of the vaccine, including how safety is affected by gender differences; and (3) uncertainty about the vaccine's efficacy. In addition, we provided information on the disadvantages of the licensed vaccine the status of federal efforts to develop an improved anthrax vaccine.
GAO report, page 16:
The dosing regimen, or protocol, for the licensed anthrax vaccine calls for a series of six shots over 18 months. An initial series of three shots is given at 2-week intervals, followed by a series of three shots at 6-month intervals. Annual boosters are required thereafter. The required six-dose schedule and annual boosters complicate the logistics and increase the cost of vaccination. At the time of our earlier reports, no studies had been done on the optimum dosing regimen. Recently, however, CDC has begun conducting studies to determine the feasibility of a three-dose schedule. FDA would have to review and approve any change in product labeling.
The long-term safety of the licensed vaccine has not been studied. Data on the prevalence and duration of short-term reactions to the vaccine are limited but suggest that women experience a higher rate of adverse reactions, both local and systemic, than men do.
Before the vaccine was licensed, a study on the efficacy of the original vaccine concluded that it provided protection to humans against cutaneous anthrax. In the 1980s, DOD began testing the efficacy of the licensed vaccine on animals, focusing on its protection against inhalation anthrax. DOD's studies, while showing some positive results, may not be extrapolated to humans until serologic correlates of immunity in an animal model that can be applied to humans are established.
According to researchers and the Institute of Medicine of the National Academy of Sciences, the licensed anthrax vaccine has several additional disadvantages. The amount of protective antigen in the vaccine varies from lot to lot, because the manufacturing process cannot precisely quantify the antigen. Also, there is some evidence that the current anthrax vaccine may have diminished efficacy against certain virulent strains of anthrax.
GAO-06-756T
EXCERPTS relating to BioPort anthrax vaccine absorbed (AVA):
GAO report, page 5:
"...With regard to the licensed anthrax vaccine, we identified a number of problems, including, among others, greater understanding of 1. the need for a six-shot regimen and annual booster shots; 2. the long-term and short-term safety of the vaccine, including gender differences; and 3. the vaccine's efficacy. In addition, we provided information on the disadvantages of the licensed anthrax vaccine and the status of federal efforts to develop an improved vaccine.
Given these problems, and taking into account promising early DOD research into an alternative, recombinant protective antigen (rPA) vaccine for anthrax, we recommended the development of a second-generation vaccine, based on this technology..."
GAO report, page 15:
The Licensed Anthrax Vaccine Had Several Limitations
Starting in 1999, we identified a number of problems with the licensed anthrax vaccine. These included, among others, (1) the need for a six-shot regimen and annual booster shots; (2) questions about the long-term and short-term safety of the vaccine, including how safety is affected by gender differences; and (3) uncertainty about the vaccine's efficacy. In addition, we provided information on the disadvantages of the licensed vaccine the status of federal efforts to develop an improved anthrax vaccine.
GAO report, page 16:
The dosing regimen, or protocol, for the licensed anthrax vaccine calls for a series of six shots over 18 months. An initial series of three shots is given at 2-week intervals, followed by a series of three shots at 6-month intervals. Annual boosters are required thereafter. The required six-dose schedule and annual boosters complicate the logistics and increase the cost of vaccination. At the time of our earlier reports, no studies had been done on the optimum dosing regimen. Recently, however, CDC has begun conducting studies to determine the feasibility of a three-dose schedule. FDA would have to review and approve any change in product labeling.
The long-term safety of the licensed vaccine has not been studied. Data on the prevalence and duration of short-term reactions to the vaccine are limited but suggest that women experience a higher rate of adverse reactions, both local and systemic, than men do.
Before the vaccine was licensed, a study on the efficacy of the original vaccine concluded that it provided protection to humans against cutaneous anthrax. In the 1980s, DOD began testing the efficacy of the licensed vaccine on animals, focusing on its protection against inhalation anthrax. DOD's studies, while showing some positive results, may not be extrapolated to humans until serologic correlates of immunity in an animal model that can be applied to humans are established.
According to researchers and the Institute of Medicine of the National Academy of Sciences, the licensed anthrax vaccine has several additional disadvantages. The amount of protective antigen in the vaccine varies from lot to lot, because the manufacturing process cannot precisely quantify the antigen. Also, there is some evidence that the current anthrax vaccine may have diminished efficacy against certain virulent strains of anthrax.
