Conditional Licensure of Vaccines (General Info)
- ***MODERATORS NOTE: I thought this might be intriguing in re a possible vaccine for VHD in future. God forbid we ever need it!--PA******Ed Curlett (301) 734-3256
Jerry Redding (202) 720-6959
USDA ISSUES CONDITIONAL LICENCE FOR HORSE VACCINE
WASHINGTON, Dec. 18, 2000 The U.S. Department of Agriculture announced today
that it has issued a conditional license to Fort Dodge Laboratories, Inc. of Fort Dodge, Iowa, a
division of American Home Products, Inc. for a vaccine intended to aid in the prevention of
equine protozoal myeloencephalitis.
The Animal and Plant Health Inspection Service issues conditional product licenses
under its regulatory authority to meet an emergency condition, limited market, local situation, or
other special circumstances.
"Under these regulations, a product that is shown to be pure and safe and demonstrates a
reasonable expectation of efficacy may be licensed while data to establish efficacy and potency
are obtained," said Alfonso Torres, deputy administrator for APHIS' veterinary services
program. The center for veterinary biologics, licensing and policy development staff of
veterinary services issued the license.
EPM is a debilitating and sometimes fatal neurologic disease of horses linked to infection
by a protozoal parasite most often identified as Sarcosystis neurona. Opossums and birds are the
normal hosts for S. neurona; horses may become infected by ingesting the organism in food
contaminated by opossum fecal material. In some cases, infection by the parasite may result in
damage to the central nervous system, particularly the spinal cord.
Diagnostic procedures currently available for use on living animals are difficult and often
unreliable. Treatment regimes for EPM are costly, often of limited effectiveness, and in a small
number of treated animals symptoms recur when therapy is discontinued.
Nationwide, exposure of horses to S. neurona has been estimated to be as high as 50
percent based on the presence of antibodies to the organism in tested horses, with higher rates
reported in certain areas. Evidence of exposure and subsequent development of disease,
however, are not well correlated and most estimates of the incidence of EPM disease are less
than 1 percent.
Conditional licenses are generally issued with restrictions and for a limited period of
time. At the end of the conditional licensure period, data obtained in support of the product’s
efficacy, potency, and product performance are evaluated to determine if the conditional license
should be renewed or if a regular product license may be issued.
In keeping with these regulations, the product described above has been issued a
conditional license for six months. The product is restricted to use by a veterinarian, in those
states where use of the product has been approved by the appropriate state regulatory authorities.
Any adverse reactions made known to the manufacturer that may be linked to use of the
product are to be reported immediately to USDA by the manufacturer. Promotion, advertising,
and marketing materials to be used in conjunction with the product are subject to prior review by
At the conclusion of the six-month conditional licensure period, the manufacturer is to
provide all data collected relevant to product performance in support of any request for
reissuance of a product license.
NOTE: USDA news releases, program announcements, and media advisories are available on
the Internet. Access the APHIS Home Page by pointing your web browser to
http://www.aphis.usda.gov and clicking on "APHIS Press Releases." Also, anyone with an
e-mail address can sign up to receive APHIS press releases automatically. Send an e-mail
and leave the subject blank. In the message, type