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Current Trends Withdrawal of Approval for Subcutaneous Administration of Norden Rabies Vaccines for Dogs and Cats

Effective August 17, 1987, the U.S. Department of Agriculture (USDA) is withdrawing approval for subcutaneous administration of Endurall-K*and Rabguard-TC*, manufactured by Norden Laboratories, Inc., Lincoln, Nebraska Endurall-K (a vaccine that imparts a 1-year duration of immunity) and Rabguard-TC (a 3-year vaccine) should now be administered only intramuscularly to dogs and cats.

In July 1985, the USDA gave provisional approval for subcutaneous administration of these vaccines to dogs and cats, pending completion of a duration-of-immunity study and rabies challenge tests. In the study, rabies-neutralizing antibody responses following subcutaneous vaccination were comparable to those observed following intramuscular vaccination throughout the 3 years after vaccination. However, when dogs and cats were injected with live rabies virus in separate challenge studies, they were not adequately protected 3 years after subcutaneous vaccination. Therefore, all dogs and cats that received these vaccines subcutaneously should be revaccinated intramuscularly with a Norden vaccine or with another approved vaccine (1). Since July 1985, several million doses of these vaccines have been sold annually in the United States and Canada (Norden Laboratories, Inc., unpublished data). The number of animals vaccinated subcutaneously is not known.

Veterinarians who have administered the Norden vaccines subcutaneously should inform pet owners of the need for revaccination. Health agencies and other organizations that have sponsored rabies vaccination clinics should inform their communities. Questions regarding procedures for revaccination should be addressed to Norden Laboratories, Inc., collect, at (402) 475-6843 between 8:00 a.m. and 4:00 p.m. CDST. This withdrawal of approval for subcutaneous administration of Norden vaccines does not apply to other rabies vaccines licensed for subcutaneous use. Reported by: Veterinary Svcs, USDA. Viral and Rickettsial Zoonoses Br, Div of Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: The rabies challenge study was conducted with laboratory dogs and cats 3 years after they had received only a single dose of vaccine subcutaneously. It is likely that most pets have received more than one rabies vaccination because the recommended schedule for primary rabies immunization in dogs and cats is an initial dose at 3 months of age, followed by an additional dose 1 year later (1). Therefore, most animals receiving a Norden vaccine subcutaneously for primary immunization should have already received a second vaccination. In addition, because the vaccines were not approved for subcutaneous use until July 1985, most dogs and cats receiving them subcutaneously as booster immunizations should have received at least one previous immunization with an approved vaccine by an approved route.

The level of protection conferred by administering the Norden vaccines subcutaneously in a primary immunization series (2 doses) or a booster immunization is not known. Therefore, animals that have received the Norden vaccines subcutaneously but have not been subsequently revaccinated intramuscularly with a Norden vaccine or another approved vaccine should be regarded as unvaccinated for the purposes of rabies postexposure management.


  1. CDC. Compendium of animal rabies control, 1987--prepared by: the National Association of State Public Health Veterinians, Inc., (sic). MMWR 1987;35:807-10, 815-8. *Use of trade names is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services or the Public Health Service.

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