An Update on Rabies Titers and Booster Checks
Elisabeth Lawaczeck, State Public Health Veterinarian
Most veterinarians are vaccinated for rabies while in veterinary school. However, few may be aware of their immune status. Per guidelines from the Advisory Committee on Immunization Practices (ACIP) titled “Human Rabies Prevention,” serological testing every two years is recommended for veterinarians and veterinary clinic staff in rabies enzootic areas.
I consider portions of Colorado with skunk rabies endemic as a “rabies enzootic area.” If the titer is below the acceptable level, a booster is recommended. Per the ACIP guidelines, “Minimum acceptable level is complete virus neutralization at a 1:5 serum dilution by the rapid fluorescent focus inhibition test” (RFFIT). Serology via enzyme linked immunosorbent assay (ELISA) is not recommended! Per staff from the Centers for Disease Control and Prevention, the RFFIT is the only valid method at this time to verify rabies virus neutralizing antibodies.
Titers should be checked through primary care physicians or occupational health clinics. The blood must be sent to a laboratory that runs RFFIT tests. A list of laboratories that perform RFFIT testing is provided.
Rabies Vaccination: Boosters and Pre-Exposure Prophylaxis
Primary Care Physicians, Travel Clinics & Occupational Health
If you need a rabies booster vaccination, or if your staff needs rabies pre-exposure prophylaxis (three doses over a month), there are a few options, depending on what part of the state you live. A few large veterinary clinics have an account set up with an occupational health clinic such as Concentra Medical, some branches of which carry the rabies vaccine for pre-exposure prophylaxis. A veterinarian can get a referral from their primary care physician and go to a travel clinic to be vaccinated, after checking with the travel clinic to ensure that they have rabies vaccine in stock. A list of travel clinics is available on the Colorado Department of Public Health and Environment Immunization Program webpage at www.cdphe.state.co.us/dc/Immunization/travel.html. Primary care providers can also try to order the vaccine for their veterinary staff patients. The insert provides information on pre- and post- exposure prophylaxis, with phone numbers of the vaccine manufacturers, which can be given to a physician.
Local Health Departments
Veterinarians can also try contacting their local health department to inquire about where within their county that pre-exposure prophylaxis vaccination may be available. However, some local health departments do not provide rabies vaccination. According to the results of a recent survey, local health departments that already offer pre-exposure rabies vaccination to high-risk groups include Broomfield, Crowley, El Paso, Garfield, Jefferson, Larimer, Mesa, Mineral, Montrose, the Northwest Colorado Visiting Nurses Association, Otero, Pueblo Rio Grande, San Juan, San Miguel, Tri-County, and Weld. Counties that would be willing to vaccinate their high-risk populations, but traditionally have not done so in the past, include Bent, Boulder, Chaffee, Cheyenne, Conejos, Costilla, Delores, Delta, Denver, Eagle, Elbert, Fremont, Grand, Kit Carson, Lake, Las Animas-Huerfano, Park, Prowers, Rio Blanco, Saguache, and Teller counties. For all of the aforementioned health departments, the rabies vaccine will be ordered upon request, and the cost of the vaccination and administration would likely be passed along to the individual or organization that requested the rabies vaccine. Counties that do not currently offer administration of the pre-exposure vaccination to their high-risk populations are Alamosa, Custer, Gilpin, Hinsdale, Jackson, Lincoln, the Northeast Colorado Health Department, Pitkin, and Summit. Clear Creek County has been unavailable for the survey.
If an exposure to a rabid animal occurs, personnel who were previously vaccinated for rabies with a cell culture vaccine will only have to receive two boosters of rabies vaccine, instead of five doses of vaccine and human rabies immunoglobulin (HRIG). The HRIG is the most expensive portion of the post-exposure prophylaxis, with several ml of HRIG being infiltrated into a large muscle group, with the volume dependent on weight (20 I.U./kg).
For questions related to this article, please contact the Colorado Department of Public Health and Environment, at 303.692.2628.
updated May 2010