Rabies Immunization Description
KEY POINTS
Rabies is virtually uniformly fatal and animal bites or scratches or contact with their saliva can transmit the virus.
Outside the U.S., dogs and cats are the main source of rabid illness. In the U.S., domesticated animals are almost universally vaccinated against rabies, but often not at all in other countries. Bats are the most frequent source of U.S. rabies. Whether a rabies vaccinated animal is "safe" has to do with when its last vaccination was done and is next due and whether the animal has any problem that might weaken its immune system. This issue requires expert review.
PRE-EXPOSURE VACCINATION is recommended for,
Individuals spending substantial time in Third World countries.
Substantial exposure to stray, wild, undomesticated animals.
Expatriates.
POST-EXPOSURE VACCINATION is indicated for bites, scratches, or saliva exposure to rabies animal vectors.
Rabies vaccine shots are no more uncomfortable than flu shots (minimally), contrary to those 40 – 50 yrs. ago.
DISEASE: A central nervous system infection with rabies virus manifested by symptoms of encephalitis (brain inflammation)
SYMPTOMS/SIGNS:
1. Pain
2. Behavioral Changes
3. Seizures
4. Paralysis
5. Coma
6. Choking
PROGNOSIS: Almost invariably fatal, usually within 7 days of illness onset
Incubation: Several weeks – months (avg = 2 months), but range is 5 days – to over a year (1 documented case more than 19 yrs)
PREVALENCE:
Worldwide, EXCEPT FOR New Zealand, most South Pacific Islands, and Antarctica. Southeast Asia, Africa, and India lead in cases.
In the U.S., most cases are from wild animals, by far bats; also, skunks, raccoons, coyotes, foxes, and livestock. In other countries, most rabies is from unvaccinated domestic animals (dogs and cats).
TRANSMISSON:
Animal bites – especially to the face and hands
Scratches
Saliva (licks)
Airborne (caves with bats)
NOTE:
Touching rabid animals, their fur, blood, urine, or feces is not a valid exposure and does not require prophylaxis. Only contact with saliva.
Animals may not appear sick or ferocious when infected with rabies; in fact, they may be docile.
TREATMENT: None for the virus, other than as described below, under “Prevention”
PREVENTION:
Avoid contact with wild animals or unvaccinated pets.
Thorough washing with soap and water for several minutes of any animal-related wound or saliva contaminated tissue.
PRE-EXPOSURE RABIES PREVENTION PROTOCOL
2 vaccine doses – day 0 and day 7 (perhaps more in immune-compromised individuals).
Boosters – to be given per waning of immunity as determined by rabies antibody blood tests every 6 months (continuous exposure) or every 2 yrs (frequent exposure); the schedule is to be individualized.
Rabies shots are no more uncomfortable than flu shots (minimally), contrary to those 40 – 50 yrs ago.
POST EXPOSURE:
PREVIOUSLY RABIES UNIMMUNIZED,
Human Rabies Immunoglobulin (HRIG) x 1, intramuscular
Vaccine: day 0, 3, 7, 14 (and 28 in the immune-compromised)
PREVIOUSLY RABIES IMMUNIZED: days 0 and 3 (vaccine alone*)
*HRIG should also be given if immune compromised
NOTE: This protocol should be started ASAP after exposure,
unless uncertain if animal was rabid -
if so, can quarantine animal 10 days (cats, dogs, ferrets only) and
obviate the immunization protocol altogether if the animal remains well.
VACCINE TARGETS
Pre-Exposure
Increased risk of rabies virus exposure by occupation or residence
Travelers with extensive outdoor activities and exposed to animals, where immediate access to appropriate medical care is questionable
Children in rabies virus endemic areas
Post-Exposure
Depends on type of contact (consult Infectious Diseases rabies specialist)
VACCINE SIDE-EFFECTS
Mild, local (30 – 75%): Injection site pain, inflammation
Mild, systemic (5-40%): Headache, nausea, abdominal pain, muscle aches, local gland swelling, fever, dizziness
Hives, itching, malaise, 2-21 days post booster doses (6%)
Rare, usually self-resolving neurological reactions (such as Guillain-Barré syndrome)
VACCINE PRECAUTIONS/CONTRAINDICATIONS
With moderate current, unrelated illness, consider postponing pre-exposure vaccination. (discuss with rabies expert physician)
Hypersensitivity to neomycin sulfate
Immunocompromised persons should be vaccinated by IM (intramuscular) route and have a blood test to confirm adequate rabies antibody production post-vaccine series.
Pregnancy is not a contraindication to post exposure preventive protocol.
Note: The rabies vaccine is killed, and so cannot cause rabies.