What is rabies?
Rabies is a viral illness that is nearly always fatal. Symptoms can begin from 5 days to 1 year (typically 2 to 8 weeks) after exposure. Symptoms begin with apprehension and convulsions. Death due to paralysis of the muscles that control breathing occurs in two to six days. The virus is transmitted to humans through the bite of an infected animal or by contact with saliva or when the virus gets into the air. Person-to-person transmission is very rare.
The vaccine virus is collected from infected human diploid cells (HDC), inactivated, and stored in a freeze-dried state. The vaccine (HDCV) contains no preservatives and must be used immediately once reconstituted.
Who should get rabies vaccine?
People are offered rabies vaccine before they are exposed to the disease (pre-exposure) if it is likely that they will be exposed to rabies virus through the course of their work or travel activities. It is also given to people when they are known or suspected to have been exposed (post-exposure) to rabies virus.
The schedule for vaccination depends upon whether the person is getting the vaccine pre- or post-exposure. Pre-exposure vaccination doses may be given by either intradermal or intramuscular route in the upper arm. Post-exposure doses are given by intramuscular route in the upper arm.
Booster doses are indicated when there is frequent or continuous risk of exposure to rabies virus and blood testing indicates no or low levels of immunity against rabies.
The schedule consists of three doses. The second dose is given 7 days after the first vaccination; the third dose is given 21 or 28 days after the first vaccination.
Someone who is exposed and who has never been vaccinated against rabies, should receive 5 doses of rabies vaccine. The first dose should be given as soon as possible after the exposure; the subsequent doses should be received on 3, 7,14, and 28 days after the first vaccination. In addition a dose of Human Rabies Immune Globulin is indicated. This is usually given on the first visit for vaccination or within the first week after immunization with rabies vaccine has begun.
Someone who is exposed but who has been previously vaccinated against rabies should receive 2 additional doses of vaccine. The second dose is given 3 days after the first dose. Human Rabies Immune Globulin is not necessary in these cases.
Possible side effects from the vaccine
- Local reactions include pain, redness, swelling, or itching at the injection site. Mild local reactions are reported by 30-74 % of vaccine recipients.
- Systemic reactions, including headache, nausea, abdominal pain, muscle aches, and dizziness, have been reported by 5-40% of people who received the vaccine.
- Six percent have an allergic reaction 2 to 21 days after vaccination.
- Signs and symptoms include a generalized pruritic rash, angioedema, arthritis, arthralgias, nausea, vomiting, and malaise.
- Less common reactions are fever and difficulty breathing.
- Three cases of neurologic illness resembling Guillain-Barre syndrome have occurred, but the illness went away within 12 weeks.
- Most of these side effects can be treated with the use of antihistamine, and fever/pain reducing medications.
Is there anyone who should not be immunized?
The risk of getting rabies should always be weighed against the risk of side effects from the vaccine or immune globulin. Someone who has had an exposure to rabies should never delay treatment due to concern about side effects.
If you are allergic to the antibiotic Neomycin, please tell the nurse before you are immunized.
Steroids or other drugs or therapies may suppress the immune system and interfere with the ability of the vaccine to stimulate the immune system. A lower level of protection against rabies may result. If possible, drugs or therapies that suppress the immune system should not be used during post exposure. If these drugs or therapies are used, a blood test is essential to be sure that the vaccinations took effect.
Chloroquine, and perhaps mefloquine, may interfere with the vaccine. For international travelers, intradermal doses of rabies vaccine should be given early to allow for the completion of the 3 dose rabies series 30 days or more before the trip. If this is not possible, intramuscular rabies vaccinations should be used instead.
Pregnant women may be vaccinated when the risk of rabies is high. There is no indication that damage to the fetus occurs with this vaccine. Precautions should be used when the person to be immunized has had a previous allergic reaction to rabies vaccine or neomycin.
Questions and reactions
If you have questions about rabies (HDCV) vaccination, please contact Public Health Seattle & King County or call your health care provider. If you experience a severe reaction, contact your health care provider and notify Public Health Seattle & King County.