What Happens if Rabies Exposures Are Not Treated?

For individuals who have been exposed to the rabies virus, failing to get postexposure prophylaxis is almost invariably fatal. Rabies has the highest case fatality rate of any infectious disease. There are only 6 documented cases of survival.1,2

Even preexposure vaccination may need additional postexposure prophylaxis to be fully effective.2

Female medical professional holding a box of human rabies immune globulin (HRIG).

The Symptoms of Rabies in Humans2,3

In humans, the incubation period for rabies is usually several weeks to months. However, it can be as short as a few days or as long as a year. Following the onset of an acute neurological syndrome (encephalitis), rabies can manifest 2 ways in humans. The first is marked by hyperactivity. This is referred to as “furious rabies” and presents in two-thirds of rabies cases. 

Furious rabies is characterized by3:

  • Persistent fever
  • Agitation
  • Confusion
  • Seizures

The presence of hydrophobia, aerophobia, hypersalivation, and dysphagia distinguish it from other forms of encephalitis.
Rabies may also manifest as a paralytic syndrome (known as dumb rabies). This form is marked by ascending paralysis or symmetric quadriparesis. 

Symptoms of paralytic syndrome rabies may include3:

  • Piloerection
  • Fasciculations
  • Persistent fever
  • Myoedema
  • Bladder dysfunction

Death results 7-10 days after the first sign of symptoms—usually by cardiac or respiratory failure.3

Is There a Treatment for Rabies?

No. There is no recognized medical treatment with proven efficacy after the development of clinical signs of rabies.2

Learn More About Human Exposure and the Effect of Failing to Receive PEP for Rabies

Postexposure Prophylaxis Is the Only Proven Approach to Addressing Rabies Exposure2

Important Safety Information for HyperRAB® (rabies immune globulin [human])

Indication and Usage
HYPERRAB® (rabies immune globulin [human]) is indicated for postexposure prophylaxis, along with rabies vaccine, for all persons suspected of exposure to rabies.

Limitations of Use
Persons who have been previously immunized with rabies vaccine and have a confirmed adequate rabies antibody titer should receive only vaccine. For unvaccinated persons, the combination of HYPERRAB and vaccine is recommended for both bite and nonbite exposures regardless of the time interval between exposure and initiation of postexposure prophylaxis. Beyond 7 days (after the first vaccine dose), HYPERRAB is not indicated since an antibody response to vaccine is presumed to have occurred.

Important Safety Information

For infiltration and intramuscular use only.

Severe hypersensitivity reactions may occur with HYPERRAB. Patients with a history of prior systemic allergic reactions to human immunoglobulin preparations are at a greater risk of developing severe hypersensitivity and anaphylactic reactions. Have epinephrine available for treatment of acute allergic symptoms, should they occur.

HYPERRAB is made from human blood and may carry a risk of transmitting infectious agents, eg, viruses, the variant Creutzfeldt-Jakob disease (vCJD) agent, and, theoretically, the Creutzfeldt-Jakob disease (CJD) agent.

The most common adverse reactions in >5% of subjects during clinical trials were injection-site pain, headache, injection-site nodule, abdominal pain, diarrhea, flatulence, nasal congestion, and oropharyngeal pain.

Do not administer repeated doses of HYPERRAB once vaccine treatment has been initiated as this could prevent the full expression of active immunity expected from the rabies vaccine.

Other antibodies in the HYPERRAB preparation may interfere with the response to live vaccines such as measles, mumps, polio, or rubella. Defer immunization with live vaccines for 4 months after HYPERRAB administration.

Please see full Prescribing Information for HYPERRAB.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088


  1. Nigg AJ, Walker PL. Overview, prevention, and treatment of rabies. Pharmacotherapy. 2009;29(10):1182-1195.
  2. Manning SE, Rupprecht CE, Fishbein D, et al. Human rabies prevention—United States, 2008: recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep. 2008;57(RR-3):1-28. 
  3. Crowcroft NS, Thampi N. The prevention and management of rabies. BMJ. 2015;350:g7827.