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Summer 2020 - Vaccines

Rabies: A Physician’s Perspective

Dr. John J. RossJOHN J. ROSS, MD, is an associate physician and hospitalist at Brigham and Women’s Hospital, Boston, an assistant professor of medicine at Harvard Medical School and a fellow of the Infectious Diseases Society of America.

BSTQ: What should medical professionals know about rabies?

Dr. Ross: While rabies is rare in the United States, it retains a disproportionate importance because of its historic 100 percent fatality rate. Hospitalists should know this about rabies: Suspect rabies in all patients with undiagnosed neurological disease. Making the diagnosis of rabies as early as possible is more critical than ever, now that a potential treatment exists. Unfortunately, in the U.S., rabies is rarely considered when patients first present for medical attention.

BSTQ: What are the symptoms?

Dr. Ross: During the prodromal phase of rabies, which lasts about four days, patients have nonspecific symptoms of fever, malaise and nausea. This is quickly followed by paresthesia at the bite or wound site, personality change and hallucinations, and the classic manifestations of “furious rabies”: agitation, delirium, hydrophobia, aerophobia, aggression and spasms affecting swallowing and respiration. In up to 20 percent of patients, the disease may present in atypical form as “dumb rabies,” an ascending paralysis that may mimic Guillain-Barré syndrome.

BSTQ: How is rabies diagnosed?

Dr. Ross: Tests for rabies include polymerase chain reaction of cerebrospinal fluid or saliva, antibody testing of serum and cerebrospinal fluid, and direct fluorescent antibody of biopsy from the nape of the neck, where the virus congregates in hair follicles.

BSTQ: What questions should physicians ask if they suspect rabies exposure?

Dr. Ross: Ask all patients about bat and animal exposure when rabies is in the differential. Worldwide, there are 55,000 cases of human rabies a year, the vast majority of which occur in developing countries as a result of dog bites. In the U.S., there are only a handful of human cases of rabies each year, almost always associated with bat exposure. It is not necessary to get a bat bite or scratch to be at risk for rabies. Some U.S. patients seem to have contracted rabies after exposure to bat saliva or vapors, sometimes having been bitten while asleep. Any patient who wakes up in a room or cabin and finds a bat should be considered at risk for rabies. Other animals commonly infected with rabies in the U.S. include raccoons, skunks and foxes. Unvaccinated dogs and cats also are at risk of transmitting rabies.

BSTQ: What is the prescribed treatment plan for rabies exposure?

Dr. Ross: Post-exposure prophylaxis with rabies vaccine is still the mainstay of prevention. Sometimes antibodies to rabies are given as well. There are no other proven therapies to prevent or treat rabies.

BSTQ: What are the best ways to avoid rabies infection?

Dr. Ross: Consider prevention the best treatment. If a patient is bitten by an animal, wash bite wounds with 20 percent soap and irrigate with povidone-iodine to reduce the risk of rabies by up to 90 percent. If the biting animal is available for observation, the rabies vaccine may be deferred or not administered at all if the animal is well after 10 days. Many state laboratories will also perform rabies testing on euthanized animals. If the biting animal is unavailable for observation, promptly give the rabies vaccine and immune globulin.

BSTQ: Are rabies vaccines safe?

Dr. Ross: Current rabies vaccines are safe and highly effective in preventing infection after exposure, provided they are given in a timely fashion. Vaccine and immune globulin have no role in treatment once rabies symptoms have developed.

BSTQ: What is the biggest misconception about post-exposure treatment?

Dr. Ross: Many people are still leery about getting rabies vaccine, as the older version of the vaccine consisted of several large and painful shots in the belly with significant side effects. No shots in the stomach are required! The current version of the vaccine consists of four shots in the shoulder muscle over four weeks. Side effects are usually limited to soreness at the injection site, which is much better than dying of an untreatable brain infection.

BSTQ: Jeanna Giese-Frassetto is the first known survivor of rabies without a vaccine. Is her treatment method (now known as the Milwaukee Protocol) still being used? And, if so, have other patients survived without a vaccine?

Dr. Ross: Jeanna Giese-Frassetto is still the only person to have survived rabies without vaccination. Further experience with the Milwaukee Protocol has been profoundly disappointing. There have been at least more than 40 other patients reported in the research literature who died despite receiving the Milwaukee Protocol. Some specialists believe some of the components of the Milwaukee Protocol such as therapeutic coma are actually harmful and should be avoided.

Trudie Mitschang
Trudie Mitschang is a contributing writer for BioSupply Trends Quarterly magazine.