Do You Need a Rabies Shot?

Human cases of rabies are rare in the United States—fewer than five people develop the disease per year—but exposure to an animal that might be infected with the fatal viral disease is an understandably worrisome, and far more common, situation.

Every year, about 100,000 people receive a rabies vaccination after contact with a potentially infected animal—often a bat, raccoon, skunk, fox, or unvaccinated dog. Sean Grogan, DO, MS, a Yale Medicine emergency medicine physician and fellow in wilderness medicine, knows the concern firsthand.

A few years ago, Dr. Grogan awoke to find a bat flying around his bedroom. When he tried to catch the bat, it scratched him. “The benefit of catching the bat is that it can then be tested for rabies, but I strongly recommend against trying to do this yourself. Let animal control do the catching instead of risking what happened to me,” Dr. Grogan says.

Rabies spreads primarily through saliva from bites and scratches from an infected animal and attacks the central nervous system. Without timely medical care, it can progress to severe brain disease and is almost always fatal within four weeks of symptom onset, which can take months to years to present. If you’re exposed, it’s important to head to your nearest emergency department (ED) for post-exposure prophylaxis, which includes wound care and a series of vaccines.

Fortunately, the rabies vaccine is extremely effective. “You just need to get treatment soon enough,” Dr. Grogan says.

Worldwide, dogs are responsible for more than 95% of the estimated 70,000 human deaths from rabies each year. In the U.S., however, widespread vaccination among dogs means more than 90% of rabid animals live in the wild, with bats being the primary carriers.

Rabies is most often spread through saliva, typically via a bite. But scratches can transmit the virus, too.

“The reason scratch is in the list of reasons people need a vaccine is that most animals clean themselves regularly, so if they are licking part of their body and then they scratch you with it, it can have saliva on it,” Dr. Grogan explains. “And the thing with bats is that their teeth are so small that they can bite you and you may not see the bite mark at all.”

The initial symptoms of rabies look like the flu and include fever, headache, and weakness. Within two weeks of the first symptoms, people may experience anxiety, confusion, insomnia, seizures, and inflammation in the brain.

“The classic presentation has the nickname of ‘encephalitic rabies,’ due to abnormal, hyperactive behavior,” Dr. Grogan says. “And when it’s become more severe, one of the hallmark symptoms is hydrophobia, or a deathly fear of water. People stop drinking because they get these horrific pharyngeal spasms when they drink.”

Once rabies causes brain involvement, it’s almost always fatal. “There have been some rare case reports of people surviving it, but they usually have significant neurological issues,” he says.

If an animal that could possibly have rabies bites or scratches you, the first step is to take care of the wound, if you have one. “Wash it vigorously with hot, soapy water. That helps reduce the viral load significantly,” Dr. Grogan says. Then go immediately to the nearest ED.

In some instances—for example, if you are certain the animal did not touch you—it is appropriate to call your local health department for guidance. “If they can safely catch the bat, or whatever animal it is, you might not need treatment,” he says. “They usually observe the animal or kill it to take a look at its brain and test for rabies.”

The animal’s behavior is also a clue when it comes to determining risk. “If you are holding an animal and trying to feed it or pet it and it bites you, that is considered ‘provoked.’ But if you are bitten out of nowhere, with the animal coming at you, that is an unprovoked attack—it’s abnormal behavior, and might be an indication of rabies,” he adds.

At the ED, a doctor will determine if you need post-exposure prophylaxis. The rabies vaccine comes in two main types: one grown in human cells and another grown in chick embryo cells. After the initial rabies vaccine injection, doses are given on days three, seven, and 14.

Some people may also receive an injection of human rabies immune globulin (HRIG), which provides immediate antibodies against the virus, before the first vaccine dose. People who were previously vaccinated only need two vaccine doses and do not need HRIG.

“The vaccine gives your body a template so it can make its own antibodies for the rabies virus,” Dr. Grogan explains. “But that takes time, so the immune globulin neutralizes the virus right away.”

The vaccine is injected in the shoulder, while the immune globulin is injected as close to the wound as possible. When the vaccine is deemed medically necessary, health insurance usually covers the cost.

Yes. Pre-exposure prophylaxis vaccination is recommended for people who work directly with animals that could have rabies—such as veterinarians or wildlife workers—or for travelers visiting parts of the world where the disease is common and access to emergency medical care is limited.

For this type of vaccination, two doses are given and protection lasts for up to three years.

When someone comes to urgent care or the hospital because of a dog bite and they are concerned about rabies exposure, doctors often ask the patient if they know the dog and if they have the phone number of the owner.

“People are often worried that they’re going to get the dog in trouble and the dog will be put down, but that’s usually not the case,” Dr. Grogan says. “It’s really so that the dog’s owner or veterinarian can be contacted to confirm the dog’s vaccination status and ensure that the animal is healthy and observed appropriately.”