Rabies Vaccine: How It Works and When You Need It

Rabies only rarely affects humans in the United States. But for people who do contract the virus, it's almost always fatal without prompt medical care.

This serious virus, which is typically transmitted via animal bites and scratches, attacks the central nervous system, explains William R. Dodge, MD, an emergency medicine physician with Providence Mission Hospital in Mission Viejo, California.

Once the virus reaches your brain, it causes neurological symptoms, like confusion, hallucinations, and seizures, followed by coma and eventually death.

That's why you'll want to contact a doctor right away if you've received a bite or scratch from a wild animal or unvaccinated pet, Dodge says, even if you aren't sure they have rabies.

Here's the good news: The rabies vaccine can protect you from the virus. But you'll typically get this vaccine after exposure to the virus, unlike preventive vaccines that you get before potentially contracting a condition.

Below, find answers to seven commonly asked questions about the rabies vaccine, including why it's so important and how to tell when you need it.

"Getting a rabies vaccine immediately after a bite from an animal that might have rabies can jumpstart your body's fight against the virus," Dodge says.

The rabies vaccine triggers your immune system to produce antibodies, Dodge explains. These special proteins can recognize foreign invaders, like viruses, and destroy them.

The rabies vaccine may prevent you from getting the virus if you receive it as soon as possible — ideally within 1 to 2 days of exposure.

The incubation period for the rabies virus typically ranges from a few days to several months. During the incubation period, you won't experience symptoms because the virus has yet to reach your brain. Once the virus reaches your brain and symptoms develop, the vaccine can no longer offer protection.

FYI
Adults and older children will receive the rabies vaccine in the shoulder muscle, while younger children and babies will receive injections in the thigh muscle.

Your pets might get a yearly rabies booster or one every few years. But humans often need multiple injections for full protection.

The number of doses you'll need depends on two things: whether you've had a rabies vaccine in the past and the type of exposure you're receiving treatment for.

It's essential to get medical attention as soon as possible after a bite from an animal that could have rabies, even if you've recently had a rabies vaccine booster, Dodge emphasizes.

"Depending on your risk of coming into contact with a rabid animal in the future, your doctor might recommend getting another booster within 3 years after your first two doses," Dodge says.

The most common side effects of the rabies vaccine include:

pain at the injection site
skin discoloration
swelling
induration, or hardening or thickening of the skin at the injection site

These mild, local reactions typically go away within a few days. You can usually treat them with over-the-counter medications like ibuprofen or acetaminophen.

You might also experience:

If you experience any of these symptoms, Dodge advises contacting your doctor. They can monitor your symptoms and offer more guidance on options for relief.

Keep in mind that if you may have been exposed to rabies, you'll need to get the vaccine even if you're immunocompromised, pregnant, breastfeeding or chestfeeding, or have existing health conditions. This is because rabies is almost always fatal.

Before getting vaccinated, let your doctor know if you've ever had an allergic reaction to a vaccine. They can monitor you for signs of an allergic reaction after you receive the rabies vaccine.

Unlike most other vaccines, you typically only receive the rabies vaccine after you've had exposure or potential exposure to the virus. You may also choose to get the vaccine if you plan to travel to countries where rabies is endemic, or regularly found.

Any mammal can carry rabies, including both wild animals and unvaccinated pets, such as:

bats
raccoons
skunks
squirrels
foxes
dogs
coyotes
cats
ferrets

The virus lives in saliva and brain and nervous system tissue. So an animal with rabies doesn't have to bite you to transmit the virus. You could contract the virus from a scratch, or even a lick.

If you have any doubts about an animal's vaccine status, you should assume it may have rabies and contact your doctor immediately if the animal:

scratches you, even if the scratch doesn't bleed
nibbles uncovered skin
bites you, even if it doesn't bleed
licks your skin

Maybe you came into contact with an animal that could have rabies, but don't know for sure if the animal bit you. For example, you might wake up to find a bat in your bedroom. In this case, you should assume it bit you and call your doctor or head to the emergency room immediately.

You'll typically only receive a preventive rabies vaccine if you:

work with or frequently come in contact with animals — examples include veterinarians, animal control officers, and animal quarantine facility staff
plan to spend a month or longer in an area of the world where rabies is common
plan to participate in activities that may expose you to rabid animals, like hiking in the wilderness, in areas where rabies is common

The rabies vaccine does not provide lifelong protection. Protection can last for anywhere from 6 months to 2 years, depending on how many doses you've had.

For example, if you get two doses of the rabies vaccine as a preventive measure, you'll need a booster dose in 2 years if you still have a high risk of exposure to rabies.

If you get all four doses of the vaccine after exposure to rabies, you'll need the vaccine again if you're exposed to the virus again.

The out-of-pocket cost of the rabies vaccine ranges from about $1,200 to $6,500.

When medically necessary — after a bite from a stray dog or wild squirrel, for instance — health insurance will usually cover the vaccine.

Your health insurance provider may not cover preventive vaccines given before exposure. Those are generally considered elective rather than medically necessary.

If you think you may have been exposed to rabies, your best option is to head to your nearest emergency room (ER).

Many primary care and urgent care clinics don't administer this vaccine. So, if you make an appointment with your regular doctor and they recommend a rabies vaccine, they'll typically send you to the ER anyway.

If you want to get the vaccine as a preventive measure, you can make an appointment at some pharmacies, including certain CVS and Walgreens locations.

Thanks to widespread animal vaccination, rabies has significantly declined in the United States. But if you do happen to encounter an unvaccinated or wild animal, a postexposure rabies vaccine can save your life.

When administered in time, the rabies vaccine can help your immune system fight off the virus effectively. The sooner you get it after exposure, the greater your chances of protecting yourself.

Always contact your doctor immediately after receiving a scratch or bite from an animal if you don't know its vaccination status.

Rebecca Strong is a Boston-based freelance writer covering health and wellness, fitness, food, lifestyle, and beauty. Her work has also appeared in Insider, Bustle, StyleCaster, Eat This Not That, AskMen, and Elite Daily.