Tick-borne encephalitis (TBE) is caused by tick-borne encephalitis virus (TBE virus). TBE virus is a type of flavivirus. That means it is related to West Nile virus, dengue virus, yellow fever virus, Zika virus and Japanese encephalitis virus. These viruses mostly spread to people through the bite of an insect. While many of these are spread by mosquito bites, TBE virus is spread through tick bites. 

TBE occurs in many parts of Europe and Asia. However, the disease is uncommon in the U.S. Only 12 U.S. travelers were diagnosed with TBE between 2000 and 2023. The U.S. does not recommend the TBE vaccine for all travelers visiting countries where TBE is found. Rather, the vaccine recommendation is based on aspects of the trip, such as length of stay and the chance of being exposed to infected ticks. TBE vaccines have been available for decades in many countries where the disease is common, but the U.S. only approved its first TBE vaccine in 2021. 

The disease

What is tick-borne encephalitis (TBE) and how do you catch it? 

TBE is caused by tick-borne encephalitis virus (TBE virus). The virus survives in ticks where it can spread through eggs to the next generation of ticks. It also spreads from infected animal hosts to uninfected ticks. Small mammals, particularly rodents, are the most efficient hosts. But the virus can also live in larger mammals, like goats, sheep, dogs, cows and horses. People are considered “dead-end” hosts for TBE because although they can be infected, they don’t spread the virus to other ticks or to each other. Most people are infected through the bite of a tick, but about 1 of 100 people are infected after consuming unpasteurized dairy products from infected animals, most often goat milk. 

Many people infected with TBE virus do not have any symptoms. If symptoms occur, they usually start about seven to 14 days after infection, but this timing can be as short as two days and as long as 28 days. The timing is also shorter when people are infected through unpasteurized dairy products. In this scenario, the incubation period is around three to four days. Cases tend to occur seasonally based on when ticks are prevalent in the affected region. 

For people who experience symptoms, the symptoms occur in one or two phases. The first phase includes “flu-like” symptoms, like fatigue, headache, aching back and limbs, nausea, and general malaise. Fevers are common. Sometimes the fevers get very high, particularly in children. This first phase generally lasts a few days. After the initial flu-like illness resolves, those with TBE may not have any symptoms for up to three weeks. After this asymptomatic phase, a sudden high fever may mark the beginning of the second phase of disease. The second phase of disease usually involves the nervous system, causing meningitis (inflammation of the lining of the brain and spinal cord) or encephalitis (inflammation of the brain). Symptoms can include: 

• Altered mental status (e.g., confusion, loss of memory, hallucinations)
• Cognitive dysfunction (e.g., difficulty thinking, paying attention, problem-solving)
• Limb paralysis
• Lack of flexibility
• Difficulty moving
• Seizures or tremors 

Children typically experience milder disease compared with adults. The number of deaths from TBE varies. From 2 to 40 of 100 people with neurological symptoms die from the infection. 

The vaccine

The TBE vaccine protects against disease caused by TBE virus. TBE vaccine is considered a travel vaccine, but not all travelers need to be vaccinated. Most people will benefit from taking steps to avoid tick bites, such as using insect repellent that contains DEET (N,N-diethyl-3-methylbenzamide), wearing protective clothing, and checking themselves for ticks. People traveling in areas where TBE is occurring should also avoid consuming unpasteurized dairy products.

People recommended to get the vaccine include those traveling to areas where TBE is occurring during the time of year when disease is prevalent and whose activities increase their risk for exposure, such as hiking, camping, hunting, fishing or other activities in wooded areas where ticks are likely. Other factors, such as length of trip, personal risk for severe disease, and likelihood for multiple exposures over time should also be considered. If you are not sure whether you need the TBE vaccine before a trip, talk to your healthcare provider or schedule an appointment at a travel medicine clinic. See “Vaccine Considerations for Travelers” webpage.

People who work with TBE virus in a laboratory setting are also recommended to get the vaccine, but those who handle clinical specimens do not typically need to be vaccinated. Individuals should talk with their occupational safety team if they are unsure whether they should get TBE vaccine based on their work.

The vaccine is given as a series of three shots:

• Children 1 to 15 years of age: The second dose is given one to three months after the first dose, and the third dose is given five to 12 months after the second dose.
• People 16 years and older: The second dose is given 14 days to three months after the first dose, and the third dose is given five to 12 months after the second dose. 

A fourth dose may be given as a booster three or more years after the third dose if someone remains at risk for TBE or has recently been exposed. 

How is the TBE vaccine made?

The TBE vaccine is made by taking whole TBE virus and killing it with the chemical formaldehyde. The dead virus cannot replicate, so the vaccine cannot cause TBE disease in people who receive it. See “How Are Vaccines Made?”

How does the TBE vaccine work?

The inactivated TBE virus causes the immune system to make a protective immune response without causing TBE disease. 

Does the TBE vaccine have side effects?

The TBE vaccine can cause mild side effects, such as pain or soreness where the shot was given. Children up to 15 years of age may have a headache, fever or restlessness after receipt of the vaccine. People 16 years and older may experience tiredness, headache and muscle aches. Side effects occur in the first few days after receipt of the vaccine and are not long lasting.

Other questions you might have

Where can I get the TBE vaccine if I need it?

The TBE vaccine is not a routinely recommended vaccine, so most healthcare provider offices and pharmacies will not have it readily available. Travel clinics are more likely to have the vaccine. Having an appointment with a travel medicine expert is useful for finding out about a variety of considerations before, during and after travel. Travel medicine clinicians will ask about where exactly you are going, for how long, and what activities you will be doing. This information can help them offer guidance not only about vaccines, but also about other health-related considerations as well. Also to note, since it takes time to get the three doses, it is important to discuss your travel plans with a provider as soon as possible. See “Vaccine Considerations for Travelers” webpage.

You can also check with your local public health department to see if they are aware of where you can get the vaccine. 

What if I am traveling with an infant too young for the vaccine?

The TBE vaccine is not recommended for those less than 1 year of age, so you will need to try to protect them from tick bites in other ways. Insect repellants should not be used on infants less than 2 months of age, and for those older than 2 months, the percent of DEET (N,N-diethyl-3-methylbenzamide) should be 10% or less. Combination products that contain insect repellant and sunscreen are not recommended since sunscreen may need to be reapplied.

You can also make sure the baby’s clothing is light-colored (to better spot ticks) and covers their skin, such as long sleeves and pants, closed-toe shoes, socks and a hat. If they have longer hair, keep it secured close to their head, so a tick doesn’t get into their hair and onto their scalp. Pant legs can be tucked into the socks to protect their ankles. Always check the entire family for ticks after being outside.

Finally, make sure infants or other family members do not consume unpasteurized dairy products if you are in an area where TBE is circulating.

Relative risks and benefits

Do the benefits of the TBE vaccine outweigh the risks?

TBE disease does not occur in the U.S., and only 12 cases have been reported in U.S. travelers between 2000 and 2023. Even when people go to areas of Europe and Asia where TBE disease is occurring, most people are at minimal risk for exposure. A person’s risk depends on their likelihood for exposure to infected ticks, so when they are traveling as well as their activities and length of stay inform their individual risk. 

Even when people do get TBE, most do not experience symptoms. The disease can be fatal or cause lasting damage resulting from the effects of the virus on the nervous system, so some people can benefit from vaccination prior to travel. 

People who may be exposed to the virus because they work with it in a laboratory setting may also benefit from vaccination.

Taken together, even though the vaccine is safe, it is only recommended for a limited number of people in the U.S. based on risk of disease.

Disease risks

• Fever, headache, nausea, vomiting, weakness
• Encephalitis (inflammation of the brain and spinal cord)
• Meningitis (inflammation of the brain)
• Lasting difficulties with memory or concentration
• Paralysis of arms or legs or difficulty speaking
• Death

Vaccine risks

• Pain or soreness at the injection site
• Headache, fever or restlessness in people 1 to 15 years of age
• Tiredness, headache and muscle aches in people 16 years and older

Reference

• Orenstein WA, Offit PA, Edwards KM and Plotkin SA. Ebola Vaccines in Plotkin's Vaccines, 8th Edition. 2024, 1142-1157.

Reviewed by Paul A. Offit, MD, on June 24, 2025.