Thru-hiking the Appalachian Trail can be the experience of a lifetime. It's a chance to spend several months out in nature, simply seeing the sights and moving your body. It is important, however, to prepare for such an adventure. And part of that preparation is getting the necessary immunizations to protect yourself from disease. Here are the key immunizations to consider prior to your thru-hike.
Tetanus is an infection caused by the bacterium Clostridium tetani. It causes severe muscle stiffness, including locking of the jaw, which makes it very difficult to manage and treat. Tetanus bacteria live in the dirt and can be introduced to your body through a cut or wound. Most people are routinely vaccinated for tetanus, but if your vaccine is not up to date, you should get another one before heading out on the AT. You would not want a simple scratch from a rock to turn into a medical emergency that takes you off the trail.
Tick-borne encephalitis is a disease carried by certain species of ticks. It causes brain swelling and a host of related symptoms such as confusion, dizziness, nausea, and loss of consciousness. TBE vaccines have more recently become available in the United States and are a good idea for anyone who is going to be spending lots of time out in nature, including thru-hikers. A TBE vaccine does not mean you won't still need to be careful about ticks. Ticks can also carry other diseases, such as Lyme and anaplasmosis, and there are no human vaccines for those diseases. Get your TBE vaccine, and also take other tick prevention methods, such as treating your clothing with permethrin.
Most thru-hikers spend their time out in the fresh air, away from other humans. However, there may be times when you sleep in a crowded lean-to or a hostel, in which case, you could be exposed to the influenza virus. Getting the flu while on the trail can be frustrating since it will hold you up. You also risk spreading it to others. Getting your flu shot will help reduce the transmission of the flu in general while also protecting you personally.
Hiking the AT is bound to be an experience you will remember forever. Just make sure it's not an experience that ends with you becoming ill with a preventable disease. Get vaccinated for the conditions above, and stay safe.