Clinical Update
2011 Earthquake, Tsunami, and Radiation Release in Japan: Health Information for Humanitarian Aid Workers

The US Department of State and the US Nuclear Regulatory Commission recommend that Americans in Japan remain at least 50 miles (80 km) away from the damaged Fukushima Dai-ichi nuclear power plant.

On March 11, a 9.0 magnitude earthquake occurred off the east coast of Japan and triggered a tsunami. These events killed thousands of people and caused serious, widespread damage to buildings, roads, and power lines, particularly along the east coast of the Tohoku region. For more information about the situation in Japan, please see the US embassy in Japan’s Travel Alert for Japan.

If you are traveling to Japan to assist with recovery efforts, CDC recommends that you take precautions to protect your health and safety. Schedule a visit with a travel medicine provider, ideally 4–6 weeks before you leave, to discuss individualized recommendations.


Your health care provider should ensure that you are up-to-date on routine vaccines, especially tetanus, and you should also receive a hepatitis B vaccination series. Japanese encephalitis is endemic, and flooding from the tsunami may expand the mosquito breeding range, so workers who are in Japan during the summer should consider vaccination against Japanese encephalitis.


Damage to the Fukushima Dai-ichi nuclear power plant after the earthquake and tsunami resulted in a leak of radioactive material from this facility. At this time, the risk of contamination from radioactive materials and the risk of exposure to radiation are thought to be low, especially for anyone staying at least 50 miles from the nuclear power plant. Humanitarian aid workers traveling to Japan should follow guidance from appropriate authorities to ensure their safety. Workers who believe they have been contaminated with radioactive material or exposed to radiation should seek immediate medical care.

Because the risk for contamination with radioactive materials is thought to be low, there is no indication that taking potassium iodide (KI, iodine pills) will become necessary. People who have KI tablets should take them only after being told to do so by a doctor, emergency management officials, or public health authorities. For more information on KI, see the Potassium Iodide webpage on the CDC Radiation website.


Floodwaters, downed power lines, wet electrical outlets, interrupted gas lines, and debris all pose health and safety risks. Any wound or rash can become infected and should be cleaned thoroughly with soap and water. Injuries and infected wounds should be evaluated as soon as possible by a health care professional. Wear sturdy, thick-soled shoes to protect your feet in earthquake and tsunami-affected areas. Avoid downed power lines. For more advice, visit CDC’s information on tsunamis and earthquakes.

Mental Health

Because of the tremendous devastation, loss of life, and worry about radiation, you may find the situation extremely stressful. Keeping items such as family photos, favorite music, or materials that provide spiritual support nearby can offer comfort in such situations. Checking in with family members and close friends from time to time can also be a source of support. For detailed information about mental health resources after a disaster, visit

Food and Water Precautions

Although travelers’ diarrhea is generally considered to be a low risk in Japan, the tsunami could have contaminated water sources. You should follow basic food and water precautions in affected areas: drink only bottled beverages, eat only food that is cooked and served hot, and eat raw fruits and vegetables only if you have washed and peeled them yourself. You should also bring loperamide and an antibiotic for presumptive self-treatment of diarrhea, should it develop. For more information on travelers’ diarrhea, visit

Seeking Care Abroad and Evacuation Planning

Health care resources in some areas of Japan may be nonexistent or strained. You can avoid straining these resources further by avoiding travel to the most affected areas; in the event that you need care, locate a local health care provider and confirm that the facility is operational. It is best to identify a health care provider before leaving the United States.

Your insurance may not cover medical care you receive overseas, so check with your insurance company and, if necessary, consider purchasing supplemental travel health insurance. Because of the continued risk of earthquakes and tsunamis and the possibility that the radiation situation may become more severe, evacuation may be necessary, and you may also consider purchasing evacuation insurance. For more information on travel health and evacuation insurance, see the Travel Insurance and Evacuation Insurance webpage.

After You Return

Illness in returning humanitarian aid workers is rare, but in the event that you become ill, especially with a fever, seek health care immediately, and make sure your provider knows you have recently returned from Japan.

When entering the United States, international travelers and their luggage are screened for contamination with radioactive material. The chances of detecting contamination on a traveler from Japan are extremely small. If contamination is detected, the traveler will be notified and given health information from CDC. In the unlikely event that a high level of contamination is detected in a traveler, CDC will follow up with that person to discuss any health concerns.

Items to Bring With You

Plan for limited or no services, including electricity, safe water, and food distribution systems. Pack to be as self-sufficient as possible, but bring only those items necessary for the trip. Make sure that you pack a basic travel health kit in your carry-on luggage.

For more information, visit CDC’s 2011 Earthquake, Tsunami, and Radiation Release in Japan: Travel Information webpage.