Here is the official word on the subject of shots:
Health Information for Travelers to Mexico and Central America
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Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama
NOTE: Please check the Outbreaks section for important updates on these and other countries
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To find out about current U.S. Department of State travel warnings and public announcements, see
http://travel.state.gov
Food and waterborne diseases are the number one cause of illness in travelers. Travelers diarrhea can be caused by viruses, bacteria, or parasites, which are found throughout the region and can contaminate food or water. Infections may cause diarrhea and vomiting (E. coli, Salmonella, cholera, and parasites), fever (typhoid fever and toxoplasmosis), or liver damage (hepatitis). Make sure your food and drinking water are safe. (See below.)
Malaria is a serious, but preventable infection that can be fatal. Your risk of malaria may be high in these countries, including cities. Prevent this deadly disease by seeing your health care provider for a prescription antimalarial drug and by protecting yourself against mosquito bites (see below).
Malaria risk exists in some parts of Mexico and Central America. Travelers to malaria-risk areas, including infants, children, and former residents of Mexico and Central America, should take an antimalarial drug.
Chloroquine is the recommended drug for Mexico, Belize, Guatemala, El Salvador, Nicaragua, Honduras, Costa Rica, and the Bocas Del Toro Province of Panama.
Travelers to Darién Province and San Blas Province in Panama (including the San Blas Islands) should take one of the following antimalarial drugs: (listed alphabetically): atovaquone/proguanil, doxycycline, mefloquine, or primaquine (in special circumstances).
For additional information on malaria risk and prevention, see Malaria Information for Travelers to Central America and Mexico. See also Preventing Malaria in the Pregnant Woman (Information for the Public) and Preventing Malaria in Infants and Children (Information for the Public).
A yellow fever vaccination certificate may be required for entry into certain of these countries if you are traveling from a country in tropical South America or sub-Saharan Africa. For detailed information, see Comprehensive Yellow Fever Vaccination Requirements. Also, find the nearest authorized U.S. yellow fever vaccine center.
Dengue, filariasis, leishmaniasis, onchocerciasis, and American trypanosomiasis (Chagas disease) are diseases carried by insects that also occur in this region. Protecting yourself against insect bites (see below) will help to prevent these diseases.
Because motor vehicle crashes are a leading cause of injury among travelers, walk and drive defensively. Avoid nighttime travel if possible and always use seat belts.
CDC recommends the following vaccines (as appropriate for age):
See your doctor at least 46 weeks before your trip to allow time for immunizations to take effect.
Hepatitis A or immune globulin (IG).
Hepatitis B, if you might be exposed to blood (for example, health-care workers), have sexual contact with the local population, stay longer than 6 months, or be exposed through medical treatment.
Rabies, if you might be exposed to wild or domestic animals through your work or recreation.
Typhoid, particularly if you are visiting developing countries in this region.
Yellow fever for travelers to Panama who will be going outside urban areas.
As needed, booster doses for tetanus-diphtheria and measles. Hepatitis B vaccine is now recommended for all infants and for children ages 1112 years who did not receive the series as infants.
To stay healthy, do...
Wash hands often with soap and water.
Drink only bottled or boiled water, or carbonated (bubbly) drinks in cans or bottles. Avoid tap water, fountain drinks, and ice cubes. If this is not possible, make water safer by BOTH filtering through an absolute 1-micron or less filter AND adding iodine tablets to the filtered water. Absolute 1-micron filters are found in camping/outdoor supply stores.
Eat only thoroughly cooked food or fruits and vegetables you have peeled yourself. Remember: boil it, cook it, peel it, or forget it.
If you will be visiting an area where there is risk for malaria, take your malaria prevention medication before, during, and after travel, as directed. (See your doctor for a prescription.)
Protect yourself from mosquito bites:
Pay special attention to mosquito protection between dusk and dawn. This is when the type of mosquito whose bite transmits malaria is active.
Wear long-sleeved shirts, long pants, and hats.
Use insect repellents that contain DEET (diethylmethyltoluamide).
Read and follow the directions and precautions on the product label.
Apply insect repellent to exposed skin.
Do not put repellent on wounds or broken skin.
Do not breathe in, swallow, or get into the eyes (DEET is toxic if swallowed). If using a spray product, apply DEET to your face by spraying your hands and rubbing the product carefully over the face, avoiding eyes and mouth.
Unless you are staying in air-conditioned or well-screened housing, purchase a bed net impregnated with the insecticide permethrin or deltamethrin. Or, spray the bed net with one of these insecticides if you are unable to find a pretreated bed net.
DEET may be used on adults, children, and infants older than 2 months of age. Protect infants by using a carrier draped with mosquito netting with an elastic edge for a tight fit.
Children under 10 years old should not apply insect repellent themselves. Do not apply to young childrens hands or around eyes and mouth.
For details on how to protect yourself from insects and how to use repellents, see Protection against Mosquitoes and Other Arthropods.
If you are visiting friends and relatives in your home country in areas where malaria occurs, please read the malaria prevention recommendations for recent immigrants on the CDC malaria site.
To prevent fungal and parasitic infections, keep feet clean and dry, and do not go barefoot.
Always use latex condoms to reduce the risk of HIV and other sexually transmitted diseases.
To avoid getting sick...
Dont eat food purchased from street vendors.
Dont drink beverages with ice.
Dont eat dairy products unless you know they have been pasteurized.
Dont share needles with anyone.
Dont handle animals (especially monkeys, dogs, and cats), to avoid bites and serious diseases (including rabies and plague). (For more information, please see Animal-Associated Hazards.)
Dont swim in fresh water. Salt water is usually safer. (For more information, please see Swimming and Recreational Water Precautions.)
What you need to bring with you:
Long-sleeved shirt, long pants, and a hat to wear while outside whenever possible, to prevent illnesses carried by insects (e.g., malaria, dengue, and leishmaniasis).
Insect repellent containing DEET.
Bed nets impregnated with permethrin. (Can be purchased in camping or military supply stores. Overseas, permethrin or another insecticide, deltamethrin, may be purchased to treat bed nets and clothes.)
Flying-insect spray or mosquito coils to help clear rooms of mosquitoes. The product should contain a pyrethroid insecticide; these insecticides quickly kill flying insects, including mosquitoes.
Over-the-counter antidiarrheal medicine to take if you have diarrhea.
Iodine tablets and water filters to purify water if bottled water is not available. See Dos above for more details about water filters.
Sunblock, sunglasses, hat.
Prescription medications: make sure you have enough to last during your trip, as well as a copy of the prescription(s).
After you return home:
If you have visited a malaria-risk area, continue taking your antimalarial drug for 4 weeks (chloroquine, doxycycline, or mefloquine) or seven days (atovaquone/proguanil) after leaving the risk area.
Malaria is always a serious disease and may be a deadly illness. If you become ill with a fever or flu-like illness either while traveling in a malaria-risk area or after you return home (for up to1 year), you should seek immediate medical attention and should tell the physician your travel history.
For more information:
Ask your doctor or check the CDC web sites for more information about how to protect yourself against diseases that occur in Mexico and Central America, including the following:
Diseases carried by insects
Dengue
Malaria
- Frequently asked questions
- Prescription drugs
Diseases carried in food or water
Escherichia coli diarrhea
Hepatitis A
Typhoid fever
Diseases from person-to-person contact
Hepatitis B
HIV/AIDS
- Prevention
- HIV-infected travelers
For more information about these and other diseases, please check the Diseases page and CDC Health Topics AZ.
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This document is not a complete medical guide for travelers to this region. Consult with your doctor for specific information related to your needs and your medical history; recommendations may differ for pregnant women, young children, and persons who have chronic medical conditions. In addition, you may also check the following CDC sites:
Malaria: Frequently Asked Questions
Preventing Malaria in the Pregnant Woman (Information for the Public)
Preventing Malaria in the Pregnant Woman (Information for Health Care Providers)
Preventing Malaria in Infants and Children (Information for the Public)
Preventing Malaria in Infants and Children (Information for Health Care Providers)
Prescription Drugs for Preventing Malaria (Information for the Public)
Prescription Drugs for Preventing Malaria (Information for Health Care Providers)
Vaccine Recommendations for Infants and Children
Food and Water Precautions and Travelers' Diarrhea Prevention
Be sure to read the information about all the regions you are planning to visit.
I'm guessing the pools won't be filled with Evian. 
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