Last updated 4 months ago. Our resources are updated regularly but please keep in mind that links, programs, policies, and contact information do change.

More than half of Americans traveling to developing countries get sick during their trips. About 8% end up seeking medical care for travel-related illness.

These aren’t just minor inconveniences—they can mean significant medical expenses and, in some cases, life-threatening situations.

The Centers for Disease Control and Prevention provides science-based guidance to help Americans travel safely worldwide. As the nation’s leading public health agency, the CDC’s mission extends beyond U.S. borders to protect people from health threats globally.

This guide helps you understand and use the CDC’s tools, particularly Travel Health Notices, to prepare for your journey, stay healthy abroad, and protect your community when you return.

The CDC’s Global Health Guardian Role

Core Mission and Reach

The Centers for Disease Control and Prevention protects health and safety by controlling and preventing disease, injury, and disability in the United States and worldwide. While its work covers chronic diseases and workplace safety, the CDC has dedicated centers focused specifically on global health, infectious diseases, and travelers’ health.

This specialized focus makes the CDC the authoritative source for U.S. travelers seeking to understand and mitigate health risks before leaving home. The agency’s recommendations aren’t suggestions—they’re cornerstones of safe travel planning, grounded in extensive scientific research and global health expertise.

A Global Disease Surveillance Network

The travel health guidance on the CDC website results from a vast, interconnected global health security network. It’s informed by constant data flow from around the world through the International Health Regulations (IHR), a binding agreement among 196 countries, including the United States.

Under the IHR, member countries must build and maintain capacity to detect, assess, report, and respond to public health threats that could cross borders. When a country identifies a potential Public Health Emergency of International Concern, it must assess the risk within 48 hours and, if deemed notifiable, report it to the World Health Organization within the next 24 hours.

This rapid reporting is crucial because diseases can spread from remote villages to major cities on any continent in as little as 36 hours.

The CDC’s Global Role

The CDC works directly with countries to help them comply with IHR standards, strengthen public health infrastructure, and develop National Action Plans for Health Security. The agency has trained over 18,000 “disease detectives” through Field Epidemiology Training Programs in more than 80 countries.

These on-the-ground experts often first identify and investigate outbreaks. Their data, along with information from surveillance networks like GeoSentinel (a CDC-International Society of Travel Medicine collaboration), flows through this global system.

When the CDC issues a Travel Health Notice, it represents the final output of this complex global intelligence apparatus—an alert backed by international treaties, global surveillance, and scientific investigation.

Understanding CDC Travel Health Notices

The CDC uses two distinct systems for Travel Health Notices. One is the standard system for general health threats, and another was adapted for COVID-19’s unique challenges.

The Standard 3-Level System

A Travel Health Notice is an official CDC alert informing travelers and healthcare providers about current health issues that could affect them abroad. These range from disease outbreaks like Ebola or Cholera to risks from natural disasters or large international gatherings.

Level 3: Warning (Orange)

Recommended Action: Avoid Nonessential Travel

This is the highest alert level, signifying serious health risk at the destination, often due to large-scale outbreaks of severe diseases where protective measures may be limited or difficult to access. The CDC strongly recommends postponing or canceling any non-essential travel.

Examples: A Level 3 Warning might be issued for a country experiencing widespread outbreaks of deadly diseases like Marburg virus or Ebola, particularly in regions with overwhelmed healthcare systems.

Level 2: Alert (Yellow)

Recommended Action: Practice Enhanced Precautions

This level indicates increased health risk at the destination. The notice provides specific risk details and outlines extra precautions travelers should take. This level may also highlight risks for specific groups, such as pregnant people or those with weakened immune systems.

Examples: Level 2 Alerts are often issued for ongoing outbreaks of diseases like Polio, Diphtheria, or Yellow Fever in certain countries. Enhanced precautions typically include ensuring relevant vaccinations are current and taking rigorous measures to prevent insect bites for vector-borne diseases.

Level 1: Watch (Green)

Recommended Action: Practice Usual Precautions

This is the most common notice level. It indicates a known health risk is present, but travelers can effectively protect themselves by following standard, routine precautions. The notice describes what those usual precautions are.

Examples: A global Level 1 Watch for Measles reminds international travelers to ensure full MMR vaccination. A notice for Dengue, a year-round risk in many tropical areas, reminds travelers to prevent mosquito bites diligently.

The COVID-19 4-Level System

In response to the global COVID-19 pandemic, the CDC implemented a more granular 4-level system to better communicate specific and rapidly changing virus-related risks. Initially, levels were determined primarily by quantitative data, including incidence rates and testing data.

The criteria evolved significantly. In April 2022, the CDC changed how it determined the highest level, reflecting a key public health communication principle: risk messaging must adapt as threats become better understood and population immunity changes through vaccination and prior infection.

Level 4: Special Circumstances / Do Not Travel: Reserved for destinations with special circumstances, such as new variant emergence, rapidly escalating cases threatening to overwhelm health systems, or local healthcare infrastructure collapse. No longer based on case counts alone.

Levels 1-3: Primarily determined by 28-day incidence of COVID-19 cases.

Level Unknown: Used for destinations where reliable COVID-19 data isn’t available. The CDC advises following Level 3 or 4 precautions.

Travel Health Notice Levels at a Glance

CDC vs. State Department: Two Essential Perspectives

A critical but often overlooked travel planning step is understanding the difference between health-focused CDC advisories and security-focused State Department advisories. For complete risk understanding, you must consult both sources.

CDC Travel Health Notices: The Health Guide

The CDC’s mission is protecting public health. Therefore, Travel Health Notices focus exclusively on health-related threats, serving as your guide to specific health risks you might encounter:

• Infectious disease outbreaks (Measles, Polio, Dengue)
• Contaminated food and water risks (Cholera, Typhoid)
• Insect-borne diseases (Malaria, Zika)
• Environmental health hazards and natural disasters creating health risks

State Department Travel Advisories: The Safety Guide

The U.S. Department of State, found at travel.state.gov, has a different primary mission: safety and security of U.S. citizens overseas. Its Travel Advisories assess a much broader range of potential dangers using specific Risk Indicators:

• C – Crime
• T – Terrorism
• U – Civil Unrest
• K – Kidnapping or Hostage Taking
• N – Natural Disaster
• E – Time-Limited Event (elections, major sporting events)
• H – Health (incorporates CDC assessments)
• D – Wrongful Detention
• O – Other potential risks

Why You Must Check Both

The two systems use similar four-level structures but for completely different reasons. Failing to check both can leave you dangerously unprepared.

Scenario One: A country might be CDC Level 1: Practice Usual Precautions, indicating very low disease risk. However, that same country could be State Department Level 4: Do Not Travel due to widespread civil unrest and high kidnapping risk. Relying only on the CDC notice would leave you unaware of significant physical danger.

Scenario Two: A different country could be State Department Level 1: Exercise Normal Precautions, indicating political stability and low crime rates. Yet it might have a CDC Level 2: Alert for Yellow Fever outbreak, meaning entry requires vaccination proof and travelers face serious health risk without it. Relying only on the State Department notice would leave you unprepared for critical health requirements.

The Smart Traveler Enrollment Program

One of the most important actions you can take is enrolling in the Smart Traveler Enrollment Program (STEP). This free Department of State service lets you register trip details with the nearest U.S. Embassy or Consulate.

STEP enrollment provides several key benefits:

• Receive important security alerts and updates directly from the U.S. Embassy in your destination
• Help the embassy contact you in emergencies like natural disasters or political crises
• Help family and friends reach you during emergencies back home

CDC vs. State Department: Key Differences

Your Pre-Travel Health Preparation Guide

Proactive planning is key to healthy travel. This chronological guide outlines essential steps every international traveler should take before departure.

Pre-Travel Medical Consultation (4-6 Weeks Before Departure)

The single most important step in health preparations is scheduling a pre-travel consultation with a healthcare provider, ideally one specializing in travel medicine. Do this at least 4 to 6 weeks before your trip.

This timing is critical because some vaccines must be given in series over several weeks, and your body needs time to build full immunity before exposure to potential diseases.

Personalized Risk Assessment

During this consultation, your provider conducts a personalized risk assessment tailored to:

Your personal health history: Including pre-existing conditions, allergies, and immunization records

Your destination: Specific countries or regions you’ll visit

Your itinerary and duration: A short city trip has different risks than a month-long rural trek

Your travel style: Five-star resorts differ from backpacking and hostels

Your planned activities: Working in refugee camps, caving, or extensive hiking carry unique risks

Last-Minute Travelers

For travelers departing in less than two weeks, consultations remain essential. While there may not be time for full vaccine series, providers can still offer critical advice, prescribe essential medications for malaria or travelers’ diarrhea, and prioritize the most important risks. Even telehealth visits can provide vital prevention counseling.

Understanding Travel Vaccinations

Vaccines are a cornerstone of travel health, falling into three main categories:

Routine Vaccines

These are vaccinations all Americans should maintain regardless of travel plans, including vaccines for measles, mumps, and rubella (MMR), diphtheria, tetanus, and pertussis (DTaP), polio, and annual flu shots. Many diseases now rare in the U.S. remain common elsewhere, making routine immunizations your first and most important defense.

Recommended Vaccines

The CDC recommends these for travelers going to specific destinations where they risk exposure to certain diseases. Common examples include vaccines for Hepatitis A, Typhoid, and Japanese Encephalitis. Your healthcare provider determines which recommended vaccines you need based on your personalized risk assessment.

Required Vaccines

These refer to vaccines countries legally require for entry. The most common required vaccine is for Yellow Fever. If traveling to a country requiring it, you must have proof of vaccination in the form of an International Certificate of Vaccination or Prophylaxis (ICVP), often called the “Yellow Card.”

Finding Your Destination’s Health Profile

Beyond consulting your doctor, you can and should research using official CDC resources.

Navigating the CDC Website

The main portal for travel health information is the CDC’s Travelers’ Health website. From here, navigate to the “Destinations” page where you can select your destination country to access comprehensive health risk overviews, including current Travel Health Notices, recommended and required vaccines, and specific advice on topics like malaria prevention.

The CDC Yellow Book

For those wanting deeper information, the CDC Yellow Book: Health Information for International Travel is the ultimate resource. Available online, this comprehensive reference underpins all CDC travel health guidance. While written for healthcare professionals, it’s accessible to the public and offers detailed chapters on everything from preventing travelers’ diarrhea to managing high-altitude health risks.

Planning for Healthcare Abroad

Before traveling, plan for the possibility of needing medical care.

Check Your Insurance

Contact your domestic health insurance provider to see if your plan offers overseas coverage. Many plans don’t, which could leave you responsible for 100% of medical care costs.

Consider Supplemental Insurance

Purchase supplemental travel health insurance covering medical care and, critically, medical evacuation. Medical evacuation insurance covers the potentially enormous cost of transporting you to locations with adequate medical facilities, or even back to the U.S., in serious emergencies.

Prepare Your Documents

If you have pre-existing medical conditions, ask your doctor for a letter detailing your condition, treatment plan, and all medications (using generic names, as brand names vary by country) and any allergies. Check with your destination country’s embassy to ensure your prescription medications are legal to bring into the country.

Essential Prevention Strategies While Traveling

While vaccines are powerful tools, they don’t exist for every disease. Your daily habits and behaviors while traveling are your primary shield against the most common health threats.

Food and Water Safety: The Golden Rule

Contaminated food and water are leading causes of traveler illness, responsible for travelers’ diarrhea and serious diseases like cholera and hepatitis A. Following simple rules can dramatically reduce your risk.

Safe Foods to Eat

Thoroughly cooked food served steaming hot

Fruits you can peel yourself like bananas, oranges, and mangoes. Avoid pre-cut fruit.

Pasteurized dairy products like milk, cheese, and yogurt

Dry, packaged foods from factory-sealed containers (crackers, chips, bread)

Risky Foods to Avoid

Food served at room temperature, especially from buffets or street vendors

Raw or undercooked meat, fish, and shellfish, including dishes like ceviche where seafood is “cooked” in citrus juice

Salads and unpeeled raw vegetables, as they may have been washed in contaminated water

Unpasteurized dairy products

“Bushmeat” (wild game like monkeys or bats), which can carry dangerous diseases

Safe Drinks

Bottled, sealed beverages: Carbonated drinks are safest, as fizz confirms the factory seal hasn’t been broken

Water boiled vigorously for at least one minute

Hot tea or coffee made with boiled water

Pasteurized milk

Risky Drinks to Avoid

Tap water or well water

Ice, as it’s almost always made from local tap water

Fountain drinks and reconstituted juices mixed with tap water

If bottled water isn’t available, disinfect water by boiling (most reliable method), using chemical disinfection tablets (iodine or chlorine), or using a water filter rated for “cyst removal” to protect against parasites like Giardia and Cryptosporidium.

Preventing Insect Bites: Your First Defense Line

Bites from mosquitoes, ticks, and other insects can transmit serious diseases including malaria, dengue, Zika, yellow fever, chikungunya, and Lyme disease. Protecting yourself from bites is non-negotiable in many parts of the world.

Use EPA-Registered Insect Repellent

Apply Environmental Protection Agency-registered repellent to all exposed skin. Look for products containing DEET, Picaridin, Oil of Lemon Eucalyptus (OLE), or IR3535. Generally, higher concentrations of active ingredients provide longer-lasting protection. When applying both sunscreen and repellent, apply sunscreen first, let it dry, then apply repellent.

Treat Clothing and Gear with Permethrin

For extra protection, treat clothing, shoes, socks, and tents with products containing 0.5% permethrin. You can also buy pre-treated gear. Permethrin is an insecticide that kills or repels insects and remains effective through multiple washings. Don’t apply permethrin directly to your skin.

Wear Protective Clothing

Long-sleeved shirts, long pants, socks, and hats create physical barriers between you and insects.

Create Safe Sleeping Environments

Choose lodging with air conditioning or windows and doors with intact screens. If sleeping in areas exposed to outdoors, use permethrin-treated mosquito nets tucked securely under your mattress.

Protect Yourself After Your Trip

Continue protecting yourself from mosquito bites for three weeks after returning home. This prevents you from potentially spreading viruses you may have acquired abroad (like Zika or dengue) to local mosquitoes, which could then infect people in your community.

The Ultimate Travel Health Kit

All travelers should pack personalized travel health kits to manage minor injuries and common illnesses. Store your kit in a durable, water-resistant container that’s easily accessible.

When Things Go Wrong: Health Issues Abroad and at Home

Despite the best preparations, you might still get sick or injured while traveling. Knowing what to do in emergencies is crucial to your travel plan.

If You Get Sick or Injured During Your Trip

If you experience medical issues abroad, your first priority is seeking appropriate care. A vital resource is the nearest U.S. Embassy or Consulate. Embassy staff can provide lists of local English-speaking doctors, hospitals, and medical facilities. They can’t provide medical care themselves, but they can help you find it.

The Department of State maintains a 24/7 emergency assistance line you can call from anywhere in the world:

• From the U.S. & Canada: 888-407-4747
• From overseas: +1-202-501-4444

If you receive medical treatment, request copies of all medical records, including diagnoses, treatments, and any medications administered. This documentation will be essential for your doctor at home to ensure continuity of care.

After You Return Home

Your health vigilance doesn’t end when your trip does. Monitor your health after returning. Some travel-related illnesses can take weeks or even months to manifest symptoms. If you feel unwell after your trip—even long after returning—see a doctor immediately.

When you see your provider, it’s absolutely critical to tell them about your recent international travel. Be specific about where you went and what you did. This information is one of the most important clues your doctor has for accurate diagnosis, as many exotic diseases present with symptoms like fever or fatigue that can easily be mistaken for common domestic illnesses like flu.

Closing the Global Health Loop

This final step closes the loop on the global public health surveillance system. The system beginning with international agreements and on-the-ground disease detectives relies on returned travelers to be the final link in the chain.

When you report post-travel illness to your doctor, that information can be relayed to local and national public health authorities, including the CDC. This data acts as real-time, early-warning signals, helping the CDC detect emerging outbreaks, update Travel Health Notices, and ultimately protect future travelers’ health.

Your individual action directly contributes to the strength and responsiveness of the very system designed to keep all Americans safe. By taking responsibility for your health before, during, and after travel, you’re not just protecting yourself—you’re participating in a global network that protects everyone.

The CDC’s Travel Health Notices represent more than simple advisories—they’re the culmination of a sophisticated global surveillance system designed to keep travelers safe. Understanding how to use these tools, combined with proper preparation and responsible behavior, can make the difference between a trip that enriches your life and one that endangers it.

Whether you’re planning a business trip to Bangkok, a safari in Kenya, or a backpacking adventure through South America, the principles remain the same: prepare early, stay informed, protect yourself, and report back if you get sick. In our interconnected world, your health is everyone’s health.

Our articles make government information more accessible. Please consult a qualified professional for financial, legal, or health advice specific to your circumstances.