Yellow Fever Is Spreading Into New Parts of South America: What the CDC Level 2 Notice Means for Your Trip
The CDC is maintaining a Level 2 Practice Enhanced Precautions travel notice for yellow fever across South America, covering Colombia, Bolivia, Brazil, and Peru, and PAHO reports the virus is now reaching areas that were never on the historic risk map, including Sao Paulo state in Brazil and Tolima in Colombia. In 2025, seven South American countries reported 346 confirmed cases and 143 deaths, and yellow fever kills up to half of the people who develop severe disease. There is no antiviral treatment, so the single most important step is the yellow fever vaccine, which gives lifelong protection to about 99 percent of recipients but must be given at least 10 days before you travel. Our providers coordinate yellow fever vaccination and the official certificate. Start your free destination check on Wandr.
Yellow Fever Is Spreading Into New Parts of South America: What the CDC Level 2 Notice Means for Your Trip
The CDC is maintaining a Level 2 Practice Enhanced Precautions travel notice for yellow fever across South America, covering Colombia, Bolivia, Brazil, and Peru, and the Pan American Health Organization reports the virus is now reaching areas that were never on the historic risk map, including Sao Paulo state in Brazil and Tolima in Colombia. In 2025, seven South American countries reported 346 confirmed cases and 143 deaths, and yellow fever kills up to half of the people who develop severe disease. There is no antiviral treatment, so the single most important step is the yellow fever vaccine, which gives lifelong protection to about 99 percent of recipients but must be given at least 10 days before you travel. As clinicians who prepare travelers for exactly these regions, we plan the vaccine and the paperwork well ahead of departure so nothing is left to the last week. Start your free destination check on Wandr.
What is actually happening in South America in 2026
Yellow fever is not new to South America, but where it is showing up has changed. PAHO issued an epidemiological alert on 13 March 2026 describing sustained transmission and, importantly, human cases in geographic areas without recent transmission. Sao Paulo state in Brazil and the department of Tolima in Colombia both recorded cases outside the zones where vaccination was traditionally recommended.
That geographic drift is the reason CDC keeps an active Level 2 notice in place. The notice names Colombia, Bolivia, Brazil, and Peru, and there is a separate active notice for Venezuela, where cases have been reported across many states.
The numbers give the trend shape. In 2025, seven countries reported 346 confirmed cases and 143 deaths: Brazil with 120 cases and 48 deaths, Colombia with 125 cases and 46 deaths, Peru with 49 cases and 19 deaths, Venezuela with 32 cases and 19 deaths, Ecuador with 11 cases and 8 deaths, Bolivia with 8 cases and 2 deaths, and Guyana with a single death.
The early 2026 data continued the pattern. Between the first and seventh epidemiological weeks of the year, four countries reported 34 confirmed cases and 15 deaths, with Colombia accounting for 25 cases and 13 of those deaths. That is a high death count for a small case count, which tells you the cases being caught are severe.
Why yellow fever deserves your attention
Yellow fever is a viral infection spread by mosquitoes, and it earns respect because of what it does in its worst form. Most people who are infected have a mild illness or none at all. Roughly 15 percent progress to a toxic phase marked by high fever, jaundice, which is the yellowing that gives the disease its name, bleeding, and kidney and liver failure.
Among people who reach that severe phase, up to half die. There is no specific antiviral drug. Hospital care is supportive, which means fluids, monitoring, and management of complications rather than a treatment that clears the virus.
That combination, a high fatality rate in severe cases and no cure, is exactly why the entire strategy is prevention. For yellow fever, prevention is unusually effective, because one vaccine dose does almost all the work.
The yellow fever vaccine: one dose, lifelong protection
The yellow fever vaccine is one of the most effective travel vaccines in existence. A single dose provides protective immunity in about 99 percent of recipients, and for most travelers that protection lasts a lifetime with no booster required.
The catch is timing. The vaccine takes about 10 days to generate immunity, so it must be given at least 10 days before you enter a risk area. Many countries also refuse to accept a vaccination certificate dated fewer than 10 days before arrival. A traveler who books a vaccine three days before a flight has effectively booked nothing.
It is a live vaccine, which means it is not right for everyone. Infants under 6 months should not receive it. Travelers who are pregnant, over 60, or immunocompromised need an individual risk assessment, because the small risk of a serious vaccine reaction rises in these groups. When the vaccine is not appropriate, a clinician can issue a medical waiver letter, though a waiver protects your paperwork, not your body, so bite prevention becomes even more important.
We build all of this into a single pre-trip visit. Our providers confirm whether your specific itinerary enters a risk zone, check the timing against your departure date, screen for the factors that would change the recommendation, and coordinate the certificate. If you want the deeper reference on requirements and side effects, our complete yellow fever vaccine guide walks through it country by country.
The certificate and the yellow card
Yellow fever is the one travel vaccine that can be a legal entry requirement, not just a medical recommendation. Proof is recorded on the International Certificate of Vaccination or Prophylaxis, the document travelers call the yellow card.
Some South American countries require the certificate from travelers arriving from or transiting another yellow fever country. The rules are route-specific and they change without much warning, so the certificate you needed last year may not match this year's requirement. Confirm the current rule for your exact itinerary before you fly. We check the certificate requirement for your route as a standard part of trip prep, so you are not sorting it out at an airport counter.
Which travelers this affects most
If your South America trip stays in high-elevation cities well above the mosquito zone, your yellow fever risk may be low. The picture changes fast once an itinerary includes lowland jungle, river regions, or the Amazon basin.
Classic higher-risk plans include an Amazon lodge stay in Peru, Brazil, Ecuador, or Bolivia, riverboat travel, and trips into rural areas of the affected states. Because the risk map expanded in 2025 and 2026, some itineraries that looked low-risk a few years ago now pass through areas with reported cases. That is the practical meaning of the CDC notice: do not rely on an old mental map.
A useful rule is to treat the vaccine decision as itinerary-specific rather than country-specific. Two travelers going to the same country can have very different yellow fever risk depending on where they actually go.
Yellow fever and malaria often travel together
Here is the part many travelers miss. The same South American regions that carry yellow fever risk frequently carry malaria risk too. The Amazon basin is the clearest example. A traveler who sorts out the yellow fever vaccine but forgets malaria has covered only half the problem.
The good news is that the two do not conflict. The yellow fever vaccine and antimalarial medications such as atovaquone-proguanil work through entirely different mechanisms and are used together routinely. What they share is a timing requirement. The vaccine needs 10 days of lead time, and antimalarials need to be started before you enter the risk area, so both push you toward planning weeks ahead rather than days.
Our providers plan the vaccine and the antimalarial as one package when your route calls for both. If you want to understand the malaria side in depth, our complete malaria prevention guide covers which drug fits which trip. For a country-level view of the risks and requirements, our Peru travel health guide and Brazil travel health guide break it down by region.
Mosquito-bite prevention still matters
Even fully vaccinated, you want to avoid bites, both because no single measure is perfect and because the same mosquitoes carry other illnesses like dengue that have no vaccine for most travelers.
Use an EPA-registered repellent. DEET at 20 to 30 percent, picaridin at 20 percent, or oil of lemon eucalyptus all provide reliable protection when applied correctly. Treat clothing and gear with permethrin, which is applied to fabric and never to skin. Cover up during the day, since the mosquitoes that spread yellow fever bite in daylight hours, and sleep in screened or air-conditioned rooms where possible.
What to do before a South America trip in 2026
Start early. The 10-day vaccine window is the hard constraint that catches people, and travel clinics book up. Confirm whether your itinerary enters a yellow fever risk area, get vaccinated at least 10 days out if it does, sort out the certificate for your route, and pair the vaccine with an antimalarial if the Amazon or another malaria zone is on your plan.
You do not need to assemble this from a stack of government PDFs the week before you leave. Our providers review your destinations, tell you exactly which vaccines and medications your route requires, and handle the yellow fever vaccine and certificate coordination. Start your free destination check on Wandr and let us build the plan around your actual itinerary.
Frequently asked questions
Do I need a yellow fever vaccine for South America in 2026? For most travelers heading into the Amazon basin or other risk areas of Brazil, Peru, Colombia, Bolivia, Ecuador, or Venezuela, yes. CDC recommends yellow fever vaccination for travel to risk areas, and the risk map expanded in 2025 and 2026 to include places like Sao Paulo state. Because immunity takes 10 days to build, the vaccine has to be given at least 10 days before departure.
How dangerous is yellow fever? Most infections are mild, but about 15 percent of people progress to a severe phase with jaundice, bleeding, and organ failure. Among those severe cases, up to half die. There is no specific antiviral treatment, which is why prevention through vaccination and mosquito-bite avoidance is the entire strategy. In 2025, South America reported 143 yellow fever deaths.
How long before my trip should I get the yellow fever vaccine? At least 10 days before travel. The yellow fever vaccine takes about 10 days to produce protective immunity, and many countries will not accept a certificate dated fewer than 10 days before entry. A single dose protects roughly 99 percent of recipients and provides lifelong immunity for most travelers, so there is no routine booster.
Which South American countries have a CDC yellow fever notice right now? As of 2026, CDC has an active Level 2 Practice Enhanced Precautions notice covering yellow fever in South America, naming Colombia, Bolivia, Brazil, and Peru, along with a separate notice for Venezuela. The notices exist because cases have appeared in new areas bordering or outside the regions where vaccination was historically recommended.
Do I need a yellow fever certificate to enter these countries? Sometimes. Some countries require proof of yellow fever vaccination on the International Certificate of Vaccination or Prophylaxis, often when you are arriving from or transiting another risk country. Requirements change without notice, so confirm the current rule for your exact route before you travel. We verify certificate requirements as part of a pre-trip visit.
Can I get the yellow fever vaccine if I take antimalarials too? Yes. The yellow fever vaccine and antimalarial medications such as atovaquone-proguanil work through completely different mechanisms and are routinely used together for Amazon travel. Many South American itineraries need both, because the same regions carry yellow fever and malaria risk. Our providers plan the vaccine and the antimalarial together so the timing lines up before departure.
Is the yellow fever vaccine safe for everyone? Most healthy adults tolerate it well, but it is a live vaccine, so it is not recommended for infants under 6 months, and it needs careful review for people who are pregnant, over 60, or immunocompromised. Serious reactions are rare. Our providers screen for these factors during your visit and advise on a medical waiver letter if the vaccine is not appropriate for you.
Get your South America trip covered
Yellow fever is a serious disease with a simple solution, as long as you act on the timeline. Book your vaccine appointment through Wandr and let our providers confirm what your route needs. Book your travel vaccines online, or start your free destination check and we will map the vaccines and medications to your exact itinerary.
Medical disclaimer: This article is for general educational purposes and reflects public health data available as of 15 July 2026. Travel health notices and entry requirements change frequently. It is not a substitute for an individual medical consultation. Our licensed providers give personalized recommendations based on your health history and itinerary.
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The Wandr Team is the editorial group at Wandr Health; every article is reviewed by a licensed clinician before publication.