If you are travelling to parts of Africa or South America, the Yellow Fever Certificate may be the single most important travel document you carry — more consequential at some borders than your visa. Get it wrong and you can be denied boarding at your home airport, turned back at immigration, quarantined for up to six days, or required to receive the vaccine on the spot in conditions that are impossible to verify. Get it right and it is a straightforward piece of paperwork that costs one appointment and lasts a lifetime.
This guide explains exactly what the certificate is, who issues it, which countries require it, when transit triggers the requirement, who cannot get the vaccine, what happens if you turn up without it, and the specific situations that catch experienced travellers off guard.
What Is the ICVP?
The full name is the International Certificate of Vaccination or Prophylaxis. It is commonly called the yellow card, the yellow fever card, or simply the ICVP. It is a small yellow booklet — standardised under the International Health Regulations of the World Health Organization — that officially documents that you have received the yellow fever vaccine at an authorised vaccination centre.
The ICVP is the only form of proof that counts at borders. A letter from your GP does not count. A record from your national health system does not count. A screenshot of your vaccination record does not count. The physical booklet — or in some countries a digital equivalent issued by an authorised clinic — is what immigration officials and airline check-in staff are trained to look for. Without it, your vaccination effectively does not exist from a border control perspective.
The ICVP must be completed correctly to be valid. Under the International Health Regulations, the WHO is explicit that any amendment, erasure, or failure to complete any part of the certificate may render it invalid. NaTHNaC, the UK's National Travel Health Network and Centre, has reported cases of travellers being challenged at borders for poorly completed certificates, with consequences including forced vaccination, fines, and quarantine. Your personal details on the ICVP must match your passport exactly. The date of vaccination must be written in full with the month spelled out in letters, not numbers. The manufacturer and batch number of the vaccine must be recorded. The certificate must carry the official stamp of the authorised clinic. Sources: NaTHNaC — International Certificate of Vaccination or Prophylaxis | NaTHNaC — Yellow Fever
When Does the Certificate Become Valid?
The yellow fever vaccine does not provide immediate protection. The ICVP becomes valid ten days after the date of vaccination. This is a hard rule under the International Health Regulations. You are not considered vaccinated — and are not in compliance with any country's entry requirements — until ten days have passed from the date the vaccine was administered.
This means that if you receive the vaccine on Monday and board a flight the following Saturday, you are not covered. Border officials in strictly enforcing countries will check the date on your certificate and calculate the ten-day period. Getting vaccinated the week before departure is not sufficient for most destinations. Book your travel health appointment at least three to four weeks before departure to allow the ten days to pass comfortably before you travel, and to give time to sort out any issues. Sources: NaTHNaC Yellow Fever Zone — ICVP factsheet | App-Savvy Traveller — Yellow Fever Certificate Guide 2026
How Long Is the Certificate Valid?
The yellow fever certificate is valid for life under current WHO rules. This change came into effect in 2016, when the WHO revised the International Health Regulations to remove the previous ten-year validity period. A single dose of the yellow fever vaccine is now recognised as providing lifelong protection, and the certificate issued after that dose never expires.
However, there are exceptions and complications worth knowing. Some countries still apply the old ten-year rule in practice, particularly if you are entering from or transiting through a high-risk area. A booster dose may be recommended — not always required — for certain travellers in higher-risk situations, including those who received their original vaccination more than ten years ago and are travelling to areas with active yellow fever transmission, or certain vulnerable groups. As of February 2025, Saudi Arabia introduced a new requirement that travellers arriving from nineteen specified countries must show proof of yellow fever vaccination given at least ten days before entry — making it one of the more recently updated entry requirements. Always confirm current requirements with your travel health clinic and the destination country's embassy before travel. Sources: NaTHNaC — Yellow Fever | American Journal of Medicine — Vaccines for International Travelers, 2025
Where Is the Vaccine Available?
Yellow fever vaccine can only be administered at authorised vaccination centres. It is not available at ordinary GP practices, standard pharmacies, or walk-in clinics that are not officially designated. In the United States, the CDC maintains a searchable list of authorised yellow fever vaccine centres by state. In the UK, NHS yellow fever vaccination centres are listed on the NaTHNaC website. In Canada, provincial travel health clinics and some pharmacies are authorised. In Australia, the Australian Department of Health maintains a register of approved providers.
Do not attempt to get the vaccine from an unauthorised provider. Even if the vaccine is the same formulation, only an authorised centre can issue the ICVP, and the certificate issued by an unauthorised provider will not be valid. Sources: CDC — Find an Authorised Yellow Fever Vaccine Centre | NaTHNaC Yellow Fever Zone
Which Countries Require the Certificate?
There are two distinct categories: countries that require the certificate for all arriving travellers regardless of origin, and countries that require it only if you are arriving from — or in some cases transiting through — a country with yellow fever transmission risk.
Countries requiring the certificate for all travellers include many in sub-Saharan Africa: Uganda requires it for all international travellers over one month of age. Ghana requires it for all travellers over nine months of age. Angola, Cameroon, the Democratic Republic of the Congo, Ivory Coast, Guinea, Guinea-Bissau, Niger, Sierra Leone, and Togo are among others that require it for all arrivals. These are non-negotiable regardless of your country of origin or your travel history.
Countries requiring the certificate based on your travel history — where you have come from or transited through — include Kenya, Tanzania, South Africa, Brazil (for certain states), and many others. For these countries, the rule is triggered if you have been in, or transited for twelve hours or more through, a country on the WHO's list of nations with yellow fever transmission risk. This includes most of sub-Saharan Africa and tropical South America.
The transit rule is the one that catches most travellers off guard. Flying from London to Nairobi via Addis Ababa (Ethiopia) on Ethiopian Airlines? Ethiopia is on the WHO list. Your transit there triggers Kenya's certificate requirement even if you never left the airport. Flying from New York to Cape Town via São Paulo? Brazil is on the WHO list for most of its territory. That transit can trigger South Africa's requirement. Flying within East Africa — from Uganda to Kenya, for example — requires the certificate because Uganda itself is on the WHO list. Sources: Aqua Travel Clinic — Which Countries Require Yellow Fever Certificates | NaTHNaC — Changes to Yellow Fever Certificate Requirements | African Portfolio — Guide to Yellow Fever Vaccines
What Happens If You Arrive Without the Certificate?
The consequences depend on the country and the border official, but none of the possible outcomes are good. You may be denied boarding at your departure airport — many airlines check yellow fever documentation before letting you board, particularly on routes to affected regions. If you make it onto the plane, you may be denied entry at immigration and placed on the next available flight home. You may be quarantined for up to six days while authorities decide what to do with you. You may be required to receive the vaccine on the spot — in conditions where you have no control over the clinic, the cold chain, or the documentation.
Trek slots for gorilla watching in Uganda and Rwanda are non-refundable. Safari game drives, multi-country tours, and connecting flights are not paused while border complications are sorted out. The practical and financial consequences of arriving without valid documentation can be severe beyond just the entry problem itself. Sources: Aqua Travel Clinic | App-Savvy Traveller — Yellow Fever Guide 2026
What If You Cannot Get the Vaccine?
The yellow fever vaccine is a live attenuated virus and is not suitable for everyone. Groups for whom the vaccine may be contraindicated or for whom extra care is required include:
Infants under nine months of age. Pregnant women, though vaccination may be considered if travel to a high-risk area is unavoidable after a careful risk-benefit assessment. People who are severely immunocompromised, including those on immunosuppressive therapy. People with a severe allergy to eggs, as the vaccine is produced using egg protein. People aged sixty and over, for whom the risk of a rare but serious adverse reaction (yellow fever vaccine-associated viscerotropic disease or neurological disease) is higher than in younger adults — though vaccination is still considered for this group when travelling to areas with genuine risk. Sources: NaTHNaC — Medical Letter of Exemption
If the vaccine is medically contraindicated, an authorised vaccination centre can issue a Medical Letter of Exemption (MLoE). This is a formal document, ideally issued on the headed paper of the clinic or hospital and completed in the ICVP, that explains to border authorities why you have not been vaccinated. The MLoE must be issued on a trip-by-trip basis and should clearly state it is valid for the current trip only.
A critical caveat: countries are not obliged under international law to accept a Medical Letter of Exemption. Some will; some will not. If you have a genuine medical contraindication and are planning travel to a country with a strict requirement, check directly with that country's embassy before you book. Sources: NaTHNaC — Medical Letter of Exemption | American Journal of Medicine — Vaccines for International Travelers 2025
The Active Yellow Fever Situation in 2025 and 2026
The yellow fever risk context has worsened significantly compared to earlier years, and requirements are being enforced more strictly as a result. In March 2026, the Pan American Health Organization issued an epidemiological alert noting sustained yellow fever transmission across parts of South America, with 34 confirmed human cases and 15 deaths in the first seven weeks of 2026 alone across Bolivia, Colombia, Peru, and Venezuela. Cases were detected in areas outside the traditional Amazon basin, including São Paulo state in Brazil. As of 14 June 2026, NaTHNaC confirmed 51 yellow fever cases and 24 deaths globally since the start of that year.
The CDC issued a Level 2 travel notice for yellow fever in South America. NaTHNaC reported a temporary disruption to yellow fever vaccine supply in the UK in August 2025, which resolved but highlighted the importance of not leaving vaccination to the last minute. PAHO noted that the vast majority of confirmed cases in both 2025 and 2026 were in unvaccinated people.
The practical implication for travellers: enforcement of certificate requirements is tightening across the continent, and the risk of actually contracting yellow fever in some areas is at a multi-year high. This is not a risk to take casually. Sources: PAHO — Yellow Fever Alert, March 2026 | NaTHNaC — Yellow Fever, updated June 2026
Practical Checklist: Your ICVP Before Travel
Before any trip to Africa or South America, work through the following:
Check whether your destination requires the certificate for all arrivals, or only for those coming from affected countries. Check whether any transit airport on your route is in a country on the WHO yellow fever list — if so, your destination may require the certificate regardless. Book an appointment at an authorised yellow fever vaccination centre at least three to four weeks before departure so that the ten-day validity period passes before you travel. After vaccination, check that your ICVP has been correctly completed — your name matches your passport exactly, the date is written with the month spelled in full, the vaccine batch number is recorded, and the clinic stamp is present. Keep your ICVP with your passport at all times during travel — never pack it in checked baggage. If your certificate is more than ten years old, discuss with a travel health professional whether a booster is advisable for your specific itinerary. If you cannot get the vaccine for medical reasons, see an authorised clinic to obtain a Medical Letter of Exemption and check with the relevant embassy whether it will be accepted.
Where to Check Current Requirements
Yellow fever requirements change, and the WHO publishes updated country-by-country lists periodically — but requirements can also change between publications. For the most current information, check:
The NaTHNaC TravelHealthPro country pages for UK travellers. The CDC Travelers' Health country pages for US travellers. The destination country's embassy or high commission website. Your travel health professional, who will have access to the most current clinical guidance.
You can use the Travel Vaccine Map to check quickly which countries have yellow_fever_required: true in our database — countries like Uganda, Ghana, Kenya, Tanzania, Cameroon, Senegal, Guyana, and Suriname — as a quick starting reference, then confirm the specific rules for your routing with an authorised clinic.
For context on specific regions, see also our guides to East Africa safari health prep and South America travel health.
Sources
- NaTHNaC — International Certificate of Vaccination or Prophylaxis (ICVP)
- NaTHNaC — Yellow Fever, updated June 2026
- NaTHNaC — Medical Letter of Exemption
- NaTHNaC — Changes to Country Yellow Fever Certificate Requirements
- CDC — Countries at Risk for Yellow Fever: South America
- CDC — Yellow Fever Level 2 Travel Notice for South America
- CDC Yellow Book — Yellow Fever chapter, April 2025
- PAHO — Sustained Yellow Fever Transmission in South America, March 13, 2026
- American Journal of Medicine — Vaccines for International Travelers: Current Status and Recent Developments, 2025