WHO Health Warning

From: World Health Organization

Yellow fever vaccination

Yellow fever vaccination is carried out for two different purposes:

• To protect individual travellers who may be exposed to yellow fever infection. Vaccination in these cases is recommended but not mandatory. As yellow fever is frequently fatal for those who have not been vaccinated, vaccination is recommended for all travellers (with few exceptions—see Chapter 6) intending to visit areas where there may be a risk of exposure to yellow fever.
• To protect countries from the risk of importing yellow fever virus. This is mandatory vaccination and is a requirement for entry into the countries concerned.

Travellers should be warned that the requirement for vaccination against yellow fever is not related to the risk of exposure to the disease.

The countries that require proof of vaccination** are those where the disease does not occur but where the mosquito vector and non-human primate hosts of yellow fever are present. Consequently, any importation of the virus by an infected traveller could result in its establishment and propagation in the local mosquitoes and primates, leading to a risk of infection for the human population.

Proof of vaccination is required for all travellers coming from countries where yellow fever occurs, including transit through such countries. The international yellow fever vaccination certificate becomes valid 10 days after vaccination and remains valid for a period of 10 years.

The fact that a country has no mandatory requirement for vaccination does not imply that there is no risk of yellow fever infection.

In accordance with the International Health Regulations, countries are required to notify all cases of yellow fever to WHO. Such countries are then considered to be “infected areas”. This terminology is likely to change in the revised version of the Regulations, but is meantime retained in the following country list to maintain consistency with the official reports provided by the WHO Member States. The list of infected areas is published in the Weekly epidemiological record.

In addition, countries are considered to be “endemic areas” for yellow fever if the virus is present in mosquitoes and non-human primates and where there is therefore a potential risk of infection for humans (see map).

**Please note that the requirements for vaccination of infants over 6 months of age by some countries is not in accordance with WHO's recommendations (see Chapter 6). Travellers should however be informed that the requirement exists for entry into the countries concerned.

Malaria

General information about the disease, its geographical distribution and details of preventive measures are included in Chapter 7. Protective measures against mosquito bites are described in Chapter 3. Specific information for each country is provided in this section, including epidemiological details for all countries with malarious areas (geographical and seasonal distribution, altitude, predominant species, reported resistance).

The recommended prevention is also indicated. The recommended prevention for each country is decided on the basis of the following factors: the risk of contracting malaria; the prevailing species of malaria parasites in the area; the level and spread of drug resistance reported from the country; and the possible risk of serious side-effects resulting from the use of the various prophylactic drugs. Where P. falciparum and P. vivax both occur, prevention of falciparum malaria takes priority.

The numbers I, II, III and IV refer to the type of prevention based on the table below.

Malaria Risk		Type of prevention
Type I	Very limited risk of malaria transmission	Mosquito bite prevention only
Type II	Risk of P. vivax malaria or fully chloroquine-sensitive P. falciparum only	Mosquito bite prevention plus chloroquine chemoprophylaxis
Type III	Risk of malaria transmission and emerging chloroquine resistance	Mosquito bite prevention plus chloroquine+proguanil chemoprophylaxis
Type IV	High risk of falciparum malaria plus drug resistance, or moderate/low risk falciparum malaria but high drug resistance	Mosquito bite prevention plus either mefloquine, doxycycline or atovaquone/proguanil (take one that no resistance is reported for in the specific areas to be visited

Please note that altitudes quoted in this list are averages for guidance only.