Yellow fever is a viral disease, found in tropical regions of Africa and the Americas. It principally affects humans and monkeys, and is transmitted via the bite of Aëdes mosquitoes. It can produce devastating outbreaks, which can be prevented and controlled by mass vaccination campaigns.
Updated: 18 May 2017
Yellow Fever Risk Areas
These are areas where the virus is present in monkeys and is a potential risk to humans as defined by the World Health Organisation. Some of these countries demand a yellow fever certificate from travellers as a condition of entry to their country. Many of these, and other countries, will ask you for a certificate if you are entering from an infected country. Your travel agent should inform you if you need a certificate when you are booking your holiday or flight. You can double check if in doubt with your local yellow fever vaccination centre.
Mode of transmission
Vector-borne transmission occurs via the bite of an infected mosquito, primarily Aedes or Haemagogus spp. Nonhuman and human primates are the main reservoirs of the virus, with anthroponotic (human-to-vector-to-human) transmission occurring. There are 3 transmission cycles for yellow fever: sylvatic (jungle), intermediate (savannah), and urban.
- The sylvatic (jungle) transmission cycle involves transmission of the virus between nonhuman primates and mosquito species found in the forest canopy. The virus is transmitted via mosquitoes from monkeys to humans when the humans encroach into the jungle during occupational or recreational activities.
- In Africa, an intermediate (savannah) cycle involves transmission of YFV from tree hole-breeding Aedes spp. to humans living or working in jungle border areas. In this cycle, the virus may be transmitted from monkeys to humans or from human to human via these mosquitoes.
- The urban transmission cycle involves transmission of the virus between humans and urban mosquitoes, primarily Aedes aegypti.
Humans infected with YFV experience the highest levels of viremia and can transmit the virus to mosquitoes shortly before onset of fever and for the first 3–5 days of illness. Given the high level of viremia, bloodborne transmission theoretically can occur via transfusion or needlesticks.
Epidemiology
Yellow fever occurs in sub-Saharan Africa and tropical South America, where it is endemic and intermittently epidemic (see Tables 1 and 2 for a list of countries with risk of YFV transmission). Most yellow fever disease in humans is due to sylvatic or intermediate transmission cycles. However, urban yellow fever occurs periodically in Africa and sporadically in the Americas. In Africa, natural immunity accumulates with age, and thus, infants and children are at highest risk for disease. In South America, yellow fever occurs most frequently in unimmunized young men who are exposed to mosquito vectors through their work in forested or transitional areas.
ANNEX 1 – UPDATE – AS OF 22 JANUARY 2016
Countries1 with risk of yellow fever transmission2 and countries requiring yellow fever vaccination
|
Country |
Country with risk of yellow fever transmission |
Country requiring yellow fever vaccination for travellers3 |
Country statement on period of validity for yellow fever vaccination certificate3 |
|
|---|---|---|---|---|
|
|
|
arriving from countries with risk of yellow fever (age of traveller) |
from all countries (age of traveller) |
|
|
Afghanistan |
|
Yes |
|
Not communicated |
|
Albania |
|
Yes (> 1 year) |
|
Not communicated |
|
Algeria |
|
Yes4 (> 1 year) |
|
Life |
|
Angola |
Yes |
|
Yes (> 9 months) |
Life |
|
Antigua and Barbuda |
|
Yes (> 1 year) |
|
Not communicated |
|
Argentina |
Yes |
|
|
Not applicable |
|
Australia |
|
Yes4 (> 1 year) |
|
10 years |
|
Bahamas |
|
Yes4 (> 1 year) |
|
Life |
|
Bahrain |
|
Yes4 (> 9 months) |
|
Life |
|
Bangladesh |
|
Yes (> 1 year) |
|
Not communicated |
|
Barbados |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Belize |
|
Yes5 (> 1 year) |
|
Not communicated |
|
Benin |
Yes |
Yes5 (> 1 year) |
|
Life |
|
Bhutan |
|
Yes5 |
|
Not communicated |
|
Bolivia, Plurinational (State of) |
Yes |
Yes4 (> 1 year) |
|
Life |
|
Botswana |
|
Yes5 (> 1 year) |
|
10 years |
|
Bonaire, Saba, Sint Eustasius |
|
Yes (> 6 months) |
|
Not communicated |
|
Brazil |
Yes |
|
|
Not applicable |
|
Brunei Darussalam |
|
Yes4 (> 1 year) |
|
Life |
|
Burkina Faso |
Yes |
Yes5 (> 9 months) |
|
10 years |
|
Burundi |
Yes |
|
Yes (> 1 year) |
Life |
|
Cabo Verde |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Cambodia |
|
Yes4 (>1 year) |
|
Not communicated |
|
Cameroon |
Yes |
|
Yes (> 9 months) |
Life |
|
Central African Republic |
Yes |
|
Yes (> 9 months) |
Not communicated |
-
For the purpose of this publication, the terms “country” and “countries” cover countries, territories and areas
-
Risk of yellow fever transmission is defined as yellow fever being currently reported or having been reported in the past and presence of vectors and animal reservoirs representing a potential risk of infection and transmission.
-
Country requirements are subject to change at any time. It is important that travellers ensure that they know the requirements of the country to which they are travelling by checking with the relevant consulate or embassy.
Period of validity: Until 10 July 2016, the IHR (2005) continue to provide that the period of validity of these certificates of vaccination against yellow fever is ten years from the date that the vaccination is effective; see IHR (2005), Annex 7. However, in accordance with the amendment to the IHR (2005) adopted by the World Health Assembly resolution WHA67.13, beginning 11 July 2016 the period of validity of all such certificates of vaccination against yellow fever will change from 10 years to the duration of the life of the person vaccinated, including for certificates already issued and new certificates. Accordingly, as of 11 July 2016, valid certificates of vaccination presented by arriving travellers cannot be rejected on the ground that more than ten years have passed since the date vaccination became effective as stated on the certificate; boosters or revaccination cannot be required.
As stated in the fourth column of the table above, some countries have already started accepting these certificates as valid for the life of the person vaccinated. -
Includes yellow fever vaccination requirement for traveller having transited more than 12 hours through the airport of a country with risk of yellow fever transmission.
-
Includes yellow fever vaccination requirement for traveller having transited through the airport of a country with risk of yellow fever transmission.
|
Country |
Country with risk of yellow fever transmission |
Country requiring yellow fever vaccination for travellers3 |
Country statement on period of validity for yellow fever vaccination certificate3 |
|
|---|---|---|---|---|
|
|
|
arriving from countries with risk of yellow fever (age of traveller) |
from all countries (age of traveller) |
|
|
Chad |
Yes |
Yes |
|
Not communicated |
|
China |
|
Yes5 (> 1 year) |
|
Not communicated |
|
Christmas Island |
|
Yes4 (> 1 year) |
|
10 years |
|
Colombia |
Yes |
|
|
Not applicable |
|
Congo |
Yes |
|
Yes (> 9 months) |
Life |
|
Costa Rica |
|
Yes4 |
|
Life |
|
Côte d’Ivoire |
Yes |
|
Yes (> 9 months) |
Not communicated |
|
Curaçao |
|
Yes (> 6 months) |
|
Not communicated |
|
Democratic People’s Republic of Korea |
|
Yes (> 1 year) |
|
Not communicated |
|
Democratic Republic of the Congo |
Yes |
|
Yes (> 9 months) |
Life |
|
Djibouti |
|
Yes5 (> 1 year) |
|
10 years |
|
Dominica |
|
Yes4 (>1 year) |
|
Not communicated |
|
Ecuador |
Yes |
Yes4 (> 1 year) |
|
Life |
|
Egypt |
|
Yes4 (> 9 months) |
|
Life |
|
El Salvador |
|
Yes4 (> 1 year) |
|
Life |
|
Equatorial Guinea |
Yes |
Yes(> 6 months) |
|
Not communicated |
|
Eritrea |
|
Yes4 (> 9 months) |
|
Life |
|
Ethiopia |
Yes |
Yes4 (> 9 months) |
|
10 years |
|
Fiji |
|
Yes4 (> 1 year) |
|
10 years |
|
French Guiana |
Yes |
|
Yes (> 1 year) |
Life from 1st Feb 2016 |
|
French Polynesia |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Gabon |
Yes |
|
Yes (> 1 year) |
10 years |
|
Gambia |
Yes |
Yes (> 9 months) |
|
Not communicated |
|
Ghana |
Yes |
|
Yes (> 9 months) |
Life |
|
Grenada |
|
Yes4 (> 1 year) |
|
10 years |
|
Guadeloupe |
|
Yes4 (> 1 year) |
|
Life from 1st Feb 2016 |
|
Guatemala |
|
Yes4 (> 1 year) |
|
Life |
|
Guinea |
Yes |
Yes (>1 year) |
|
Not communicated |
|
Guinea-Bissau |
Yes |
|
Yes (> 1 year) |
Not communicated |
|
Guyana |
Yes |
Yes5 (> 1 year) |
|
Life |
|
Honduras |
|
Yes4 (> 1 year) |
|
Life |
|
India |
|
Yes (> 6 months) |
|
Not communicated |
|
Indonesia |
|
Yes (> 9 months) |
|
Not communicated |
|
Iran (Islamic Republic of) |
|
Yes4 (> 9 months) |
|
Life |
|
Iraq |
|
Yes4 (> 9 months) |
|
10 years |
|
Jamaica |
|
Yes5 (> 1 year) |
|
Life |
|
Jordan |
|
Yes4 (> 1 year) |
|
Life |
|
Kazakhstan |
|
Yes |
|
Not communicated |
|
Kenya |
Yes |
Yes (>1 year) |
|
Not communicated |
|
Kiribati |
|
Yes (>1 year) |
|
Not communicated |
|
Kyrgyzstan |
|
Yes4 (>1 year) |
|
Not communicated |
|
Lao People’s Democratic Republic |
|
Yes |
|
Not communicated |
|
Lesotho |
|
Yes4 (> 9 months) |
|
Not communicated |
|
Liberia |
Yes |
|
Yes (> 1 year) |
Not communicated |
|
Libya |
|
Yes5 (> 1 year) |
|
Life |
|
Madagascar |
|
Yes4 (> 9 months) |
|
Life |
|
Malawi |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Malaysia |
|
Yes4 (> 1 year) |
|
Life |
|
Maldives |
|
Yes4 (> 1 year) |
|
Life |
|
Mali |
Yes |
|
Yes (> 1 year) |
Not communicated |
|
Malta |
|
Yes4 (> 9 months) |
|
Life |
|
Martinique |
|
Yes4 (> 1 year) |
|
Life from 1st Feb 2016 |
|
Mauritania |
Yes |
Yes (> 1 year) |
|
Not communicated |
|
Mauritius |
|
Yes4 (> 1 year) |
|
10 years |
|
Mayotte |
|
Yes4 (> 1 year) |
|
Life from 1st Feb 2016 |
|
Montserrat |
|
Yes (> 1 year) |
|
Not communicated |
|
Mozambique |
|
Yes4 (> 9 months) |
|
Life |
|
Myanmar |
|
Yes4 (> 1 year) |
|
Life |
|
Namibia |
|
Yes5 (> 1 year) |
|
Not communicated |
|
Nauru |
|
Yes (> 1 year) |
|
Not communicated |
|
Nepal |
|
Yes4 (> 1 year) |
|
10 years |
|
New Caledonia |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Niger |
Yes |
|
Yes (> 1 year) |
Not communicated |
|
Nigeria |
Yes |
Yes (> 1 year) |
|
Not communicated |
|
Niue |
|
Yes (> 9 months) |
|
Not communicated |
|
Oman |
|
Yes5 (> 9 months) |
|
Life |
|
Pakistan |
|
Yes4 (> 1 year) |
|
10 years |
|
Panama |
Yes |
|
|
Not applicable |
|
Paraguay |
Yes |
Yes4 (> 9 months) |
|
Life |
|
Peru |
Yes |
|
|
Not applicable |
|
Philippines |
|
Yes5 (> 1 year) |
|
Not communicated |
|
Pitcairn Islands |
|
Yes (> 1 year) |
|
Not communicated |
|
Reunion |
|
Yes4 (> 1 year) |
|
Life from 1st Feb 2016 |
|
Rwanda |
|
|
Yes (> 1 year) |
Not communicated |
|
Saint Barthelemy |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Saint Kitts and Nevis |
|
Yes4 (> 1 year) |
|
Life |
|
Saint Lucia |
|
Yes (> 1 year) |
|
Not communicated |
|
Saint Martin |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Saint Vincent and the Grenadines |
|
Yes (> 1 year) |
|
Not communicated |
|
Samoa |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Sao Tome and Principe |
|
Yes5 (> 1 year) |
|
Life |
|
Saudi Arabia |
|
Yes4 (> 1 year) |
|
Life |
|
Senegal |
Yes |
Yes5 (> 9 months) |
|
Life |
|
Seychelles |
|
Yes4 (> 1 year) |
|
10 years |
|
Sierra Leone |
Yes |
|
Yes |
Not communicated |
|
Singapore |
|
Yes4 (>1 year) |
|
10 years |
|
Solomon Islands |
|
Yes |
|
Not communicated |
|
Somalia |
|
Yes4 (> 9 months) |
|
10 years |
|
South Africa |
|
Yes4 (> 1 year) |
|
Life |
|
South Sudan |
Yes |
|
|
Not applicable |
|
Sri Lanka |
|
Yes4 (> 9 months) |
|
Life |
|
Sudan |
Yes |
Yes4 (> 1 year) |
|
Life |
|
Suriname |
Yes |
Yes4 (> 1 year) |
|
Life |
|
Swaziland |
|
Yes |
|
Not communicated |
|
Thailand |
|
Yes4 (> 9 months) |
|
10 years |
|
Timor Leste |
|
Yes5 (> 1 year) |
|
Not communicated |
|
Togo |
Yes |
|
Yes (> 9 months) |
Not communicated |
|
Tristan da Cuhna |
|
Yes5 (> 6 months) |
|
10 years |
|
Trinidad and Tobago |
Yes |
Yes5 (> 1 year) |
|
10 years until June 2016 |
|
Tunisia |
|
Yes |
|
Not communicated |
|
Uganda |
Yes |
Yes (> 1 year) |
|
Not communicated |
|
United Republic of Tanzania |
|
Yes4 (> 1 year) |
|
Life |
|
Venezuela (Bolivarian Republic of) |
Yes |
|
|
Not applicable |
|
Viet Nam |
|
Yes (> 1 year) |
|
Not communicated |
|
Wallis and Futuna |
|
Yes4 (> 1 year) |
|
Not communicated |
|
Zambia |
|
Yes4 (> 9 months) |
|
Life |
|
Zimbabwe |
|
Yes4 (> 9 months) |
|
Life |
(see the current country list within the International Travel and Health publication (Annex 1) at http://www.who.int/ith/2016-ith-annex1.pdf?ua=1).
Updated: 18 May 2017
0 Comments