Updates on yellow fever vaccination recommendations for international travelers related to the current situation in Brazil
This is an update to the WHO advice posted in the Disease Outbreak News of 27 January 2017, 6 March 2017, 20 March 2017, 4 April 2017, and 24 November 2017, and on the WHO International Travel and Health web page on 31 January 2017, 14 February 2017, 17 March 2017, 4 April 2017 and 16 January 2018.
Between 1 July 2017 and 24 April 2018, a total of 1,218 confirmed human cases of yellow fever virus infection, including 364 deaths – corresponding to a case fatality rate of 30% –, were observed in Brazil. Mirroring the geographical distribution of yellow fever related epizootics, the number and distribution of reported human cases reflect the spread of yellow fever virus within highly and densely populated metropolitan areas, such as Rio de Janeiro and Sao Paulo, encompassing a population of over 32 million inhabitants. Up until April 2017, these areas were not deemed to be at risk for yellow fever virus transmission.
As of 24 April 2018, 19 confirmed cases of yellow fever virus infection were reported among unvaccinated international travelers. These include three detected in Brazil, and 16 reported from Argentina, France, Germany, the Netherlands, Romania, Switzerland, and the United Kingdom. Fourteen of the 19 cases reported among international travelers had a history of travel to Ilha Grande, a 190km2 National Park touristic island in Angra dos Reis Municipality, Rio de Janeiro State. Yellow fever related epizootics had been detected on Ilha Grande during the first weeks of February 2018, before and around the 2018 Carnival celebrations.
All confirmed human cases of yellow fever virus infection registered in Brazil, or with travel history to Brazil, during the period of observation (1 July 2017 and 24 April 2018) were associated with the sylvatic cycle of yellow fever virus transmission, with no evidence of transmission related to the urban cycle.
Considering the progression and dynamics of yellow fever virus transmission currently observed amongst non-human primates, and consistent with those observed since the upsurge of yellow fever activity in Brazil since the end of 2016, it is expected that, in the coming months, the spread of yellow fever virus will continue along the Atlantic Forest ecosystem in Sao Paulo State, towards Paraná State and the south of the country.
Therefore, the WHO Secretariat has determined that, in addition to the areas listed in previous updates, the entire States of Paraná, Santa Catarina and Rio Grande do Sul should also be considered at risk of yellow fever transmission. Consequently, vaccination against yellow fever is recommended for international travelers visiting these states.
The determination of new areas considered to be at risk for the yellow fever transmission is an ongoing process and updates will be provided regularly.
The current advice by the WHO Secretariat for international travellers going to areas in Brazil deemed to be at risk is the following:
- Vaccination against yellow fever at least 10 days prior to the travel. Note that, as per Annex 7 of the International Health Regulations (2005), a single dose of a yellow fever vaccine approved by WHO is sufficient to confer sustained immunity and life-long protection against yellow fever disease. Travellers with contraindications for yellow fever vaccine (children below 9 months, pregnant or breastfeeding women, people with severe hypersensitivity to egg antigens, and severe immunodeficiency) or, over 60 years of age should consult their health professional for advice;
- Adoption of measures to avoid mosquito bites;
- Awareness of symptoms and signs of yellow fever;
- Seeking care in case of symptoms and signs of yellow fever, while travelling and upon return from areas at risk for yellow fever transmission.
For 2017, updates on country requirements for the International Certificate of Vaccination or Prophylaxis, with proof of vaccination against yellow fever, and WHO vaccination recommendations for international travellers, are available on the WHO International Travel and Health website: Annex 1 and country list . More specific information about requirements for the International Certificate of Vaccination or Prophylaxis, with proof of vaccination against yellow fever, implemented by Member States related to the current situation in Brazil in the Region of the Americas is available on the PAHO yellow fever website.
WHO - International Travel and Health
Routine WHO recommendations and country requirements
Countries with risk of yellow fever transmission and countries requiring yellow fever
Country list: 2017 updates