15 May 2018

Yellow fever outbreak in Brazil: further expansion to risk areas- May 2018

Risk areas expanded to include the entire States of Paraná, Santa Catarina and Rio Grande do Sul (south Brazil) Yellow fever outbreak in Brazil: further expansion to risk areas- May 2018

An outbreak of yellow fever is ongoing in Brazil. Between 1 July 2017 and 24 April 2018, a total of 1,218 confirmed human cases; including 364 deaths were reported [1]. Considering the progression and dynamics of yellow fever virus transmission currently observed, the World Health Organization (WHO) expects that the yellow fever virus will continue to spread along the Atlantic Forest ecosystem in Sao Paulo State, towards Paraná State and the south of the country in the coming months [1].

Following a recent review, on 3 May 2018, WHO has extended the areas considered at risk of yellow fever transmission to include the entire states of:

  • Paraná
  • Santa Catarina
  • Rio Grande do Sul

These three states are in the south of the Brazil.

Yellow fever vaccination is recommended for international travellers visiting these additional areas of risk [1]. The TravelHealthPro website provides a full list of areas where yellow fever vaccine is currently recommended for travellers in the Brazil country page.

The determination of new areas considered to be at risk for the yellow fever transmission is an ongoing process and vaccination recommendations are subject to change.

It may sometimes be appropriate for travellers visiting areas close to but outside the areas where vaccine is currently recommended in Brazil, to consider vaccine. Further specialist advice is encouraged in such circumstances following a detailed risk assessment.

Cases in travellers

As of 24 April 2018, WHO reported 19 confirmed cases of yellow fever virus infection among unvaccinated international travellers to Brazil. 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 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 [1].

On 4th May 2018, a further case was reported by Czech Republic in an unvaccinated traveller who visited Brazil between 20 February and 6 March 2018 [4].

Advice for travellers

Yellow fever is transmitted to humans via the bite of an infected mosquito. You should take insect bite avoidance measures, day and night, when visiting countries with a risk of any disease transmitted by insects.

If you are travelling to the affected areas of Brazil or any other countries with risk of yellow fever; vaccination is also recommended for your personal protection. Full details of yellow fever vaccination recommendations for countries can be found on our Country Information pages; please note that due to the current outbreak recommendations may be subject to change.

Details of the countries that require proof of yellow fever vaccination as a condition of entry under the International Health Regulations (IHR) (2005) are also provided. Travellers are reminded that countries may change their certificate requirements at short notice.

If you have recently visited a yellow fever risk area, and become unwell with symptoms such as fever or flu like illness you are advised to seek advice from your GP or NHS111. Remember to tell your healthcare provider that you have travelled abroad.

Advice for health professionals

When undertaking yellow fever risk assessment, health professionals should refer to the individual Country Information pages which provide detail relating to risk areas, recommendation for yellow fever vaccination and IHR (2005) certificate requirements.

Certificate requirements are subject to change; yellow fever vaccine certificate requirements are published each year by WHO, usually in Spring. The 2018 publication is expected (likely May/June.

Health professionals are also encouraged to access the Outbreak Surveillance section where the details of outbreaks are posted.

Yellow fever should be considered in the differential diagnoses for illnesses in relation to unvaccinated individuals returning from yellow fever risk areas [5]. Discussion with the local microbiology, virology or infectious disease consultant is recommended. Health professionals can contact the Imported Fever Service (IFS) for advice about unwell returned travellers. Health professionals seeking information about testing samples from patients with a possible viral haemorrhagic fever (VHF) should read Viral haemorrhagic fever: sample testing advice.


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