World Health Organization: Emergencies preparedness, response: January 2017
On 6 January 2017, the Brazil Ministry of Health (MoH) reported 12 suspected cases of yellow fever from six municipalities in the state of Minas Gerais.
WHO risk assessment
Yellow fever outbreak has previously been detected in Minas Gerais. The most recent outbreak occurred in 2002–2003, when 63 confirmed cases, including 23 deaths (CFR: 37%), were detected.
The current yellow fever outbreak is taking place in an area with relatively low vaccination coverage, which could favor the rapid spread of the disease. The concern is that transmission may extend to areas located in proximity of Minas Gerais, such as the state of Espírito Santo and the south of Bahia, which have favorable ecosystems for the transmission of the virus.
These areas were previously considered to be at low risk of transmission and, consequently, yellow fever vaccination was not recommended. The introduction of the virus in these areas could potentially trigger large epidemics of yellow fever.
There is also a risk that infected humans may travel to affected areas, within or outside of Brazil, where the Aedes mosquitoes are present and initiate local cycles of human-to-human transmission. Response efforts are further complicated by the fact that it is occurring in the context of concomitant outbreaks of Zika virus, chikungunya and dengue.
Yellow fever can easily be prevented through immunization provided that vaccination is administered at least 10 days before travel. WHO, therefore, urges Members States especially those where the establishment of a local cycle of transmission is possible (i.e. where the competent vector is present) to strengthen the control of immunisation status of travellers to all potentially endemic areas.
WHO does not recommend any restriction of travel and trade to Brazil based on the current information available.