Brazil is currently facing an outbreak of yellow fever in endemic areas, that is, in the areas where there is a risk of infection. Yellow fever is a viral hemorrhagic fever borne by infected Aedes aegypti mosquitoes. Patients can be affected by jaundice, hence the name of the disease.
According to Centro de Informação em Saúde para Viajantes (Cives), the travelers' health information center at Universidade Federal do Rio de Janeiro, the Brazilian Ministry of Health reported 31 confirmed cases of yellow fever between December 2007 and February 2008. Sixteen people died. All evidence, albeit inconclusive, points to infection in rural areas of the Central-West region.
The Yellow Fever Vaccine
Yellow fever can be prevented by an effective vaccine that must be taken at least 10 days before entering an endemic area and lasts for 10 years. As the Brazilian Ministry of Health reported to the World Health Organization, none of the people who died in the recent outbreak were immunized against yellow fever - either they had never taken the vaccine, or had taken it longer than 10 years ago.
As of the time of this writing, Brazil's yellow fever vaccination guidelines for travelers are: recommended for risk areas; not required from incoming travelers.
Transmission Patterns in Brazil
There are three yellow fever transmission patterns: sylvatic, urban and intermediate. There isn't intermediate trasmission in South America. The cases reported in Brazil configure sylvatic transmission, that is, non-immunized people were infected in rural areas by mosquitoes that had bitten infected monkeys.
In Brazil, urban transmission - infection carried by Aedes aegypti from one person to another - has been considered eradicated since the 1940s. However, since the reintroduction of Aedes aegypti in the country in the 1970s, there has bee a permanent risk of a yellow fever comeback, according to Cives.Can Everyone Take the Yellow Fever Vaccine?
No. Infants under 9 months of age can't. Many other people shouldn't. Restrictions may be applicable to people with conditions that lower immunity, for example. Only a doctor can help vaccine candidates weigh risks and benefits.
Other Preventive Measures
Aedes aegypti transmits another tropical disease: dengue fever. Brazil has been engaged in a countrywide campaign to eliminate mosquito breeding sites for years and on Feburary 22, 2008 the Brazilian Ministry of Health reported a 40% reduction in the number of dengue fever cases in Brazil for the first five weeks of the year, compared to the same period in 2007. However, Health Minister José Gomes Temporão also acknowledged a 117,42% rise in dengue incidence in Rio de Janeiro State for the same period.
Unfortunately, there is no vaccine available for dengue fever. Preventive measures must be adopted when you travel to tropical areas, including Brazil. These measures also apply to preventing yellow fever infection, but they can't compare to the effectiveness of the vaccine.
Status of Yellow Fever Vaccination in Brazil
According to a February 5, 2008 World Health Organization (WHO) report, Brazil is one of WHO's pre-qualified manufacturers of yellow fever vaccine. In Brazil, the vaccine is available at all times at public health clinics and Anvisa vaccination rooms.
In the February 5,2008 report, WHO also informed that not only had Brazil suspended exports in order to supply internal demand, but had also borrowed 4 million doses from the global emergency stockpile kept by the International Coordinating Group on Vaccine Provision for Yellow Fever Control (YF-ICG) to reinforce the country's stocks. The Brazilian press noted the fact that the government had not officially disclosed those facts prior to the WHO announcement. But there isn't a shortage of yellow fever vaccine in Brazil, as confirmed by a rush to vaccination clinics all over the country and the fact that demand was met despite an increase of up to four times in the number of doses administered.
Since yellow fever vaccination is not required prior to entering Brazil, whether or not to take it becomes a matter of informed common sense. Travelers bound for many non-endemic touristic areas in Brazil, such as Rio, São Paulo or Salvador, need not worry about taking the vaccine. The constantly updated Cives chart of risk states and cities in Brazil is one of the reliable sources of information. Find tips about using the chart in the Cives listing as one of the Top 7 Online Resources About Yellow Fever for Brazil travelers.
