On May 17 the World Health Organization announced a change in their yellow fever vaccination recommendations, which should make it easier for people at risk.
Previously, the WHO recommended (similar to many vaccines) that a “booster” vaccination be given at 10 years, but in their current guidelines, the WHO says booster shots are not necessary. This is good news since yellow fever vaccination carries a higher side effect risk than most vaccinations.
While there are relatively few cases of yellow fever in Brazil, many foreigners who consider travel to Brazil are concerned about becoming infected. Probably they have heard much more, over many years, about yellow fever than they have heard about dengue, for example (which is now much more common).
Also, a person infected with yellow fever who develops the severe form of this disease (about 15% of cases), is much more likely to die from yellow fever than dengue. In contrast, a person infected with dengue who progresses to the severe form of dengue has a much lower chance of death— about 5%.
From 1990 to 2010, Brazil reported 587 confirmed yellow fever infections, about half of those persons died.
Yellow fever is caused by a virus that is spread by the bite of an infected mosquito. The WHO estimates 200,000 cases throughout Africa and Latin America per year, but about 90% of the cases and deaths occur in Africa, not Latin America.
Many people can be infected with yellow fever but are not definitively diagnosed, as early symptoms are similar to many other viral diseases (including dengue), and the only way to diagnose the disease is with a sophisticated blood test. Symptoms include fever, chills, nausea, muscle pain, backache, and headache.
These symptoms strike about 3 to 6 days after being bitten by the infected mosquito, but again, 85% of people recover within a few days. An unlucky 15% of people, after that initial recovery, develop a more severe secondary infection with high fever and sometimes they suffer bleeding from the nose, mouth, stomach, and even from the eyes. Their skin and eyes turn yellow—hence the name of the disease—because of jaundice (liver infection), and they may develop kidney failure.
The vaccination against yellow fever is over 99% effective in preventing the disease, but if an individual is infected with the disease, there is no good treatment, only general support.
In summary, if you have foreign friends that bring up yellow fever as a reason not to visit Brazil, you can reassure them that infection would be very unlikely, and if they are concerned they should talk to their doctor about vaccination before travel.
Esta postagem também está disponível em: Portuguese (Brazil)