What are the characteristics of yellow fever?

It is a disease caused by a virus, considered to be a haemorrhagic fever. The virus is transmitted by the Aedes mosquito. After a short incubation period, the infected person may develop slight symptoms common to the majority of viruses (flu, malaria etc.), or even no symptoms at all, and nothing more may occur, which is what happens in about 80% of cases. But there may be a second phase, known as yellow because the liver is affected. This phase may also become haemorrhagic if other organs are affected. In this second phase, the mortality rate can be high: around 25% or 30%.

From a medical point of view, which tools are available to fight the disease?

Yellow fever wreaked havoc at the end of the 19th century and at the beginning of the 20th century in many parts of the world. Research led to the development of a highly effective vaccine. Systematic vaccination campaigns were launched and considerably reduced the epidemics. But at the end of the 20th century, systematic vaccination of the population became less of a priority in certain African countries and this led to new epidemics, such as the one that struck Guinea in 2000.

In view of the shortage of vaccines on the market, an international coordination group (ICG) was set up to manage a strategic stock of six million doses per year, so as to be able to respond to an epidemic. However, there is no specific treatment available. The treatment is symptomatic: the patient is helped to overcome the disease by attacking the symptoms. During the second phase, when the virus disappears and the patient is no longer contagious, the most important thing is to prevent the liver from becoming necrotic.