Yellow fever is an acute infectious disease
caused by a virus that is transmitted by various species of Aedes
mosquito and, in South America, Haemogogus species.
The WHO estimates that there are some 200 000
cases of the disease each year, and 30 000 deaths.
In Sub-Saharan Africa, 468 million people in
33 countries are considered to be at risk of the disease. In recent
years, the number of epidemics of yellow fever has increased. There
are few specific treatments for yellow fever, and vaccination is
the single most important measure for preventing the disease.
A single dose of the existing vaccine is highly
effective and provides protection for at least a decade, and probably
for life. More than 300 million doses have been given.
The World Health Organization strongly recommends
routine childhood vaccination against yellow fever. The vaccine
can be given safely to babies of 9 months, at the same time as measles
Seventeen African nations have so far agreed
to incroporate yellow-fever vaccination into their routine national
immunization programmes. However, to prevent epidemics, at least
80 per cent of the population of a country must be immunized, and
very few countries have achieved this level of coverage to date.
For more information see:
- Weekly Epidemiological Record No 46, 13 November
1998, and No 47, 20 November 1998.
More vaccines that are available now