The World Health Organization says a yellow fever booster vaccination given
10 years after the initial shot isn't necessary.
The UN's global health agency said that its expert group on
immunisation believes a single dose of vaccination is sufficient to confer
lifelong immunity against the disease.
The Geneva-based body says only 12 known cases of yellow fever after
vaccination have ever been identified. Some 600 million doses have been
dispensed since yellow fever vaccination began in the 1930s.
Yellow fever is an acute viral hemorrhagic disease transmitted by infected
mosquitoes that is endemic to 44 countries in tropical areas of Africa and the
There are an estimated 200 000 cases of yellow fever and up to 15 000 deaths
worldwide each year.