SUNDAY, SEPTEMBER 25, 2016

WHO concludes yellow fever vaccine booster not required

An advisory group to the World Health Organization announced on Friday that the yellow fever booster vaccination given ten years following an initial vaccination is not needed.

The WHO's Strategic Advisory Group of Experts on immunization reviewed the latest evidence related to the booster and determined that a single vaccine is enough to confer life-long immunity against yellow fever disease. Since vaccination for yellow fever started in the 1930s, there have been only 12 known cases of yellow fever after vaccination following the use of 600 million vaccine doses. All 12 cases occurred within five years of vaccination.

"The conventional guidance has been that the yellow fever vaccination has had to be boosted after ten years," Helen Rees, the chair of SAGE, said. "Looking at really very good evidence, it was quite clear to SAGE that in fact a single dose of yellow fever vaccine is effective. This is extremely important for countries where yellow fever is endemic, because it will allow them to reconsider their vaccine scheduling. It is also important for travelers."

Yellow fever is an acute viral hemorrhagic disease transmitted by infected mosquitoes that is endemic in 44 countries in tropical areas of the Americas and Africa. Infection can cause mild to severe symptoms, including bleeding, jaundice and death. There are approximately 200,000 cases of yellow fever worldwide each year.

The yellow fever vaccine confers protective immunity within 30 days for 99 percent of people receiving the vaccine.

SAGE is the principal advisory group to WHO for immunization and vaccines. The announcement was made in WHO's Weekly Epidemiological Record.