WHO has announced that the yellow fever “booster” vaccination administered 10 years after the initial one is not necessary, according to a press release.
The WHO’s Strategic Advisory Group of Experts (SAGE) on immunization has reviewed the latest evidence and concluded that a single dose of the vaccine is sufficient for lifelong immunity against yellow fever.
“The conventional guidance has been that the yellow fever vaccination has had to be boosted after 10 years,” Helen Rees, MD, who chairs SAGE, said in the press release. “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 the vaccine scheduling. It is also important for travelers.”
Since vaccination began in the 1930s, only 12 cases of yellow fever after vaccination have been identified, after 600 million doses have been dispersed. Evidence also showed that the cases all occurred within 5 years of the vaccination.
Vaccination is considered the most important and effective measure against yellow fever. Immunity develops within 30 days for 99% of people receiving the vaccine. For routine immunization programs in Africa, home to 31 of the 44 yellow fever endemic countries, the vaccine costs about 82 cents per dose.
Each year, there are an estimated 200,000 cases of yellow fever worldwide. About 15% of people infected progress to a severe form of illness and up to half of those will die. There is still no cure for yellow fever.
Disclosure: The researchers report no relevant financial disclosures.