Long-Term Protection After Fractional-Dose Yellow Fever Vaccination | Annals of Internal Medicine | American College of Physicians

Long-Term Protection After Fractional-Dose Yellow Fever Vaccination | Annals of Internal Medicine | American College of Physicians





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Fractional dose of yellow fever vaccine provides lasting protection, study shows

Inoculating someone with a yellow fever vaccine that is one-fifth the standard dose still provides protection against the virus for at least 10 years, researchers reported. The finding adds to the evidence that using a so-called fractional dose is an adequate strategy when responding to outbreaks of the mosquito-borne disease. To stretch the vaccine supply, health authorities have started deploying fractional-dose campaigns, including in the Democratic Republic of the Congo in 2016. Previous studies showed the one-fifth dose extended protection for up to a year, but questions remained about the long-term strength of a smaller dose. For the new study, the researchers studied 40 adults who were given a fractional dose a decade ago as part of an earlier trial, and found that 39 of them still had protective antibodies in their systems without receiving boosters.