ArticleTransactions of the Royal Society of Tropical Medicine and Hygiene2026
A cohort study of the duration of immunity to yellow fever after 4 years of primary vaccination in children and adults.
Article in Transactions of the Royal Society of Tropical Medicine and Hygiene, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
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20 authors.
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Abstract
backgroundLifelong protective immunity from a single dose of yellow fever (YF) vaccine remains controversial. We evaluated variations in YF neutralizing antibody titres over 4 years after primary vaccination.
methodsA cohort study was conducted in three municipalities in northeastern Brazil. The 17DD vaccine was administered between 2016 and 2018. Blood samples were collected to measure YF neutralizing antibodies before, 30-45 d, 1 y and 4 y after vaccination. Generalized linear mixed models with a Tweedie distribution were constructed for children and adults separately to estimate variation in antibody titres over the 4-y period.
resultsOf the 4761 individuals, 2753 were children between 9 months and 4 y of age and 2008 adults ages 18-50 y. Four years after vaccination, seropositivity rates were 67.9% and 72.1% in children 9-23 months and 2-4 y, respectively, and 91.2% and 94.4% in adults 18-35 and 36-50 y, respectively. The ratio of means for neutralizing antibody titres 4 y after vaccination decreased to about one-third of that observed at 30-45 d after vaccination.
conclusionsThe evidence of waning immunity after a single dose of YF vaccine appears to support revaccination if primary vaccination targets infants and toddlers in endemic countries.
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