Yellow fever in older adults: an overlooked high-risk population in South American outbreaks

Rodriguez-Morales A.J. · Sustainable Microbiology (2026) · DOI: 10.1093/sumbio/qvag018

Resumen

Yellow fever (YF) remains a re-emerging public health threat in South America, with recent outbreaks reporting high case-fatality rates. Although transmission has predominantly affected rural and sylvatic populations, mounting evidence indicates that older adults experience disproportionately severe outcomes and mortality. This commentary highlights the elderly as an overlooked high-risk group in the current epidemiological landscape. Age-related immunosenescence, comorbidities, endothelial dysfunction, and reduced hepatic reserve likely amplify the pathophysiological impact of YF virus infection. At the same time, concerns about vaccine-associated adverse events in individuals ≥60 years complicate risk–benefit decision-making, contributing to under-vaccination in this vulnerable population. Delayed diagnosis and shifting eco-epidemiological patterns further exacerbate risk. As South America undergoes demographic aging alongside environmental change, targeted, age-specific strategies, including prioritized vaccination, tailored risk communication, and enhanced surveillance for older adults, are urgently needed to reduce preventable fatalities. © The Author(s) 2026. Published by Oxford University Press on behalf of Applied Microbiology International. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site-for further information please contact journals.permissions@oup.com

Instituciones: Universidad Científica del Sur