Integrative biology of patients acutely infected with yellow fever virus

Yellow fever (YF) is a life-threatening mosquito-borne disease prevalent in South America and Africa, accounting for up to 60,000 annual deaths. Between December 2016 and May 2018, Brazil reported its worst YF outbreak this century with a fatality rate of 33.6%. While YF vaccines have shown protective capabilities, the genetic profile of those infected with the wild-type YF virus (YFV) remains uncharacterized. Building on recent findings by Kallas et al. (2019), which discerned clinical and immunological determinants of YF mortality, we conducted a comprehensive transcriptional profiling of blood samples from YFV-infected patients. Our investigation integrated omics data with clinical and immunological metrics, contrasting the wild-type YFV acute infection signature against the response triggered by the YF17D vaccine strain and the signature linked to severe COVID-19. Our analyses revealed key molecular mechanisms of YFV infection and determinants of disease severity. Notably, a comparative assessment elucidated distinct gene expression patterns between wild-type YFV infections, YF17D vaccination, and severe COVID-19. This study offers pivotal insights into the molecular underpinnings of YFV infection and its severity, potentially enhancing our comprehension of viral infections at large.