From January to June of this year, of the 39 people with yellow fever assisted at the Hospital das Clínicas of FMUSP, only two have passed, which represents a case fatality rate of 5%. That number is very different from the past, when the fatality rate for the disease was about 27,6% among the patients who entered the Emílio Ribas Infectology Institute (IIER). The HC attended the minor cases and in this group, among the gravest ones, the case fatality rate reached 67%, at the peak of the yellow fever outbreak in the State of São Paulo, in January 2018.

The drastic reduction in the mortality of the disease was obtained through a monumental research effort, undertaken by researchers of HC and IIER. The advances in the diagnosis and treatment of the disease are the theme of an extensive report of the Fapesp Journal, at the August 2019 edition, titled “Strike back on Yellow Fever”, signed by the journalist Carlos Fioravanti.

The article shows after a year and a half of research and five scientific articles published from May to July, the doctors have been able to better understand the indicators of severity of yellow fever. With it, the most precise triage allows to determine the kind of follow-up to the patient and even the criteria to receive the liver transplant, for instance, as shown by professor Esper Kallás, infectologist of the Infectious Diseases Department of FMUSP, in a seminar held in March at the Medical School, when one of the articles was still about to be published. “Predictors of Mortality in Yellow Fever Patients: an Observational Cohort Study”, published at the renowned Journal The Lancet Infectious Diseases.

A successful strategy adopted at the HCFMUSP has been primarily on the exchange of plasma, which is the liquid portion of the blood, in order to reduce the viral charge. The technique was detailed in articles published at the Journal of Travel Medicine and also in the American Journal of Tropical Medicine and Hygiene.

The article on the Fapesp Journal details the action of the virus and the results found in the study, highlighting the effort of the researchers to find a way out of an epidemic outbreak that had already plagued Brazil in the 19^th century. In a brief history, the article shows the disease hasn’t spared even renowned health professionals, such as the Paulista oncologist Drauzio Varella, who contracted the yellow fever in 2004, during a research travel to the Rio Negro, in Amazonia.