A new study, which defines the main predictor factors of mortality by Yellow Fever will be known by the academic community. The article “Predictors of Mortality in Yellow Fever Patients: an Observational Cohort Study” will be published soon in the scientific journal The Lancet Infectious Diseases. One of the authors of the paper, professor Esper Kallás, infectologist of the Department of Infectious Diseases of FMUSP, presented the central results during the seminar “Yellow Fever: Clinical presentation, prognostic factor and development of new therapies”, held on march 13^th by the Laboratories of Medical Investigation (LIMs) Of FMUSP.

Without symptoms in most of the infected, the yellow fever is a serious virus, yet without a defined treatment protocol. At his lecture, Kallás approached the work of groups of scientists from FMUSP, Hospital das Clínicas and the Institute of Infectology Emílio Ribas, which has been studying several aspects of the infection since the first epidemics in 2017 in the State of São Paulo.

Among the advancements, Kallás has shown the mortality rates grow with the increase of the number of neutrophils with a viral charge in the blood. The studies also show every year in the aging process of the patient, there is a 5% increase in the mortality rate.

“These results seem obvious, but, in the literature, no work so far has determined the viral charge and the increase of neutrophils are predictors of mortality. If the count of neutrophils is below 4.000 cells/MCL and the viral charge are under 100 million RNA copies per plasma ml, the mortality is of 11%. If the patient arrives with the count of neutrophils above 4.000 cells/MCL and the viral charge are above 100 million RNA copies per plasma ml, the mortality is of 100%”, says the professors.

The parameters found are crucial to help determine the kind of monitoring of the patient and even the criteria to receive the liver transplant, for instance. “If there is a way to predict the mortality chances, perhaps a specific treatment, an early antiviral or even an early transplant could help the patient”, says Kallás.

The incubation period of the virus is from three to six days. After this period, the symptoms start with a subtle fever, chills, intense headache, back and body ache, nausea and vomit, besides fatigue and weakness. “Among the symptoms, the back ache is a warning. In spite of the name, in the acute phase the patient doesn’t present jaundice, a symptom which only appears later on.”, states Kallás.

Considered one of the most renowned HIV researchers in the Country, Kallás declared some research groups have already shown the Sofosbuvir can act against the infection caused by the yellow fever virus in laboratory studies, however the drug is still being evaluated in a clinical study.

“A work force was assembled to respond if the Sofosbuvir will be useful. A multi-centric study under the coordination of Professor Ana Sara Levin, of the Department of Infectious Diseases of FMUSP, held with patients admitted in the HC and in the Institute of Infectology Emílio Ribas will soon answer if the Sofosbovir is working or not”, he claimed.

The researchers are also initiating the study with other drugs, such as the Galidesvir and monoclonal antibodies, according to Kallás.

In 2017, the mortality for the State of São Paulo was of 37% among the infected, a rate considered very high. In 2018 the FMUSP researchers cleansed a cohort of 76 cases and reached a mortality of 35%. Curiously, during the epidemics that started to spread this year in the region of Registro in the Vale do Ribeira, among 48 cases there were 10 deaths, a mortality of 21%. “The rate has dropped. The suspect is that we improved the treatment and the services are more aware and attending less serious cases and initiating the treatment early. I believe this proportion is closer to the real mortality of the disease than in relation to the data in those moments of crisis”, he said.