Recent cases of yellow fever in Brazil’s Vale do Paraíba region have raised alarm among health authorities. The São Paulo Department of Health confirmed three instances of the illness, including the death of a 38-year-old man. None of the affected individuals had been vaccinated, underscoring the crucial role of immunization in preventing the disease.
Expert Warning: Yellow Fever Could Cause Death in Half of Severe Cases
Dr. Flávia Falssi, an infectious disease specialist at Grupo Santa Joana and the Emílio Ribas Institute, provided insights on the disease during an interview. Yellow fever is a viral infection transmitted by mosquitoes, primarily the Aedes mosquito in urban areas and Haemagogus in rural regions. Dr. Falssi highlighted the potential severity of yellow fever, stating that while about 60% of cases may resolve with mild symptoms, 20% to 40% can develop severe illness, with half of those at risk of death.
Symptoms and Disease Progression
The initial symptoms of yellow fever appear two to three days after a mosquito bite. Early signs include:
- Fever
- Malaise
- Headache
- Body aches
Following this phase, patients may enter a remission period, where mild cases can improve. However, severe cases may worsen after a brief improvement, leading to toxic symptoms primarily affecting the liver, resulting in hepatitis. Symptoms of severe yellow fever can include:
- Jaundice (yellowing of the skin and eyes)
- Dark urine
- Cardiac irregularities
In advanced stages, patients risk liver or kidney failure, which may require intensive care or even transplantation. Dr. Falssi noted that many patients seek medical help during this critical stage.
Vaccination as the Primary Preventive Measure
The yellow fever vaccine is part of Brazil’s national immunization schedule. It is recommended for all children at nine months of age, with a booster at four years. Adults who missed vaccination in childhood should receive a single dose before turning 59. Dr. Falssi encourages eligible adults to visit a healthcare center for vaccination, emphasizing the need to carry their vaccination card.
Individuals with immune system disorders or those undergoing specific treatments should consult a doctor prior to vaccination.
The newly reported cases in the Vale do Paraíba are under investigation to ascertain their origins. Dr. Falssi speculated that the cases might not be of urban transmission, as the affected individuals were involved in agriculture, indicating exposure to rural environments.
She reiterated the importance of vaccination: “Even if you are exposed to areas where yellow fever transmission can occur, vaccination protects you,” Dr. Falssi concluded.
