Scientists Warn of Potential Global Pandemic from Yellow Fever

Scientists are raising alarms about the potential for yellow fever (YF) to trigger a global pandemic, one that could surpass the severity of the Covid-19 crisis. Yellow fever is transmitted to humans via the bites of infected mosquitoes, and due to factors like urban expansion and heightened travel, its prevalence has been on the rise. A recent study published in the journal npj Viruses stated that individuals infected with the yellow fever virus (YFV) showcase increased levels of the virus in their blood, making them effective hosts for mosquitoes to acquire and subsequently transmit the virus to other humans.

The research team noted that while yellow fever has not yet reached the Asia-Pacific region, the likelihood of its emergence is growing, with significant expansion observed in numerous studies. They warned that a pandemic caused by YF in the modern world could lead to an unprecedented public health emergency, one that could be far more lethal than Covid-19. The paper emphasized that the concerns regarding the spread of yellow fever, initially raised by Carter a century prior, are still exceedingly relevant today, if not more so.

The onset of yellow fever symptoms typically occurs three to six days after exposure and may include fever, headaches, muscle aches, nausea, and vomiting. In severe instances, the disease can lead to jaundice, dark urine, abdominal pain, and bleeding from various body parts. Approximately 15% of individuals may enter a critical "toxic phase," with a mortality rate of up to 50% within a week to ten days. It is important to note that yellow fever is not transmitted between humans through respiratory means. In its natural cycle, the virus primarily exists among mosquitoes and non-human primates like monkeys in forest ecosystems. Annually, it is estimated that yellow fever infects around 200,000 people and results in about 30,000 deaths. Vaccination remains the most effective prevention strategy, offering immunity within ten days for a significant majority of individuals vaccinated, and over 99% immunity for those vaccinated within thirty days.