Over the past few centuries, yellow fever outbreaks have led to numerous cases and related fatalities. While the World Health Organization says most severe yellow fever (YF) cases have a fatality rate of around 39%, recent data from South America indicates an unfortunate increase in deaths.
Since 2024, the Republic of Colombia has faced an active YF outbreak. As of February 21, 2025, 40 cases have been confirmed (17 in 2025), with 19 related deaths, representing a case fatality rate (CFR) of 47%.
Yellow Fever Fatality Rate Increases 20%
Protective Genes Enable Tuberculosis Airborne Transmission
For over 100 years, a vaccine has been deployed 4 billion times to prevent tuberculosis (TB) outbreaks. Unfortunately, versions of the Bacille Calmette-Guérin (BCG) vaccine have only been about 50% protective at reducing severe disease.
To understand this shortcoming and why TB treatments often fail, researchers recently identified genes that the tuberculous bacteria rely on to survive and spread. These genes could help stop the spread of the world's leading infectious disease killer.