When antiviral drugs are widely used, resistance usually follows. Viruses mutate, treatments lose strength, and scientists scramble to adapt. That pattern has been seen with influenza, HIV, and many other infections. When the anti-viral drug Paxlovid was rolled out globally to treat COVID-19, many experts expected that the virus would eventually evolve ways to evade it. But several years on, meaningful resistance has not taken hold. In two closely connected studies, Dr Brent Iverson and colleagues set out to understand why. Their findings suggest that the virus may be more constrained than many had assumed – and that those constraints are helping Paxlovid remain effective.

For decades, fat tissue was treated as little more than the body’s storage cupboard – a place where excess calories were tucked away for later use. But research from Dr. Jamie Rausch, Assistant Professor of Nursing at Indiana University, is helping to overturn that simplistic view. Fat, or adipose tissue, is now understood to be one of the body’s most active and influential biological systems, constantly sending chemical signals that shape metabolism, inflammation, and long-term health.

Pulmonary fibrosis is a devastating disease in which lung tissue becomes scarred and stiff, making it harder to breathe. The outlook for patients remains poor, with many surviving only a few years after diagnosis. Current treatments can slow the damage, but they cannot reverse it. New research by the team of Prof. Christian Bär and Dr. Shambhabi Chatterjee of Hannover Medical School and their colleagues explore a promising alternative – one that works at the level of our cells’ biological ‘aging clock’.

Electronic cigarettes have been marketed as a safer alternative to traditional tobacco, but a growing body of research is painting a more troubling picture. Two studies from North Carolina Central University, conducted by Rob Onyenwoke and colleagues, suggest that vaping doesn’t just harm the lungs on its own – it may also make them far more vulnerable when infection strikes.

Depression affects nearly one in five Americans at some point in their lives. Sadly, for roughly a third of patients, standard antidepressants simply don’t work. Now, researchers at Johns Hopkins University School of Medicine believe they may have found a promising new path forward – one that targets the brain’s own immune cells. Dr. Xiaolei Zhu, Dr. Barbara Slusher, and their colleagues have been investigating why the brain’s resident immune cells, called microglia, appear to go into overdrive in people with major depressive disorder.

The human gut is more than a long tube for digesting food – it is one of our body’s largest and busiest borders, constantly deciding what may enter and what must stay out. Most of these decisions are made by a nervous system embedded within the gut wall, often called ‘the brain in the gut’, and supported by the local immune system. When this border becomes too permeable, often described as a ‘leaky gut’, problems can arise throughout the body. Researchers Vedrana Bali and Vladimir Grubišić, at the New York Institute of Technology College of Osteopathic Medicine, argue that this leaky-gut phenomenon may cause far more than stomach troubles.

Cancer treatments are increasingly moving beyond one-size-fits-all approaches, and new research led by Marc de la Roche and Maike de la Roche shows how a single biological target could open the door to multiple, more precise immunotherapies. The work focuses on LGR5, a protein found at unusually high levels on the surface of certain cancer cells, including colorectal cancer, liver cancer, and a form of leukaemia.

How does a single fertilized egg produce the hundreds of cell types that make up the body – from neurons and skin cells to muscle and blood? This question has long been one of biology’s great mysteries. Dr. Bruce Lahn and his team at the University of Chicago believe they have uncovered a fundamental mechanism behind this process, which could reshape how scientists think about development and cellular identity.