Human dengue trial shows immune memory can help—or backfire

A recent human dengue trial has shown that immune memory can either help or backfire. The study highlights how the body’s response to a first dengue infection may not protect against, and can sometimes worsen, a second infection with a different serotype.

Dengue, transmitted by bites of Aedes mosquitoes, is a viral illness that can produce mild fever, flu‑like symptoms, joint pain, or the severe form known as dengue hemorrhagic fever. What makes the disease particularly dangerous is that a second infection with a different strain can trigger more severe disease rather than stronger immunity.