A Natural Vaccine? Corals Can ‘Remember’ Infections and Fight Back

Researchers at King Abdullah University of Science and Technology have discovered that corals may develop vaccine-like protection against disease after previous exposure to pathogens. Although corals lack the adaptive immune systems found in humans, researchers found evidence of immune priming that could help them respond more effectively to later infections.

Scientists exposed fragments of the Red Sea coral Pocillopora favosa to low doses of live or chemically inactivated Vibrio coralliilyticus bacteria. The corals were later subjected to heat stress and a full pathogen challenge. Primed corals experienced less bleaching and physiological decline than corals without previous exposure. Researchers also observed changes in gene expression and coral microbiomes.

The findings could eventually contribute to new coral conservation and reef restoration strategies, particularly as warming oceans increase disease vulnerability. Researchers emphasized that the study represents proof of concept rather than a treatment ready for reefs. Importantly, inactivated bacteria produced protection comparable to live pathogens, offering a potentially safer approach for future research.