Kerecis grafts cod skin onto human wounds because fish can't give people their diseases

Skin substitutes made from pig or cow tissue had long been used to treat burns, diabetic ulcers and other wounds that wouldn't heal on their own, but because pigs and cows are close enough to humans biologically for viruses and prions to cross over, every batch of mammalian graft material had to go through harsh viral-inactivation processing — detergents and treatments that strip lipids and denature the tissue's natural structure to make it safe, at the cost of much of what made it useful for healing in the first place.

Iceland's fishing industry, meanwhile, threw away the great majority of every cod's skin as a low-value byproduct of filleting, alongside heads, bones and offal sold cheaply for fishmeal. Sigurjónsson's problem was not finding a source of skin — Iceland's fleet produced far more than any grafting business could use — it was finding a source of skin that didn't carry the disease risk mammalian material did, while still resembling human dermis closely enough to work.

Used cod skin, whose cold-blooded biology means no known virus or prion can infect humans, so it needs only mild processing that preserves its natural healing structure.

Mammal grafts require harsh processing to kill viruses and prions, degrading the tissue.

Fish are biologically distant enough that no known pathogen crosses to humans.

Cod skin's collagen resembles human dermis, so it works as a graft.

Mild processing preserves natural structure and fatty acids, improving healing.

When a risk is inherent to a material's category, find a source outside that category to sidestep the risk entirely.

FDA-cleared and used across US and European hospitals for burns and wounds, Kerecis was acquired by Coloplast in 2023 for over $1.3 billion. Kerecis built an entirely new medical-device category — intact fish-skin grafts — out of a seafood byproduct, and its Ísafjörður plant now processes cod skins that would otherwise go to fishmeal into one of Iceland's most valuable non-fishing exports.