Prehistoric crabs help test vaccine safety

These extraordinary creatures have been swimming in our oceans for 450 million years. They're known as horseshoe crabs but aren't actually crabs at all. Nivette Perez-Perez, manager of community science for Delaware's inland bays, explains.

Nivette Pérez-Pérez: "Horseshoe crabs, in, in difference of their common name, they're not crabs. They're actually arthropods that are related to spiders and scorpions. This is a female, and one of the ways to see that is this first pair of legs. They're actually pinchers."

In the 1970s, horseshoe crab blood became a biomedical tool. Scientists discovered it contained a special ingredient. It's called limulus amebocyte lysate. It's used to uncover dangerous bacteria, or endotoxins. This is key in preventing contamination of medications, needles, joint replacements and vaccinations.

Its use in vaccines has grown significantly, explains Glenn Gauvry.

Glenn Gauvry: "One of the things that has always been tested with this test is vaccines. So we've got vaccines around the world for all kinds of things, but we now have a whole new wave of vaccines being produced and developed for the battle against Covid. And they're being tested on, on the same test made from the horseshoe crab blood."

Approximately 500,000 horseshoe crabs are caught and bled annually. The process of collecting the chemical kills around 15 percent of the creatures, which also face other environmental dangers. With the need to find an alternative to horseshoe crab blood, Swiss biotech company Lonza has begun developing an artificial compound. However, this substance, which is called recombinant factor C, hasn't been licensed yet.

Volunteers in the US regularly check the populations of these prehistoric animals on the beaches of Delaware. It's the best place to find them, says education coordinator Laurel Sullivan.

Laurel Sullivan: "We have the largest spawning population in the world in the Delaware Bay. So it's something that people in this area take very seriously and they're really passionate about, because it's something that's really unique to this area."

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