Horseshoe crab blood is key to making a COVID-19 vaccine—but the ecosystem may suffer.
Each spring, guided by the full moon, hundreds of thousands of horseshoe crabs clamber onto beaches across the U.S. mid-Atlantic to lay their eggs. For hungry birds, it’s a cornucopia. For drug companies, it’s a crucial resource for making human medicines safe. That’s because these animals’ milky-blue blood provides the only known natural source of…