Coronavirus vaccine could come thanks to horseshoe crab blood

GREENVILLE, S.C. – Allen Burgenson had a job, his father explained as they stood on the sand.

This was Allen's first fishing trip, but he wasn't going to take anything from the bay. He was to return the water's gifts to the deep, where they'd belonged for hundreds of millions of years. 

If he spotted a horseshoe crab on its back, his father said as he held Allen's hand, that meant it was in trouble and needed Allen's help to get home. Allen just had to flip it over. Its 10 legs could make it the rest of the way back to the crashing waves.