Here's What To Know About Vaccines and Sharks

Roughly 3 million sharks are killed annually for squalene, an ingredient used as a boosting agent in vaccines — now, researchers are testing alternatives to the substance to protect the vulnerable species. Don’t worry, the COVID-19 vaccines available in the U.S. are squalene-free. 

Squalene is a fatty substance that helps sharks regulate their buoyancy at depth, but it’s also used by humans as an adjuvant, or boosting agent, in vaccines, reportedly boosting the immune system and making the vaccine more effective. Approximately 3 million sharks are killed annually for squalene.

The Pfizer and Moderna vaccines are squalene-free, but at least 5 of the 200+ vaccine candidates use squalene in their formulations.