COVID vaccine researchers turn to immunity boosters from a Chilean tree

Health authorities reinforce the 2020 vaccination schedule in Santiago, Chile. The Ministry of Health of Chile reported in late September that they green-lit clinical trials of two vaccines against the coronavirus, including one from Chinese company Sinovac. Photo by Rodrigo Balladares/Minsa/Handout/Latin America News Agency

Vaccines commonly contain adjuvants — substances that help fire up people’s immune systems. These adjuvants are sourced from obscure places like the soapbark tree, which only grows in Chile. The tree’s particular adjuvant is an important ingredient in one of the leading COVID-19 vaccines in the U.S. government’s Operation Warp Speed.