Tl;dr. They mounted a strong yet restrained immune response when exposed without it running away to cytokine storm. This might be due to previous exposure to s

Tl;dr. They mounted a strong yet restrained immune response when exposed without it running away to cytokine storm. This might be due to previous exposure to something that “looked the same” to the immune system, advantageous genetic variation, limited viral load or just luck. These people are the raw material for creating broad-spectrum antivirals, if their genetics could be understood and the relevant antibodies (or other mechanisms) cloned.