- Volunteers are crucial to the success of Zika vaccine trials
- "It's clearly altruism" that drives most volunteers, says study director
(CNN)It's another life-defining moment for 33-year-old Virginia Bliss. She's about to receive one of the first doses of an experimental Zika vaccine administered at the Hope Clinic in Atlanta, part of the clinical trials unit of the Emory Vaccine Center. She's one of an army of volunteers the clinic relies upon to test new vaccines.