Ethics(2) Vaccines(2) Research Ethics(1) undue influence(1) Risks(1) burdens of research/beneficence(1) Equality(1) human infection challenge studies(1) developing countries(1) In-depth interviews(1) undue inducement(1) healthy volunteers(1) volunteer infection studies.(1) Benefits(1) non-maleficence(1) disparity(1) end of trial(1) payment for research participation(1) bioethics(1) international research(1) equity(1) deception(1) clinical trials(1) Qualitative methods(1) vaccine trials.(1) Therapeutic misconception(1)