In a recent article, Steel, Buchak and Eyal argue that current levels of uncertainty do not present a good reason to bar controlled human infection trials of COVID-19 vaccines from proceeding. We argue that their argumentation for this conclusion is flawed. SBE are mistaken about the effects which different forms of ignorance have on participants’ ability to provide valid informed consent. Decision-makers considering whether to allow such trials, we argue, must ultimately consider the likelihood that consent to participation in such trials under current conditions would be valid, and whether this likelihood is high enough to permit such trials. This is a question that SBE completely ignore. We conclude that there indeed are valid concerns about conducting CHI trials given the current state of knowledge about COVID-19, concerns which SBE fail to address.