Me either, but it is considered so. Challenge trials can be considered ethical, but only when the risk to the volunteer is minimal. Even if we (society) did de

Me either, but it is considered so. Challenge trials can be considered ethical, but only when the risk to the volunteer is minimal. Even if we (society) did decide that doing a challenge trial is worth the risk, we would be amiss to not look for a safer strain to use first. Only if we can’t find one after making a serious effort should we even think about using a dangerous strain.