Recently the WHO Ad Hoc Expert Group proposed that it is ethical to continue placebo-controlled Covid-19 vaccine trials in countries where vaccines are not available even if this vaccine is marketed and being used elsewhere. The reason for this proposal is the usual scientific argument claiming that these trials are the most efficient method to obtain reliable results, and individuals in these countries will continue to get the local standard of care, meaning no vaccination, and thus participants are not being left worse off. We refute this argument on two counts. First the global equity and justice issue, that the scarcity of vaccines in most countries is created by the rich nations that have hoarded vaccines. Second, the science versus research ethics issue, that there are valid scientific methods like non-inferiority trials which can give reliable results, and that applying a standard of care imposed by rich nations is both unethical and possibly exploitative. Thus, we feel that the WHO Ad Hoc Expert Group is wrong in proposing to continue placebo-controlled Covid-19 vaccine trials.