There has been debate about sponsor-investigator ethical responsibilities to address participants' medical needs in trials in resource-constrained contexts. Certain ethical guidelines make detailed recommendations. This study explored whether ethical guideline recommendations for care in HIV vaccine trials were being met, and whether stakeholders were facing difficulties addressed by guidelines. It sampled key stakeholders involved in two trials across five sites in South Africa, and reviewed relevant documentation. It concluded that sites were largely meeting guideline recommendations for addressing needs, with some exceeding these. Recommendations for writing protocols were only partially achieved. Recommendations for engaging participating community were mostly met, except for "moral negotiation" recommendations. Suggestions are made to strengthen practices, and to improve guidelines so they address empirical concerns.