Over 100 passengers on Malaysian Flight MH17 were headed for an HIV conference in Sydney, many reports indicated now, as with this story from the UK Independent by Lizzie Dearden, here. The collective knowledge that could lead essentially to cures or finally effective vaccines could have been lost to the struggle from Russian separatists. Former President Clinton was to meet the researchers in Australia.
here, wlin links to Vox explanation panels.
Wikipedia link for map of Donbass insurgency area near crash.