It would be difficult but not impossible in gain of function research. You don't need as deadly a virus to kill off older people or those with severe illness as you would someone younger. It would seem logical if you wanted to produce such a virus then you'd find a cure first to immunize those you wouldn't want infected. We've know all along that hydroxychloroquine works not only to minimize serious illness but acts like a prophylactic to prevent one from getting the disease. The whole concept behind gain of function research is to enhance the most deadliest viruses you could find in nature so you can research a cure gaining an upper hand on the virus. If you didn't want people dropping dead by the millions you could control the amount of people it effected by enhancing the virus to be more deadlier. The kind of people that'd work a gain of function research as an objective to kill people would be people with a total disregard for human life, like the Chinese. Why would China want to do something of that nature is rather simple, to topple world governments to become the world's economic powerhouse. They've also been collecting human DNA of different races for years. I am not saying for one hundred percent sure that's what was or has been going on but I am convinced this virus came out of a lab and was not found in nature as it currently stands.