One "out-there" thought that occurred to me - The Mossad developed a "weaponized fentanyl" spray for secret assassination, that a victim would inhale and seemingly develop pneumonia and die - this was in the late 90's I think. They had an antidote as well. I think it was revealed by a whistle-blower, a former Mossad agent who defected to Canada and wrote two books. Can never remember his name, victor something.

Anyway, there has been speculation in some corners that it was used in early 2020 to take out a bunch of Iranian politicians and leaders under the cover of the pandemic. "Covid" magically appeared in Iran just after China before anywhere else. And it could be even more prevalent then that. They could utilize it to "give covid" to dissenters ("covid" is basically pneumonia) - and it may have been used to kill Kary Mullis, inventor of the PCR, who died of pneumonia in the summer of 2019, just before the covid debacle started.