since my previous post was deleted i am citing my source this time
autopsy said "Avery Koonce, 19, of Tyler, Texas, died Sept. 4 as the result of “paeniclostridium sordelli sepsis complicating parainfluenza laryngotraceobronchitis......”"
you folks have your cause and effect mixed up. as my previous post (deleted for no good reason) stated, she got the virus -- which causes upper respiratory infections, croup, bronchitis, pneumonia -- and then got a secondary bacterial infection causing sepsis. ergo an autopsy saying the bacteria complicated the virus. “In essence she died of untreated pneumonia,” said a pathologist who read the autopsy.
sometimes when you get sick, your immune system is depressed, and you get a secondary infection on the rebound.
you get HPIV from air droplets, surfaces, swapping spit with someone. kind of like coronavirus. that's the primary infection.
you are correct that the complicating bacteria infection can come from vaginal microbiome but also soil or her GI tract. but per the autopsy, she's getting the bacterial infection because she already had pneumonia and was very ill and then some minor GI or vaginal thing just cuts loose with her immunosurpressed and likely in her dorm of a hospital hacking up a lung.