I still think it was man-made but accidentally released, and I'm not normally a conspiracy theories type guy.
Your sister's experience sounds awful. The smell and taste loss a month later has to be especially frustrating, because she is probably starting to wonder if she will ever get it back. I could handle the loss of smell, but not being able to taste things for more than the short term would be a terrible way to live.
I'm a guy who didn't even bother getting the flu shot for the past 10 years, but this thing scares me big time.