Interesting... I work in health care, have for years, and im not sure i have ever heard of something like this... Or contemplated the reasons/corration behind my patients sore throats and/or sinus infections. Frankly, some of them im not sure i want to haha!
The vagina is a "self-cleaning" organ so to speak- so the chance of this causing any infection is unlikely. However, some women colonize strep bacteria in their vagina (harmless in my experience to the female or sexual partner) that needs to be treated usually only during child birth.
Not sure what other advice i could offer at this point but would be glad to provide any info i can... Let me know