Hi. Read and understood the history related to your daughter. To answer your question first: The loss of voice or strained voice of 7 weeks is a long time to suffer. This could have been started by an bacterial infection and to make you aware strep is not the only bacteria that can cause this problem. I would suggest you the following: Get an ENT endoscopy done from an ENT Surgeon so that the exact problem why is your daughter having strained voice. Once the proper diagnosis is done, the treatment will be easy. She will be given proper antibiotics, anti-inflammatory and symptomatic and supportive medicines . In addition she should take the following care: - Steam inhalations. -Oral steroids if required. - Voice rest- this is the most important