We both had our interviews last week. They just checked the originals of the documents that we submitted with the application. They asked about the petitioners details such as where she lives, where she works etc. Next day we received an email from US Embassy saying that they handed over our passports to the courier company. Couple of days later, we both received the passports with the visas. Visas are valid for six months from the date of your medical exam. Hope this explanation helps you.