What happens during the Verification of Employment for an FHA loan?

I just got asked for my hr information for my loan through FHA. I have submitted my W2's and pay stubs. I know that this will be faxed to my employer, which is fine. However will the underwriter still call once they have the VOE faxed back to them. Reason I ask is because my HR rep will be on vacation. Just curious if this will delay my closing. Thank you for your answers!