Democratic Pennsylvania Senate candidate John Fetterman's campaign released an updated letter from his doctor on Wednesday, five months after he suffered a stroke only days before the state primary and as he faces ongoing questions about his health from Republican opponent Dr. Mehmet Oz.   The new letter is dated Oct. 15 one day after the campaign says Fetterman had a follow-up visit with his primary care physician. It states overall that the Senate candidate is recovering well from his stroke and his health continues to improve.  "He has no work restrictions and can work full duty in public office," writes Dr. Clifford Chen of UPMC.  Since returning to the campaign trail this summer – Fetterman has been using a closed captioning device to read questions during interviews as he continues to struggle with auditory processing challenges during his recovery.  "He spoke intelligently without cognitive deficits," his doctor wrote. "His speech was normal and he continues to exhibit symptoms