Vermont's largest health care provider has had few problems with patients using health insurance provided by the state's new health care exchange since coverage began Jan. 1, an official said Wednesday. The report from Burlington's Fletcher Allen Health Care comes as the Department of Vermont Health Access continues to overcome technical problems on the Vermont Health Connect website and enroll people in health insurance policies provided by Blue Cross Blue Shield of Vermont and MVP Healthcare. Shannon Lonergan, director of registration at Burlington's Fletcher Allen Health Care, said only a small percentage of the thousands of patients the hospital and its affiliated offices see every day have been covered by insurance provided through Vermont Health Connect.