Days after progressive challenger Dean Preston declared victory in the District 5 race, Supervisor Vallie Brown has conceded the tight contest.

Brown, an appointee of Mayor London Breed, called Preston Wednesday morning to congratulate him on the victory.

“The campaign is now officially over and we’re moving full steam ahead with the transition,” Preston said in a statement on Twitter.

Brown lost by less than 200 hundred votes and was considering a recount before deciding to concede the race, she said in a letter to her supporters.

“We’ve determined that the chances of any change in the result are too slim to justify the time and cost,” Brown wrote in the letter.

“Our community is bigger than any one of us, and though my time as your supervisor may be coming to a close, I am certainly not going anywhere,” she continued.

S.F. Examiner Staff Writer Joe Fitzgerald Rodriguez contributed to this report.

mbarba@sfexaminer.com