In the year following the success in Rio de Janeiro, Brown struggled, despite a promising gold medal win for Canada's 4x200 m relay team at the 2017 World Relay Championships. After a false start at the 100 m final of the 2017 Canadian Championships, he was disqualified and thus only sent to race the 200 m at the 2017 World Championships in Athletics. Upon arrival in London for the championship, he was one of many athletes there to contract norovirus. He recorded the fastest time in his heat, but was disqualified as a result of a lane violation. He also competed in the 4x100 metres relay. Missing their anchor Andre De Grasse, the Canadian relay team ultimately placed sixth in the finals.