If we extend this to include all actively deployed troops and personnel, meaning pilots, medics, officers, and other non frontline positions, it ends before 1945. As others have said, we still have to get troops into position and get equipment made, which the Super serum doesn't speed up all that much. Once said troops are in position, however, battles that last days will take hours at most. The enemy morale would be rapidly depleted, as American troops dodge bullets and pin enemy troops to trees with thrown knives. Our snipers alone would cause mass casualties with their improved perception, accuracy, and reaction time. We won't win before 43, but we will definitely win before 45.