Frank Gore carried three times for 33 yards on the drive, and Kaepernick hit Davis on a 32-yard pass.
The 49ers' defense quickly got the ball back for Kaepernick. Campbell tried to hit wide receiver Devin Hester along the left sideline, but 49ers cornerback Tarell Brown cut in front for an easy interception and it returned 5 yards to the Chicago 44.
The 49ers drove to the Bears' 12-yard line but backtracked. After Kaepernick was sacked by Corey Wootton and Israel Idonije on third down, San Francisco settled for a 37-yard Akers field goal. The boot put the 49ers ahead 20-0 with 6:32 left in the half.
NOTES: Bears rookie wide receiver Alshon Jeffery was active after missing four games with a fractured right hand, but he left the game midway through the second half with a knee injury and did not return. ... Chicago defensive end Shea McClellin, who suffered a concussion last week against Houston, was inactive. Bears defensive lineman Amobi Okoye suited up after missing the previous three games. ... Bears nickel back D.J. Moore was inactive for the first time this season. ... Cutler and McClellin did not make the trip to San Francisco. ... San Francisco running back Brandon Jacobs, who has yet to play a down this season, was inactive again.