The injured were rushed to Badalgachi Upazila Health Complex and Naogaon Sadar Hospital. Five of the seriously injured were later shifted to Rajshahi Medical College and Hospital (RMCH) after their condition deteriorated.
"The child succumbed to his injuries at Naogaon Sadar Hospital on Wednesday night. Another of the injured died at Badalgachi Upazila Health Complex on Thursday morning, OC Azam Uddin Mahmud said.
Two of the deceased were identified as Abdur Rashid, 37, and Girij Pahan, 35, of Soasa village in Badalgachi upazila. The identity of the child and another deceased are yet to be confirmed.
A case has been filed with the Mohadevpur police station over the incident on the allegation of reckless driving and speeding.