The accident, which happened shortly after 8.15pm, was on the A42 near Measham in Leicestershire.
Leicestershire ambulance service said four of the injured were seriously hurt, including one victim originally thought to have died at the scene but whom paramedics managed to resuscitate.
The cause of the crash has not yet been determined but visibility had been down to 150 yards.
Police accident teams are carrying out an investigation. Some 10 ambulances from five counties were mobilised for the crash and the injured taken to three local hospitals.Reuse content