I can't quickly find a source, but back of the envelope is there have been 134 Soyuz manned missions. The number of people varies 1-3, most often 3 but occasionally 2. There were 135 Shuttle manned missions. Number there varied between 2-7, but ballpark looks like 6 was common.
So if we say 3 x 134 on Soyuz, there are 402 person-trips and 6 x 135 on Shuttle it is 810 person-trips. There were 4 Soyuz fatalities and 14 on the shuttle. So Soyuz fatality rate is about 1/100 and the shuttle is 1/56. So maybe it is closer to a factor 2 of difference.
The fatal mission rate is nearly identical (both have 2 fatal missions each).