Diaper leakage ?

So I’m a FTM to a 2 week old boy. Have been using newborn size pampers swaddlers. The problem is he almost always leaks ... either up the back or up the sides. I’ve tried putting the diaper on really tight or higher in the back but it still leaks. He is usually changed at least every two hours. What am

I doing wrong? I’m thinking about going up a size... he is over 8 lbs.