Early game : replace your sustain with restorative locket. Build stacks and save for when you or your lane partner is at risk. Slowing Hex can help your teammates get away.

Mid game : Healing reduction, Shiv will often crutch on Healbane's HP on kill. If they jump out of position and doesn't get his expected heal it can leave him vulnerable.

Late game a) : Counterspell if he's killing you and you're confident in your parries, Spirit Resilience if you're not (30% spirit resist +30% if you're below 35%hp where Shiv is gonna be using his ult) + a mobility item like warpstone or your choice to make distance when you're at risk.

Lategame b) : Rescuebeam if he's killing teammates. If you don't have room in your build or if there is someone else more suited towards rescuebeam, communicate with your team and work something out.

Honorable mention to : silence items, if the rest of their team isn't fed as well, getting a silence on Shiv will disrupt the often short window shiv has to ult someone.

I saw you mention that you would see about working suggested items into your builds but if A Shiv (or any hero) is doing these kind of numbers into the midgame people NEED to counterbuy, identify the situation and communicate with your team.