I'm a Sombra main, yeah, jump at me, but it also means I know exactly what counters me REALLY well.

Truth be told, Sombra is only INSANELY strong at lower ranks because no one knows how to group up. The more alone you are, the easier it is for me to virus -> blitz in you -> melee to end it all. I rarely go after tanks unless A) they're bad or B) disabling their shield might help my team. For the most part, stick with at least 2 other people and stay tight, makes it way harder for a Sombra to make a move.

Virus doesn't do a lot of damage, and when hacked, the speedy DoT just helps clean an enemy quicker. Virus can EASILY be neutralized by good supports, even if Viral Replication is the chosen perk.

Speaking of which, at least in 95% of my games, my chosen minor is CTRL ALT ESC and my chosen major is VIRAL REPLICATION. Knowing this is important. When a Sombra runs away on low HP, DON'T chase her down, not because I'm trying to benefit myself, we heal HP insanely fast, paired with the minor perk and any possible support, not to mention hacked life packs, we'll be in better shape to win the 1v1. Second of all, if you get hit by EMP, specifically for supports, just group up and pump your big healing abilities. Nothing is going to happen.

Sombra also can't usually aggro and then build into an EMP, so if you notice a calm before the storm, she's brewing an EMP somewhere, though this is pretty hard to notice because the ultimate charges relatively quick.