Yes, there are still studies about how best to wash your hands! This latest study from Rutgers University says it doesn’t matter if you use hot, warm, or cold water, as long as you use plenty of soap and rub for at least 20 seconds. Interesting, though I will still use hot water.
Also confirmation about what we’ve known for a long time that most commercial antibacterial soaps are no better than regular soap, and some can actually be harmful.
http://articles.mercola.com/sites/articles/archive/2017/06/17/washing-hands-with-cold-water.aspx