The nurse captioned the photo: "How it started … How it's going".
In a follow up post Kathryn explained she loved being a nurse but getting into the workforce in the middle of the coronavirus pandemic was a huge learning curve.
"I didn't exactly expect to be a new nurse in the middle of a highly politicised pandemic but life comes at you fast and even in a pandemic, there's nothing else I want to do. Caring for the sickest of the sick is an honour and I treasure my patients," she wrote.
"It is devastating to watch people die when those deaths were avoidable and it's even more devastating when you watch them die the same way, time after time after time. It's devastating that basic common sense and decency has been politicised."
She went on to say that Covid-19 is a "brutal disease" that she wouldn't wish on her worst enemy.
"Please understand that you aren't just protecting yourself, you are protecting the people around you," Kathryn wrote.
The photo quickly went viral, with more than 972,000 likes and more than 88,500 shares.
The post was flooded with thousands of comments, with many thanking Kathryn for her service and drawing attention to the impact it has on frontline workers.
"The human toll of being a nurse working in a rampant pandemic is written on your face. Thank you for your patient care. Please take care of yourself. It is such an impossible time for you and your colleagues. If I could give you strength I would," one person wrote.
"Thank you for what you do. Thank you for caring, for sacrificing, for putting yourself at risk to help others. Thank you for being a compassionate human being," another said.
One person added: "It's terribly sad that we have found out how unwilling many of our citizens are willing to do for others when it matters. Sure, they will wave the flag and bring potluck suppers and do patriotic parades. But, they still won't put a stinkin' mask on."
Kathryn's post inspired other medical professionals to share their own before and after photos.
Kathryn told CTVNews that most people don't see the true reality of the Covid-19 crisis and thought she might be able to shed some light on the every day struggles of health workers.
"I mean just the physical effects of wearing all that PPE (personal protective equipment) for so long," she said.
"We're dehydrated all the time because we're sweating so much and because with the masks on, you can't drink until you leave the floor or go into the break room to take your mask off and drink."
Kathryn also had a message for people who aren't taking the pandemic seriously.
"There's still no definitive treatment for this disease and so to see my patients, these people that I provide care for, suffer so intensely and then see other people acting like that's not happening, or like they couldn't cause that to happen to someone else, is infuriating," she said.
