TURIN, ITALY – DECEMBER 13: Greta Thunberg attends Fridays For Future Strike on December 13, 2019 in Turin, Italy. (Photo by Giorgio Perottino/Getty Images)

Swedish climate change activist Greta Thunberg thinks she contracted COVID-19 during her recent travels around central Europe. The  17-year-old announced on Tuesday that for the past two weeks she’s been self-isolating with her father after returning home from her trip, saying that the pair both suffered from symptoms of the virus while staying at a friend’s empty home away from the rest of their family.

Thunberg says that while her symptoms were mild, it was “extremely likely” that she had contracted the virus, explaining on Instagram that in Sweden you can not test yourself for COVID-19 “unless you’re in need of emergent medical treatment,” but that she was “feeling tired, had shivers, a sore throat and coughed.” Her father, Svante, had symptoms but they were “much more intense” and came with the addition of a fever.

“Now I’ve basically recovered,” Thunberg wrote. “But – AND THIS IS THE BOTTOM LINE: I almost didn’t feel ill. My last cold was much worse than this! Had it not been for someone else having the virus simultaneously I might not even have suspected anything. Then I would just have thought I was feeling unusually tired with a bit of a cough.”

“This it what makes it so much more dangerous,” she continued. “Many (especially young people) might not notice any symptoms at all, or very mild symptoms. Then they don’t know they have the virus and can pass it on to people in risk groups. We who don’t belong to a risk group have an enormous responsibility, our actions can be the difference between life and death for many others.”

She finished her post by imploring people to stay home to avoid the risk of accidentally spreading the virus to others. “Please keep that in mind, follow the advice from experts and your local authorities and #StayAtHome to slow the spread of the virus. And remember to always take care of each other and help those in need.”