When a person contracts COVID-19, it’s suspected that your nails stop growing and when growth resumes, it leaves a white line as your nails continue to extend from your body.
These odd lines are a telltale sign that you had previously been infected with COVID-19 says Tim Spector, a professor of genetic epidemiology at King’s College.
“Do your nails look odd? COVID nails are increasingly being recognized as the nails recover after infection and the growth recovers leaving a clear line. Can occur without skin rashes and appears harmless,” Spector said.
The data comes from a COVID-19 symptom study using an app called “ZEO COVID Symptom Study” that has millions of global users. Those users enter their symptoms into the database and many report the strange horizontal lines on their fingernails and toenails.
It’s common that when people are sick for long periods of time and experience a long-term illness, these lines can form, so Spector warns it’s not a COVID-19 specific symptom, but has been recorded in many recovered COVID-19 patients.