The research team behind the study used an app to gather data from over 4,100 COVID patients and found that roughly 13 percent of participants experienced “long-COVID,” an extended illness lasting at least 28 days. An additional one in 20 patients was sick for over eight weeks, and one in 50 was sick for over twelve weeks. Among those protracted cases, patients who experienced five or more symptoms over the course of the first week were more likely to experience extended cases. But even within the long-COVID group, two symptoms stood out as early predictors of complications, which ultimately led those patients disproportionately to the hospital. “In the individuals with long duration, ongoing fever and skipped meals were strong predictors of a subsequent hospital visit,” the study explains. This means that among the groups that suffered through coronavirus longest, people with these two serious COVID symptoms were among the hardest hit. Though the study cautioned against generalizing based on their analysis and was quick to point out its own limitations (in particular that the study subjects were predominantly female, under the age of 70, and responsible for self-reporting their own data), this could help doctors identify serious cases of COVID sooner. Read on for more signs that you could be in for a case of long-COVID, and for a more extensive list of what to look out for when it comes to coronavirus, check out The Most Common COVID Symptoms You Could Have. The study found that those with ongoing fatigue were more likely than others to experience a protracted case of coronavirus. In fact, 97 percent of long-term patients reported this particular symptom, and many people reported that this was their only symptom. And for more on how to detect coronavirus, check out There’s an 80 Percent Chance You Have COVID If You Have This Symptom. Headaches were the second most common symptom among long-COVID patients within the study. The researchers found that over 91 percent of long-term patients reported headaches, while only 13 percent of the more general COVID population typically presents with this particular symptom. Respiratory symptoms including labored breathing could indicate that you’re in it for the long-haul. The researchers found that this symptom disproportionately affects long-COVID patients, and could also indicate a more serious case. And for more on serious signs of coronavirus, find out why 80 Percent of COVID Patients Have This Scary Symptom.ae0fcc31ae342fd3a1346ebb1f342fcb While not typically present early on in cases, having low oxygen is a surefire sign that you’re dealing with a more difficult COVID case than the average. While many people assume that low oxygen levels go hand in hand with labored breathing, research has shown that in some cases oxygen can dip to seriously low levels while other symptoms remain mild. Checking your own oxygen levels with an at-home pulse oximeter can help you assess your risk levels.