New Research Highlights Persistent and Unique Symptoms of Long COVID

Dahyun Kim

May 9, 2025

Recently, University of Texas researchers offered strong evidence that long COVID is not only real but is distinct from post-viral symptoms that have to do with flu or pneumonia—commonly known respiratory-related diseases. These followings, published in PLOS recently analyzed  the medical research data from more than 121,000 COVID-19 patients in 2020 and compared them to tens and thousands of flu and pneumonia patients diagnosed before the pandemic. 

According to the Mayo Clinic, this lingering illness is often called long COVID or post-COVID-19 syndrome, long-haul COVID or post-acute sequelae of SARS-CoV-2 (PASC). The most commons symptoms patients reported to experience are: extreme tiredness, brain fog (problems with memory), feeling of being lightheaded or dizzy, lowered sense of smell and/or taste, sleep problems, shortness of breath, cough, headache, irregular heartbeat, digestion problems (loose controls, constipation, bloating), heart disease, and more depending on patients own condition of their health. Aside from physical aftermath the long COVID lingers in patients, there can be further illness rooted from the long COVID such as mood disorders, anxiety, stroke/blood clots, postural orthostatic tachycardia syndrome (POTS), myalgic encephalomyelitis-chronic fatigue syndrome (ME-CFS), diabetes, hyperlipidemia, and more. 

The CIDRAP (University of Minnesota) mentions how the researchers stalked symptoms in the term of one, three and six months after the diagnosis and found that COVID-19 patients had significantly different timeline and type of lingering symptoms compared to those with flu or pneumonia. For instance, while fly patients generally declined more quickly in lingering symptoms, pneumonia patients tend to show high symptom levels early on—none of these persisting as long as in severe COVID-19 cases. Fatigue, joint pain, and shortness of breath were the most common long-term symptoms among the COVID-19 patients–¼ experiencing each after even a month. On the other hand, shortness of breath and fatigue were also common in pneumonia patients, but COVID-19 symptom profile had more neurological and systemic effects such as brain fog and anxiety, specifically in those who showed greater levels of infections. 

The severity of initial illness was one of the big role in long-term recovery. Patients who were placed the most in level 7 and 9 on the severity scale were significantly more likely to have their symptoms persist after six months. Fatigue and breathing difficulties were the ones that were likely to persist.. Additionally, people with chronic conditions such as asthma, heart disease or rheumatoid arthritis reported to face higher odds of prolonged symptoms.

Other than the severity of symptoms and patient’s medical backgrounds, demographics influenced such outcomes where older patients ranging between the age 70 to 79 and White were more likely to have long-term issues such as anxiety and fatigue. It also showed that the northeastern US had the highest prevalence of most lingering symptoms, including headaches. Researchers concluded that the pattern of the long COVID cannot be fully proved and supported by post-infection recovery in flu or pneumonia, reinforcing the idea that COVID-19 creates a special, long term health burden that should be studied further to put an end to this lingering concerns of pandemics that has been continued for 5 years.