Tens of millions of people worldwide are thought to have developed long-term symptoms and conditions following SARS-CoV-2 infection. But this sometimes debilitating phenomenon, often called high COVID, remains a puzzle to researchers. What causes this? Who got it? And, perhaps, the most infuriating: What is it?
Advanced COVID patients report a broad spectrum of more than 200 symptoms. Some are common, like loss of smell, while others are more unusual, like tremors. Some patients have familiar constellations of symptoms, others seem to have completely different ones.
Researchers hypothesize that elevated COVID may be an umbrella term for a collection of variable—and likely overlapping—post-COVID conditions that may have different causes. Causes may include autoimmunity, dysregulation of the immune system, organ damage, viral persistence, and intestinal microbiome imbalance (dysbiosis).
While millions continue to struggle with the realities of their circumstances, research on long-term COVID is, unfortunately, before it’s infancy. But a study published Thursday in JAMA offers a hopeful small step toward understanding the situation. With data from 9,764 participants, the researchers narrowed down the high COVID more than 200 symptoms to a weighted list of 12 main symptoms. The list is not a final definition of high COVID because it needs to be validated in further studies. But it’s a start. This will help direct further research, identify different subtypes of elevated COVID, and develop diagnostic tools, such as biomarkers.
The study—part of the National Institutes of Health’s Researching COVID to Enhance Recovery (RECOVER) Initiative—surveyed symptoms and conditions in people with a previous infection with SARS-CoV-2 (8,646 people) and those without (1,118 ). The researchers looked at the frequency of each symptom identified and the symptoms that distinguished the infected from the uninfected.
They came up with a core list of 12 symptoms and gave each symptom a score representing the likelihood that it is related to COVID-19. The scores for each of the 12 symptoms ranged from 1 to 8, and the researchers added up the symptom points for each person on the test. Based on the spectrum of total scores seen in uninfected people, the researchers concluded that a score of 12 is a reasonable cutoff for determining whether a person has long-term COVID. And that cutoff was confirmed when they looked at how it correlated with participants’ reports of quality of life and health.
Here is a list of 12 symptoms and their scores:
| symptom | score |
| Loss of smell or taste | 8 |
| Post-exertional malaise (feeling tired after little physical or mental activity) | 7 |
| Chronic cough | 4 |
| Brain fog | 3 |
| thirst | 3 |
| Palpitations | 2 |
| Chest pain | 2 |
| tiredness | 1 |
| Changes in sexual desire or capacity | 1 |
| dizziness | 1 |
| Gastrointestinal symptoms | 1 |
| Abnormal movements | 1 |
| Hair loss | 1 |
