A survey of long-haulers found 66 symptoms that lasted more than 6 months. Tiredness and brain fog were most common.

• Researchers at University College London say there may be up to 203 symptoms related to long COVID.
• In a survey of more than 3,600 long-haulers, fatigue and brain fog were commonly reported.
• The leader of the research said there may be "thousands of long COVID patients suffering in silence."

Long haulers may experience up to 203 different symptoms, a new survey found.

A paper published in The Lancet's EClinicaMedicine on Thursday describes the results of a survey of 3,672 people in the Body Politic COVID-19 support group. Adults from more than 50 countries responded to the survey, which consisted of 257 questions on the nature of long COVID symptoms and the impact those symptoms have on people's daily lives.

The UCL researchers defined long COVID as "a collection of symptoms that develop during or following a confirmed or suspected case of COVID-19 that continued for more than 28 days." But the team documented a set of 66 symptoms that lasted up to seven months. The three symptoms patients reported as most debilitating were fatigue, breathing problems, and brain fog.

Within the survey group, 2,454 long-haulers said they had symptoms for six months or more. The most common were generalized fatigue, tiredness after exertion, brain fog, headache, and memory loss. Among respondents who said they experienced brain fog, memory loss, or both, 85% said those symptoms affected their ability to work. The study authors reported that about 45% of respondents said they needed a reduced work schedule, and an additional 22% were not working at the time of survey due to illness.

Other symptoms reported in the survey included: visual hallucinations, tremors, itchy skin, changes to the menstrual cycle, sexual dysfunction, heart palpitations, bladder control issues, shingles, blurred vision, diarrhea, and tinnitus.

Dr. Athena Akrami, a neuroscientist at University College London who led the research, said in a statement that there are "likely to be tens of thousands of long COVID patients suffering in silence, unsure that their symptoms are connected to COVID-19."

Real-world data from the UK in June estimated that one in three people who get symptomatic COVID-19 develop long COVID, though that analysis defined the condition as symptoms lasting more than 12 weeks.

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The recent survey adds to a growing body of research that attempts to characterize long COVID. A group of scientists from Imperial College London said on Monday that laboratory studies showed blood samples from people with the condition have "auto-antibodies" that mistakenly attack the body's healthy cells. This may be one cause of long COVID symptoms, they said.

But the survey results also come with caveats. For example, it did not require all respondents to show test results proving they were diagnosed with COVID-19, and 43% of the respondents had been diagnosed with another medical condition after their coronavirus infection. What's more, the majority of respondents were white (78%), most were women (84.5%), and nearly all came from English-speaking countries - about 41% were American and 35% were Brits, the study authors said.