CNN  — 

Lyth Hishmeh kept feeling ill months after contracting coronavirus a year ago in March. He had chest pain and couldn’t concentrate. At 26 years old, the former regular runner was fatigued and breathless, struggling to function properly. Yet medical professionals kept telling him he simply could not still be ill.

“They were telling me it’s all in my head,” he said. For Hishmeh who lives in London and many sufferers of long Covid, proving they are sick has become a big part of trying to get better.

Another Londoner, Monique Jackson, has lost count of the number of times her pain was described as ‘just anxiety.’ The 32-year old illustrator was repeatedly told by medical professionals to go to the accidents and emergency, only to be discharged soon after. “I felt like I was wasting people’s time, that people either didn’t believe me … or the ones who were sympathetic and supportive said ‘we don’t know, it’s a new disease and we just don’t know,’” she said.

Learning that they were not alone, that other people were experiencing the same issues, was a huge revelation for both Hishmeh and Jackson. This was not just in their heads. They were not imagining the pain. They really were sick.

Long Covid, also called post-Covid syndrome, is shaping up to be a major, long-term public health issue. In the UK alone, almost 700,000 people reported having symptoms for at least three months after getting infected with Covid-19, according to a survey done by the UK Office for National Statistics in March. A majority of the 700,000 said their illness was limiting their day-to-day activities and for almost 70,000, the symptoms have lasted for more than a year.

A separate study published last month showed that seven in 10 people who had been hospitalized for Covid-19 have not fully recovered five months after being discharged.

While the figures made big headlines, they did not come as a surprise to those suffering from long Covid and their doctors.

About 10% suffer long-term

Dr. Manoj Sivan, an associate clinical professor and consultant at University of Leeds, was one of the first physicians to start writing about Covid long haulers last spring. As a rehabilitation medicine expert, he knew previous epidemics of SARS and MERS left some patients suffering with post-viral syndromes a long time after the epidemics were declared to be over. He was seeing the same patterns with the coronavirus.

“Anyone who’s recovering from Covid is expected to make a good recovery, a full recovery, within four to six weeks,” he said. “In about 10% to 20% of people, the symptoms can linger beyond the four to six week period and in about 10% of people, the symptoms can persist even beyond 12 weeks, when it becomes a real problem.”

Sivan said that while symptoms can vary from patient to patient, there are some that appear to be very common. “I would say the big five are fatigue, breathlessness, pain, brain fog, and psychological problems,” he continued.

Many patients also experience symptoms associated with dysautonomia, which is caused by an imbalance in the autonomic nervous system and which can include palpitations, dizziness, and psychological problems like anxiety, depression and PTSD, Sivan added. Some people have had rashes and joint swelling and some have developed new allergie