Kolkata: A substantial number of Covid patients in Kolkata — about one in five, according to a doctor — have been struggling to regain full fitness due to lingering symptoms — or ‘long-haul Covid’ (LHC) — that have been refusing to recede more than a month after the patient contracted the virus.
While some have remained positive for three-four weeks, unusually long for Covid patients, others continue to be dogged by low-grade fever, joint pain, persistent cough and a general weakness for over a month after testing negative.
Doctors say LHC is a global phenomenon and afflicts a substantial number, possibly due to a ‘disregulation’ of the immune system, which fails to settle down after fighting the virus. Some felt it could even be triggered by a high viral load or an inadequate immune response.
A 42-year-old woman, who was treated at home after testing Covid-positive with mild symptoms, continued to have low-grade fever for more than a month. She got a Covid test done, but it was negative. Her doctor said she was likely to be suffering from a ‘smouldering’ immune response to Covid that made the fever persist long after the virus was dead.
A 35-year-old executive continued to feel fatigued and groggy after joining work a week after testing negative. His symptoms had been severe and they refused to go away. “My doctor said it could be due to a high viral load. My symptoms have been ebbing very slowly,” said the patient.
Once activated, the immune system often fails to regulate its response to the viral attack, leading to persistent symptoms and weakness, said Belle Vue Clinic internal medicine consultant Rahul Jain.Rahul Jain, Belle Vue Clinic internal medicine consultant, said: “While in extreme cases, a cytokine storm is triggered by the immune response, in others it continues to remain active after the virus has been evicted. It’s like a smouldering piece of coal that keeps flaring up even after being taken off the fire. This results in low fever, joint pain, sleep disorder and fatigue, which are very common during the post-Covid recovery period.” He added that LHC afflicted about one in every five patients in Kolkata. According to a UK study, around 10% suffer from LHC.
It can strike either mild or severe Covid patients, pointed out doctors. “While it is more expected in the case of severe patients who are admitted in ICU and take longer to recover, even those with mild symptoms, who got treated at home, have been experiencing it. They continue to feel weak and unsteady two-three weeks after testing positive,” said a physician who has been treating Covid patients.
Long-haulers could also be those who have a high viral load and continue to remain positive for inordinately long, according to RN Tagore International Institute of Cardiac Sciences (RTIICS) consultant Arindam Biswas. “I have come across several patients who got tested when the symptoms persisted for a month. Some of them were still positive, which could be due to their high viral load,” he said.
An exaggerated immune response was more likely to be the reason, felt Fortis Hospital pulmonologist Raja Dhar. “Around 60%-70% of LHC cases are triggered by a hyper immune response, which results in damage to healthy tissues. The rest are due to an inadequate immune reaction, which is more common among patients with co-morbidities who have lower immunity,” said Dhar. He added that the common symptom of LHC was persistent low-grade fever. “That is the only real marker, for the other symptoms vary,” he said.
Others, like Apollo Gleneagles Hospital consultant Shyamasis Bandopadhyay, differed. “It is triggered by inadequate immune response, which fails to eradicate the virus completely. Long-haulers could also be suffering from secondary infections that prolong the same set of symptoms, again due to a weaker immune response,” said Bandopadhyay.