On September 15, Mazibul Haque Kislu travelled from Barguna to Barisal to retest his lungs.

The journey was arduous as every step he took felt heavier than before – before he had been infected with the novel coronavirus.

It reminded him of how much he struggled in the third week of June to climb to the fourth floor of Barguna District Hospital. Doctors seemed puzzled as they saw his blood oxygen level drop to 65. The safe range is 95 to 100.

For the next one-and-a-half months, he constantly felt he was close to death.

He thought his fight against Covid-19 would be over with his discharge from a private hospital in the capital on August 4, but it was not. Mazibul is unsure about when he will be able to recover fully from the damage wreaked by the virus and resume his law practice.

What Mazibul, 55, has been going through is termed "post-Covid symptoms" – a phase that drew attention in the developed world about two to three months ago and is beginning to be seen in Bangladesh as a problem that needs to be addressed.

The tale of Mazibul is not an exception but it is not common either among those who have overcome the virus.

As far as doctors caring for Covid-19 patients have experienced, those infected who have been in critical condition have higher chances of incurring severe damage to their major organs including the heart, lungs, kidneys, and brain. Therefore, they need a long time to heal.

"The virus leaves the body but the damage remains. Patients must get treatment as long as the impact is undone," said Brig Gen Zulfiquer Ahmed Amin, director of Bangabandhu Sheikh Mujib Medical University (BSMMU) Hospital.

In a majority of Covid-19 cases, however, lungs lose their efficiency as the novel coronavirus affects them the most. The sponge-like organs become stiff, disrupting the flow of oxygen to other organs.

To treat long-haulers like Mazibul, the BSMMU opened a post-Covid-19 unit in the first week of September, which comprises doctors of different specialisations. The services are available two days a week – Saturday and Tuesday.

Meanwhile, private healthcare facility Evercare Hospital Dhaka has also planned to operate a Post-Covid Recovery Clinic from October 1.

Doctors and nurses will communicate with patients by phone and video conference on social media platforms to check on their health and help them get back to a normal life. The follow-up treatment will continue for at least three months.

Evercare considered the move two-three months after it began admitting Covid-19 patients on April 22, as a lot of survivors of the disease started to show up with health complaints.

Almost 80% of the critical care patients return to seek medical help. Lots of resources had to be put in place to serve those people. So, to streamline patient management, a separate system will be set up.

SM Abdullah Al Mamun, senior consultant of respiratory medicine at Evercare, said patients with moderate to severe symptoms, who needed support in high-dependency units or intensive care units with high-flow nasal cannulas or ventilators, were seen to have post-Covid symptoms.

"It is yet to be determined whether these [long-term impacts] are side-effects of the medications and treatment or are caused by Covid-19," Dr Mamun said, adding that many changes are reversible while some changes may never be undone.

In extreme instances, a patient may need to have a lung transplant, which has already happened in Chicago of the USA and Wuhan of China.

With persisting breathing distress, Mazibul saw a chest specialist through telemedicine after he was discharged from the hospital in August. As prescribed, he has been taking 10 medicines every day, which cost him over Tk3,000. He will soon see the doctor in person to evaluate his test reports and his present health condition.

After some signs of recovery, he appeared in court, in Barguna, to conduct legal cases of significance but eventually realised that his body could not endure the physical exhaustion. His hips, down to knees, still lack sensation.

Chronic fatigue syndrome is another sign of the lingering impact of Covid-19, in which patients find it hard to gather the strength to do simple tasks such as holding a glass of water.

Mazibul said his hands used to tremble so much that "many glasses fell and broke. There were days when I could not even hold a pen." Mazibul heaved frequent, short breaths as he spoke with The Business Standard over the phone from Barguna on Friday.

The prolonged sense of fatigue and complications of heart, lungs or kidneys resulting from Covid-19 may take a toll on one's mental health as well.

In Bangladesh, doctors have yet to learn about long haulers but a study by researchers at North Bristol NHS Trust in England provides an illustrative example. Eighty-one of the 110 discharged patients were suffering from symptoms like breathlessness, excessive fatigue, and muscle aches as much as three months after they were discharged from the hospital, according to the study report published in August.

Prof Nezamuddin Ahmad, a doctor as well as Covid-19 survivor, described his last one-and-a-half-month spell as horrific and depressing.

When he was discharged from hospital, he did not have any idea about what awaited him. He was given an incentive spirometer, a device that measures how deeply one can inhale, and was advised to do breathing exercises every four hours.

Part of the exercise was to suck in air to lift at least two of the three balls inside the spirometer. The first two to four days at home were fine but later Nezamuddin felt that he was taken over by an "unwillingness to do anything".

"You feel so exhausted – after doing almost nothing – that you don't even want to turn on your side in the bed. Life felt meaningless at one point," said Prof Nezamuddin, who recently retired as the head of the palliative department at the BSMMU.

It was also impossible to explain how he felt to others. On several occasions, some of his colleagues and loved ones suggested that he was upset because of his retirement.

"I asked myself, 'Am I making it up?' but I wasn't." Nezamuddin later sought help from a psychiatrist. Over the past week, he has been having a much better time.

Doctors think there are many things to uncover about post-Covid symptoms. As Nezamuddin put it, "The post-Covid-19 era will give rise to many more physical issues."