The Covid-19 treatment sub-committee under the Health Ministry said his smile carried a lot of meaning, showing increased consciousness and awareness.

The digestive system of "patient 91," a 43-year-old British man working for national flag carrier Vietnam Airlines, has improved. The distension in his stomach has reduced, his kidney functions have recovered and he has been able to move his hands and legs, said doctors said Cho Ray Hospital in Ho Chi Minh City.

The patient has also developed a stronger cough reflex. His pulmonary ventilation has increased and is more stable than previous days.

However, he is still dependent on life support and remains on the extracorporeal membrane oxygenation (ECMO) machine. The blood flowing through his ECMO currently stays at 3.7 liters per minute, and doctors are working to gradually reduce the system’s oxygen flow to 1.5 liters per minute. Previously, while the pilot was still in a severely critical condition, the oxygen flow could go up to 5.7 liters per minute.

On Monday, doctors at Cho Ray began a regimen of physical therapy twice a day.

Tran Thanh Linh, deputy head of the emergency department at the hospital, said an X-ray image of his lungs a week ago had revealed tissue or fluid blocking blood vessels in both lungs, but one taken on Tuesday showed that more than half of the left lung has completely recovered from the situation.

"His muscle weakness has also reduced. This is the right time to reduce his dependence on the ECMO," the doctor said.

Earlier, the patient had suffered from cytokine storm syndrome, which happened when his immune system overreacted to the novel coronavirus attacking the body, releasing too many cytokines and damaging his organs.

He is still infected with Burkholderia cenocepacia, a type of opportunistic bacteria, which doctors said is difficult to treat.

He is still on blood thinners. Doctors are also feeding him either directly or intravenously. They will focus now on curing his lung infections and making him less reliant on the ECMO machine. They are also looking for suitable donors for a lung transplant, as decided earlier by the Health Ministry.

The patient was confirmed to have contracted the novel coronavirus on March 18. His condition worsened and he slipped into a coma for over two months. He has been on ECMO for 57 days.

He was declared free of the novel coronavirus on May 20 after seven negative tests in a row, and transferred from the HCMC Tropical for Hospital Disease to Cho Ray Hospital for further treatment.

Vietnam has recorded 328 Covid-19 cases so far, of which 298 have recovered, leaving 30 active patients.