A British pilot who went down with novel coronavirus disease (COVID-19) last month has exhibited no sign of recovery, despite having tested negative for the virus.

The condition of the 43-year-old patient, Vietnam’s 91th case, has neither become worse nor improved as of Sunday morning, the government said on its verified Facebook account, citing the Ho Chi Minh City Hospital for Tropical Diseases, where he is treated.

His lungs’ damage has stalled but pulmonary ventilation is limited, the hospital was quoted as saying.

The patient’s bleeding disorder has yet to improve.

He is on life support in the form of extracorporeal membrane oxygenation (ECMO).

In ECMO, the blood is pumped outside of the body to a heart-lung machine that removes carbon dioxide and sends oxygen-filled blood back to tissues in the body, according to Mayo Clinic, an academic medical center based in the U.S.

This technique lets the blood "bypass" the heart and lungs, allowing the organs to rest and heal.

But virus tests on him have returned negative, according to doctors.

The British man works as a pilot for national flag carrier Vietnam Airlines and resides in District 2, Ho Chi Minh City.

Between March 13 and 18, he visited a number of catering and entertainment establishments in the city, including attending a Saint Patrick’s Day party at Buddha Bar & Grill in District 2 on March 14.

He developed a fever and coughing on March 17 and was admitted to the Ho Chi Minh City Hospital for Tropical Diseases the next day with a damaged right lung.

He tested positive for the novel coronavirus twice on March 18 and March 20 and has since been quarantined and treated at the infirmary.

The patient has maintained a high fever, along with increasingly bad health since hospitalization.

Doctors in Vietnam have said that his worsening conditions may be associated with his obesity, considering a BMI of 30.1.

At least 18 COVID-19 cases in Vietnam have been linked to the Buddha bar.

Health workers will stop monitoring the infection cluster at the bar on April 15 if there continues to be no new case traced back to the venue, the Ho Chi Minh City Center for Disease Control said on Sunday.

Vietnam has recorded 258 cases so far, with 144 having recovered and no fatality reported.

Ho Chi Minh City has confirmed 54 patients to date, 40 cleared of the virus.

Infection rates have seemed slower over the past week, apparently thanks to social distancing, as merely a few cases have been announced daily.

The Southeast Asian country reported zero new patient on Sunday morning.

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