SINGAPORE - Madam Loh Luan Kim has lupus, an autoimmune disease, but medication has kept it at bay to the extent that no one knows she has the disease.
The 50-year-old Malaysian, who works as a cashier in a massage outlet, got her Covid-19 vaccination the moment she could.
All was well until she was infected with breakthrough Covid-19 on Nov 2.
Now, almost two months on, and more than a month after she became free of the virus, the after-effects of the disease still linger.
She suffers from long Covid, a name coined for the extended suffering by some people following a Covid-19 infection that could last for weeks, months, even a year or more.
International data says as many as half the patients suffer some form of long Covid. In Singapore, one in 10 people infected suffer long Covid for more than six months.
Some lose their sense of taste or smell, tire easily, have muscle and joint pain, loss of appetite, or like Madam Loh whose lungs were affected, become easily breathless with minor exertion.
This can happen not just to people who had severe illness, but also those with just a mild bout.
Dr Mark Chan, divisional chairman for integrative and community care and a senior geriatric medicine consultant at Tan Tock Seng Hospital (TTSH), said long Covid may affect people without pre-existing medical conditions, although older patients and those with existing medical conditions are more likely to suffer from it.
Madam Loh was one of those with a pre-existing medical condition.
An X-ray following her Covid-19 infection found black spots in her lungs, and she was in TTSH for a week.
She needed to be on oxygen supplementation at a concentration of two litres a minute even after her body was clear of the virus and she had been moved to TTSH’s Covid-19 treatment facility (CTF) at Ren Ci Community Hospital to recover.
"When I walked, my heart beat very fast. It was like I couldn't breathe," she said in Cantonese. "It was usually worse in the morning, and better in the afternoon."
The second week she was at the CTF, a nurse taught her how to start exercising, with frequent rests in between.
She recalled: "Even going to the toilet, I needed to rest. I was very worried when I got so tired just going to the toilet.
"But the nurses kept saying I would recover, so I was not so concerned, not so depressed, even though I saw older patients in their 80s and 90s who did not need oxygen."
She was on two weeks of medical leave after her discharge on Nov 23.
Her oxygen level was still low, but the doctor said a level above 90 per cent was good for her. For most people, the oxygen level should be 95 per cent to 100 per cent.
She exercised religiously as she was desperate to recover her stamina. But every movement, including going to neighbourhood shops, had to be done "in slow motion, or my heart starts beating very fast", she said.
Patients like Madam Loh are sent to a CTF only after they have passed the acute stage of the disease and their condition is stable. They would have spent five to eight days in a hospital.
Singapore set up CTFs, with about 3,700 beds by the end of October, to free up beds in acute hospitals. TTSH runs two CTF wards at the nearby Ren Ci Community Hospital - one with 36 beds and the other 18 beds.
Dr Chan said that based on patient profiles at these CTF wards, there is definitely a larger proportion of unvaccinated patients with symptoms requiring prolonged stay, compared with vaccinated patients.
In general, patients above 80 years old require longer stays regardless of their vaccination status, he added.
Less than half the patients at the CTF are fully vaccinated. The average length of stay is slightly over nine days, with more than half needing follow-up care with a specialist for Covid-19-related problems, he said.
While their conditions might be stable, patients in the CTF could take a turn for the worse and have to be transferred back to TTSH or the nearby National Centre for Infectious Diseases (NCID).
Said Dr Chan: "Sadly, it has happened. Two patients probably had unprovoked heart attacks; another one had a bleed from a gastric ulcer and passed blood; and the oxygen level for a fourth patient fell so much that it was not safe to continue to stay here."
Dr Chan added that the TTSH CTF gets relatively more sick patients, compared with other CTFs, as they are near the NCID. Those who are less likely to deteriorate are sent to other CTFs.
Almost all the patients in the TTSH CTF require oxygen. A number of older patients develop confusion and delirium, which is partly due to Covid-19 and partly from the isolation and being away from their home environment, said Dr Chan.
Many also do not eat very well, adding to their frailty. The vast majority need sessions with a physiotherapist to build up their strength after losing muscle mass from being bed-bound.
They also need help from a speech therapist to check their ability to swallow, a dietician who might have to assess their intake, and an occupational therapist to train them on activities of daily living, such as putting on clothes.
Patients at the 36-bed TTSH CTF need to be closely monitored. Ms Wee Fong Chi, the hospital's deputy director of nursing, said monitoring their oxygen levels is particularly important, as this could drop easily.
If the oxygen level remains below an acceptable level for several minutes, organs, including the brain and heart, could be damaged.
Instead of going around measuring patients' vital signs from bed to bed several times a day, the hospital is testing a new device to detect quickly any drop in oxygen levels or changes to heart rate and temperature.
The device, the size of a mobile phone, is attached to a patient's arm and monitors changes continuously. Any breach of pre-set parameters will trigger an alarm, and is similar to the monitoring system in an intensive care unit (ICU).
"We hope to be able to pick up deterioration more quickly. The conventional method is to check intermittently. (With this device), we can then attend to the patient more promptly, giving the patient a better chance," said Ms Wee.
Ms Lynn Chua, the principal physiotherapist caring for patients at the TTSH CTF, said that if the oxygen level drops while a patient is in the toilet, the device will send an alert and oxygen can be rushed in.
She said such patients are told to take things easy and not to exert themselves as this could trigger oxygen desaturation - low oxygen levels in the blood.
Dr Chan said the biggest issue for recovering Covid-19 patients is lung complications. "Some are slow to wean down oxygen and may have a bit of scarring of lung tissue. Some recover fully, others may not."
Madam Loh is one of the lucky ones.
The black spots in her lung have disappeared. While she is still not back to her pre-Covid-19 level of health and gets breathless occasionally, she is grateful she can return to work.
Correction note: An earlier version of this article said Madam Loh needed about two litres of oxygen a day even after her body was clear of the virus. This has been corrected. We are sorry for the error.