While she was having dinner one day, Dr Nguyen Thi Bay, an associate professor at the University Medical Center HCMC, received a call from a stranger.
She quickly put down her bowl to answer since she thought it might be a Covid-19 patient calling the 1022 helpline.
It was a middle-aged male. He said, "Doctor, I have trouble breathing."
"Calm down, follow the instructions exactly as I say so I can make an accurate diagnosis.
"Put your hand on your stomach and count the number of times the hand rises. Put your hand on your left chest and count the heart rate. Remember to breathe normally, not with any urgency."
After doing so, the man said, sounding worried: "My respiration rate is 16 and my heart rate is 80 per minute. What should I do?"
She reassured him they were normal and explained to him the signs when a Covid patient needs medical intervention, and told him to continue to monitor his health at home.
Bay has been helping out with the 1022 hotline for two weeks and has counseled many Covid patients and people who came into contact with patients. Every night at 7-9 p.m. she provides consultation to around 30 people.
"Many Covid-19 patients isolated at home are very worried about ... their health, so they need help from doctors," Bay said.
"As in the case of the above patient, a breathing rate of below 24 times per minute and a heart rate of less than 100 per minute is normal. But he was so scared he thought his condition was getting worse."
But there are also cases of patients being seriously ill, and Bay needing to determine if emergency assistance is needed, record the address and condition of the patient, and enter it into the system so that related units can support the patients.
Thirty two experts have been signed up for the 1022 helpline to consult on Covid-19 prevention and other health-related issues.
They are all academics, doctors from the HCMC Medical Association (HMA) and HCDC or infectious disease specialists and epidemiologists at hospitals.
After completing their regular work they are on duty for two hours a day, 10 of them on average per shift. The operator automatically connects people's calls to them.
The toll-free call center was jointly established by the Departments of Information and Communications and Health amid a rising number of infections and people in self-quarantine who needed to be supported by medical professionals.
The helpline provides instructions on handling various situations that arise in the course of monitoring the disease, taking care of severe cases, exercising, and using over-the-counter drugs.
People facing economic hardships because of the pandemic can also call the hotline to receive support from authorities.
Bay said she and many colleagues signed up immediately after learning that the call center needs assistance from doctors, nurses and medical professionals.
"Through the hotline, we also hear many happy and sad stories. We feel sorry for them during this challenging time and for frontline workers who are trying to fight the epidemic. We are very happy we are able to lend a helping hand."
Associate Professor Dr Nguyen Thi Ngoc Dung, chairman of the HMA, also helps out with the call center.
During her shift at 8-10 p.m. she counsels some 40 patients on average.
She said it is very important to communicate with Covid patients who are isolated and monitored at home.
In addition to medical support, the doctors also provide the patients with psychological support.
According to the city Department of Information and Communications, the number of operators has been increased with 20-30 people being divided into three shifts to be on duty 24 hours a day, and the number of calls each attends remains very high.
Between July 22 and 25 the helpline received more than 190,000 calls and transferred more than 9,700 to the doctors, but could not answer the remaining 180,000.
Bay said: "Compared to the first week of operation, things are now more stable both for the call center as well as for the on-call doctors. The work is gradually settling down."