All three patients were related to the Buddha Bar & Grill, the largest Covid-19 hotspot in HCMC.

One man among them had attended a party at the District 2 bar in Thao Dien Ward on March 14.

The other two are a couple. The wife had contracted the novel coronavirus from a colleague who attended the same party.

All three of them had been announced free of Covid-19 and discharged from Cu Chi Field Hospital last month, but relapsed during the 14-day period of medical monitoring that followed the discharge.

They were readmitted to the hospital; and between April 27 and May 10, they tested negative repeatedly.

For now, though, they will be monitored further.

Doctors in Vietnam have recently confirmed that virus samples taken from relapsed patients are "inactive" and could not be transmitted to others.

The relapsed patient were not given as much medicine as a fresh patient. The focus was on monitoring their health and watching out for symptoms like cough or fever, apart from repeated testing of their samples for the virus.

In the wake of relapses, HCMC health authorities had announced May 1 that they will keep recovered Covid-19 patients under health monitoring for 30 days instead of 14, as had been done until then. During this period, the city will conduct tests every day on the recovered patients, instead of once a week as the nation's been doing.

With the latest update, Vietnam has discharged 252 of 288 patients it has recorded so far.

The nation’s tally has been kept unchanged since last Thursday evening, when 17 Vietnamese repatriated from the UAE were confirmed infected. It has gone 26 days in a row without recording any domestic transmission.