32 cases were recorded in Bac Giang, nine in Bac Ninh, eight in Lang Son and one in Long An.

All the cases in Bac Giang are associated with existing coronavirus outbreaks at the province's industrial parks and have been quarantined.

Two cases in Bac Ninh had made contact with confirmed Covid-19 patients, while five others were associated with outbreaks either in the community or industrial parks. Two cases were detected thanks to Covid-19 screening.

Four of the cases in Lang Son made contact with confirmed Covid-19 patients, while the other four are associated with outbreaks at industrial parks.

The case in Long An is a 22-year-old man who studies in HCMC. He returned home on May 23, got caught in the rain on the way and started having symptoms including coughing, sore throat and muscular pains after that. Believing that he had a cold, he bought medicine from a drugstore, and only went to a medical center on Monday when he suffered difficult breathing.

Authorities are conducting contact tracing to determine his infection source. He's being treated at the HCMC Hospital for Tropical Diseases.

Over a month into its fourth wave, which is by far the most challenging that Vietnam has encountered, the country has recorded 4,407 cases in 36 of its 63 cities and provinces.

Bac Giang is leading the case count with 2,329 infections, followed by neighbor Bac Ninh with 866.