All the patients, four men and four women, were treated at the National Hospital of Tropical Diseases in the capital city.
Four of the eight are natives of the capital's Ha Loi Village in Me Linh District, a major outbreak site that had a four-week lockdown lifted May 6.
Among the villagers is a 51-year-old man with a chronic kidney disease who's had to undergo regular dialysis during his Covid-19 treatment.
Of the remaining four, two men and a woman had returned to Vietnam from other countries.
The fourth, a 44-year-old woman, is an employee of the Truong Sinh Company, which provided food and logistic services for several Hanoi hospitals, including the Bach Mai Hospital, also a major outbreak site.
Before she tested positive and was transferred to the National Hospital for Tropical Diseases on March 28, she had traveled from Bach Mai back to her hometown in the northern province of Thai Nguyen, then gone to a local hospital in Dai Tu District.
Vietnam recorded no new coronavirus infections Monday evening, marking day 25 without community transmission. The nation’s Covid-19 tally has stood at 288 since last Thursday, of whom 249 have recovered.