The new cases were recorded in HCMC, Hanoi, Bac Giang and Bac Ninh provinces in the north, and central Ha Tinh Province.
In Bac Giang, 45 cases are linked to clusters at its industrial parks.
Of the 18 cases in HCMC, 11 had come into contact with Covid-19 patients, five are linked to the Christian mission that emerged as a Covid cluster on May 26. The sources of transmission of the remaining two are still unclear.
In Bac Ninh, eight are linked to hotspots at two industrial parks and one had had contact with a Covid-19 patient.
The five cases in Hanoi are related to two previously confirmed patients.
In Ha Tinh, two had had contact with a Covid-19 case and the authorities are tracking the transmission source for the other two.
Vietnam entered its fourth wave of Covid-19 community transmission on April 27 and since then infections have been registered in 39 cities and provinces.
Bac Giang continues to have the highest infections, at 3,764, followed by its neighbor Bac Ninh with 1,240 cases and HCMC with 590.