Of the new cases, 16 were in the central city of Da Nang, one in Dong Nai with links to the Da Nang Hospital, and one was imported.
The 16 new patients in Da Nang were all detected while in quarantine. The patient in Dong Nai had visited a relative in Da Nang Hospital and had close contact with patient 510.
The number of cases with links to the outbreak in Da Nang has risen to 222.
A total of 378 COVID-19 patients have given the all-clear so far, while there have been eight fatalities.
Among the patients under treatment, 18 have tested negative for SARS-CoV-2 once and 13 others negative for at least twice.
More than 133,270 people who had close contact with COVID-19 patients or returned from pandemic-hit areas are being quarantined across the country.