Vietnam’s Ministry of Health documented 91 coronavirus infections on Thursday, including a hefty 84 local cases in two northern provinces.
Seven of the new patients were imported cases who had been quarantined upon arrival by plane from abroad, the health ministry said in a report.
The remainder were domestic infections registered in Hai Duong and Quang Ninh Province, both located in the northern region.
Eleven of the locally-transmitted cases were logged in Quang Ninh while the remaining 73 were documented in Hai Duong.
Thursday saw the largest daily COVID-19 case hike since the virus first struck Vietnam on January 23, 2020, according to the ministry’s data.
Health officials have pushed for fast contact tracing to suppress the new wave while warning of far worse scenarios.
But they are still not sure about the primary source of the new local infections even though 82 of the locally-infected patients were already linked to two cases – patients No. 1,552 and 1,553.
Patient No. 1,552 is a 34-year-old Vietnamese woman working for Vietnam Poyun Electronics Co. Ltd. in Hai Duong.
She had come into contact with a woman who left Vietnam for Japan on January 17. That woman had tested negative for the virus on January 14 and 15 prior to her departure from Vietnam.
The woman retested positive in Japan on Tuesday for the new variant, 70 percent more transmissible, that has raged in the UK recently.
Patient 1,552 was diagnosed with COVID-19 on Wednesday evening.
Patient No. 1,553 is a 31-year-old Vietnamese security guard at Van Don International Airport in Quang Ninh.
He had a fever, dry cough, and sore throat so he went to the hospital for a check-up.
The man was tested for the novel coronavirus and the result returned positive at the Quang Ninh Center for Disease Control on Wednesday evening.
Vietnam has documented 1,642 coronavirus patients as of Thursday evening, with 1,430 recoveries and 35 virus-related deaths, according to the Ministry of Health.
The country had spent nearly two months detecting no local transmission before the new clusters were uncovered in the said provinces.