The patient from the US is a 58-year-old woman from HCM City who landed at Van Don International Airport on July 16. She was then taken to a quarantine site in the northern province of Hai Duong.
After being tested positive for the virus twice, she is being treated at Hai Duong Hospital of Tropical Diseases.
The four others aged 24 and 25 boarded the VN5062 flight from Russia to Vietnam on July 17 with the transit in Belarus. When arriving at Van Don International Airport, they were placed under quarantine in the northern province of Hoa Binh.
Earlier, 12 other passengers from the Russia-Vietnam flight were also infected with Covid-19, including eight from Ninh Binh Province and four from Nam Dinh Province.
Vietnam has confirmed 401 Covid-19 patients in total, including 261 imported from abroad. The country has seen no community infection since April 16.
At present, 12,484 are being quarantined, consisting of people repatriated from foreign countries and those who had contacts with them.
