Health officials said both cases are female residents.
A 64-year-old victim living in Nha Trang showed symptoms identical to those linked to the Zika virus, including a mild fever, headache, a rash on her legs and red eyes. After two days of taking medication at home that failed to reduce fever, she went to the Khanh Hoa Hospital of Tropical Diseases for a check-up.
The other case is a 32-year-old woman from District 2 in Ho Chi MinhCity. She started developing symptoms of severe fever, conjunctivitis and fatigue last Tuesday and went to the district general hospital the same day. She subsequently tested positive for the Zika virus.
The National Institute of Hygiene and Epidemiology confirmed yesterday these as first known cases of the virus in Vietnam.
The Zika virus is an emerging mosquito-borne virus that was first identified in Uganda in 1947. The most recent outbreak of the virus is in the Americas. The WHO announced that the Zika virus has so far been recorded in 59 countries and territories.
The virus is also thought to be present in a number of Southeast Asian countries such as Thailand, the Philippines, Indonesia and Malaysia following reports of foreigners returning from these countries having contracted the virus. However, the WHO is not recommending travel restrictions to these countries.
Most victims experience mild symptoms, while recovery is usually complete and fatalities are rare.
The most significant health threat is for pregnant women because Zika virus infections have been linked to the birth defect microcephaly and miscarriage.
The virus can also lead to guillain-barre syndrome, which can attack the nervous system.
There is no vaccine or preventative medication available for Zika.
Vietnam's health sector was placed on high alert last week after an Australian was diagnosed with the virus following a visit to Vietnam.
The ministry said the victim arrived in Vietnam on February 26 and returned to Australia on March 6. While in Vietnam, the victim travelled to Ho Chi Minh City, the Central Highland province of Lam Dong, the central province of Khanh Hoa and the south-central province of Binh Thuan. However it has not been confirmed that this case of Zika was contracted in Vietnam.