Two suffered from anaphylaxis and three others developed diarrhea, allergies and low pulse pressure, according to the national Expanded Program on Immunization.
They are being treated and in stable condition.
The vaccination campaign began on Monday and hundreds of medical staff in Hanoi, HCMC and Hai Duong and Gia Lai provinces have received the first dose of the vaccine developed by the British-Swedish company in collaboration with Oxford University.
Initial reports said most of the vaccinated people displayed expected symptoms like muscle pain, fatigue, fever, headache, chill, pain at the injection spot, and nausea.
Vietnam has ordered 30 million doses, and 117,600 arrived late last month.
It is also negotiating with the U.S.’s Pfizer and Moderna and other vaccine manufacturers in Russia and China.
In the latest outbreak of community transmission that broke out on January 28, there have been 894 cases so far, including one diagnosed on Tuesday evening in Hai Duong, its 710th.