The last 22 volunteers received the second shots, with two receiving the 50mgc dose, and 20 getting the 75mgc dose.
Experts said Nano Covax has proven safe and effective against the coronavirus SARS-CoV-2, even its new variant.
Most of the volunteers are in stable conditions after vaccination. Only few had light injection site pain and fever that disappeared after one to two days.
The objective of the first phase is to evaluate the safety of the vaccine, developed and manufactured by HCM City-based Nanogen Pharmaceutical Biotechnology JSC.
Nearly 400 people have registered for the second phase that is expected to last for six months, during which 560 volunteers will be injected. The third phase will see the engagement of more than 10,000 volunteers, beginning from August.
If the result is good, Vietnam would administer the vaccine to the public in early 2022.
