Thirty-five volunteers in Hanoi and 38 in southern Long An Province were divided into four groups for the second phase of human trials of Nanocovax, a Vietnamese Covid-19 vaccine produced by Nanogen Pharmaceutical Biotechnology JSC.

Groups would be injected with placebos, as well as 25 microgram, 50 microgram and 75 microgram doses each. Volunteers would not know which type of shot they received.

Following their shots, all volunteers would be monitored for 60 minutes. Afterwards, they would be medically monitored by local authorities at home.

Deputy Prime Minister Vu Duc Dam visited the site Friday morning, saying Vietnam is doing its best to hasten progress for a Covid-19 vaccine while still ensuring the process adheres to the highest standards.

Nhu, 36 and a teacher, was one of the first Covid-19 vaccine trial volunteers during the first phase commenced last year. She said her health so far has been very good, and she has formed a Facebook group to counsel those who wish to participate in the trial's second phase.

Nhu participated in the second phase Friday too.

"I'm the evidence to prove the success of the trial vaccine, and I'm very proud," she said.

Dan, 63, said she had known of the vaccine trials weeks ago. After much consideration, she signed up to participate in the second phase.

"At my age, there could be risks and complications if I’m infected. As such, I want to take active care of my health and joined this phase of vaccine trials," she said, adding she would recommend her neighbors as well.

Another 52-year-old man in Long An said he had "absolute trust" in the Vietnamese Covid-19 vaccine. He had arrived at the injection site at 7 a.m. for his shot.

"I'm not worried at all; instead I feel happy and proud to contribute to our medical field," he said.

A total 560 people in Hanoi and Long An would be involved in the second phase of the Nanocovax human trials, in collaboration with Vietnam Military Medical University and HCMC Pasteur Institute. Nearly 200 people in Hanoi had been screened as vaccine trial volunteers Wednesday and Thursday, with 100 more screened Friday.

The first phase, which commenced last December with 60 volunteers, revealed Nanocovax to be safe, immunogenic and causing no severe side effects, said Do Quyet, director of Vietnam Military Medical University. Preliminary results also showed antibodies produced by Nanocovax had an effect on a coronavirus variant originating from the U.K., which is up to 70 percent more transmissible than ordinary strains, he added.

The second phase would allow researchers to see how exactly immunogenic Nanocovax is. Volunteers for the second phase could now include those aged 65 and above, along with those with underlying, non-severe conditions like hypertension and diabetes, according to the National Research Ethics Committee.

Preliminary results for the second phase should be expected within May, said Quyet. Afterwards, the Ethics Committee and the Ministry of Health would determine the most optimal doses for the third phase.

"If everything goes well, preparations for the third phase could begin by May. In this phase, the number of volunteers could reach between 10,000-15,000," said Quyet.

As of Wednesday, Vietnam has recorded 2,421 Covid-19 cases, with 578 still active.