According to the Hanoi Center for Disease Control, he came to a vaccination station at the medical center of Nam Hong Commune in Dong Anh District to get his first jab of the vaccine on Sunday morning.

As regulated, his health was checked prior to the inoculation and he was confirmed to be eligible for vaccination. After the shot, he was let to rest for 30 minutes at the medical center.

On Monday evening, local health authorities received a notice from his family saying he had a seizure. Medics from the medical center of Dong Anh District was sent to his home 15 minutes later to give him emergency aid. They also informed the 115 Emergency Center of Hanoi for support.

After 30 minutes of emergency aid, his condition worsened and he was transferred to the Dong Anh General Hospital as his whole body was cyanotic and no radial pulse could be found and the blood pressure was zero. The hospital gave him intensive care but he died late Monday night.

Hanoi's Health Department on Tuesday morning held a meeting of a professional advisory council to assess the use of vaccine. Joining the meeting were leading experts in the field of emergency resuscitation from Hanoi's largest hospital Bach Mai Hospital and the National Institute of Hygiene and Epidemiology.

They concluded that "this is a fatality of unknown cause after 39 hours of vaccination against Covid-19." Clinical manifestations and forensic tests have not yet shown evidence of death due to anaphylaxis or embolism. Therefore, the council needs to continue to perform microscopic tests and gene sequencing to draw conclusions, it said.

According to the health department, 100 people besides the man were vaccinated at the station at Nam Hong medical center on Sunday morning. They were injected with the AstraZeneca vaccine that belongs to the ABX1466 batch that will expire on August 31, 2021. All other people who got vaccinated have been stable.

This man, a teacher, is the third person to have died after receiving Covid-19 vaccination in Vietnam.

The first was a 35-year-old female medical staff in the southern province of An Giang, who died last month after getting her first Covid-19 vaccination shot. Her cause of death was identified as anaphylaxis due to non-steroidal anti-inflammatory drug allergy.

In early June, a 28-year-old man in the northern Bac Giang Province died two days after receiving his first Covid-19 vaccine shot, and the Health Ministry concluded that his death was not related to the vaccination.

Vietnam has been using the AstraZeneca vaccine for its mass vaccination program since March, inoculating more than 1.5 million people.