The National Institute of Hygiene and Epidemiology (NIHE) is conducting the third stage of tests to determine whether the H5N1 vaccine is safe for humans.
The testing is expected to finish by the end of 2012.
Nguyen Thi Thu Van, director of the Company for Vaccine and Biological Production No.1, the producer of the vaccine, said 1,200 healthy volunteers in Thanh Hoa and Ha Nam Provinces had signed up for the clinical trials of the vaccine.
Previously, the first and second stages of the testing proved the vaccine does meet safety standards.
The NIHE started conducting research on the production of bird flu vaccines in 2005. If the third stage of the testing establishes the vaccine as safe, Vietnam may begin producing it for humans as soon as next year.
Meanwhile, the Ministry of Agriculture and Rural Development is seeking government permission to import 50 million doses of the H5N1 vaccine.
Bird flu has reemerged in 11 cities and provinces across the country, according to the Department of Animal Health. Around 35,000 fowl have been culled.
The H5N1 virus has killed two people in Vietnam this year, both last month, including an 18-year-old duck farmer in Kien Giang and a 26-year-old pregnant woman in Soc Trang.
Since 2003, bird flu outbreaks have killed and led to the forced culling of tens of millions of fowl in Vietnam, which is among the countries most affected by H5N1.
According to a World Bank report in October last year, 119 human cases of the disease were confirmed in Vietnam as of March 2011, of which 59 were fatal.