In a document sent to local Centers for Disease Control (CDC) on Monday, the National Institute of Hygiene and Epidemiology announced seven more batches of vaccines have had their expiration dates extended, totaling nine batches so far.
It has not been confirmed exactly how many doses are contained within the nine batches, but two of the batches contained over 2.9 million doses. The institute also haven't announced where the batches would end up.
On Oct. 22, the Drug Administration of Vietnam allowed the extension of expiration dates on imported Pfizer vaccines in accordance with recommendations from Pfizer. Batches manufactured from August would see their expiration dates extended by another three months, under cold storage between minus 90 and minus 60 degrees Celsius.
"There are absolutely no changes to the vaccine in order to extend its use period. Therefore, its safety and effectiveness remains intact," according to a representative for Pfizer Vietnam.
Minister of Health Nguyen Thanh Long said Vietnam extends the expiration dates of vaccine batches in accordance with international regulations, and that all vaccine imports have been approved in accordance with WHO standards.
Earlier this month, Hanoi suspended the use of two Pfizer vaccine batches after parents informed the municipal Department of Health they had their expiration dates extended.