He said Omicron sub-variant BA.2 still remains dominant in Viet Nam.
Over the past two months, about 142,000 new infections had been confirmed in Viet Nam and fatality rate dropped sharply.
The Department of Preventive Medicine will keep a close watch on new strains and announcements from the WHO.
Phan warned that people who have yet get booster shots are likely to catch the virus.
COVID-19 vaccines remain the reliable shield to protect the community and provide substantial protection against severe disease, and vaccine makers are working on updated shots that might elicit a stronger immune response against the variants.
The World Health Organisation has announced several sublineages of the Omicron variants, namely BA.1, BA.2, BA.3, BA.4, BA.5 and XE. However, only sub-variants BA.1, BA.2, and BA.5 have been found in Viet Nam./.