The move came after some northern localities and several countries in the region have reported rising seasonal flu cases recently.
In a directive issued on Sunday, the municipal health department urged health facilities to require people to follow preventive measures, including wearing face masks inside.
According to a report from the Ministry of Health, the country has recorded 912 influenza cases since the beginning of this year, primarily involving the A/H1N1, A/H3N2, and B strains.
"Compared to the same period last year, the epidemic has shown a declining trend with no signs of increased virulence and no fatalities, the report said. "However, major hospitals in Hanoi have reported a rise in severe influenza cases, particularly among patients with underlying health conditions. The number of flu patients in January 2025 was six times higher than in December 2024."
The Hanoi-based National Hospital for Tropical Diseases is currently treating eight influenza patients, one of whom requires extracorporeal membrane oxygenation intervention. Several other severe flu cases were reported at the National Children's Hospital.
Hanoi Medical University Hospital has recorded a rapid increase in seasonal flu cases in the past months.
In HCM City, nearly 2,900 flu cases were recorded in 2024, including 11 severe cases.
The municipal Department of Health has closely monitored the situation at medical institutions and implemented measures to prevent and control the spread of the flu.
