The number of patients increased by eight times in the northern region and doubled in the central and central highland regions.

In Hanoi, in the past nine months, there were more than 6,000 cases of dengue fever, half of them recorded in August alone. The prevention work faces a number of difficulties due to a surge in the number of patients and the spread of A/H1N1 flu.

Experts say that the epidemic in Hanoi peaked in August.