HANOI - Swine flu was showing a trend to fewer cases of infection but the cases were getting more serious and faster, doctors said yesterday.

National Institute of Hygiene and Epidemiology deputy director Tran Nhu Duong said the number of swine flu cases reported in the last month had reduced from 90 to 60 per cent of all flu cases, of which the remainder were seasonal flu.

He told a weekly meeting of the national steering committee for A/H1N1 flu pandemic prevention yesterday that research showed that there was no mutation of A/H1N1 flu virus in Vietnam.

Hospital of Infectious and Tropical Diseases director Nguyen Van Kinh said swine flu symptoms in patients cared at his hospital was getting more serious and faster.

Meanwhile the number of swine flu fatalities nationwide had reached 42 out of 11,000 cases with the death of a 23-year-old woman in Phuoc Long District, Binh Phuoc Province, the Ministry of Health said yesterday.

The woman, a newly confined mother, was sent to the HCM City Tropical Disease Institute on October 30, five days after onset of the disease. She was treated in intensive care with antibiotics and Tamiflu and placed on a machine respirator. She died on November 12 despite tests showing her to be negative for swine flu after six days treatment with Tamiflu.