H5N1 virus in Vietnam has reduced its virulence

Research by the National Institute of Hygiene and Epidemiology shows that, compared to when it first appeared in Vietnam, H5N1 has had a slight change in genetics and pathogenicity. Over the past year, the gene that regulates its virulence has decreased from 99.1% to 98.2%.

Dr. Nguyen Thuy Hoa, Head of Epidemiology Institute of National Hygiene and Epidemiology said, with the above change, the virus may have been more adaptable to the human body, leading to an increase in the number of infected people (especially is the number of infected people without symptoms), the clinical situation is lighter, the mortality rate is lower.

Surveys also show that influenza A type H5N1 occurs at all ages with the youngest being 4 months, the highest being 81 years old. However, the epidemic is concentrated in ages under 40, the highest in the age group of 10-19. The number of deaths in each age group corresponds to the number of deaths. In the North, mortality is significantly lower than in the South (38.1% compared to 83.3%).

Dr. Nguyen Tran Hien, Director of the National Institute of Hygiene and Epidemiology, said that the agency continues to take samples for testing. The national influenza surveillance program was carried out in Hanoi, Thai Binh, Nha Trang, Buon Me Thuat, Ho Chi Minh City from February, with taking samples of people with flu for testing. To date, thousands of samples have been transferred to the laboratories of the Institute and the regional Pasteur institutes, to detect H5N1 cases and study the transformation of the virus.