Last week, fresh bird flu outbreaks were reported in Vinh Phuc, Ha Nam, Quang Nam, Hung Yen and Thai Binh provinces, bringing the total affected provinces and cities to 15. Outbreaks were still detected on scattered scale in Nghe An province while the epidemic tended to spread on a large scale in Nam Dinh and Ninh Binh provinces and Hai Phong City. 

According to Mr Phat, vaccination will still prove highly effective if localities strictly follow instructions. However, he quoted initial results of recent surveys as saying vaccinations have not been carried out well.

In test carried out to gauge suitability for vaccination, results are variable. In Quang Ninh province, among 13 flocks of tested chickens, nine acquired an immunity rate of 70 percent, three others had a rate varying between 30.3 percent and 56.6 percent, and one flock did not produce any antibodies to counteract the virus. Meanwhile, three out of six flocks of ducks reported an immunity rate of 70 percent and two other flocks had the rate of between zero to 3.3 percent.

In Hai Duong province, four out of nine flocks of chickens had an immunity rate of more than 70 percent and the remaining flocks reported the rate of 50 percent. Meanwhile, no antibodies were found in three flocks of ducks.  

In Bac Giang province, 10 out of 30 blood samples tested positive for the bird flu virus and the immunity rate among ducks and chickens ranged between 20 and 33.3 percent.

Mr Phat expressed concern about the spread of bird flu on a large scale across the country, which he said could make it possible for the virus to transmit from poultry, particularly waterfowl, to humans.

According to the National Steering Committee for Bird Flu Prevention and Control, unaffected provinces and cities are facing a high risk of new outbreaks due to lax controls on the hatching and transport of waterfowl as well as poor vaccination work. The committee warned that the bird flu virus could acquire genetic changes to form new strains with higher risks, which are transmittable from human to human.