Importance of new H5N1 variant downplayed

//02 Sep 2011
The World Health Organization (WHO) and the World Organization for Animal Health (OIE) have downplayed the significance of a new H5N1 avian influenza variant that the FAO warned about this week.
In an Aug 29 statement, the United Nations Food and Agriculture Organization (FAO) said a new H5N1 strain called clade 2.3.2.1 had emerged recently in Vietnam and China and that existing poultry vaccines were ineffective against it. The statement also cited recent increases in H5N1 bird outbreaks and warned about a possible major resurgence of the virus.

The WHO said that its Global Influenza Surveillance and Response System recognised the H5N1 variant in February. "Based on available information, this evolution of the H5N1 virus poses no increased risk to public health," the WHO statement said. "It is not considered unusual because influenza viruses are constantly evolving, especially in areas where they circulate regularly in poultry."

The OIE made similar points stating that the emergence of clade 2.3.2.1 is a result of minor genetic changes that typify the natural evolution of the virus.

"This is not immediate cause for alert but, as with the emergence of any new strain, reinforces the need for sustained monitoring of viruses in animal populations so that changes in viruses circulating in the field are detected at an earliest stage and that most appropriate disease control strategies are chosen to best protect animal and public health, the OIE said.

The agency also commented that avian flu vaccines, like human flu vaccines, need to be tested regularly to see if they are effective against the viruses in circulation. The OIE reference laboratory in Harbin, China, has developed a vaccine that, in trials, has protected poultry from clade 2.3.2.1, the statement said. Once available for field use, the vaccine will be employed in countries where the new variant has been identified.

"Registration and manufacturing of a poultry vaccine with the new seed strain is in progress," the OIE said.

Source: Centre for Infectious Disease Research and Policy CIDRAP

Related websites:
World Health Organization (WHO)
World Organization for Animal Health (OIE)