EID Weekly Updates:
Emerging and Reemerging Infectious Diseases, Region of the Americas
Vol. 2, No. 5—5 February 2004
Rome, 3–4 February 2004: Several conclusions and recommendations were made during this consultation to strengthen WHO recommendations for protecting humans due to the consequences of widespread outbreaks of highly pathogenic H5N1 avian influenza in poultry in several Asian countries.
Experts at the consultation recognized the need for immediate application of measures to prevent human infection among specific groups, notably poultry workers and cullers, who are at high risk of exposure to the H5N1 avian influenza virus. Personal protective equipment (PPE) should be available for all persons in these groups, who also need to be trained in the proper use of this equipment. WHO has issued guidelines for the protection of cullers.
The experts further recognized the need to reduce opportunities for the simultaneous infection of humans with H5N1 and with human strains of influenza virus. Such dual infections give the avian and human viruses opportunities to exchange genes, possibly resulting in the emergence of a new influenza virus subtype. The consultation recommended that poultry workers who experience intensive exposure be administered the existing seasonal influenza vaccine (the vaccine protects against infection with currently circulating human influenza viruses but does not protect against H5N1 infection). WHO has issued guidelines for the targeted administration of seasonal vaccines.
WHO priorities for responding to the current situation include rapid control of the animal H5N1 reservoirs, since doing so reduces both the risk of additional cases and deaths among humans, and the opportunity for a new subtype of the influenza virus to emerge. Recommendations from the consultation also support this priority.
The consultation concluded that culling or 'stamping out' infected flocks remains the preferred option for controlling H5N1 outbreaks among poultry. However, the present outbreaks among such birds are historically unprecedented in their scale, geographical spread, and devastating economic consequences for both the poultry industry and rural farmers.
While culling remains the preferred option for infected flocks, as mentioned above, targeted vaccination of healthy poultry can be used as a complementary tool for achieving the rapid reduction of the risk posed by the H5N1 virus in its avian host—an objective which supports both the elimination of the disease in poultry and the prevention of further human cases and deaths.
Vaccination alone will not be sufficient to bring the present outbreaks in poultry under control. Experts at the consultation stressed that, although vaccination is being considered as a complementary control tool, it must be used in conjunction with a comprehensive strategy that includes
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Source: Avian Influenza A (H5N1)—Update 18 (5 February 2004). Geneva: World Health Organization (WHO).