Download National Advisory Committee on Immunization (NACI) Influenza

National Advisory Committee on Immunization (NACI) Influenza vaccination
recommendations: what about the swine workers?
Objective:
To analyze the scope and rationale for the NACI recommendations for influenza vaccination
of farm workers.
Methods:
Review of published NACI statements on influenza vaccination, over the period 2004 – 2010.
Review of reports of transmission of 2009 pandemic strain H1N1 (pH1N1) between humans
and animals.
Results:
The ‘mixing bowl’ hypothesis states that swine are a species in which reassortant viruses of
pandemic potential that include avian, swine and human genes could be generated. Since
2004, NACI has recommended influenza vaccination for persons involved in poultry culling.
The basis of the recommendation is the theoretical concern of generation of a pandemic
influenza strain through human-avian gene reassortment within workers directly involved in
culling operations who might become simultaneously infected with human and avian viruses.
The 2009 pH1N1 virus included human, avian and swine genes. Outbreaks occurred in
which the virus was transmitted from infected humans to naive swine. Asymptomatic
shedding occurred in both humans and swine. NACI statements, including for the 20102011 season, identify only poultry workers involved in culls as target populations for
vaccination.
Conclusion:
Given that the rationale for vaccination of poultry workers is the that of prevention of
generation of reassortant strains of pandemic potential, the recommendations should be
broadened to include both poultry and swine workers. As asymptomatic shedding occurs in
both humans and swine, all poultry and swine workers should be included as target
populations for vaccination.