The Taiwan Centers for Disease Control (Taiwan CDC) has examined 141 throat swabs and serum samples taken from poultry workers and quarantine officers in 5 poultry farms where H5N2 virus has been detected. All throat swabs had negative findings, but three serum samples revealed positive reactions to A/H5N2 antibody. Further investigation documented that all three workers were in good health and did not develop influenza-like symptoms.

These three workers all received the seasonal influenza vaccine in 2011 and the vaccine for humans against the avian influenza virus A/H5N1 between March and April 2012. Therefore, the seropositivity could possibly result from the cross-reactivity of the human influenza virus antibody with that of an avian influenza virus.

According to reports from the H5N2 AI outbreak in South Africa in 2003 and Japan in 2004 to 2005, some subjects had higher H5N2-neutralizing antibody titer. Additionally, a few studies has pointed out that history of seasonal influenza or influenza A/H5N1 vaccination might raise the neutralizing immunity.

 In order to prevent human infections of H5N2 AI virus, poultry and livestock workers should take appropriate personal protective measures and citizens should avoid unnecessary contacts with poultry and birds. It is strongly recommended that people should wash hands frequently, and consume only thoroughly cooked poultry meat and eggs to minimize the risk of infection. If influenza-like symptom or conjunctivitis develops, please don a surgical mask and seek medical attention immediately. Please also inform the doctor of any recent travel history and poultry exposure history. For further information about the international epidemic situation of avian influenza and relevant preventive measures, please visit the Taiwan CDC’s website (http://www.cdc.gov.tw), or call the toll-free Communicable Disease Reporting and Consultation Hotline, 1922, or 0800-001922 if calling from a cell phone.