Seroprevalence of Pandemic Influenza Viruses, New York, New York, USA, 2004

摘要

To the Editor: Exposures to in. uenza viruses can lead to immune responses that substantially affect susceptibility to infection with related viruses. Characterization of preexisting immunity within a population can inform public health, as highlighted during the in. uenza A(H1N1)pdm09 virus pandemic, when surveillance data demonstrated that older persons (>65 years old) were less likely than younger persons to have in. uenza (1). Seroprevalence studies of prepandemic samples show that older persons had preexisting antibody responses to A(H1N1)pdm09 virus, presumably because of prior exposure to related strains (2). The A(H1N1)pdm09 virus possesses hemagglutinin and neuraminidase genes derived from classical swine in. uenza virus (3).