ABSTRACT History suggests that the 2009 pandemic H1N1 influenza virus faces extinction unless it mutates to avoid already high global population immunity. The immune escape mechanisms potentially at its disposal include antigenic drift. antigenic shift via genetic reassortment. and intrasubtypic reassortment. https://www.roneverhart.com/Port-Company-Long-Sleeve-Performance-Blend-Tee-PC381LS-Port-Company-PC381LS/