The 5 Overall health treatment workers have been definitively seronegative from H5 in all assays, which means they were not infected with H5. This examine demonstrates a development of weakening binding affinity of existing antibodies from H5 isolates as time passes, indicating that the H5N1 virus is evolving immune escape https://www.dailypioneer.com/2015/business/big-relief-for-vodafone.html