The 5 Health and fitness care workers were definitively seronegative towards H5 in all assays, which suggests they were not infected with H5. Hemagglutinin inhibition (HI) assay: The HI assay checks for antibodies to your hemagglutinin of the specific influenza virus making use of purple blood cells (RBC). Multiple varieties https://www.dailypioneer.com/2020/state-editions/social-policing-programme-held.html