Based on lab studies, researchers found the currently circulating H5N1 clade 2.3.4.4.b virus attaching better in the human respiratory tract than a well-characterised 2005 H5N1 clade 2.1.3.2 virus Based on lab studies, researchers found the currently circulating H5N1 clade 2.3.4.4.b virus attaching better in the human respiratory tract than a well-characterised 2005 H5N1 clade 2.1.3.2 virus Health Health News, Wellbeing Tips, Diseases, Treatment and Nutrition | The Hindu