Although a great diversity of viral strains develop in patients due to frequent mutations, not all of these strains are transmitted. (sciencemag.org)
These include tests for antibodies and to identify different viral strains. (sciencemag.org)
When the researchers checked a database with genome sequences of more than 6000 flu virus variants, they found that the amino acid sequence of this region remains constant in many viral strains. (sciencemag.org)