Figure 4.
Strain names of representative members from each of the clusters seen in Fig. 3. Note that strains considered as antigenically distinct by the WHO (using HI assay) can fall in the same cluster.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.