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.
Example decision tree. A representative of B/Yam or B/Vic strain has to be chosen for the vaccine. Both choices lead to two possible outcomes: the vaccine lineage dominates (outermost branches of the tree), or the non-vaccine lineage dominates (innermost branches of the tree).
