claim: genomic surveillance of sars-cov-2 in africa reveals mixed imported populations, a local lineage expansion and a virus with truncated orf7a
evidence_1: several virus lineages supposedly originated in many countries were found, and a thai-specific lineage, designated a/thai-1, has expanded to be predominant in thailand.", "a virus sample in the sars-cov-2 a/thai-1 lineage contains a frame-shift deletion at orf7a, encoding a putative host antagonizing factor of the virus.")