HCV 6a was expanding and became the predominant subtype among blood donors between 2004 and 2019 in Guangdong, China

•Currently, HCV 6a has replaced 1b as the most prevalent subtype in blood donors in Guangdong.•HCV 6a was the predominant subtype in males and older donors, while 1b predominated in females and younger donors.•HCV 6a may expand from Guangdong to other districts of China, and is worthy of attention.