Both strains XL and XE are recombinant variants of the novel coronavirus Omicron strain, of which 17 exist worldwide, named XA-XS. Although both XL and XE are composed of Omicron BA.1 and BA.2, there are some differences in the specific recombination method and time of discovery. The XE and XL strains inherited the advantages of BA.1 and BA.2 strains and have higher transmission rates and disease levels than their parents. In addition, due to the late appearance of the XL strain, there are no specific studies with information on its transmission characteristics and rate of severe disease, but in combination with other recombinant strains, it is not rare and most of them will die out relatively quickly without too much concern. Therefore, active vaccination with the new crown vaccine and daily attention to personal protection are still recommended to help reduce the chance of infection.