Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes corona virus disea-se 2019 (COVID-19), has been widely spread around the world for three years, and has spawned many va-riants. At present, the Omicron variant, which causes large-scale transmission in the world, has the charac-teristics of high infectivity and low toxicity, and has evolved into BA.4, BA.5, XBB and other subvariants. These strains can escape the vaccine-induced immunity, but neutralizing capacity elicited by vaccination can be restored to a certain degree by a booster dose. New vaccines and therapeutic drugs against the Omi-cron variant are available, providing better immunity and treatment methods for humans. This article sum-marized and analyzed the characteristics of Omicron strains, human immune mechanism against the infec-tion, current vaccine and drug development, and COVID-19 sequelae. It also made suggestions on how to cope with SARS-CoV-2 in the future.