The coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still develops. Because several viral variants have increased transmissibility and/or virulence, while some governments and people have slackened their pandemic control measures, the COVID-19 situations in some countries and regions have become worsen. After worldwide rollout of SARS-CoV-2 vaccines, different vaccination rates have different effect on local pandemic situations. This paper covers the relationship between COVID-19 situations and the rollout of SARS-CoV-2 vaccines as well as viral variants, the difficulties on COVID-19 vaccination and their solutions, and recommends to speed up vaccination, at the same time, various preventive and control measures on COVID-19 should be carry out seriously.