Vaccines are critical cost-effective tools to control the COVID-19 pandemic. However, the emergence of more transmissible SARS-CoV-2 variants may threaten the potential herd immunity sought from mass vaccination campaigns.The objective of this study was to provide an up-to-date comparative analysis of the characteristics, adverse events, efficacy, effectiveness and impact of the variants of concern (Alpha, Beta, Gamma and Delta) for fourteen currently authorized COVID-19 vaccines (BNT16b2, mRNA-1273, AZD1222, Ad26.COV2.S, Sputnik V, NVX-CoV2373, Ad5-nCoV, CoronaVac, BBIBP-CorV, COVAXIN, Wuhan Sinopharm vaccine, QazCovid-In, Abdala and ZF200) and two vaccines (CVnCoV and NVX-CoV2373) currently in rolling review in several national drug agencies.Overall, all COVID-19 vaccines had a high efficacy against the traditional strain and the variants of SARS-CoV-2, and were well tolerated. BNT162b2, mRNA-1273 and Sputnik V had the highest efficacy (>90%) after two doses at preventing symptomatic cases in phase III trials. Efficacy was ranging from 10.4% for AZD1222 in South Africa to 50% for NVX-CoV2373 in South Africa and 50 % for CoronaVac in Brazil, where the 501YV.2 and P1 variants were dominant. Seroneutralization studies showed a negligible reduction in neutralization activity against Alpha for most of vaccines, whereas the impact was modest for Delta. Beta and Gamma exhibited a greater reduction in neutralizing activity for mRNA vaccines, Sputnik V and CoronaVac. Regarding observational real-life data, most studies concerned the Pfizer and Moderna vaccines. Full immunization with mRNA vaccines effectively prevents SARS-CoV-2 infection against Alpha and Beta. All vaccines appeared to be safe and effective tools to prevent symptomatic and severe COVID-19, hospitalization and death against all variants of concern, but the quality of evidence greatly varied depending on the vaccines considered. There are remaining questions regarding specific populations excluded from trials, the duration of immunity and heterologous vaccination. Serious adverse event and particularly anaphylaxis (2.5-4.7 cases per million doses among adults) and myocarditis (3.5 cases per million) for mRNA vaccines ; thrombosis with thrombocytopenia syndrome for Janssen vaccine (3 cases per million) and AstraZeneca vaccine (2 cases per million) and Guillain-Barre syndrome (7.8 cases per million) for Janssen vaccine are very rare. COVID-19 vaccine benefits outweigh risks, despite rare serious adverse effect.