No sponsor

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (COVID-19) have afflicted tens of millions of people in a worldwide pandemic. Considering its high mortality and rapid spread, an effective vaccine is urgently needed to control this pandemic. Recently, mass vaccination campaigns using newly approved vaccines, ranging from conventional viral and protein-based vaccines to those that are more cutting edge, including DNA- and mRNA-based vaccines are beginning in many parts of the world. Randomized clinical trials of different vaccines reported efficacies for preventing COVID-19 in the range of 50% to 95%.

Although these randomized clinical trials are considered the "gold standard" for evaluating intervention effects, they have notable limitations of sample size and subgroup analysis, restrictive inclusion criteria, and a highly controlled setting that may not be replicated in a mass vaccine rollout.

The aim of this study is to evaluate the safety, tolerability, immunogenicity, and efficacy of different vaccines against COVID-19 under real-world practice conditions.

Inclusion Criteria:

• Subjects received COVID-19 vaccines;
• Able to comprehend and provide written informed consent in accordance with institutional guidelines.

Exclusion Criteria:

• Not received any COVID-19 vaccines;
• Not willing to participate and/or give their written informed consent.

Subjects who received COVID-19 vaccines under real-life practice conditions in the World