A multi-centered clinical follow-up study to investigate the long-term dynamic of COVID-19 antibody level after vaccination.

From December 2019, coronavirus disease 2019 (COVID-19), caused by a β-coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread across the globe. As of July 6, 2021, more than 180 million confirmed cases and around 4 million deaths have been reported globally. Till now, many treatment methods has gradually formed a consensus. At the same time, several domestic vaccines have been offered to the public for free inoculation in our country. However, due to the urgent form of the epidemic, the short vaccine development cycle and heavy tasks, there is no clear conclusion on the long-term changes in antibody levels after vaccination.Therefore, we plan to carry out a multi-center prospective observational trial to better understand the dynamic changes of the antibody levels in patients after vaccination.

Inclusion Criteria:

• Adult (18 years old or elder) who prepare or have been vaccinated against COVID-19, and has not participated in similar clinical studies.

Exclusion Criteria:

• People who are allergic to any active ingredient of the vaccine, any inactive ingredient which was used in the production process, or those who have been allergic to the same kind of vaccine before.
• People who have had severe allergic reaction to vaccine before (such as acute allergic reaction, vascular neuroedema, dyspnea, etc.)
• People with uncontrolled epilepsy and other serious neurological diseases (such as transverse myelitis, Guillain-Barre syndrome, demyelinating diseases, etc.)
• People who are feverish, or suffering from acute diseases, or suffering from acute episodes of chronic diseases, or with serious chronic diseases without control.
• Pregnant woman
• Juvenile

All population who has been vaccinated or are prepared to get vaccinated.