Core Viewpoint - Chengdu has officially launched the COVID-19 vaccine booster shot program as part of a unified national and Sichuan provincial deployment [3] Group 1: Importance of Booster Shots - The neutralizing antibody levels decrease over time after vaccination, leading to reduced protection; administering a booster can significantly enhance immunity, with studies showing a more than tenfold increase in antibody levels after a third dose six months post the second dose [4] Group 2: Safety of Booster Shots - The types and incidence of adverse reactions following the booster shot are not significantly different from those observed during the initial vaccination series, confirming that the booster is safe and effective [5] Group 3: Eligibility for Booster Shots - Individuals aged 18 and above who have completed the full vaccination with inactivated COVID-19 vaccines or received one dose of adenovirus vector vaccines at least six months prior are eligible for the booster. Priority is given to high-risk groups, including healthcare workers, customs officials, and those in essential services [6][7] Group 4: Administration of Booster Shots - Individuals who received two doses of the same inactivated vaccine should receive the same vaccine for the booster. If different inactivated vaccines were used, the same vaccine as the second dose is preferred for the booster, with alternatives available if necessary [8] Group 5: Co-administration with Other Vaccines - It is currently not recommended to administer the COVID-19 vaccine simultaneously with other vaccines, with a minimum interval of 14 days suggested between COVID-19 and other vaccinations, except in specific cases such as rabies or tetanus vaccines [10]