First-generation SARS-CoV-2 vaccines have played a significant role in controlling the COVID-19 pandemic, preventing severe diseases, and reducing mortality. However, the continuous emergence of SARS-CoV-2 variants, the persistence of breakthrough infections, and the seemingly rapid decline in the protective efficacy of SARS-CoV-2 vaccines have presented additional challenges for the next phase. There is an urgent need to confirm the necessity of further booster vaccination and combination vaccine approaches. This paper summarizes the latest literature on SARS-CoV-2 variants and vaccine effectiveness and concludes that it is essential to implement booster immunization strategies. Priority should be given to high-risk groups, the elderly, and immunocompromised people. In addition, heterologous vaccination has a longer duration of effect and a broader spectrum than homologous vaccination, making it more conducive to managing the immune escape of SARS-CoV-2 variants.

中文翻译：

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COVID-19 加强疫苗接种的策略和安全考虑。

第一代 SARS-CoV-2 疫苗在控制 COVID-19 大流行、预防严重疾病和降低死亡率方面发挥了重要作用。然而，SARS-CoV-2 变异体的不断出现、突破性感染的持续存在以及 SARS-CoV-2 疫苗的保护功效看似迅速下降，都为下一阶段带来了额外的挑战。迫切需要确认进一步加强疫苗接种和联合疫苗方法的必要性。本文总结了有关 SARS-CoV-2 变体和疫苗有效性的最新文献，并得出结论认为实施加强免疫策略至关重要。应优先考虑高危人群、老年人和免疫力低下的人群。此外，