自1960年代麻疹疫苗問世以來，全球麻疹的發病率與死亡率顯著下降，但近年來即使在疫苗接種率高的國家，麻疹疫情仍不斷復燃。COVID-19疫情期間，常規疫苗接種服務受到干擾，進一步削弱群體免疫，為疫情反彈創造了有利條件。本文綜合分析了美國、歐洲及台灣等地的疫苗接種策略，並參考香港、南韓、義大利及台灣等地的血清學研究數據，探討疫苗誘導免疫力隨時間衰退的現象及其對群體免疫的影響。研究結果顯示，青少年、年輕成人及醫護人員中，疫苗接種後獲得的抗體水準隨年齡增長而逐漸降低，相較於自然感染者，其免疫保護力更易出現衰退。此外，多項研究證實，施打麻疹、腮腺炎、德國麻疹(MMR)加強劑可顯著提升抗體濃度，恢復免疫保護，從而降低病毒傳播風險。綜上所述，持續監控麻疹免疫狀況並在特定高風險族群中推動加強劑接種策略，對於維持長期群體免疫和有效防控未來麻疹疫情具有重要臨床與公共衛生意義。

Measles remains a significant public health concern despite the substantial global reduction in morbidity and mortality following the introduction of the measles vaccine in the 1960s. Recent outbreaks, even in regions with historically high vaccination coverage, have raised concerns about the durability of vaccine-induced immunity. This review synthesizes current evidence on measles vaccination strategies with a particular focus on the potential need for booster doses to sustain long-term protection. We examine epidemiological data that document a resurgence of measles cases globally—exacerbated by disruptions in routine immunization programs during the COVID-19 pandemic—and analyse variations in vaccination schedules across regions such as the United States, Europe, and Taiwan. Furthermore, serological studies from diverse settings (including Hong Kong, South Korea, Italy, and Taiwan) reveal a decline in measles antibody levels with age, especially among adolescents, young adults, and healthcare workers, suggesting that waning immunity may compromise herd protection. Notably, evidence indicates that administration of a measles-mumps-rubella (MMR) booster dose can effectively restore seroprotection, thereby reducing the risk of transmission. These findings underscore the importance of continuous surveillance of measles immunity levels and support the consideration of booster vaccination strategies as an adjunct to primary immunization programs. In conclusion, adapting vaccination policies to include targeted booster doses may be critical for achieving sustained measles control and preventing future outbreaks.