(1) Background: Vaccination reluctance is a major worldwide public health concern as it poses threats of disease outbreaks and strains on healthcare systems. While some studies have examined vaccine uptake within specific countries, few provide an overview of the barriers and trends among migrant groups. To fill this knowledge gap, this narrative review analyzes immunization patterns and vaccine hesitancy among immigrant populations. (2) Methods: Four researchers independently evaluated the quality and bias risk of the 18 identified articles using validated critical appraisal tools. (3) Results: Most studies focused on vaccine hesitancy among migrants in the United States and Canada, with a higher COVID-19 vaccine reluctance than native-born residents. Contributing factors to this hesitancy include demographics, cultural views, obstacles to healthcare access, financial hardship, and distrust in health policies. Additionally, immigrants in North America and Europe face unfair vaccine challenges due to misinformation, safety concerns, personal perspectives, language barriers, immigration status, and restricted healthcare access. (4) Conclusions: Tailored vaccine education programs and outreach campaigns sensitive to immigrants’ diversity should be developed to address this issue. It is also important to investigate community-specific obstacles and assess the long-term sustainability of current efforts to promote vaccination among marginalized migrant groups. Further research into global immunization disparities among immigrant populations is crucial.

(1) Background: The COVID-19 pandemic has led to the fast-tracked development of vaccines under emergency use authorization. In light of the growing concerns about fast-tracked vaccines, this article reviews the safety, efficacy, and lessons learned of previously fast-tracked vaccines. (2) Methods: An article search regarding the safety and efficacy of fast-tracked vaccines was done in PubMed, Embase, Web of Science, and ScienceDirect. Of the 104 results, 24 articles were included. Five articles about BiovaxID, THERATOPE^®, Sipuleucel-T, and AIDSVAX were also reviewed. (3) Results: The overall efficacy was shown to be 77–100%, with seroprotection against the viruses ranging from 87 to 100%. The antibody responses for optimal protection against the viruses fall within 85–97%. Generally, the fast-tracked vaccines were well-tolerated and had few significant adverse events, except for the H1N1 pandemic vaccine and its association with narcolepsy. To have accurate, precise, and timely fast-tracked vaccines, communication, sharing resources/data, and improving the current structures/outbreak operations are crucial. (4) Conclusions: This review found the FDA’s fast-tracking process for vaccines to have rigorous standards similar to the normal process. The previous fast-tracked vaccines were safe and efficacious. The lessons drawn from previous studies highlighted the significance of planning and utilizing global resources during significant outbreaks.