Adaptive immune receptor repertoire sequencing (AIRR-SeqorREP-Seq) is a powerful and long-established technology that analyzes the immune system by sequencing the recombined V(D)J regions of antibodies and T-cell receptors. AIRR-Seq has not only been applied to multiple areas of biological research such as infectious disease, cancer, and autoimmunity, but the technology itself has continued to mature within the ever-evolving landscape of biotechnology. Here, we demonstrate the greatly improved long read data quality on the new MiSeqTMi100 instrument, both at a 2x300 read length and extended lengths of up to 2x500. We sequenced as et of control libraries, provided and analyzed through Takara Biosciences, MiLaboratories and the SEQC-BCR consortium, to establish baseline primary sequencing performance. Our sequencing results show much improved basecall quality throughout the read lengths as well as accurate detection of expected control clonotypes. In addition, we report on an AIRR-Seq time series of two donors (SARS-CoV-2 naïve and experienced), following a Moderna mRNA-1273SARS-CoV-2 vaccination schedule. Both donor samples were sequenced on the new MiSeqTMi100. Our sequencing data demonstrate that the greatly improved quality along the full read lengths, and in particular at read-ends, results in a substantial increase in full-length V(D)J clonotype detection and sensitivity thereof. Furthermore, our data highlights the importance of high-quality, extended read-lengths for achieving accurate and reliable characterization of the immune response following SARSCoV-2 vaccination.