CONCLUSION: The anti-N positivity rate is an effective and straightforward retrospective serological tool for tracking epidemiological trends, while the anti-S rate is influenced by vaccination and epidemiology as well, making it inept for the tracing of epidemiological changes. Although the recent development in SARS-CoV-2 epidemiology with increasing intervals between infection waves already provide an enhanced statistical robustness, we recommend the determination of the anti-N …