Real-World Validation of Titer-Guided Precision Immunization against Covid19 over the years 2021 to 2026 from safety and efficacy point of view
Real-World Validation of Titer-Guided Precision Immunization Against COVID-19 in Rheumatic Patients: A 5-Year non-interventional Longitudinal Cohort Observation To the Editor: The ethical mandate of primum non nocere requires that universal mass vaccination strategies continuously justify their safety and socioeconomic efficacy against personalized, precision alternatives. While evolutionary modeling estimates a median reinfection interval of 16 months,¹ systematic meta-analyses confirm that frequent reinfections continuously stabilize long-term protection against severe outcomes.² Epidemiologically, a substantial proportion of the global population currently maintains immunological memory through natural exposure rather than repeated booster interventions. I report a 5-year longitudinal cohort observation (August 2021 to August 2026) evaluating a strict, titer-guided precision re-immunization protocol within a highly vulnerable cohort of 1,034 rheumatic patients under active immunosuppression, providing 737 fully evaluable individuals with reporting structured according to the STROBE guidelines.³,⁴ Differentiated S1 and non-neutralizing antibody screening paired with prospective D-dimer vascular monitoring was utilized to identify patients with stable natural immune plateaus. These individuals were withheld from non-targeted mass-booster regimens under strict shared decision conditions. Due to close, continuous primary care and rheumatological surveillance within my integrated clinical practice, no further dropouts occurred among these 737 per-protocol patients. In early 2022, a highly selective, protein-based clinical re-intervention (Nuvaxovid, n = 133) was executed for patients with levels below 150 BAU/ml according to 2022 titer guidance reports.⁵ Continuous multi-year antibody surveillance (maximum cost: €36 per patient-year) revealed that only three subsequent patients met the strict biological criteria requiring protein-based re-vaccination over the remaining 4-year tracking period. Threshold titer levels could be systematically reduced from <150 to <128 to <64 to <50 BAU/ml due to endemic progression and growing experience within this titer-guided vaccination strategy. Despite withholding universal mass-boosters from the vast majority (n = 734) of this immunosuppressed cohort from May 2022 on, and accounting for 22 patients who died of non-COVID-19-related causes during the 5-year follow-up, systematic clinical follow-up demonstrated zero COVID-19-related hospitalizations and zero COVID-19-related deaths since August 2022 (Rule of three failure: 3/715 = 0.420%). This empirical evidence indicates that a targeted "screen-before-you-inject" approach provides non-inferior clinical protection while mitigating the cumulative risks of reactogenicity, e.g. induced work-loss days and vascular adverse events. By demonstrating that universal mass-boosting fails to establish clinical superiority over a titer-guided protocol, these findings provide a real-world proof of concept for precision epidemiology. This framework served as the foundation for the "Inferiority Test Design" (The Pohl Hypothesis), where a protocol is mathematically validated by failing to reject the null hypothesis of its own clinical inferiority.⁶ Limitations of this observation include its monocentric, non-randomized design and the potential confounding effect of proactive shielding behaviors within this cohort. However, given the high clinical vulnerability of these patients under active immunosuppression, the complete absence of severe outcomes underscores the safety of this strategy and establishes pre-vaccination antibody screening as an effective instrument to optimize healthcare resource allocation.⁵ Declaration of Generative AI and AI-Assisted Technologies in the Manuscript Preparation Process:During the preparation of this work, the author used OpenAI's Large Language Model to support the linguistic polishing, grammatical refinement, and bibliographical formatting of the manuscript. The author reviewed and edited the output as needed and takes full responsibility for the content of the published article. Funding Statement:This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The longitudinal cohort tracking was fully funded by the author's institutional practice resources. References: Townsend JP, Hassler HB, Wang Z, et al. The durability of immunity against reinfection by SARS-CoV-2: a comparative evolutionary study. Lancet Microbe. 2021;2:e666–75. COVID-19 Forecasting Team. Past SARS-CoV-2 infection protection against re-infection: a systematic review and meta-analysis. Lancet. 2023;401:833–42. Pohl C. Safety and Efficacy Assessment of COVID-19 Immunizations / Vaccinations in Patients of a German General Rheumatological Practice. Ann Rheum Dis. 2022;81(suppl 1):935–6. doi:10.1136/annrheumdis-2022-eular.1389 Pohl C. COVID-19: after two years of iatrogenic and biologic immunization/ vaccination do we actually need further booster immunization/ vaccination? Ann Rheum Dis. 2023;82(suppl 1):2129. doi:10.1136/annrheumdis-2023-eular.689 Pohl C. Real-World Validation of Titer-Guided Precision Immunization against Covid19 over the years 2021 to 2026 from safety and efficacy point of view. Zenodo. July 2026. [Preprint]. DOI: 10.5281/zenodo.21206436 Pohl C. Baseline Immunity and its Natural Course against Respiratory Syncytial Virus (RSV) in Rheumatic Patients while starting Vaccination Program-Medical and Economic Critical Insights by using a New Inferiority Design Principle. Ann Rheum Dis. 2026;85(suppl 1):POS0032. doi:10.1136/annrheumdis-2026-eular.B.3586 Table 1. Clinical Disposition, Immunological Thresholds, and Longitudinal Outcomes of the Rheumatic Titer-Guided Cohort Clinical Parametric Step Patient Count (n) Clinical & Immunological Criteria COVID-19 Hospitalizations / Deaths Total Cohort Screened 1,034 Rheumatic patients under active immunosuppression — Per-Protocol (pp) Evaluable 737 Completed multi-year serial antibody and D-dimer tracking — Selective Re-Intervention (2022) 133 Initial Nuvaxovid booster due to anti-SARS-CoV-2 titers < 150 BAU/ml 0 / 0 Monitored Control Group (May 2022+) 734 Withheld from universal boosters due to stable natural plateaus 0 / 0 Late Biological Re-Interventions 3 Required delayed protein vaccine due to late titer drop over 4-year period 0 / 0 Censored Cohort Dropouts 22 Deceased due to verified non-COVID-19-related clinical causes 0 / 0 Final Adverse Clinical Events — Systematic follow-up from May 2022 to July 2026 0 (0.0%) [Statistical Margin: 0.420%]