Background: Long COVID (Post-Acute Sequelae of SARS-CoV-2, PASC) presents as a heterogeneous, treatment-resistant chronic syndrome. Conventional anti-inflammatory monotherapies frequently fail in clinical trials, exhibiting post-treatment rebound oscillations. We hypothesize that Long COVID represents a non-equilibrium bi-stable dynamical system where inflammatory pathology (I) and regulatory repair kinetics (R) form a persistent attractor state, requiring phase-synchronized dual modulation to traverse the separatrix into permanent remission. Methods: We formulated a 2D stochastic Langevin dynamical system describing non-linear auto-amplifying inflammation I (t) coupled with regulatory repair R (t), parameterized by an HLA-DRB1*13: 02 genetic risk coefficient (χ) derived from epidemiological odds ratios (OR = 6. 74, βH = 1. 908). An in silico randomized clinical trial was conducted on a virtual cohort (N = 1, 000) over 12 weeks across three primary arms: Arm A (Control / Natural History), Arm B (Empirical Periodic Anti-Inflammatory Pulse, uI), and Arm C (Phase-Synchronized Model Predictive Control Dual-Target Modulation, uI + uR). We further benchmarked a heuristic fixed-window controller (v1. 0) against a Pontryagin's Minimum Principle (PMP) costate-guided, HLA-adaptive controller (v2. 0). Results: Natural recovery was completely absent in Arm A (0. 0% remission, mean disease AUC: 232. 39). Empirical anti-inflammatory monotherapy (Arm B) yielded negligible efficacy (1. 3% remission, AUC: 172. 02) due to depletion of repair feedback and subsequent rebound. Controller v1. 0 achieved 63. 4% remission. Controller v2. 0 achieved a 69. 7% remission rate (p < 0. 001, Log-rank test), reduced mean disease AUC to 29. 42 (87. 3% reduction vs control), cut post-exertional flare-ups by 51. 3%, and shortened median time-to-remission from 42. 1 days to 32. 4 days (Hazard Ratio = 1. 34, 95% CI: 1. 20–1. 50). Conclusions: Phase-synchronized dual-target modulation successfully destabilizes the chronic Long COVID attractor and steers state trajectories into the recovery basin. These findings provide a mathematical foundation for digital biomarker-guided, wearable-driven personalized therapies in post-viral syndromes.
Yuji Marutani (2026) studied this question.
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