# Immunological Density Shapes Recovery Trajectories in Long COVID

arXiv: https://arxiv.org/abs/2601.07854 · HTML: https://mlsanity.com/paper/2601.07854/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- Builds on 8 of its 16 references that are in the map.
- First posted on arXiv 9 Jan 2026.

## Builds on (most cited first, 8 of 8)

- [Qwen3 Technical Report](https://mlsanity.com/paper/2505.09388/) (2025)
- [Attribute-Efficient Learning of Halfspaces with Malicious Noise: Near-Optimal Label Complexity and Noise Tolerance](https://mlsanity.com/paper/2006.03781/) (2020)
- [Sample-Optimal PAC Learning of Halfspaces with Malicious Noise](https://mlsanity.com/paper/2102.06247/) (2021)
- [A Large-Language Model Framework for Relative Timeline Extraction from PubMed Case Reports](https://mlsanity.com/paper/2504.12350/) (2025)
- [Metric-Fair Prompting: Treating Similar Samples Similarly](https://mlsanity.com/paper/2512.07608/) (2025)
- [MIMIC-RNum4-Ext-22MCTS: A 22 Millions-Event Temporal Clinical Time-Series Dataset with Relative Timestamp for Risk Prediction](https://mlsanity.com/paper/2505.00827/) (2025)
- [Active Learning for Forecasting Severity among Patients with Post Acute Sequelae of SARS-CoV-2](https://mlsanity.com/paper/2506.22444/) (2025)
- [Visual Processing by a Unified Schatten-p Norm and ℓq Norm Regularized Principal Component Pursuit](https://mlsanity.com/paper/1608.05856/) (2016)

## Built on by (most cited first, 1 of 1)

- [C-kNN-LSH: A Nearest-Neighbor Algorithm for Sequential Counterfactual Inference](https://mlsanity.com/paper/2602.02371/) (2026)

## Abstract (arXiv)

Post-acute sequelae of SARS-CoV-2 infection (Long COVID) frequently persists for months, yet drivers of clinical remission remain incompletely defined. Here we analyzed 97,564 longitudinal PASC assessments from 13,511 participants with linked vaccination histories to disentangle passive temporal progression from vaccine-associated change. Using a clinically validated threshold (PASC ≥ 12), trajectories separated into three phenotypes: Protected (persistently sub-threshold), Refractory (persistently symptomatic), and Responders (transitioning from symptomatic to recovered). Across the full cohort, symptom severity increased modestly with elapsed time (r=0.0521, P=1.26×10-59), whereas cumulative vaccination showed an inverse association with severity (r=-0.0434, P=5.95×10-42). In summary, baseline Long COVID severity appears clinically deterministic. In the absence of intervention, symptoms typically persist without spontaneous resolution. Recovery is primarily associated with repeated immunization.