Long COVID vs Gulf War Illness: symptoms, biomarkers, trials and research
A data-driven comparison of Long COVID and Gulf War Illness built from the Open Source Medicine Foundation biomarker atlases, PubMed literature feeds, ClinicalTrials.gov registry extract and post-acute infection syndrome (PAIS) cohort database.
Gulf War Illness is the main chronic multisymptom illness without an infectious trigger, so it is the natural control case for asking which Long COVID biomarkers reflect persistent infection and which reflect a generic post-insult state.
What each condition is
Long COVID
Also known as: PASC, Post-Acute Sequelae of COVID-19, Post-COVID-19 condition
Long COVID describes symptoms that persist or emerge more than three months after SARS-CoV-2 infection and cannot be explained by another diagnosis. The World Health Organization calls it post-COVID-19 condition; the US National Institutes of Health uses the term PASC. Common features include fatigue, post-exertional symptom exacerbation, cognitive difficulties, orthostatic intolerance, breathlessness and chest pain. Because the triggering infection is known and recent, Long COVID has attracted large prospective cohorts (RECOVER, PHOSP-COVID) and the largest clinical-trial pipeline of any post-infectious illness.
Atlas scope: Molecular, metabolic, and immunological alterations reported in post-acute sequelae of COVID-19 (PASC / long COVID) compared to healthy controls and fully recovered individuals.
OSMF resources: biomarker atlas · literature feed
Gulf War Illness
Also known as: GWI, Gulf War Syndrome, Chronic Multisymptom Illness
Gulf War Illness is a chronic multisymptom condition affecting roughly a quarter to a third of the nearly 700,000 US and allied personnel deployed in the 1990-1991 Gulf War. It is defined by the Kansas or CDC criteria (fatigue, pain, cognitive and mood symptoms, gastrointestinal and respiratory complaints) rather than by a single exposure, though pyridostigmine bromide, pesticides and low-level nerve agents are the leading hypotheses. Unlike the other conditions compared here it has no infectious trigger, which makes its biomarker overlap with post-viral syndromes scientifically interesting.
Atlas scope: Inflammatory, autoimmune, metabolic, cholinergic, and exposure-related biomarker alterations in Gulf War Illness (GWI / chronic multisymptom illness) compared to healthy deployed and non-deployed Gulf War veterans.
OSMF resources: biomarker atlas · literature feed
Side-by-side summary
| Measure | Long COVID | Gulf War Illness |
|---|---|---|
| Biomarkers catalogued | 77 | 41 |
| Biomarker categories covered | metabolic (23), inflammatory (14), vascular (8), immune (7), coagulation (6), proteomic (5), lipidomic (4), neurological (4), microbiome (4), viral (2) | inflammatory (10), metabolic (8), exposure (7), autoimmune (5), neurological (4), functional (3), autonomic (2), ocular (2) |
| Markers with LOINC codes | 25 | 12 |
| Literature studies tracked | 75 | 75 |
| Most recent tracked study | 07 Jul 2026 | 25 Jun 2026 |
| Registered trials (all statuses) | 341 | 4 |
| Recruiting / not yet recruiting | 81 | 0 |
| Active, not recruiting | 26 | 0 |
| Completed | 150 | 4 |
| Terminated / withdrawn / suspended | 27 | 0 |
| Unknown status | 57 | 0 |
| Named cohorts in PAIS database | 8 | 0 |
| Therapeutic agents tracked | 405 | 10 |
Trial condition matching: Long COVID uses the registry’s mapped condition label; Gulf War Illness uses keyword matching on registry condition and title fields. Trials listing both conditions: 0.
Shared biomarkers (10)
Markers catalogued in both atlases, matched by normalised name or LOINC code. Rows marked direction differs are reported to change in opposite or inconsistent directions across the two literatures, which may reflect different comparison groups, assays or disease stages rather than true biology.
| Biomarker | Category | Direction in Long COVID | Direction in Gulf War Illness | Matched by | Sources |
|---|---|---|---|---|---|
| Interleukin-6 (IL-6) | inflammatory | Increased vs HC, R | Increased vs HGV | LOINC 26881-5 | Lai et al. 2023; Johnson et al. 2016 |
| Tumor Necrosis Factor-α (TNF-α) | inflammatory | Increased vs HC, R | Increased vs HGV | LOINC 3074-8 | Lai et al. 2023; Saito et al. 2024; Johnson et al. 2016 |
| Interleukin-1α (IL-1α) Interleukin-1β (IL-1β) in Gulf War Illness | inflammatory | Increased vs HC, R | Increased vs HGV | LOINC 26864-3 | Saito et al. 2024; Johnson et al. 2016 |
| C-Reactive Protein (CRP) | inflammatory | Increased vs HC, R | Increased vs HGV | LOINC 1988-5 | Lai et al. 2023; Johnson et al. 2016 |
| Soluble CD14 (sCD14) sCD14 in Gulf War Illness | inflammatory | Increased vs HC, R | Increased vs HGV | LOINC 30180-5 | Saito et al. 2024; Gean et al. 2021 |
| Interleukin-8 (IL-8) Interleukin-8 (IL-8 / CXCL8) in Gulf War Illness | inflammatory | Increased vs HC | Increased vs HGV | LOINC 26998-9 | Thomas et al. 2024; Johnson et al. 2016 |
| Lactate | metabolic | Increased vs HC | Increased vs HGV | LOINC 2524-7 | Baalbaki et al. 2025; Gean et al. 2021 |
| S100B direction differs | neurological | Increased vs HC | Mixed / conflicting vs HGV | name | Baalbaki et al. 2025; Gean et al. 2021 |
| Cortisol Cortisol (diurnal) in Gulf War Illness | proteomic / neurological | Mixed / conflicting vs HC | Mixed / conflicting vs HGV | LOINC 2143-6 | Baalbaki et al. 2025; Gean et al. 2021 |
| Vitamin D (25-OH) | metabolic | Mixed / conflicting vs HC | Mixed / conflicting vs HGV | LOINC 1989-3 | Kallaste et al. 2025; Gean et al. 2021 |
Distinct biomarkers
Top 15 markers catalogued for one condition but not matched in the other. Full lists are on the Long COVID atlas and the Gulf War Illness atlas.
Only in Long COVID atlas (67)
- Flt-1 / sVEGFR-1 Increased inflammatory
- CCL4 (MIP-1β) Increased inflammatory
- Cystatin D (CST5) Increased inflammatory
- Pro-inflammatory cytokines (composite) Decreased inflammatory
- Transforming Growth Factor-β (TGF-β) Increased inflammatory
- Interleukin-10 (IL-10) Mixed / conflicting inflammatory
- Ferritin Mixed / conflicting inflammatory
- Serum Amyloid A (SAA) Increased inflammatory
- ATP (plasma) Decreased metabolic
- Serine Decreased metabolic
- Sarcosine Decreased metabolic
- Aspartate Decreased metabolic
- Asparagine Decreased metabolic
- Glutamine Decreased metabolic
- Arginine Decreased metabolic
+52 more in the atlas.
Only in Gulf War Illness atlas (31)
- Neopterin Increased inflammatory
- sCD26 (soluble DPPIV) Mixed / conflicting inflammatory
- Homocysteine Increased metabolic
- Interferon-γ (IFN-γ) Increased inflammatory
- Glutathione (GSH) Decreased metabolic
- GSH:GSSG ratio Decreased metabolic
- 8-isoprostane Increased metabolic
- Coenzyme Q10 Decreased metabolic
- PON1 (paraoxonase 1) activity Decreased exposure
- PON1 Q192R polymorphism Mixed / conflicting exposure
- Butyrylcholinesterase (BChE) Mixed / conflicting exposure
- Acetylcholinesterase (AChE) Mixed / conflicting exposure
- Anti-acetylcholine receptor antibodies Increased autoimmune
- Anti-nuclear antibodies (ANA) Mixed / conflicting autoimmune
- Rheumatoid factor (RF) Mixed / conflicting autoimmune
+16 more in the atlas.
Overlapping therapeutics under investigation (2)
Agents that appear in registered trials or the OSMF therapeutic-agent database for both Long COVID and Gulf War Illness. Inclusion means an agent is being studied, not that it works.
- Coenzyme Q10 (CoQ10)
- Metformin
Research cohorts
Long COVID cohorts (8)
- NIH RECOVER-Adult Cohort prospective non inception, n=15,000, biobank active
- Long COVID Host Genetics Initiative GWAS registry linkage, n=6,450, biobank active
- Patient-Led Long COVID international cohort (Davis 2021) survey, n=3,762, biobank not_applicable
- PHOSP-COVID (UK post-hospitalisation COVID-19) prospective non inception, n=2,320, biobank active
- Jinyintan (Wuhan) COVID-19 discharge cohort (Huang) prospective non inception, n=1,733, biobank unknown
- Bergen COVID-19 home-isolated cohort (Blomberg) prospective inception, n=312, biobank active
- PACVS registry cohort (Semmler/Mundorf) cross sectional, n=191, biobank unknown
- Amsterdam Long COVID muscle-biopsy PEM cohort (Appelman) case control, n=46, biobank unknown
Gulf War Illness cohorts (0)
No named cohort for this condition in the PAIS database yet.
Recent research
Latest Long COVID studies
Latest Gulf War Illness studies
Frequently asked questions
Can you have both Long COVID and Gulf War Illness?
They are not mutually exclusive. Both are diagnosed clinically, and a person can meet criteria for Long COVID and Gulf War Illness at the same time. In the OSMF data the two conditions share 10 catalogued biomarkers, 0 registered trials list both conditions, and 0 cohorts in the PAIS database are relevant to both. Overlap in a dataset is not evidence that one condition causes the other.
How do the biomarker profiles differ?
Long COVID has 77 catalogued markers, led by metabolic (23), inflammatory (14), vascular (8). Gulf War Illness has 41, led by inflammatory (10), metabolic (8), exposure (7). 10 markers appear in both atlases, and 1 of those are reported to move in different directions (S100B). Categories unique to Long COVID: coagulation, immune, lipidomic, microbiome, proteomic, vascular, viral; unique to Gulf War Illness: autoimmune, autonomic, exposure, functional, ocular.
Which has more active clinical trials?
Long COVID has more: 107 active or recruiting trials versus 0 for Gulf War Illness (registry snapshot 07 Oct 2026). Totals including completed, terminated and unknown-status studies are 341 for Long COVID and 4 for Gulf War Illness. Condition matching for Gulf War Illness relies on keyword matching of registry condition fields and may miss trials. Trial counts measure research attention, not treatment efficacy.
Which condition has more recent research?
OSMF tracks 75 recent PubMed-indexed studies for Long COVID (latest 07 Jul 2026) and 75 for Gulf War Illness (latest 25 Jun 2026). The feeds hold a rolling window of recent publications, so they indicate current publication pace rather than lifetime output. See the Long COVID feed and the Gulf War Illness feed for the full lists.
Are the same treatments being studied for both?
2 agents appear in the trial registry or therapeutic-agent database for both conditions, including Coenzyme Q10 (CoQ10), Metformin. All of these are investigational for these indications; none is an approved treatment for either condition. Overlap usually reflects shared hypotheses (immune modulation, autonomic support, antiviral or anti-inflammatory strategies) rather than demonstrated efficacy.
Which has larger research cohorts?
The PAIS cohort database lists 8 named cohorts for Long COVID and 0 named cohorts for Gulf War Illness, the largest being NIH RECOVER-Adult Cohort (15,000 enrolled). Cohorts with stored biospecimens and open external access are the most useful for cross-condition biomarker validation.
Related comparisons
Cite this page
@misc{osmf_longcovid_vs_gulfwarillness,
author = {Open Source Medicine Foundation},
title = {Long COVID vs Gulf War Illness: symptoms, biomarkers, trials and research compared},
year = {2026},
howpublished = {\url{https://research.opensourcemed.info/compare/long-covid-vs-gulf-war-illness.html}},
note = {Data as of 2026-10-07}
}Get OSMF research updates
New biomarker, trial and cohort data, summarised for patients and researchers.
Last updated 07 Oct 2026 (page build). Underlying data: literature feeds 07 Jul 2026 / 09 Jul 2026; trial registry 07 Oct 2026; atlases 29 Jun 2026 / 29 Jun 2026. Generated by scripts/build_compare_pages.py.