Immune changes
Also: Immune risk
Hostile/Closed EnvironmentRadiationIsolation & ConfinementImmune & HematologicIn-flightPostflight RecoveryLifetime SurveillanceLEO long-durationLunar surfaceMars transit & surfacePublicClinicianResearcher
- Immune dysregulation and latent virus reactivation are common and persist through 6-month flights. ◆◆◆◇ Moderate · F
- Clinical consequences so far have been mostly minor, such as rashes and infections. Effects on missions longer than a year are unknown. ◆◆◇◇ Low · F E
Proposed certainty (◆ High → ◇ Very low) and evidence-type tags: F flight · A analog · M model/animal · C computational · E expert/operational/standards. AI-proposed, pending reviewer confirmation. How to read the grades.
NASA risk title (verbatim)
Risk of In Mission Impacts, Adverse Health Events or Long-Term Health Impacts due to Altered Immune Response
NASA short title: Immune · HRP element: Human Health Countermeasures (HHC) · Status: Active [current research ongoing] [1]
What it is
This risk covers health problems in flight and later that come from an altered immune response. Examples are new infections, reactivated dormant infections, rashes and inflammation, and possibly long-term effects such as cancer [1].
Current evidence
- Subclinical immune changes are documented in flight and after flight: shifts in cytokines and cell types, changes in virus-fighting immunity, and reactivation of latent viruses. They persist for the length of a 6-month mission [1].
- In 23 ISS astronauts, reduced T-cell function lasted throughout 6-month flights [4].
- In another group of 23 ISS astronauts, 8 shed Epstein-Barr virus, varicella-zoster virus or cytomegalovirus [5].
- On the 3-day Inspiration4 flight, 18 cytokines changed. The immune “spaceflight signature” was confirmed in the NASA Twins Study and in 817 mouse datasets [6].
- Clinical problems likely linked to immune changes include more frequent skin rashes, infections and continued herpesvirus shedding [1].
NASA’s risk posture
NASA scores each risk for each design reference mission (DRM) as likelihood × consequence (LxC). Both run from 1 (lowest) to 5 (highest) on the HSRB’s 5×5 matrix [1][3]. Each score comes with a disposition, such as “Accepted”, “Requires Characterization” or “Requires Mitigation”. These ratings were last approved by NASA’s Human System Risk Board (HSRB) in 11/2023 [1].
| Mission | Duration | In-mission (operations) | Long-term health |
|---|---|---|---|
| LEO | Short (under 30 d) | 4x2 · Accepted with Monitoring | 4x1 · Accepted with Monitoring |
| LEO | Long (30 d–1 yr) | 4x2 · Accepted with Monitoring | 4x1 · Accepted with Monitoring |
| Lunar orbit | Short | 4x2 · Accepted with Monitoring | 4x1 · Accepted with Monitoring |
| Lunar orbit | Long | 4x2 · Accepted with Monitoring | 4x2 · Requires Characterization |
| Lunar orbit + surface | Short | 4x2 · Accepted with Monitoring | 4x1 · Accepted with Monitoring |
| Lunar orbit + surface | Long | 4x3 · Requires Mitigation | 4x2 · Requires Mitigation |
| Mars preparatory | Under 1 yr | 4x3 · Requires Mitigation | 4x2 · Requires Characterization |
| Mars planetary | 730–1,224 d | 4x3 · Requires Mitigation | 4x2 · Requires Characterization |
Copied from the Human Research Roadmap on 2026-10-14. Ratings change. Check the live record before citing.
Open knowledge gaps
NASA lists 7 knowledge gaps for this risk, 7 of them open as of 2026-10-14 [1]. Each gap ID links to its page on the Human Research Roadmap (HRR).
Show NASA’s gap list (verbatim)
| Gap | NASA gap statement | Status |
|---|---|---|
| IM-106 | Characterize the effect of the stressors associated with spaceflight (stress, microgravity, radiation, altered nutrition, circadian misalignment, hypoxia, etc.) on human immunity, determine clinical relevance and biomarkers to enable monitoring of astronauts. | Open |
| IM-201 | Based on immune dysfunction biomarkers identified in gap IM-106, identify, develop, and implement in-flight immune function monitoring tools for support of research during Gateway, Lunar, and Mars missions. | Open |
| IM-301 | Identify appropriate ground-based analogs to spaceflight-induced immune dysfunction to enable ground validation of preventive/mitigative countermeasures, and derive mechanistic insights. | Open |
| IM-401 | Test, optimize and validate nutrition-based preventive/mitigative countermeasures | Open |
| IM-402 | Test, optimize and validate pharmacological preventive/mitigative countermeasures. | Open |
| IM-403 | Test, optimize and validate stress reduction techniques as preventive and mitigative immune dysfunction countermeasures. | Open |
| IM-501 | Test the finalized, integrated, multi-component immune countermeasure in flight. | Open |
See also Open questions.
Active countermeasure research
- Candidate countermeasures. These include operational procedures, functional foods and supplements, probiotics, medicines, exercise, vaccination, behavioral measures and personalized medicine [1]. They are reviewed in [7].
- Open gaps. These cover in-flight immune monitoring tools (IM-201), nutrition, drug and stress-reduction countermeasures (IM-401 to IM-403), and a flight test of an integrated countermeasure (IM-501) [1].
Project-level detail, including status, investigators and results, is in the NASA Task Book and on each HRR gap page.
Clinical articles
For practical, clinic-facing guidance, see:
Evidence profile
- Overall certainty
- ◆◆◆◇ Moderate (proposed)
- Evidence types
- F · Flight dataM · Model / animalE · Expert / operational / standards
- Literature through
- 2026-10-14
- NASA source
- Human Research Roadmap risk page (last published 05/13/25; read 2026-10-14)
Requirements referenced 1
| Requirement | Title | Plain-language meaning |
|---|---|---|
| [V1 3003] | In-Mission Preventive Health Care | Monitoring and prevention during flight (fitness, sleep, SANS, venous patency, immune function, dysbarism prevention). |
IDs as published in NASA-STD-3001 Vol. 1 Rev C (2023-09-15) and NASA-STD-3001 Vol. 2 Rev F (2026-07-14). NASA-STD-3001 binds NASA programs; it is not a regulation for commercial flights. Paraphrased. Standards quick reference.
References 7
- NASA Human Research Roadmap. Risk record: “Risk of In Mission Impacts, Adverse Health Events or Long-Term Health Impacts due to Altered Immune Response”. Accessed 2026-10-14. humanresearchroadmap.nasa.gov/Risks/?i=85 NASA E
- NASA Human Research Program. Evidence report for the Immune risk (approved June 1, 2022). humanresearchroadmap.nasa.gov/evidence/reports/IMMUNE%20EB%2… NASA E
- Antonsen EL, et al. Updates to the NASA human system risk management process for space exploration. NPJ Microgravity. 2023;9:72. doi:10.1038/s41526-023-00305-z PMID:37679359 Peer-reviewed E
- Crucian B, et al. Alterations in adaptive immunity persist during long-duration spaceflight. NPJ Microgravity. 2015;1:15013. doi:10.1038/npjmgrav.2015.13 PMID:28725716 Peer-reviewed F
- Mehta SK, et al. Latent virus reactivation in astronauts on the International Space Station. NPJ Microgravity. 2017;3:11. doi:10.1038/s41526-017-0015-y PMID:28649633 Peer-reviewed F
- Kim J, et al. Single-cell multi-ome and immune profiles of the Inspiration4 crew reveal conserved, cell-type, and sex-specific responses to spaceflight. Nat Commun. 2024;15:4954. doi:10.1038/s41467-024-49211-2 PMID:38862516 Peer-reviewed F
- Crucian BE, et al. Immune system dysregulation during spaceflight: potential countermeasures for deep space exploration missions. Front Immunol. 2018;9:1437. doi:10.3389/fimmu.2018.01437 PMID:30018614 Peer-reviewed E
Machine-checked on 2026-10-14: each URL resolved, each DOI's title/journal/year matched via Crossref, and claims were checked against the source text (abstract or full NASA page). Human verification against full text is still required before review. NASA documents are U.S. Government works (public domain) and are summarized with attribution; journal articles are summarized, not reproduced.
Article info
- Authors
- Pending (AI-assisted draft)
- Reviewer
- Pending review
- Last reviewed
- Pending review
- Literature through
- 2026-10-14
- AI-assisted
- Yes (disclosed)
- COI
- Pending
- License
- CC BY-SA 4.0
- Use
- Educational only · Disclaimer
- Cite this version
- Pending first edition