Longitudinal sequelae of COVID-19 hospitalisation 3-12 months post Omicron infection

Joseph McLaughlin; Darren McDaid; Seodhna Lynch; Andrew English; Jonathon McLaughlin; Martin Kelly; Manav Bhavsar; V. E. McGilligan; Priyank Shukla; Shu-Dong Zhang; Elaine K Murray; Taranjit Singh Rai; CP Walsh; Anthony J Bjourson; David Gibson

doi:10.1038/s41598-026-67518-6

Longitudinal sequelae of COVID-19 hospitalisation 3-12 months post Omicron infection

Joseph McLaughlin
, Darren McDaid
, Seodhna Lynch
, Andrew English
, Jonathon McLaughlin
, Martin Kelly
, Manav Bhavsar
, V. E. McGilligan
, Priyank Shukla
, Shu-Dong Zhang
, Elaine K Murray
, Taranjit Singh Rai
, CP Walsh
, Anthony J Bjourson
, David Gibson

Research output: Contribution to journal › Article › peer-review

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Abstract

Persistent symptoms are frequently reported many months after SARS-CoV-2 infection. However, evidence of the association between long COVID features and initial Omicron infection severity is lacking. A prospective observational cohort study of n=40 SARS-CoV-2 (Omicron B.1.1.529) infected individuals was performed, comprising n=20 non-hospitalised and n=20 hospitalised cases. ISARIC symptomology was recorded at baseline, 3-, 6- and 12-months post infection. Total and neutralising IgG antibody and inflammatory proteome concentrations were determined in plasma at baseline and 3 months. Pairwise comparisons were made between non-hospitalised and hospitalised subgroup biological and symptom data to investigate temporal changes. The non-hospitalised subgroup had higher median levels of Omicron variant specific ACE2 neutralising antibodies by 3 months, in particular females, though the difference was not statistically significant (BA.1+R346K p=0·06; BA.1+L452R p=0.08; BA.2 p=0·09). Inflammatory proteins type 1 keratin, prostasin and leukocyte associated immunoglobulin receptor 1 were significantly elevated in hospitalised subgroup plasma 3 months post infection (padj <0·05). Fatigue, muscle pain, headache, and cough symptoms subsided after 12 months in non-hospitalised, whilst significantly more hospitalised individuals reported continued muscle pain and shortness of breath (p<0·05). This study provides the first evidence of the link between Omicron hospitalisation and long-term humoral immune response, inflammatory plasma proteome, and symptom persistence. ClinicalTrials.gov NCT05548829.

Original language	English
Journal	Scientific Reports
Early online date	27 Aug 2026
DOIs	https://doi.org/10.1038/s41598-026-67518-6
Publication status	Published online - 27 Aug 2026

Data Availability Statement

Data and metadata will be stored according to the Ulster University policy on data management and sharing. Data will be available via Ulster University’s Research Data Repository and in accordance with their Research Data Management Policy. Any personal and identifiable information will be redacted, and data queries will be addressed on an individual basis by the research team.

Funding

Cohort A recruitment and follow up was supported by an Opportunity-Led Research Award to DSG (PI) and co-authors AJB, EM, TSR, SDZ, PS from Health and Social Care, Research and Development Division (HSC R&D), Public Health Agency (COM/5631/20) and National Core Study: Immunity (NCSi4P program) funding from United Kingdom Research and Innovation (UKRI) to DSG and PS. Cohort B recruitment was supported by a research grant to AJB (PI) and coauthors DSG, CW, SDZ, PS from the Department for the Economy Northern Ireland under its contribution to Science Foundation Ireland’s COVID-19 Rapid Response Call (Phase 2). The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Funders	Funder number
HSC Research and Development	COM/5631/20
UKRI	NCSi4P

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being
SDG 10 Reduced Inequalities

Keywords

COVID-19
Hospitalisation
Long COVID
Inflammation
Symptom persistence
Omicron

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Cite this

McLaughlin, J., McDaid, D., Lynch, S., English, A., McLaughlin, J., Kelly, M., Bhavsar, M., McGilligan, V. E., Shukla, P., Zhang, S.-D., Murray, E. K., Rai, T. S., Walsh, CP., Bjourson, A. J., & Gibson, D. (2026). Longitudinal sequelae of COVID-19 hospitalisation 3-12 months post Omicron infection. Scientific Reports. Advance online publication. https://doi.org/10.1038/s41598-026-67518-6

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abstract = "Persistent symptoms are frequently reported many months after SARS-CoV-2 infection. However, evidence of the association between long COVID features and initial Omicron infection severity is lacking. A prospective observational cohort study of n=40 SARS-CoV-2 (Omicron B.1.1.529) infected individuals was performed, comprising n=20 non-hospitalised and n=20 hospitalised cases. ISARIC symptomology was recorded at baseline, 3-, 6- and 12-months post infection. Total and neutralising IgG antibody and inflammatory proteome concentrations were determined in plasma at baseline and 3 months. Pairwise comparisons were made between non-hospitalised and hospitalised subgroup biological and symptom data to investigate temporal changes. The non-hospitalised subgroup had higher median levels of Omicron variant specific ACE2 neutralising antibodies by 3 months, in particular females, though the difference was not statistically significant (BA.1+R346K p=0·06; BA.1+L452R p=0.08; BA.2 p=0·09). Inflammatory proteins type 1 keratin, prostasin and leukocyte associated immunoglobulin receptor 1 were significantly elevated in hospitalised subgroup plasma 3 months post infection (padj <0·05). Fatigue, muscle pain, headache, and cough symptoms subsided after 12 months in non-hospitalised, whilst significantly more hospitalised individuals reported continued muscle pain and shortness of breath (p<0·05). This study provides the first evidence of the link between Omicron hospitalisation and long-term humoral immune response, inflammatory plasma proteome, and symptom persistence. ClinicalTrials.gov NCT05548829.",

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AU - Kelly, Martin

AU - Bhavsar, Manav

AU - McGilligan, V. E.

AU - Shukla, Priyank

AU - Zhang, Shu-Dong

AU - Murray, Elaine K

AU - Rai, Taranjit Singh

AU - Walsh, CP

AU - Bjourson, Anthony J

AU - Gibson, David

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N2 - Persistent symptoms are frequently reported many months after SARS-CoV-2 infection. However, evidence of the association between long COVID features and initial Omicron infection severity is lacking. A prospective observational cohort study of n=40 SARS-CoV-2 (Omicron B.1.1.529) infected individuals was performed, comprising n=20 non-hospitalised and n=20 hospitalised cases. ISARIC symptomology was recorded at baseline, 3-, 6- and 12-months post infection. Total and neutralising IgG antibody and inflammatory proteome concentrations were determined in plasma at baseline and 3 months. Pairwise comparisons were made between non-hospitalised and hospitalised subgroup biological and symptom data to investigate temporal changes. The non-hospitalised subgroup had higher median levels of Omicron variant specific ACE2 neutralising antibodies by 3 months, in particular females, though the difference was not statistically significant (BA.1+R346K p=0·06; BA.1+L452R p=0.08; BA.2 p=0·09). Inflammatory proteins type 1 keratin, prostasin and leukocyte associated immunoglobulin receptor 1 were significantly elevated in hospitalised subgroup plasma 3 months post infection (padj <0·05). Fatigue, muscle pain, headache, and cough symptoms subsided after 12 months in non-hospitalised, whilst significantly more hospitalised individuals reported continued muscle pain and shortness of breath (p<0·05). This study provides the first evidence of the link between Omicron hospitalisation and long-term humoral immune response, inflammatory plasma proteome, and symptom persistence. ClinicalTrials.gov NCT05548829.

AB - Persistent symptoms are frequently reported many months after SARS-CoV-2 infection. However, evidence of the association between long COVID features and initial Omicron infection severity is lacking. A prospective observational cohort study of n=40 SARS-CoV-2 (Omicron B.1.1.529) infected individuals was performed, comprising n=20 non-hospitalised and n=20 hospitalised cases. ISARIC symptomology was recorded at baseline, 3-, 6- and 12-months post infection. Total and neutralising IgG antibody and inflammatory proteome concentrations were determined in plasma at baseline and 3 months. Pairwise comparisons were made between non-hospitalised and hospitalised subgroup biological and symptom data to investigate temporal changes. The non-hospitalised subgroup had higher median levels of Omicron variant specific ACE2 neutralising antibodies by 3 months, in particular females, though the difference was not statistically significant (BA.1+R346K p=0·06; BA.1+L452R p=0.08; BA.2 p=0·09). Inflammatory proteins type 1 keratin, prostasin and leukocyte associated immunoglobulin receptor 1 were significantly elevated in hospitalised subgroup plasma 3 months post infection (padj <0·05). Fatigue, muscle pain, headache, and cough symptoms subsided after 12 months in non-hospitalised, whilst significantly more hospitalised individuals reported continued muscle pain and shortness of breath (p<0·05). This study provides the first evidence of the link between Omicron hospitalisation and long-term humoral immune response, inflammatory plasma proteome, and symptom persistence. ClinicalTrials.gov NCT05548829.

KW - COVID-19

KW - Hospitalisation

KW - Long COVID

KW - Inflammation

KW - Symptom persistence

KW - Omicron

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DO - 10.1038/s41598-026-67518-6

M3 - Article

SN - 2045-2322

JO - Scientific Reports

JF - Scientific Reports

ER -

Longitudinal sequelae of COVID-19 hospitalisation 3-12 months post Omicron infection

Abstract

Data Availability Statement

Funding

UN SDGs

Keywords

Access to Document

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