Leukocyte Count in Solid Organ Transplant Recipients After SARS-CoV-2 mRNA Vaccination and Infection

Marita Kern; Sebastian Rask Hamm; Christian Ross Pedersen; Dina Leth Møller; Josefine Amalie Loft; Rasmus Bo Hasselbalch; Line Dam Heftdal; Mia Marie Pries-Heje; Michael Perch; Søren Schwartz Sørensen; Allan Rasmussen; Peter Garred; Kasper Karmark Iversen; Henning Bundgaard; Caroline A. Sabin; Susanne Dam Nielsen

doi:10.3390/vaccines13020103

Leukocyte Count in Solid Organ Transplant Recipients After SARS-CoV-2 mRNA Vaccination and Infection

Marita Kern, Sebastian Rask Hamm, Christian Ross Pedersen, Dina Leth Møller, Josefine Amalie Loft, Rasmus Bo Hasselbalch, Line Dam Heftdal, Mia Marie Pries-Heje, Michael Perch, Søren Schwartz Sørensen, Allan Rasmussen, Peter Garred, Kasper Karmark Iversen, Henning Bundgaard, Caroline A. Sabin, Susanne Dam Nielsen^*

^*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

5 Downloads (Pure)

Abstract

Background: Solid organ transplant (SOT) recipients are at risk of severe COVID-19. Vaccination is an important preventive measure but may have side effects, including decreased leukocyte counts. We aimed to describe the prevalence and relative incidence of decreased leukocyte counts and changes in leukocyte counts before and after SARS-CoV-2 mRNA vaccination and SARS-CoV-2 infection in SOT recipients. Methods: Changes in leukocyte counts from before to after each vaccine dose were investigated using linear mixed models. We determined the prevalence of decreased leukocyte counts before and after each vaccine dose and before and after SARS-CoV-2 infection. Self-controlled case series analysis was used to investigate whether the period after either vaccination or infection was associated with risk of decreased leukocyte count. Results: We included 228 adult kidney, lung, and liver transplant recipients. Prior to the first vaccine dose, the mean leukocyte count was 7.3 × 109 cells/L (95% CI 6.9–7.6). Both the leukocyte counts, and the prevalence of decreased leukocyte counts remained unchanged from before to after vaccination regardless of the number of vaccine doses provided. There was no association between vaccination and decreased leukocyte counts (incidence rate ratio (IRR): 0.6; 95% CI: 0.2–2.1; p = 0.461). In contrast, SARS-CoV-2 infection was associated with increased risk of a decreased leukocyte count (IRR: 7.1; 95% CI: 2.8–18.1; p < 0.001). Conclusions: SARS-CoV-2 mRNA vaccination was not associated with risk of decreased leukocyte count and did not affect the prevalence of decreased leukocyte counts in SOT recipients. In contrast, SARS-CoV-2 infection was associated with a higher risk of a decreased leukocyte count.

Originalsprog	Engelsk
Artikelnummer	103
Tidsskrift	Vaccines
Vol/bind	13
Udgave nummer	2
Antal sider	12
ISSN	2076-393X
DOI	https://doi.org/10.3390/vaccines13020103
Status	Udgivet - 2025

Bibliografisk note

Funding Information:
This work was supported by the Research Foundation of Rigshospitalet and grants from the Carlsberg Foundation (grant no. CF20-0045), the Novo Nordisk Foundation (grant no. NFF205A0063505 and grant no. NNF20SA0064201), and the Svend Andersen Research Foundation (grant no. SARF2021). The funding sources had no role in the study design, data analysis, data interpretation, writing of the manuscript, or in the decision to submit the paper for publication.

Publisher Copyright:
© 2025 by the authors.

Adgang til dokumentet

10.3390/vaccines13020103Licens: CC BY

FulltextForlagets udgivne version, 563 KBLicens: CC BY

Citationsformater

Kern, M., Hamm, S. R., Pedersen, C. R., Møller, D. L., Loft, J. A., Hasselbalch, R. B., Heftdal, L. D., Pries-Heje, M. M., Perch, M., Sørensen, S. S., Rasmussen, A., Garred, P., Iversen, K. K., Bundgaard, H., Sabin, C. A., & Nielsen, S. D. (2025). Leukocyte Count in Solid Organ Transplant Recipients After SARS-CoV-2 mRNA Vaccination and Infection. Vaccines, 13(2), Artikel 103. https://doi.org/10.3390/vaccines13020103

Kern, M, Hamm, SR, Pedersen, CR, Møller, DL, Loft, JA, Hasselbalch, RB, Heftdal, LD, Pries-Heje, MM, Perch, M , Sørensen, SS, Rasmussen, A, Garred, P , Iversen, KK , Bundgaard, H, Sabin, CA & Nielsen, SD 2025, 'Leukocyte Count in Solid Organ Transplant Recipients After SARS-CoV-2 mRNA Vaccination and Infection', Vaccines, bind 13, nr. 2, 103. https://doi.org/10.3390/vaccines13020103

@article{61c9f49896af403bb1f46b4b83531c2d,

title = "Leukocyte Count in Solid Organ Transplant Recipients After SARS-CoV-2 mRNA Vaccination and Infection",

abstract = "Background: Solid organ transplant (SOT) recipients are at risk of severe COVID-19. Vaccination is an important preventive measure but may have side effects, including decreased leukocyte counts. We aimed to describe the prevalence and relative incidence of decreased leukocyte counts and changes in leukocyte counts before and after SARS-CoV-2 mRNA vaccination and SARS-CoV-2 infection in SOT recipients. Methods: Changes in leukocyte counts from before to after each vaccine dose were investigated using linear mixed models. We determined the prevalence of decreased leukocyte counts before and after each vaccine dose and before and after SARS-CoV-2 infection. Self-controlled case series analysis was used to investigate whether the period after either vaccination or infection was associated with risk of decreased leukocyte count. Results: We included 228 adult kidney, lung, and liver transplant recipients. Prior to the first vaccine dose, the mean leukocyte count was 7.3 × 109 cells/L (95% CI 6.9–7.6). Both the leukocyte counts, and the prevalence of decreased leukocyte counts remained unchanged from before to after vaccination regardless of the number of vaccine doses provided. There was no association between vaccination and decreased leukocyte counts (incidence rate ratio (IRR): 0.6; 95% CI: 0.2–2.1; p = 0.461). In contrast, SARS-CoV-2 infection was associated with increased risk of a decreased leukocyte count (IRR: 7.1; 95% CI: 2.8–18.1; p < 0.001). Conclusions: SARS-CoV-2 mRNA vaccination was not associated with risk of decreased leukocyte count and did not affect the prevalence of decreased leukocyte counts in SOT recipients. In contrast, SARS-CoV-2 infection was associated with a higher risk of a decreased leukocyte count.",

keywords = "leukocyte count, leukopenia, SARS-CoV-2 infection, SARS-CoV-2 mRNA vaccination, solid organ transplant recipient",

author = "Marita Kern and Hamm, {Sebastian Rask} and Pedersen, {Christian Ross} and M{\o}ller, {Dina Leth} and Loft, {Josefine Amalie} and Hasselbalch, {Rasmus Bo} and Heftdal, {Line Dam} and Pries-Heje, {Mia Marie} and Michael Perch and S{\o}rensen, {S{\o}ren Schwartz} and Allan Rasmussen and Peter Garred and Iversen, {Kasper Karmark} and Henning Bundgaard and Sabin, {Caroline A.} and Nielsen, {Susanne Dam}",

note = "Publisher Copyright: {\textcopyright} 2025 by the authors.",

year = "2025",

doi = "10.3390/vaccines13020103",

language = "English",

volume = "13",

journal = "Vaccines",

issn = "2076-393X",

publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",

number = "2",

}

TY - JOUR

T1 - Leukocyte Count in Solid Organ Transplant Recipients After SARS-CoV-2 mRNA Vaccination and Infection

AU - Kern, Marita

AU - Hamm, Sebastian Rask

AU - Pedersen, Christian Ross

AU - Møller, Dina Leth

AU - Loft, Josefine Amalie

AU - Hasselbalch, Rasmus Bo

AU - Heftdal, Line Dam

AU - Pries-Heje, Mia Marie

AU - Perch, Michael

AU - Sørensen, Søren Schwartz

AU - Rasmussen, Allan

AU - Garred, Peter

AU - Iversen, Kasper Karmark

AU - Bundgaard, Henning

AU - Sabin, Caroline A.

AU - Nielsen, Susanne Dam

PY - 2025

Y1 - 2025

N2 - Background: Solid organ transplant (SOT) recipients are at risk of severe COVID-19. Vaccination is an important preventive measure but may have side effects, including decreased leukocyte counts. We aimed to describe the prevalence and relative incidence of decreased leukocyte counts and changes in leukocyte counts before and after SARS-CoV-2 mRNA vaccination and SARS-CoV-2 infection in SOT recipients. Methods: Changes in leukocyte counts from before to after each vaccine dose were investigated using linear mixed models. We determined the prevalence of decreased leukocyte counts before and after each vaccine dose and before and after SARS-CoV-2 infection. Self-controlled case series analysis was used to investigate whether the period after either vaccination or infection was associated with risk of decreased leukocyte count. Results: We included 228 adult kidney, lung, and liver transplant recipients. Prior to the first vaccine dose, the mean leukocyte count was 7.3 × 109 cells/L (95% CI 6.9–7.6). Both the leukocyte counts, and the prevalence of decreased leukocyte counts remained unchanged from before to after vaccination regardless of the number of vaccine doses provided. There was no association between vaccination and decreased leukocyte counts (incidence rate ratio (IRR): 0.6; 95% CI: 0.2–2.1; p = 0.461). In contrast, SARS-CoV-2 infection was associated with increased risk of a decreased leukocyte count (IRR: 7.1; 95% CI: 2.8–18.1; p < 0.001). Conclusions: SARS-CoV-2 mRNA vaccination was not associated with risk of decreased leukocyte count and did not affect the prevalence of decreased leukocyte counts in SOT recipients. In contrast, SARS-CoV-2 infection was associated with a higher risk of a decreased leukocyte count.

AB - Background: Solid organ transplant (SOT) recipients are at risk of severe COVID-19. Vaccination is an important preventive measure but may have side effects, including decreased leukocyte counts. We aimed to describe the prevalence and relative incidence of decreased leukocyte counts and changes in leukocyte counts before and after SARS-CoV-2 mRNA vaccination and SARS-CoV-2 infection in SOT recipients. Methods: Changes in leukocyte counts from before to after each vaccine dose were investigated using linear mixed models. We determined the prevalence of decreased leukocyte counts before and after each vaccine dose and before and after SARS-CoV-2 infection. Self-controlled case series analysis was used to investigate whether the period after either vaccination or infection was associated with risk of decreased leukocyte count. Results: We included 228 adult kidney, lung, and liver transplant recipients. Prior to the first vaccine dose, the mean leukocyte count was 7.3 × 109 cells/L (95% CI 6.9–7.6). Both the leukocyte counts, and the prevalence of decreased leukocyte counts remained unchanged from before to after vaccination regardless of the number of vaccine doses provided. There was no association between vaccination and decreased leukocyte counts (incidence rate ratio (IRR): 0.6; 95% CI: 0.2–2.1; p = 0.461). In contrast, SARS-CoV-2 infection was associated with increased risk of a decreased leukocyte count (IRR: 7.1; 95% CI: 2.8–18.1; p < 0.001). Conclusions: SARS-CoV-2 mRNA vaccination was not associated with risk of decreased leukocyte count and did not affect the prevalence of decreased leukocyte counts in SOT recipients. In contrast, SARS-CoV-2 infection was associated with a higher risk of a decreased leukocyte count.

KW - leukocyte count

KW - leukopenia

KW - SARS-CoV-2 infection

KW - SARS-CoV-2 mRNA vaccination

KW - solid organ transplant recipient

U2 - 10.3390/vaccines13020103

DO - 10.3390/vaccines13020103

M3 - Journal article

C2 - 40006650

AN - SCOPUS:85218874833

SN - 2076-393X

VL - 13

JO - Vaccines

JF - Vaccines

IS - 2

M1 - 103

ER -