The healthy donor effect and survey participation, becoming a donor and donor career

Detection of SARS-CoV-2 Reinfections Using Nucleocapsid Antibody Boosting

More than 85% of US adults had been infected with SARS-CoV-2 by the end of 2023. Continued serosurveillance of transmission and assessments of correlates of protection require robust detection of reinfections. We developed a serologic method for identifying reinfections in longitudinal blood donor data by assessing nucleocapsid (N) antibody boosting using a total immunoglobulin assay. Receiver operating characteristic curve analysis yielded an optimal ratio of >1.43 (sensitivity 87.1%, specificity 96.0%). When prioritizing specificity, a ratio of >2.33 was optimal (sensitivity 75.3%, specificity 99.3%). In donors with higher anti-N reactivity levels before reinfection, sensitivity was reduced. Sensitivity could be improved by expanding the dynamic range of the assay through dilutional testing, from 38.8% to 66.7% in the highest reactivity group (signal-to-cutoff ratio before reinfection >150). This study demonstrated that longitudinal testing for N antibodies can be used to identify reinfections and estimate total infection incidence in a blood donor cohort.

Low rate of hepatitis Delta virus co-infection in first-time blood donors diagnosed with chronic hepatitis B virus infection in the Netherlands

BACKGROUND

Hepatitis Delta virus (HDV) requires co-infection with hepatitis B virus (HBV) and increases the risk of hepatitis-related morbidity and mortality compared to HBV mono-infection. HBV/HDV co-infected patients will likely benefit from new HDV antiviral drugs, but reliable estimates of co-infection rates are lacking due to limited HDV testing of HBV-infected patients.

STUDY DESIGN AND METHODS

First-time blood and bone tissue donors in the Netherlands (2006-2023) with a newly diagnosed chronic HBV infection were retrospectively tested for HDV antibodies, and for HDV RNA if HDV antibodies were detected. HBV genotyping using phylogenetic analysis was performed to determine the most likely origin of HBV infection.

RESULTS

HBV-DNA was detected in 254/758.081 (0.034%) first-time donors in the Netherlands. HBsAg-positive first-time donors had a median age of 43 years (IQR: 33-52), were predominantly male (67%), mostly first- or second-generation migrants (76%) and HBV (sub)genotype strongly correlated with the country of birth. HDV testing was performed for 200 first-time donors with chronic (HBsAg-positive) HBV infection: 5 donors (2.5%) had HDV antibodies, and 1 donor (0.5%) also had detectable HDV RNA. None of the 17 donors with occult (HBsAg-negative) HBV infection had experienced HDV infection.

DISCUSSION

Chronic HBV/HDV co-infection in first-time donors in the Netherlands is extremely rare, affecting 0.00013% of all first-time donors, and only 0.5% of HBsAg-positive first-time donors consisting predominantly of migrants from high(er) HDV-endemic countries. Despite low HBV/HDV co-infection rates, a one-time HDV reflex testing strategy for HBsAg-positive patients remains essential to identify patients and to initiate antiviral treatment if needed to reduce the risk of serious liver disease.

Syphilis-positive and false-positive trends among US blood donors, 2013-2023

BACKGROUND

US blood donors are tested for syphilis because the bacterial agent is transfusion transmissible. Here we describe trends over an 11-year period of donations positive for recent and past syphilis infections, and donations classified as syphilis false positive (FP).

METHODS

Data from January 1, 2013, to December 31, 2023 (11 years) were compiled for all American Red Cross blood donations to evaluate demographics/characteristics and longitudinal trends in donors testing syphilis reactive/positive. The prevalence of recent, past, and total (combination of recent/past) infections were evaluated, along with syphilis FP donations. Classification was based on known serological methods using treponemal and non-treponemal tests.

RESULTS

Approximately 53 million donations were included with 10,365 total syphilis infections (3463 recent and 6902 past; 0.02% total) and 48,719 FP (0.09%). Donor demographics, characteristics, and HBV/HCV/HIV nucleic acid testing reactivity differed among syphilis-positive and FP compared with nonreactive donations. Donors with a FP donation had high rates of subsequent donations testing syphilis positive (0.3%) and FP (7.7%). Median time from first FP to subsequent FP was observed to be 3.6 months. Recent infections increased over the 11 years, with past infections peaking in 2014 followed by increases in 2021-2023 paralleling recent infections. Repeating cycles of seasonal FP spikes occurred in the fall of 2013 and from 2017 to 2022 corresponding with vaccine administrations.

CONCLUSIONS

Syphilis infections in blood donors are trending upward, paralleling US population trends. Syphilis FP donors had high rates of subsequent FP and unexplained syphilis-positive donations. Seasonal syphilis FP spikes occurred for most years but are trending downwards.

Interpreting the Influence of Using Blood Donor Residual Samples for SARS-CoV-2 Seroprevalence Studies in Japan: Cross-Sectional Survey Study

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Background: Residual blood donor samples are commonly used in SARS-CoV-2 seroepidemiological studies; however their use may introduce bias due to the healthy donor effect, wherein blood donors are generally healthier than the general population. This potential bias is critical for accurately interpreting seroepidemiological data, as blood donors might not fully represent broader population-level infection rates., Objective: This study aims to assess the potential bias in SARS-CoV-2 seroprevalence estimates derived from blood donor samples in Japan by examining the association between blood donation history and COVID-19 diagnosis. By quantifying the healthy donor effect, we seek to refine the interpretation of SARS-CoV-2 seroepidemiological studies using residual blood donor samples., Methods: We conducted a web-based survey from December 14 to 28, 2023, recruiting 10,781 Japanese residents aged 16-69, stratified by demographic factors to match national representation. Participants provided information on demographics, socioeconomic status, COVID-19 vaccination history, comorbidities, and blood donation experience. A logistic regression model adjusting for confounders such as age, sex, education, occupation, comorbidities, and vaccination status, was used to estimate the odds of COVID-19 diagnosis among blood donors compared to nondonors., Results: Of the 10,781 participants, 3583 (33.2%) reported a history of COVID-19 diagnosis, and 5015 (46.5%) indicated they had donated blood at least once in their lifetime, and 1128 (10.5%) donated within the last year. Blood donors had mean of 13.5 (SD 43.6) donations and were older, with a mean age of 46.4 (SD 13.9) years, compared to 38.5 (SD 14.1) years for nondonors. Among blood donors, 39.9% had comorbidities (95% CI 38.5-41.2) compared to 27.9% (95% CI 26.7-29.0) of nondonors. Blood donors had 1.62 (95% CI: 1.48-1.78) times higher odds of COVID-19 diagnosis compared to nondonors. The higher diagnosis rate among blood donors likely reflects increased social interactions and health-seeking behaviors, a phenomenon we refer to as the inverse healthy donor effect. This suggests that blood donor samples could overestimate SARS-CoV-2 seroprevalence when generalized to the broader Japanese population., Conclusions: Higher COVID-19 diagnosis rates among blood donors may reflect increased community involvement and health-seeking behaviors, suggesting an inverse healthy donor effect. This pattern indicates that in terms of SARS-CoV-2 infection, blood donors might not represent the healthiest segment of the population. Consequently, seroprevalence studies using blood donor samples could overestimate SARS-CoV-2 infection rates in the general Japanese population. For more accurate public health surveillance, the development of statistical methods to adjust for this bias is recommended.

Iron deficiency and infection risk in Danish blood donors

BACKGROUND

We aimed to investigate if iron deficiency was associated with infection susceptibility in a large cohort of healthy individuals.

STUDY DESIGN AND METHODS

The Danish Blood Donor Study is a national ongoing prospective study of blood donors. We included 94,628 donors with 338,290 ferritin measurements from March 2010 to October 2022. We performed sex-stratified multivariable Cox regression to estimate the risk of infection for iron-deficient donors compared with iron-replete donors. Infection was defined as either a filled prescription of antibiotics registered in the Danish National Prescription Registry (NPR), or a hospital contact with infection registered in the Danish National Patient Registry (DNPR).

RESULTS

Iron deficiency was associated with an overall increased risk of infection (defined as prescriptions of antibiotics) for women (hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.02-1.15). Subgroup analyses showed an increased risk of respiratory tract infections (HR 1.16, 95% CI 1.05-1.28) and urinary tract infections (HR 1.16, 95% CI 1.04-1.29). Iron deficiency was not associated with overall risk of infection for men (HR 1.02, 95% CI 0.82-1.28). For both men and women, no association was found between iron deficiency and hospital contacts for infections.

CONCLUSION

Iron deficiency was associated with an increased risk of infection in female blood donors. However, effect sizes were small, and there was no association between iron deficiency and hospital contacts for infection. Consequently, risk of infection should not be considered an apprehension regarding blood donation. These findings support the role of iron in immune function and monitorization of iron stores in female blood donors.

Cognition Assessment in Virtual Reality (CAVIR): Associations with neuropsychological performance and activities of daily living in patients with mood or psychosis spectrum disorders

BACKGROUND

More ecologically valid tools are needed to better capture daily-life cognitive impairments in patients with mood or psychosis spectrum disorders in clinical settings and cognitive treatment trials. We developed the Cognition Assessment in Virtual Reality (CAVIR) test, which assesses daily-life cognitive skills in an immersive virtual reality kitchen scenario. This study investigated the validity and sensitivity of CAVIR, including its association with activities of daily living (ADL) ability.

METHODS

Seventy symptomatically stable patients with mood or psychosis spectrum disorders and 70 healthy controls completed CAVIR and standard neuropsychological tests and were rated for clinical symptoms, functional capacity, and subjective cognition. In addition, patients' ADL ability was evaluated with the Assessment of Motor and Process Skills.

RESULTS

Higher global CAVIR performance correlated moderately with better global neuropsychological test scores (rs(138) = 0.60, p < 0.001) and showed a weak to moderate association with better ADL process ability in patients (r(45) = 0.40, p < 0.01), also after adjusting for sex and age (ps ≤ 0.03). In comparison, neuropsychological performance, interviewer- and performance-based functional capacity, and subjective cognition were not significantly associated with ADL process ability (ps ≥ 0.09). Further, CAVIR was sensitive to cognitive impairments in patients and was able to differentiate between patients with and without the ability to undertake regular employment.

LIMITATIONS

The modest sample size and concomitant medication.

CONCLUSION

Our results indicate that CAVIR is a sensitive measure of daily-life cognitive skills in patients with mood or psychosis spectrum disorders.

Transfusion-transmissible coinfections among US blood donors

BACKGROUND

Transfusion-transmissible infection (TTI) prevalence among US blood donors has been widely documented. Here we estimate the prevalence of donors presenting with ≥2 TTIs (multiple infections past or present referred to as coinfections) and describe their demographics and associations.

METHODS

Data from the Transfusion-Transmissible Infections Monitoring System were compiled for October 2020-September 2023 (3 years). Prevalence per million donations (pmd) was calculated for each TTI coinfection combination with demographic characteristics summarized. The odds of each TTI coinfection combination were estimated using logistic regression. Reactivity by NAT and/or serology (HIV, HBV, and HCV) defined donors as consensus positive (CP) for each infection while serology-based algorithms defined syphilis CP and the subset with active syphilis infections (ASIs).

RESULTS

About 22 million donations were included, with 212 coinfections (9.7 pmd). Around 2% of donations positive for any TTI (n = 10,516) were coinfections. Coinfection prevalence per TTI combination ranged from 0.3 pmd for HIV CP and HCV CP, to 4.3 pmd for HIV CP and syphilis CP. There were high proportions of coinfections from donors who were male, aged 25-54 years, white or black, first time, and residing in the southern US Census Region. The odds of a second TTI occurring in an individual donor with a TTI ranged from 23 (95% CI: 13, 41) times more likely for HBV CP and ASI to 395 (95% CI: 298, 524) times more likely for HIV CP and ASI.

CONCLUSIONS

Coinfections are relatively uncommon among blood donors in the United States; however, associations exist among HIV, HBV, HCV, and syphilis infections.

Effect of SARS-CoV-2 Infection on Selected Parameters of the Apelinergic System in Repeat Blood Donors

Background: SARS-CoV-2 enters cells primarily by binding to the angiotensin-converting enzyme 2 (ACE2) receptor, thereby blocking its physiological functions, affecting the apelinergic system, and inhibiting the cleavage of its peptides. The appropriate concentration of peptides in the apelinergic system influences the maintenance of homeostasis and protects against cardiovascular diseases. In our research, we determined the level of selected parameters of the apelinergic system-apelin (AP), elabela (ELA), and the apelin receptor (APJ)-in repeat blood donors. Methods: We analyzed 120 serum samples obtained from 30 repeat donors (study group) within four time periods after a SARS-CoV-2 infection: <60 days, 61-90 days, 91-120 days, and >120 days. We compared the results from the study groups with those of the control group, which consisted of 30 serum samples collected from donors donating blood in the years 2018-2019. Results: We observed that the AP, ELA, and APJ concentrations in the control group are higher than in any period in the study group. In the study group, the concentrations of AP and ELA increased in subsequent study periods. AP and ELA concentrations were lower shortly after SARS-CoV-2 transfection and then slowly increased in subsequent periods. APJ concentrations, on the other hand, were lowest at 61-90 days after the infection, but the decrease, relative to their level in healthy subjects, was significant in every period studied. Conclusions: The results suggest that infection with SARS-CoV-2 causes changes in the parameters of the apelinergic system, both after a short period of time has passed since the onset of the SARS-CoV-2 infection, and even up to 4 months after the infection.

Longitudinal metabolite and protein trajectories prior to diabetes mellitus diagnosis in Danish blood donors: a nested case-control study

AIMS/HYPOTHESIS

Metabolic risk factors and plasma biomarkers for diabetes have previously been shown to change prior to a clinical diabetes diagnosis. However, these markers only cover a small subset of molecular biomarkers linked to the disease. In this study, we aimed to profile a more comprehensive set of molecular biomarkers and explore their temporal association with incident diabetes.

METHODS

We performed a targeted analysis of 54 proteins and 171 metabolites and lipoprotein particles measured in three sequential samples spanning up to 11 years of follow-up in 324 individuals with incident diabetes and 359 individuals without diabetes in the Danish Blood Donor Study (DBDS) matched for sex and birth year distribution. We used linear mixed-effects models to identify temporal changes before a diabetes diagnosis, either for any incident diabetes diagnosis or for type 1 and type 2 diabetes mellitus diagnoses specifically. We further performed linear and non-linear feature selection, adding 28 polygenic risk scores to the biomarker pool. We tested the time-to-event prediction gain of the biomarkers with the highest variable importance, compared with selected clinical covariates and plasma glucose.

RESULTS

We identified two proteins and 16 metabolites and lipoprotein particles whose levels changed temporally before diabetes diagnosis and for which the estimated marginal means were significant after FDR adjustment. Sixteen of these have not previously been described. Additionally, 75 biomarkers were consistently higher or lower in the years before a diabetes diagnosis. We identified a single temporal biomarker for type 1 diabetes, IL-17A/F, a cytokine that is associated with multiple other autoimmune diseases. Inclusion of 12 biomarkers improved the 10-year prediction of a diabetes diagnosis (i.e. the area under the receiver operating curve increased from 0.79 to 0.84), compared with clinical information and plasma glucose alone.

CONCLUSIONS/INTERPRETATION

Systemic molecular changes manifest in plasma several years before a diabetes diagnosis. A particular subset of biomarkers shows distinct, time-dependent patterns, offering potential as predictive markers for diabetes onset. Notably, these biomarkers show shared and distinct patterns between type 1 diabetes and type 2 diabetes. After independent replication, our findings may be used to develop new clinical prediction models.

Iron deficiency-related symptoms in non-anemic whole blood donors

INTRODUCTION

Whole blood donors are at increased risk for iron deficiency (ID). ID anemia is associated with several symptoms, such as fatigue, cognitive dysfunction, pica, and restless leg syndrome (RLS). However, it is unclear if these symptoms also occur when a donor has developed ID without anemia. This study aims to determine whether non-anemic ID (NAID) is associated with the occurrence of ID-related symptoms.

STUDY DESIGNS AND METHODS

We combined data from three studies in whole blood donors (i.e., Donor Insight-III, FIND'EM, and FORTE) to create a substantial sample size (N = 12,143). The self-reported occurrence and severity of ID-related symptoms, such as physical and mental health, fatigue, cognitive functioning, pica, and RLS, was measured using validated questionnaires. Associations were studied using logistic regression modeling with ID-related symptoms derived from the questionnaires as the dependent variable and ferritin level group (0-15 μg/L, 15-30 μg/L, and >30 μg/L) as explanatory variable.

RESULTS

After applying inclusion and exclusion criteria, 9829 donors were eligible for analysis. In the models corrected for age, body mass index, Hb level, and cohort, only fatigue was shown to be associated with ferritin levels in men, showing lower odds (OR 1.41, 95% CI 1.11-1.79) for fatigue with higher ferritin levels.

CONCLUSION

In these studies, NAID was only associated with self-reported fatigue in male donors. Although selection bias may have led to underestimated associations, ferritin measurements in donors should be primarily considered as a measure to prevent anemia, rather than to prevent or mitigate NAID-related symptoms.

A serosurvey examining exposure to Borrelia burgdorferi sensu lato and tick-borne encephalitis virus in Danish blood donors, August 2022

Objectives

Borrelia burgdorferi sensu lato (Bbsl) and tick-borne encephalitis virus (TBEV) are tick-borne pathogens. This study aimed to investigate the seroprevalence of these pathogens in Danish blood donors.

Methods

A total of 1000 plasma samples equally distributed (n = 200) from all five Danish regions were analyzed. Commercially available enzyme-linked immunosorbent assays were used to screen the samples for immunoglobulin G antibodies against Bbsl and TBEV. The samples positive for antibodies against TBEV were further examined with a commercially available enzyme-linked immunosorbent assay and a Luminex-based TBEV suspension multiplex immunoassay for specific antibodies against non-structural protein 1 (NS1) antigen suggestive of previous infection.

Results

A total of 62 samples tested positive for immunoglobulin G antibodies against Bbsl. A total of 40 samples were positive or borderline for antibodies against TBEV, indicating potential infection or vaccination. Of these, one had antibodies against NS1, indicating past infection. The seroprevalence of Bbsl was 6.2% (95% confidence interval 4.8-7.8), with equal seroprevalence in all five regions. The seroprevalence of TBEV was 0.1% (95% confidence interval 0.01-0.62%).

Conclusions

The seroprevalence of Bbsl was similar throughout the country and corresponds well with previous studies. The seroprevalence of TBEV NS1 was low, which is in line with a low number of reported tick-borne encephalitis cases in Denmark. The NS1 positive sample was from the Capital Region, an endemic TBEV area.

Sociodemographic influences on private and professional contact behaviour during the COVID-19 pandemic in Germany: cross-sectional analysis based on a Regional Blood Donor Cohort

OBJECTIVE

The COVID-19 pandemic has had significant health and socioeconomic impacts worldwide. Extensive measures, including contact restrictions, were implemented to control the spread of the virus. This study aims to examine the factors that influenced private and professional contact behaviour during the COVID-19 pandemic.

RESULTS

We used baseline data (January-April 2021) from the SeMaCo study (Serologische Untersuchungen bei Blutspendern des Großraums Magdeburg auf Antikörper gegen SARS-CoV-2), a longitudinal, regional cohort study assessing COVID-19 seroprevalence in blood donors from Magdeburg and surrounding areas in Germany. In the blood donor cohort (n = 2,195), there was a general reduction in private contacts (by 78.9%) and professional contacts (by 54.4%) after March 18, 2020. Individuals with higher education reduced both private (by 84.1%) and professional (by 70.1%) contacts more than those with lower education levels (private contacts 59.5%; professional contacts 37%). Younger age groups (18-30 years) reduced private contacts more frequently (by 85.4%) than older individuals (61-83 years, by 68.6%) and demonstrated a higher likelihood of private contact reduction compared to older age groups (51-60 years: odds ratio (OR) 0.45 [95% [CI] 0.32-0.65]; 61-83 years: OR 0.33 [95% [CI] 0.22-0.48]).

Association Between Social Vulnerability and SARS-CoV-2 Seroprevalence in Specimens Collected From Commercial Laboratories, United States, September 2021-February 2022

OBJECTIVE

We conducted a national US study of SARS-CoV-2 seroprevalence by Social Vulnerability Index (SVI) that included pediatric data and compared the Delta and Omicron periods during the COVID-19 pandemic. The objective of the current study was to assess the association between SVI and seroprevalence of infection-induced SARS-CoV-2 antibodies by period (Delta vs Omicron) and age group.

METHODS

We used results of infection-induced SARS-CoV-2 antibody assays of clinical sera specimens (N = 406 469) from 50 US states from September 2021 through February 2022 to estimate seroprevalence overall and by county SVI tercile. Bivariate analyses and multilevel logistic regression models assessed the association of seropositivity with SVI and its themes by age group (0-17, ≥18 y) and period (Delta: September-November 2021; Omicron: December 2021-February 2022).

RESULTS

Aggregate infection-induced SARS-CoV-2 antibody seroprevalence increased at all 3 SVI levels; it ranged from 25.8% to 33.5% in September 2021 and from 53.1% to 63.5% in February 2022. Of the 4 SVI themes, socioeconomic status had the strongest association with seroprevalence. During the Delta period, we found significantly more infections per reported case among people living in a county with high SVI (odds ratio [OR] = 2.76; 95% CI, 2.31-3.21) than in a county with low SVI (OR = 1.65; 95% CI, 1.33-1.97); we found no significant difference during the Omicron period. Otherwise, findings were consistent across subanalyses by age group and period.

CONCLUSIONS

Among both children and adults, and during both the Delta and Omicron periods, counties with high SVI had significantly higher SARS-CoV-2 antibody seroprevalence than counties with low SVI did. These disparities reinforce SVI's value in identifying communities that need tailored prevention efforts during public health emergencies and resources to recover from their effects.

SARS-CoV-2 vaccination in Canadian blood donors: Insight into donor representativeness of the general population

Introduction

Blood donors world-wide were indispensable for monitoring anti-SARS-CoV-2 antibodies generated by infection and vaccination during the pandemic. Prior to the pandemic, donor vaccination behaviours were under-studied. We aimed to compare the percentage of Canadian blood donors with SARS-CoV-2 vaccination antibodies with the percentage of the general population who received at least one dose of vaccine each month during initial vaccine deployment. We also report donor attitudes towards SARS-CoV-2 vaccination.

Methods

Canadian blood donors were randomly selected for SARS-CoV-2 antibody testing over 2021 (N = 165,240). The percentage of donor samples with vaccination antibodies were compared with the percentage of general population who received at least one dose of vaccine in each month of 2021 except February. A random sample of Canadian blood donors were surveyed about vaccination intent and attitudes (N = 4,558 participated, 30.4 % response rate).

Results

The percentages of the general population vaccinated and donors with vaccination antibodies increased from 1 % to over 90 %. General population vaccination was greater early in vaccine deployment than donors (p < 0.05), greater in donors than the general population by mid-2021 (p < 0.05) but they were similar by the end of 2021. While 52.6 % of surveyed donors had received vaccine in May 2021, a further 41.1 % intended to when eligible. Most donors thought COVID-19 infection could be serious (83.5 %) and that it was important to be vaccinated even if previously infected (77.8 %).

Conclusion

Early pandemic vaccine prioritization to at-risk individuals and healthcare workers gave rise to higher general population vaccination percentages, while donors had higher vaccine antibody percentages as vaccine was deployed to progressively younger age groups. Since blood donors may be more willing to receive vaccination, under pandemic conditions they may be valuable for monitoring vaccination-induced seroprevalence.

Serum neurofilament light chain, inflammatory markers, and kynurenine metabolites in patients with persistent post-concussion symptoms: A cohort study

BACKGROUND

Concussion leads to persistent post-concussion symptoms (PPCS) in up to one-third of those affected. While previous research has linked the initial trauma to elevated serum levels of neurofilament light chain (NFL), inflammatory markers, and neurotoxic metabolites within the kynurenine pathway, few studies have explored their relevance in PPCS. This study aims to investigate these biomarkers in PPCS patients, elucidating their relevance in the prolonged phase of concussion.

METHODS

Serum samples from 86 PPCS individuals aged 18-30 years, 2-6 months post-trauma were analyzed, with 54 providing follow-up samples after seven months. NFL was measured using single-molecule array (Simoa) technology, 13 inflammatory markers via a Luminex immunoassay, and five kynurenine metabolites using liquid chromatography-mass spectrometry. A control group of 120 healthy anonymous blood donors was recruited for comparison.

RESULTS

No significant NFL differences were found in PPCS participants compared with healthy individuals (p = 0.22). Intriguingly, a subset (9.3%) of PPCS participants initially exhibited abnormally high NFL levels (>9.7 pg/mL), which normalized upon follow-up (p = 0.032). Additionally, serum levels of the inflammatory markers, monocyte chemoattractant protein-1 (MCP-1/CCL2), and eotaxin-1/CCL11 were 25-40% lower than in healthy individuals (p ≤ 0.001). As hypothesized, PPCS participants exhibited a 22% reduction in the ratio of kynurenic acid to quinolinic acid (neuroprotective index) (p < 0.0001), indicating a shift towards the formation of neurotoxic metabolites.

CONCLUSION

NFL may serve as a biomarker to monitor recovery, and future studies should investigate the potential therapeutic benefits of modulating the kynurenine pathway to improve PPCS.

Serum calcitonin gene-related peptide in patients with persistent post-concussion symptoms, including headache: a cohort study

BACKGROUND

Calcitonin gene-related peptide (CGRP) plays an important role in migraine pathophysiology, and post-traumatic headache (PTH) frequently presents with migraine-like features. Despite several clinical similarities, few studies have explored CGRP in PTH and concussion. This study investigates serum CGRP levels in patients with persistent post-concussion symptoms (PPCS), including PTH.

METHODS

This cohort study was based on serum samples from individuals aged 18-30 years with PPCS who participated in a previously published randomized controlled trial of a non-pharmacological intervention. The primary outcome was serum CGRP concentrations, determined at baseline before randomization and at follow-up 7 months later, using an enzyme-linked immunosorbent assay (ELISA). CGRP levels at baseline were compared with healthy anonymous blood donors in the same age group.

RESULTS

Baseline serum samples were collected from 86 participants with PPCS. The participants were most often female (78%) and migraine-like headache was the most frequent headache phenotype (74%). Serum CGRP levels were higher in participants with PPCS than in 120 healthy individuals (median: 158.5 pg/mL vs. 76.3 pg/mL, p = 0.050). A stratified analysis revealed that females with PPCS had a fivefold higher median than healthy females (166.3 pg/mL vs. 32.1 pg/mL, p = 0.0006), while no differences were observed in males (p = 0.83). At follow-up, CGRP levels decreased with a median change of  - 1.3 pg/mL (95% confidence interval:  - 17.6-0, p = 0.024).

DISCUSSION

Elevated serum levels of CGRP in patients with PPCS and a decrease over time suggest an involvement of CGRP in PTH/PPCS. If confirmed in other studies, it could pave the way for CGRP-targeted therapies, which could have clinical significance.

Lifestyle and demographic associations with 47 inflammatory and vascular stress biomarkers in 9876 blood donors

BACKGROUND

The emerging use of biomarkers in research and tailored care introduces a need for information about the association between biomarkers and basic demographics and lifestyle factors revealing expectable concentrations in healthy individuals while considering general demographic differences.

METHODS

A selection of 47 biomarkers, including markers of inflammation and vascular stress, were measured in plasma samples from 9876 Danish Blood Donor Study participants. Using regression models, we examined the association between biomarkers and sex, age, Body Mass Index (BMI), and smoking.

RESULTS

Here we show that concentrations of inflammation and vascular stress biomarkers generally increase with higher age, BMI, and smoking. Sex-specific effects are observed for multiple biomarkers.

CONCLUSION

This study provides comprehensive information on concentrations of 47 plasma biomarkers in healthy individuals. The study emphasizes that knowledge about biomarker concentrations in healthy individuals is critical for improved understanding of disease pathology and for tailored care and decision support tools.

The effect of donation frequency on donor health in blood donors donating plasma by plasmapheresis: study protocol for a randomized controlled trial

BACKGROUND

The demand for plasma products is growing, necessitating an increase in plasma collection by plasmapheresis. While the 20th edition of the European Guidelines permits plasma donors in Europe to donate with 96-h donation intervals, the potential short- and long-term consequences of high-frequency plasma donations on donor health remain unknown. This study aims to measure the effect of plasma donation frequency on plasma protein composition, including total serum protein (TSP) and immunoglobulin G (IgG), in Norwegian male blood donors.

METHODS

This randomized controlled trial (RCT) included 120 male blood donors who were randomized into two intervention groups and one control group: high-frequency plasma donors (HFPDs) who donated 650 mL of plasma 3 times every 2 weeks, whereas regular-frequency plasma donors (RFPDs) who donated 650 mL of plasma 1 time every 2 weeks. The control group consisted of whole blood donors. The primary outcomes are the concentrations of TSP and IgG.

DISCUSSION

The findings from this study may have implications for recommendations related to donor health and plasma donation frequencies and may contribute to supporting the strategic independence of plasma products in Norway and Europe without compromising donor health.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05179200 . Registered December 20th, 2021.

Comparison of real-time quantitative PCR and two digital PCR platforms to detect copy number variation in FCGR3B

The importance of structural genetic variants, such as copy number variations (CNVs), in modulating human disease is being increasingly recognized. Several clinical conditions require investigation of human neutrophil antigen (HNA-1), which is encoded by the Fc gamma receptor IIIb gene (FCGR3B), including suspicion of neutropenia, infections, and proactive testing of blood component donors to reduce the potential risk in transfusion. In this study, we compared real-time quantitative polymerase chain reaction (qPCR) with two digital PCR (dPCR) platforms, namely droplet digital PCR and an array-based platform, to determine copy numbers (CNs) in FCGR3B. We initially tested 400 anonymous blood donors with qPCR using a commercially available TaqMan probe assay (Applied Biosystems) on a Quant Studio 12 Flex. CNs was determined for all 400 tested individuals with CNs ranging from zero to four. Zero copies were detected in 0.2% (1/400), one copy was detected in 3.8% (15/400), two copies were detected in 87.8% (351/400), three copies were detected in 8.0% (32/400), and four copies were detected in 0.2% (1/400) of tested individuals. From this cohort, we selected 32 donors with CNs from zero to four for analyses with Digital Real-Time PCR (dPCR) using Lab on an array (LOAA) on an On-Point analyzer from Optolane Technologies Inc. and the Droplet Digital PCR (ddPCR) platform from Bio-Rad Laboratories. We compared the obtained CNs of FCGR3B on the three platforms and found full concordance between the CNs obtained. We therefore conclude that all three platforms can be used for quantification of CNs for FCGR3B, and although dPCR has some advantages over qPCR, it was not necessary for reliably estimating CNs of the FCGR3B gene.

Exploration of the Healthy Donor Effect Among 0.6 Million Blood Donors in China: Longitudinal Study

BACKGROUND

The World Health Organization emphasizes the importance of completely voluntary blood donation to maintain safe and sustainable blood supplies. However, the benefits of blood donation for donors, such as reducing the risk of disease, remain a topic of debate due to the existence of the healthy donor effect (HDE). This effect arises because of inherent health differences between blood donors and the general population, and it is also considered a methodological issue.

OBJECTIVE

This study aims to generate a more detailed health profile of blood donors from a donor cohort study to mitigate and quantify the HDE and properly interpret the association between blood donation and disease outcomes among blood donors.

METHODS

A retrospective cohort study was conducted between January 2012 and December 2018 among donors before their first donation. One-to-one propensity score matching was conducted through a random selection of individuals without any history of blood donation, as reported from their electronic health records. We conducted a Poisson regression between blood donors and non-blood donors before the first donation to estimate the adjusted incidence rate ratio (AIRR) of selected blood donation-related diseases, as defined by 13 categories of International Classification of Diseases, Tenth Revision (ICD-10) codes.

RESULTS

Of the 0.6 million blood donors, 15,115 had an inpatient record before their first donation, whereas 17,356 non-blood donors had an inpatient record. For the comparison between blood donors and the matched non-blood donors, the HDE (the disease incidence rate ratio between non-blood donors and blood donors) was an AIRR of 1.152 (95% CI 1.127-1.178; P<.001). Among disease categories not recommended for blood donation in China, the strongest HDE was observed in the ICD-10 D50-D89 codes, which pertain to diseases of the blood and blood-forming organs as well as certain disorders involving the immune mechanism (AIRR 3.225, 95% CI 2.402-4.330; P<.001). After age stratification, we found that people who had their first blood donation between 46-55 years old had the strongest HDE (AIRR 1.816, 95% CI 1.707-1.932; P<.001). Both male and female donors had significant HDE (AIRR 1.082, 95% CI 1.05-1.116; P=.003; and AIRR 1.236, 95% CI 1.196-1.277; P<.001, respectively) compared with matched non-blood donors.

CONCLUSIONS

: Our research findings suggest that the HDE is present among blood donors, particularly among female donors and those who first donated blood between the ages of 46 and 55 years.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200055983; https://www.chictr.org.cn/showproj.html?proj=51760.

Safety and protection of plasma donors: A scoping review and evidence gap map

BACKGROUND AND OBJECTIVES

As part of a large-scale project to safely increase plasma collection in Europe, the current scoping review identifies the existing evidence (gaps) on adverse events (AEs) and other health effects in plasmapheresis donors, as well as factors that may be associated with such events/effects.

MATERIALS AND METHODS

We searched six databases and three registries. Study characteristics (publication type, language, study design, population, outcomes, associated factors, time of assessment, duration of follow-up, number and frequency of donations, convalescent plasma [y/n], setting and location) were synthesized narratively and in an interactive evidence gap map (EGM).

RESULTS

Ninety-four research articles and five registrations were identified. Around 90% were observational studies (57 controlled and 33 uncontrolled), and most of them were performed in Europe (55%) or the United States (20%). Factors studied in association with donor health included donor characteristics (e.g., sex, age) (n = 27), cumulative number of donations (n = 21), donation frequency (n = 11), plasma collection device or programme (n = 11), donor status (first time vs. repeat) (n = 10), donation volume per session (n = 8), time in donation programme (n = 3), preventive measures (n = 2) or other (n = 9).

CONCLUSION

The current scoping review provides an accessible tool for researchers and policymakers to identify the available evidence (gaps) concerning plasmapheresis donation safety. Controlled prospective studies with long-term donor follow-up are scarce. Furthermore, additional experimental studies comparing the health effects of different donation frequencies are required to inform a safe upper limit for donation frequency.

Impact of tobacco, alcohol, and marijuana on genome-wide DNA methylation and its relationship with hypertension

Tobacco, alcohol, and marijuana consumption is an important public health problem because of their high use worldwide and their association with the risk of mortality and many health conditions, such as hypertension, which is the commonest risk factor for death throughout the world. A likely pathway of action of substance consumption leading to persistent hypertension is DNA methylation. Here, we evaluated the effects of tobacco, alcohol, and marijuana on DNA methylation in the same cohort (N = 3,424). Three epigenome-wide association studies (EWAS) were assessed in whole blood using the InfiniumHumanMethylationEPIC BeadChip. We also evaluated the mediation of the top CpG sites in the association between substance consumption and hypertension. Our analyses showed 2,569 CpG sites differentially methylated by alcohol drinking and 528 by tobacco smoking. We did not find significant associations with marijuana consumption after correcting for multiple comparisons. We found 61 genes overlapping between alcohol and tobacco that were enriched in biological processes involved in the nervous and cardiovascular systems. In the mediation analysis, we found 66 CpG sites that significantly mediated the effect of alcohol consumption on hypertension. The top alcohol-related CpG site (cg06690548, P-value = 5.9·10^-83) mapped to SLC7A11 strongly mediated 70.5% of the effect of alcohol consumption on hypertension (P-value = 0.006). Our findings suggest that DNA methylation should be considered for new targets in hypertension prevention and management, particularly concerning alcohol consumption. Our data also encourage further research into the use of methylation in blood to study the neurological and cardiovascular effects of substance consumption.

Surveillance of SARS-CoV-2 infection based on self-administered swabs, Denmark, May to July 2022: evaluation of a pilot study

BackgroundDuring the COVID-19 pandemic, the Danish National Institute for Infectious Disease, Statens Serum Institute (SSI) developed a home-based SARS-CoV-2 surveillance system.AimsWe wanted to determine whether a cohort of individuals performing self-administered swabs for PCR at home could support surveillance of SARS-CoV-2, including detection and assessment of new variants. We also aimed to evaluate the logistical setup.MethodsFrom May to July 2022, 10,000 blood donors were invited to participate, along with their household members. Participation required performing a self-swab for 4 consecutive weeks and answering symptom questionnaires via a web app. Swabs were sent by post to SSI for PCR analysis and whole genome sequencing. After study completion, participants were asked to complete a questionnaire concerning their experience.ResultsIn total, 2,186 individuals enrolled (47.4% blood donors), and 1,333 performed self-swabbing (53.0 blood donors), of whom 48 had at least one SARS-CoV-2-positive sample. Fourteen different Omicron subvariants, primarily BA.5 subvariants, were identified by whole genome sequencing (WGS). In total, 29 of the 63 SARS-CoV-2-positive samples were taken from individuals who were asymptomatic at the time of swabbing. Participants collected 2.9 swabs on average, with varying intervals between swabs. Transmission within households was observed in only three of 25 households.ConclusionParticipants successfully performed self-swabs and answered symptom questionnaires. Also, WGS analysis of samples was possible. The system can support surveillance of respiratory pathogens and also holds potential as a diagnostic tool, easing access to test for at-risk groups, while also reducing the burden on healthcare system resources.

Prevalence of blood donation eligibility in Australia: A population survey

BACKGROUND

Reliable estimates of the population proportion eligible to donate blood are needed by blood collection agencies to model the likely impact of changes in eligibility criteria and inform targeted population-level education, recruitment, and retention strategies. In Australia, the sole estimate was calculated 10+ years ago. With several subsequent changes to the eligibility criteria, an updated estimate is required.

STUDY DESIGN AND METHODS

We conducted a cross-sectional national population survey to estimate eligibility for blood donation. Respondents were aged 18+ and resident in Australia. Results were weighted to obtain a representative sample of the population.

RESULTS

Estimated population prevalence of blood donation eligibility for those aged 18-74 was 57.3% (95% CI 55.3-59.3). The remaining 42.7% (95% CI 40.7-44.7) were either temporarily (25.3%, 95% CI 23.5-27.2) or permanently ineligible (17.4%, 95% CI 16.1-18.9). Of those eligible at the time of the survey, that is, with the UK geographic deferral for variant Creutzfeldt-Jakob disease included, (52.9%, 95% CI 50.8-54.9), 14.2% (95% CI 12.3-16.3) reported donating blood within the previous 2 years. Eligibility was higher among men (62.6%, 95% CI 59.6-65.6) than women (52.8%, 95% CI 50.1-55.6). The most common exclusion factor was iron deficiency/anemia within the last 6 months; 3.8% (95% CI 3.2-4.6) of the sample were ineligible due to this factor alone.

DISCUSSION

We estimate that approximately 10.5 million people (57.3% of 18-74-year-olds) are eligible to donate blood in Australia. Only 14.2% of those eligible at the time of survey reported donating blood within the previous 2 years, indicating a large untapped pool of potentially eligible blood donors.

Examining participant representation by sex, race, ethnicity and age in United States blood donation and blood transfusion clinical trials

Significant inequities based on sex, race, ethnicity, and age exist among participants in clinical trials dedicated to investigating medical disease states. While general demographic data regarding blood donors and blood transfusion recipients have been studied extensively, the demographics of participants involved in blood donation and blood transfusion clinical trials are unknown. We performed a cross-sectional analysis of United States (U.S.) -based interventional blood donation and blood transfusion clinical trials registered with Clinicaltrials.gov to ascertain the composition of participants' sex, race, ethnicity, and age, as well as diagnostic conditions and geographic trial locations.Eligible trials were undertaken between July 2003 and August 2020. Thirty-eight of the one hundred and fifty-two blood donation and blood transfusion clinical trials met inclusion criteria (seven blood donation and thirty-one blood transfusion trials). While the participant dataset from trial reports were incomplete, 100 % of blood donation trials reported sex and age, 71.4 % reported race, and 42.3 % reported ethnicity. 96.8 % of blood transfusion trials reported sex, 51.6 % reported race, 38.7 % reported ethnicity, and 100 % reported age. Among 2720 participants enrolled in the seven blood donation trials, females were underrepresented (28.5 %) compared to U.S. Census data. Conversely, female (50.8 %) and male participants (49.2 %) were equally represented in blood transfusion trials (9255 participants). White participants were overrepresented in blood donation trials (73.4 %), while Hispanic or Latinos were underrepresented in both blood donation (7.7 %) and blood transfusion (8.2 %) trials compared to 2019 U.S.Census data. Only 8.3 % of blood transfusion clinical trials open to adults reported including older adults (i.e., ≥ 65yo). Despite mandatory reporting requirements and an already established framework, researchers frequently failed to report complete demographics of blood donation and blood transfusion clinical trial participants. Furthermore, various demographic groups were underrepresented in blood donation and/or blood transfusion clinical trials, including females, Hispanic or Latino individuals, and older adults. These findings demonstrate the need for implementation of strategies to ensure equitable representation of individuals in blood donation and transfusion clinical trials.