Booster vaccinations and Omicron: the effects on SARS-CoV-2 antibodies in Dutch blood donors.

INTRODUCTION: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) booster vaccination campaign and the emergence of SARS-CoV-2 Omicron variants impact the prevalence and levels of SARS-CoV-2 antibodies in the Netherlands. In this study we determined antibody levels across age groups, the impact of Omicron variant infections, and the effect of booster vaccinations on antibody levels. METHODS: In September and December 2021 and in February 2022, over 2000 Dutch blood donors were tested for presence of SARS-CoV-2 antibodies. Donations were selected based on age, sex, and region of residence, to provide an optimal coverage and representation of the Dutch population. RESULTS: Levels of vaccination-induced spike antibodies decreased over time in all age groups. Donors vaccinated with Janssen or AstraZeneca had significantly lower antibody levels than donors vaccinated with Pfizer or Moderna vaccine. Boostering with an mRNA vaccine elevated antibody levels in all age-groups irrespective of the initial vaccine. In donors aged < 56 years, the proportion of infected donors almost doubled between December 2021 and February 2022. CONCLUSION: The booster vaccination campaign increased antibody levels in all age-groups. After a booster vaccination, donors initially vaccinated with AstraZeneca or Janssen vaccine showed antibody levels similar to donors initially vaccinated with an mRNA vaccine. The emergence of the SARS-CoV-2 Omicron variant in the Netherlands caused a substantial increase in donors with infection-induced antibodies, especially among younger donors.

[Thrombocytopenia]. / Trombocytopenie.

Thrombocytopenia can be caused by many different underlying disorders. The diagnostic approach to this haematological abnormality may, therefore, be challenging for physicians. Causes of thrombocytopenia may be classified according to decreased production, increased peripheral consumption or destruction, or abnormal distribution of platelets. Additionally, it is important to rule out pseudothrombocytopenia, a laboratory artefact caused in vitro by ethylenediaminetetraacetic acid (EDTA) anticoagulants. Here we discuss the clinical and laboratory evaluation of drug-induced thrombocytopenia based on the description of two patients, one with ceftriaxone-induced thrombocytopenia and the other with heparin-induced thrombocytopenia. Drug-induced thrombocytopenia is rare, but it is an important consideration in the differential diagnosis of thrombocytopenic patients. The aetiology is often not recognised or is ascribed to other complications such as disseminated intravascular coagulation (DIC) or immune thrombocytopenia (ITP). Misdiagnosis or late recognition may result in morbidity and mortality due to bleeding or thrombotic complications.

Negative experiences and predonation blood pressure at the subsequent donation in blood donors.

BACKGROUND: Negative donation experiences, like being deferred or experiencing an adverse reaction, might upset blood donors, resulting in anticipatory stress responses such as elevated blood pressure at the subsequent visit. We therefore explored associations between blood donors' negative donation experiences and their blood pressure at the subsequent visit. STUDY DESIGN AND METHODS: Blood pressure of donors with no history of negative experiences in three consecutive donations was compared to the blood pressure of donors with a negative experience during the second of the three donations. Blood pressure (systolic and diastolic) measured prior to the third donation was compared between the two groups, using linear regression analyses. Two types of negative experiences (adverse reactions and deferral) were analysed, stratifying for donation type and sex, and adjusting for age and predonation blood pressure at baseline. RESULTS: In total, 248 118 (50% female) donors were included in the analyses. Eleven per cent (26 380 donors, 61% female) had experienced a negative experience. Fainting and dizziness were associated with significant (P < 0·05) increases in systolic blood pressure: in men, 3·0 mmHg (fainting) and 2·0 mmHg (dizziness); in women, 2·0 mmHg (fainting) and 1·4 mmHg (dizziness). Deferral was associated with significant (P < 0·05) increases in both systolic (men: 0·7 mmHg, women: 0·3 mmHg) and diastolic (men: 0·2 mmHg, women: 0·3 mmHg) blood pressure. CONCLUSION: Whole blood donations with negative experiences were associated with a statistically significant higher predonation blood pressure at the subsequent visit. This indicates that negative experiences might cause an anticipatory stress reaction in a subsequent donation.

Increasing first-time blood donation of newly registered donors using implementation intentions and explicit commitment techniques.

BACKGROUND AND OBJECTIVES: Most blood donors stop donating blood at the beginning of their donor career. This intervention study aims to increase first-time return behaviour of newly registered donors using implementation intentions and explicit commitment techniques. MATERIALS AND METHODS: Newly registered donors (N = 937) received an extra information sheet during their medical check-up wherein implementation intentions and explicit commitment techniques were tested. Donors were randomly assigned to either the control condition, information sheet only condition, information sheet with implementation intentions condition, information sheet with explicit commitment condition, or information sheet with both implementation intentions and explicit commitment condition. Logistic regression analyses examined actual first-time return behaviour after an appeal to donate blood. RESULTS: Donors in the information sheet with both implementation intentions and explicit commitment condition had an 11.5% higher return rate than donors in the control condition. Logistic regression analyses revealed that the information sheet with both implementation intentions and explicit commitment condition significantly increased the odds on return behaviour compared with the control condition (OR = 1.65, 95%CI = 1.08-2.50). CONCLUSION: This study successfully increased actual first-time return behaviour of newly registered donors by using both implementation intentions and explicit commitment techniques.

Markers of low-grade inflammation and endothelial dysfunction are related to reduced information processing speed and executive functioning in an older population - the Hoorn Study.

Low-grade inflammation and endothelial dysfunction are related to cognitive decline and dementia, in a complex interplay with vascular factors and aging. We investigated, in an older population, low-grade inflammation and endothelial dysfunction in relation to detailed assessment of cognitive functioning. Furthermore, we explored this association within the context of vascular factors. 377 participants (73 ± 6 years) of the population-based Hoorn Study were included. In plasma samples of 2000-2001 (n=363) and/or 2005-2008 (n=323), biomarkers were determined of low-grade inflammation (CRP, TNF-alpha, IL-6, IL-8, SAA, MPO, and sICAM-1) and endothelial dysfunction (vWF, sICAM-1, sVCAM-1, sTM, sE-selectin). In 2005-2008, all participants underwent neuropsychological examination. Composite z-scores were computed for low-grade inflammation and endothelial dysfunction at both time points, and for six domains of cognitive functioning (abstract reasoning, memory, information processing speed, attention and executive functioning, visuoconstruction, and language). The association between low-grade inflammation and endothelial dysfunction, and cognitive functioning was evaluated with linear regression analysis. In secondary analyses, we explored the relation with vascular risk factors and cardiovascular disease. Low-grade inflammation and endothelial dysfunction were associated with worse performance on information processing speed and attention and executive functioning, in prospective and cross-sectional analyses (standardized betas ranging from -0.20 to -0.10). No significant relation with other cognitive domains was observed. Adjusting for vascular factors slightly attenuated the associations. Low-grade inflammation and endothelial dysfunction accounted for only 2.6% explained variance in cognitive functioning, on top of related vascular risk factors and cardiovascular disease. Bootstrapping analyses show that low-grade inflammation and endothelial dysfunction mediate the relation between vascular risk factors and cognitive functioning. This study shows that low-grade inflammation and endothelial dysfunction contribute to reduced information processing speed and executive functioning in an older population.

Vitamin D status, incident diabetes and prospective changes in glucose metabolism in older subjects: the Hoorn study.

BACKGROUND AND AIMS: Vitamin D deficiency may contribute to impaired glucose metabolism and type 2 diabetes, especially in the elderly population. We aimed to evaluate whether baseline 25-hydroxyvitamin D (25[OH]D) levels are prospectively associated with deterioration of glucose metabolism and the incidence of diabetes. METHODS AND RESULTS: We examined a subsample from the population based Hoorn study among older men and women. Physical examinations were performed from 2000 to 2001 and included measurements of 25(OH)D. Glucose tolerance tests and HbA1c measurements were performed at baseline and at a follow-up between 2007 and 2009. We included 351 study participants (51% females; 67.9 ± 5.7 years). Baseline 25(OH)D levels were 56.7 ± 18.8 nmol/L and follow-up visits were performed after 7.5 ± 0.5 years. Among 280 study participants without diabetes at baseline we recorded 45 cases of incident diabetes. There was no significant association of 25(OH)D with the incidence of diabetes and with fasting and 2h postload glucose levels at follow-up. In analyses adjusted for age, sex, and baseline HbA1c there was, however, a significant association of 25(OH)D with follow-up HbA1c levels (beta coefficient=-0.085, p=0.085). This association was attenuated after further adjustments for BMI (beta coefficient=-0.079, p=0.064). CONCLUSIONS: In this study among the older population we observed no significant association of baseline 25(OH)D with glucose metabolism and incident diabetes. We found, however, a non-significant trend towards an inverse association of 25(OH)D with prospective changes in HbA1c that deserves further investigations.

Vitamin D in relation to myocardial structure and function after eight years of follow-up: the Hoorn study.

BACKGROUND AND AIMS: To investigate associations between baseline serum 25-hydroxyvitamin D [25(OH)D] levels and myocardial structure and function after 8 years of follow-up in older Dutch subjects. METHODS: We included 256 subjects of the Hoorn Study, a population-based cohort. They underwent a standardized 2-dimensional echocardiogram at baseline between 2000 and 2001, and again between 2007 and 2009. We studied the association of 25(OH)D quartiles with echocardiographic measures of the left ventricular mass index (LVMI), left ventricular systolic function and markers of diastolic function using linear regression analyses. RESULTS: At baseline, subjects had a mean age of 67.4 ± 5.2 years and 41.4% had prior cardiovascular disease (CVD). Low serum 25(OH)D levels were only associated with higher LVMI at 8-year follow-up in subjects without prior CVD and in subjects with low kidney function (median estimated glomerular filtration rate ≤77.5 ml/min/1.73m(2)). The associations attenuated after adjustments for parathyroid hormone (PTH), which was associated with higher LVMI (g/m(2.7)) in subjects with low kidney function (regression coefficient highest quartile 6.3, 95% CI: 0.2, 12.5). CONCLUSION: This study showed no strong associations of 25(OH)D with myocardial structure and function. However, PTH - a possible modifiable mediator in the relation between 25(OH)D and myocardial structure - was positively associated with LVMI in subjects with low kidney function.