Transient Autoreactive PF4 and Antiphospholipid Antibodies in COVID-19 Vaccine Recipients.

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare autoimmune condition associated with recombinant adenovirus (rAV)-based COVID-19 vaccines. It is thought to arise from autoantibodies targeting platelet factor 4 (aPF4), triggered by vaccine-induced inflammation and the formation of neo-antigenic complexes between PF4 and the rAV vector. To investigate the specific induction of aPF4 by rAV-based vaccines, we examined sera from rAV vaccine recipients (AZD1222, AD26.COV2.S) and messenger RNA (mRNA) based (mRNA-1273, BNT162b2) COVID-19 vaccine recipients. We compared the antibody fold change (FC) for aPF4 and for antiphospholipid antibodies (aPL) of rAV to mRNA vaccine recipients. We combined two biobanks of Dutch healthcare workers and matched rAV-vaccinated individuals to mRNA-vaccinated controls, based on age, sex and prior history of COVID-19 (AZD1222: 37, Ad26.COV2.S: 35, mRNA-1273: 47, BNT162b2: 26). We found no significant differences in aPF4 FCs after the first (0.99 vs. 1.08, mean difference (MD) = -0.11 (95% CI -0.23 to 0.057)) and second doses of AZD1222 (0.99 vs. 1.10, MD = -0.11 (95% CI -0.31 to 0.10)) and after a single dose of Ad26.COV2.S compared to mRNA-based vaccines (1.01 vs. 0.99, MD = 0.026 (95% CI -0.13 to 0.18)). The mean FCs for the aPL in rAV-based vaccine recipients were similar to those in mRNA-based vaccines. No correlation was observed between post-vaccination aPF4 levels and vaccine type (mean aPF difference -0.070 (95% CI -0.14 to 0.002) mRNA vs. rAV). In summary, our study indicates that rAV and mRNA-based COVID-19 vaccines do not substantially elevate aPF4 levels in healthy individuals.

The risk of recurrent venous thromboembolism after discontinuation of anticoagulant therapy in patients with cancer-associated thrombosis: a systematic review and meta-analysis.

Background: The optimal duration of anticoagulation in patients with active cancer and venous thromboembolism (VTE) is unknown. Current clinical guidelines advocate anticoagulant therapy for 3-6 months and to continue anticoagulant therapy for as long as the cancer is active. However, an adequate systematic review on the rate of recurrent VTE after discontinuation of anticoagulant therapy has not been performed. Methods: For this systemic review and meta-analysis, we searched Embase.com, Medline (Ovid), Web of Science, Cochrane Library, and Google Scholar, from database inception to February 16, 2023, for studies on anticoagulant therapy in patients with cancer and the recurrence of venous thromboembolism after discontinuation of this therapy. We included randomised controlled trials and cohort studies published in English that reported on patients who met the following: cancer and a first VTE, completed at least 3 months of anticoagulant therapy, were followed after discontinuation of anticoagulant therapy, and with symptomatic recurrent VTE as an outcome during follow-up. Study-level data were requested from study authors. The primary outcome was the rate of recurrent VTE after discontinuation of anticoagulant therapy. A Bayesian random-effects meta-analysis was used to estimate the rate of recurrent VTE per 100 person-years for the pooled studies at different time intervals after discontinuation of anticoagulation therapy. We also calculated the cumulative VTE recurrence rate at different time intervals. Forest plots were mapped and the results were summarized by the median and 95% credible interval (CIs). This study was registered with PROSPERO, CRD42021249060. Findings: Of 3856 studies identified in our search, 33 studies were identified for inclusion. After requesting study-level data, 14 studies involving 1922 patients with cancer-associated thrombosis were included. The pooled rate of recurrent VTE per 100 person-years after discontinuation of anticoagulant therapy was 14.6 events (95% credible interval 6.5-22.8) in the first three months, decreasing to 1.1 events (95% CI 0.3-2.1) in year 2-3, and 2.2 events (95% CI 0.0-4.4) in year 3-5 after discontinuation of anticoagulant therapy. The cumulative VTE recurrence rate was 28.3% (95% CI 15.6-39.6%) at 1 year; 31.1% (95% CI 16.5-43.8%) at 2 years; 31.9% (95% CI 16.8-45.0%) at 3 years; and 35.0% (95% CI 16.8-47.4%) at 5 years after discontinuation of anticoagulant therapy. Interpretation: This meta-analysis demonstrates a high rate of recurrent VTE over time after discontinuation of anticoagulant therapy in patients with cancer-associated thrombosis. Our results support the current clinical guidelines to continue anticoagulant therapy in patients with active cancer. Funding: Erasmus MC.

Changes in incidence of hospitalization for cardiovascular diseases during the COVID-19 pandemic in The Netherlands in 2020.

This population-based cohort study aimed to describe changes in incidence of cardiovascular disease (CVD) hospital diagnoses during the COVID-19 pandemic in The Netherlands compared with the pre-pandemic period. We used Dutch nationwide statistics about hospitalizations to estimate incidence rate ratios (IRR) of hospital diagnoses of CVD during the first and second COVID-19 waves in The Netherlands in 2020 versus the same periods in 2019. Compared with 2019, the incidence rate of a hospital diagnosis of ischemic stroke (IRR 0.87; 95% CI 0.79-0.95), major bleeding (IRR 0.74; 95% CI 0.68-0.82), atrial fibrillation (IRR 0.73; 95% CI 0.65-0.82), myocardial infarction (IRR 0.78; 95% CI 0.72-0.84), and heart failure (IRR 0.74; 95% CI 0.65-0.85) declined during the first wave, but returned to pre-pandemic levels throughout 2020. However, the incidence rate of a hospital diagnosis of pulmonary embolism (PE) increased during both the first and second wave in 2020 compared with 2019 (IRR 1.30; 95% CI 1.15-1.48 and IRR 1.31; 95% CI 1.19-1.44, respectively). In conclusion, we observed substantial declines in incidences of CVD during the COVID-19 pandemic in The Netherlands in 2020, especially during the first wave, with an exception for an increase in incidence of PE. This study contributes to quantifying the collateral damage of the COVID-19 pandemic.

Levels of Fibrinogen Variants Are Altered in Severe COVID-19.

Background Fibrinogen variants as a result of alternative messenger RNA splicing or protein degradation can affect fibrin(ogen) functions. The levels of these variants might be altered during coronavirus disease 2019 (COVID-19), potentially affecting disease severity or the thrombosis risk. Aim To investigate the levels of fibrinogen variants in plasma of patients with COVID-19. Methods In this case-control study, we measured levels of functional fibrinogen using the Clauss assay. Enzyme-linked immunosorbent assays were used to measure antigen levels of total, intact (nondegraded Aα chain), extended Aα chain (α E ), and γ' fibrinogen in healthy controls, patients with pneumococcal infection in the intensive care unit (ICU), ward patients with COVID-19, and ICU patients with COVID-19 (with and without thrombosis, two time points). Results Healthy controls and ward patients with COVID-19 ( n = 10) showed similar fibrinogen (variant) levels. ICU patients with COVID-19 who later did ( n = 19) or did not develop thrombosis ( n = 18) and ICU patients with pneumococcal infection ( n = 6) had higher absolute levels of functional, total, intact, and α E fibrinogen than healthy controls ( n = 7). The relative α E fibrinogen levels were higher in ICU patients with COVID-19 than in healthy controls, while relative γ' fibrinogen levels were lower. After diagnosis of thrombosis, only the functional fibrinogen levels were higher in ICU patients with COVID-19 and thrombosis than in those without, while no differences were observed in the other fibrinogen variants. Conclusion Our results show that severe COVID-19 is associated with increased levels of α E fibrinogen and decreased relative levels of γ' fibrinogen, which may be a cause or consequence of severe disease, but this is not associated with the development of thrombosis.

The effect of COVID-19 vaccination on anticoagulation stability in adolescents and young adults using vitamin K antagonists.

INTRODUCTION: The European Medicine Agency has authorized COVID-19 vaccination in adolescents and young adults (AYAs) from 12 years onwards. In elderly vitamin K antagonist (VKA) users, COVID-19 vaccination has been associated with an increased risk of supra- and subtherapeutic INRs. Whether this association is also observed in AYAs using VKA is unknown. Our aim was to describe the stability of anticoagulation after COVID-19 vaccination in AYA VKA users. MATERIALS AND METHODS: A case-crossover study was performed in a cohort of AYAs (12-30 years) using VKAs. The most recent INR results before vaccination, the reference period, were compared with the most recent INR after the first and, if applicable, second vaccination. Several sensitivity analyses were performed in which we restricted our analysis to stable patients and patients without interacting events. RESULTS: 101 AYAs were included, with a median age [IQR] of 25 [7] years, of whom 51.5 % were male and 68.3 % used acenocoumarol. We observed a decrease of 20.8 % in INRs within range after the first vaccination, due to an increase of 16.8 % in supratherapeutic INRs. These results were verified in our sensitivity analyses. No differences were observed after the second vaccination compared to before and after the first vaccination. Complications after vaccination occurred less often than before vaccination (9.0 vs 3.0 bleedings) and were non-severe. CONCLUSIONS: the stability of anticoagulation after COVID-19 vaccination was decreased in AYA VKA users. However, the decrease might not be clinically relevant as no increase of complications nor significant dose adjustments were observed.

Lupus anticoagulant associates with thrombosis in patients with COVID-19 admitted to intensive care units: A retrospective cohort study.

Background: Thrombosis is a frequent and severe complication in patients with coronavirus disease 2019 (COVID-19) admitted to the intensive care unit (ICU). Lupus anticoagulant (LA) is a strong acquired risk factor for thrombosis in various diseases and is frequently observed in patients with COVID-19. Whether LA is associated with thrombosis in patients with severe COVID-19 is currently unclear. Objective: To investigate if LA is associated with thrombosis in critically ill patients with COVID-19. Patients/Methods: The presence of LA and other antiphospholipid antibodies was assessed in patients with COVID-19 admitted to the ICU. LA was determined with dilute Russell's viper venom time (dRVVT) and LA-sensitive activated partial thromboplastin time (aPTT) reagents. Results: Of 169 patients with COVID-19, 116 (69%) tested positive for at least one antiphospholipid antibody upon admission to the ICU. Forty (24%) patients tested positive for LA; of whom 29 (17%) tested positive with a dRVVT, 19 (11%) tested positive with an LA-sensitive aPTT, and 8 (5%) tested positive on both tests. Fifty-eight (34%) patients developed thrombosis after ICU admission. The odds ratio (OR) for thrombosis in patients with LA based on a dRVVT was 2.5 (95% confidence interval [CI], 1.1-5.7), which increased to 4.5 (95% CI, 1.4-14.3) in patients at or below the median age in this study (64 years). LA positivity based on a dRVVT or LA-sensitive aPTT was only associated with thrombosis in patients aged less than 65 years (OR, 3.8; 95% CI, 1.3-11.4) and disappeared after adjustment for C-reactive protein. Conclusion: Lupus anticoagulant on admission is strongly associated with thrombosis in critically ill patients with COVID-19, especially in patients aged less than 65 years.

The Immediate Effect of COVID-19 Vaccination on Anticoagulation Control in Patients Using Vitamin K Antagonists.

BACKGROUND: In January 2021, the Dutch vaccination program against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was started. Clinical studies have shown that systemic reactions occur in up to 50% of vaccine recipients. Therefore, COVID-19 vaccination could affect anticoagulation control, potentially leading to an increased risk of thrombotic events and bleeding complications. AIMS: This article investigates whether the BNT162b2 vaccine affects anticoagulation control in outpatients using vitamin K antagonists (VKAs). METHODS: A case-crossover study was performed in a cohort of outpatient VKA users from four Dutch anticoagulation clinics who received a BNT162b2 vaccine. International normalized ratio (INR) results and VKA dosages before the first vaccination, the reference period, were compared with those after the first and second vaccination. RESULTS: A total of 3,148 outpatient VKA users were included, with a mean age (standard deviation) of 86.7 (8.7) years, of whom 43.8% were male, 67.0% used acenocoumarol, and 33.0% phenprocoumon. We observed a decrease of 8.9% of INRs within range in the standard intensity group (target INR 2.0-3.0). There was both an increased risk of supratherapeutic (odds ratio [OR] = 1.34 [95% confidence interval [CI] 1.08-1.67]) and subtherapeutic levels (OR = 1.40 [95% CI 1.08-1.83]) after first vaccination. In the high-intensity group (target INR 2.5-3.5), the risk of a supratherapeutic INR was 2.3 times higher after first vaccination (OR = 2.29 [95% CI 1.22-4.28]) and 3.3 times higher after second vaccination (OR = 3.25 [95% CI 1.06-9.97]). CONCLUSION: BNT162b2 was associated with an immediate negative effect on anticoagulation control in patients treated with VKAs, so it is advisable to monitor the INR shortly after vaccination, even in stable patients.

Altered fibrin network structure and fibrinolysis in intensive care unit patients with COVID-19, not entirely explaining the increased risk of thrombosis.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 infection is associated with an increased incidence of thrombosis. OBJECTIVES: By studying the fibrin network structure of coronavirus disease 2019 (COVID-19) patients, we aimed to unravel pathophysiological mechanisms that contribute to this increased risk of thrombosis. This may contribute to optimal prevention and treatment of COVID-19 related thrombosis. PATIENTS/METHODS: In this case-control study, we collected plasma samples from intensive care unit (ICU) patients with COVID-19, with and without confirmed thrombosis, between April and December 2020. Additionally, we collected plasma from COVID-19 patients admitted to general wards without thrombosis, from ICU patients with pneumococcal infection, and from healthy controls. Fibrin fiber diameters and fibrin network density were quantified in plasma clots imaged with stimulated emission depletion microscopy and confocal microscopy. Finally, we determined the sensitivity to fibrinolysis. RESULTS: COVID-19 ICU patients (n = 37) and ICU patients with pneumococcal disease (n = 7) showed significantly higher fibrin densities and longer plasma clot lysis times than healthy controls (n = 7). No differences were observed between COVID-19 ICU patients with and without thrombosis, or ICU patients with pneumococcal infection. At a second time point, after diagnosis of thrombosis or at a similar time point in patients without thrombosis, we observed thicker fibers and longer lysis times in COVID-19 ICU patients with thrombosis (n = 19) than in COVID-19 ICU patients without thrombosis (n = 18). CONCLUSIONS: Our results suggest that severe COVID-19 is associated with a changed fibrin network structure and decreased susceptibility to fibrinolysis. Because these changes were not exclusive to COVID-19 patients, they may not explain the increased thrombosis risk.

COVID-19 vaccination in patients with immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an acquired autoimmune disorder that is characterized by low platelet count and increased bleeding risk. COVID-19 vaccination has been described as a risk factor for de novo ITP, but the effects of COVID-19 vaccination in patients with ITP are unknown. We aimed to investigate the effects of COVID-19 vaccination in patients with ITP on platelet count, bleeding complications, and ITP exacerbation (≥50% decline in platelet count, or nadir platelet count < 30 × 109/L with a >20% decrease from baseline, or use of rescue therapy). Platelet counts in patients with ITP and healthy controls were collected immediately before and 1 and 4 weeks after the first and second vaccinations. Linear mixed-effects modeling was applied to analyze platelet counts over time. We included 218 patients with ITP (50.9% female; mean age, 55 years; and median platelet count, 106 × 109/L) and 200 healthy controls (60.0% female; mean age, 58 years; median platelet count, 256 × 109/L). Platelet counts decreased by 6.3% after vaccination. We did not observe any difference in decrease between the groups. Thirty patients with ITP (13.8%; 95% confidence interval [CI], 9.5-19.1) had an exacerbation and 5 (2.2%; 95% CI, 0.7-5.3) suffered from a bleeding event. Risk factors for ITP exacerbation were platelet count < 50 × 109/L (odds ratio [OR], 5.3; 95% CI, 2.1-13.7), ITP treatment at time of vaccination (OR, 3.4; 95% CI, 1.5-8.0), and age (OR, 0.96 per year; 95% CI, 0.94-0.99). Our study highlights the safety of COVID-19 vaccination in patients with ITP and the importance of the close monitoring of platelet counts in a subgroup of patients with ITP. Patients with ITP with exacerbation responded well on therapy.

Venous thrombotic events in severe and critically COVID-19 patients despite high dose prophylactic low-molecular-weight heparin.

Hypercoagulation is one of the most distinct prognostic factors of patients with COVID-19 and has been associated with arterial thrombosis and other venous thrombotic events (VTE). Bleeding complications are far less encountered. The International Society on Thrombosis and Haemostasis (ISTH) guidance advises giving prophylactic low-molecular-weight heparin (LMWH) to prevent these events, although there is evidence that the incidence remains high despite using prophylactic LMWH. We describe three cases of COVID-19 pneumonia that were admitted to our intensive care unit (ICU) and developed acute pulmonary embolisms (APE) despite high dosage prophylactic LMWH. These cases raise concerns about using prophylactic LMWH instead of therapeutic anticoagulation in severe and critically COVID-19 patients.

Sports-related injuries in primary health care.

INTRODUCTION: Sports activities play an important role in today's society. However, as more people become involved in these activities, the number of sports-related injuries also increases. In the Netherlands, 3.5 million sports injuries occur annually. Twenty per cent of these injuries are first seen by a GP. Little is known about the epidemiology of these injuries in general practice. This study has been conducted to determine the incidence and prevalence of sports-related injuries in general practice and to provide information about the nature and treatment of these injuries. METHODS: Survey study conducted in 612 patients with sports-related injuries by 21 GP trainees in as many GP practices. Inclusion of study subjects took place between September 2007 and April 2009. RESULTS: In total, 694 sports-related injuries were registered. The incidence of sports-related injuries was 23.7 in 1000 patients and prevalence 27.8 in 1000 patients. Soccer-related injuries are most prominent in this population, lower extremities being three times more often involved than upper extremities. GPs often (60.9%) used a symptom-based diagnosis. In 80% of the cases, no additional diagnostic testing took place, while in 36.5% of the cases, only explanation and advice sufficed. Few patients were referred to the hospital (6.6%). DISCUSSION: Patients with sports-related injuries regularly consult GPs (on average one to two times per week). GPs tend to use non-specific diagnoses in sports-related injuries. In part, this may be due to the lack of specific diagnoses available in the current registration system (International Classification of Primary Care). Most often these injuries require only explanation and medical advice from the GP. Usually, additional tests or hospital referrals are not necessary. Presumably, mostly patients with mild sports-related injuries consult the GP.

Is home spirometry useful in diagnosing asthma in children with nonspecific respiratory symptoms?

BACKGROUND: Variation of lung function is considered to be a hallmark of asthma. Although guidelines recommend measuring it as a diagnostic tool for asthma, the usefulness of this approach has not been studied in children. AIM: To assess the usefulness of home spirometry in children with nonspecific lower respiratory tract symptoms, to diagnose or exclude asthma. METHODS: In school-aged children, referred by their general practitioner because of chronic respiratory symptoms of unknown origin, the diagnosis of asthma was made or excluded by a pediatric pulmonologist (gold standard), based on international guidelines and a standardized protocol. Additionally, children measured peak expiratory flow (PEF) and forced expiratory flow in 1 sec (FEV(1)) twice daily for 2 weeks on a home spirometer, from which diurnal variation was calculated. These results (index test) were not revealed to the pediatric pulmonologist. The value of home spirometry to diagnose asthma was calculated. RESULTS: Sixty-one children (27 boys) were included (mean age: 10.4 years; range: 6-16 years). Between asthma and no asthma, the mean difference in PEF variation was 4.4% (95% CI: 0.9-7.9; P = 0.016) and in FEV(1) variation 4.5% (95% CI: 1.6-7.4; P = 0.003). Sensitivity and specificity, based on the 95th-centile of the reference values for PEF and FEV(1) variation (12.3% and 11.8%, respectively) were 50% and 72% for PEF variation and 45% and 92% for FEV(1) variation. The likelihood ratio was 1.8 for PEF and 5.6 for FEV(1). CONCLUSIONS: The contribution of home spirometry in the diagnostic process for asthma in schoolchildren with nonspecific respiratory symptoms is limited.

Prevalence and risk factors of wheeze in Dutch infants in their first year of life.

Factors operating in the first year of life are critical in determining the onset and persistence of wheezing in preschool children. This study was designed to examine the prevalence and risk factors of wheeze in the first year of life in Dutch infants. This was a population-based survey of 13-month-old infants visiting well baby clinics for a scheduled immunization. Parents/caregivers completed a standardized validated questionnaire on respiratory symptoms in the first year of life and putative risk factors. The independent influence of these factors for wheeze was assessed by multiple logistic regression analysis. A total of 1,115 questionnaires were completed. Wheeze ever (with a prevalence in the first year of life of 28.5%) was independently associated with male gender, eczema, sibs with asthma, any allergic disease in the family, day care, damp housing, and asphyxia. Recurrent wheeze (prevalence 14.5%) showed independent associations with eczema, sibs with asthma, and day care. In addition to these factors, severe wheeze (prevalence 15.4%) was also associated with premature rupture of membranes during birth, and with damp housing. Wheeze is common during the first year of life, and places a major burden on families and the health care system. Factors associated with wheeze are mainly related to markers of atopic susceptibility, and to exposure to infections. The strongest modifiable risk factor for wheeze in the first year of life is home dampness. Interventions to reduce home dampness to reduce wheeze in infancy should be examined.