Zika virus (ZIKV) has been known for decades to circulate in Africa and Asia. However, major complications of a ZIKV infection have recently become apparent for reasons that are still not fully ...elucidated. One of the hypotheses for the seemingly increased pathogenicity of ZIKV is that cross-reactive dengue antibodies can enhance a ZIKV infection through the principle of antibody-dependent enhancement (ADE). Recently, ADE in ZIKV infection has been studied, but conclusive evidence for the clinical importance of this principle in a ZIKV infection is lacking. Conversely, the widespread circulation of ZIKV in dengue virus (DENV)-endemic regions raises new questions about the potential contribution of ZIKV antibodies to DENV ADE. In this review, we summarize the results of the evidence to date and elaborate on other possible detrimental effects of cross-reactive flavivirus antibodies, both for ZIKV infection and the risk of ZIKV-related congenital anomalies, DENV infection, and dengue hemorrhagic fever.
SARS-CoV-2 has been identified as the causative agent of a global outbreak of respiratory tract disease (COVID-19). In some patients the infection results in moderate to severe acute respiratory ...distress syndrome (ARDS), requiring invasive mechanical ventilation. High serum levels of IL-6, IL-10 and an immune hyperresponsiveness referred to as a 'cytokine storm' have been associated with poor clinical outcome. Despite the large numbers of COVID-19 cases and deaths, information on the phenotype and kinetics of SARS-CoV-2-specific T cells is limited. Here, we studied 10 COVID-19 patients who required admission to an intensive care unit and detected SARS-CoV-2-specific CD4
and CD8
T cells in 10 out of 10 and 8 out of 10 patients, respectively. We also detected low levels of SARS-CoV-2-reactive T cells in 2 out of 10 healthy controls not previously exposed to SARS-CoV-2, which is indicative of cross-reactivity due to past infection with 'common cold' coronaviruses. The strongest T-cell responses were directed to the spike (S) surface glycoprotein, and SARS-CoV-2-specific T cells predominantly produced effector and Th1 cytokines, although Th2 and Th17 cytokines were also detected. Furthermore, we studied T-cell kinetics and showed that SARS-CoV-2-specific T cells are present relatively early and increase over time. Collectively, these data shed light on the potential variations in T-cell responses as a function of disease severity, an issue that is key to understanding the potential role of immunopathology in the disease, and also inform vaccine design and evaluation.
Introduction Since the introduction of combination antiretroviral therapy, human immunodeficiency virus (HIV) infection is a manageable chronic disease. However, school-age children (4-18 years) ...living with HIV could still experience problems with functioning at school, due to the impact of the virus itself, medication, comorbidities and social stigma. School functioning covers academic achievement, school attendance, and social relationships and is of utmost importance to optimize normal participation. Methods To gain insight in school functioning problems of perinatally HIV-infected children, we performed a systematic review of the literature in multiple databases from January 1997 up to February 2019. Studies were included if they described outcomes of school functioning of school-age children perinatally infected with HIV, in high-income countries. Meta-analyses were performed for sufficiently comparable studies. Results and discussion Results from 32 studies show that HIV-infected children experience more problems in various areas of school functioning in comparison with national norms, matched healthy controls, siblings and HIV-exposed uninfected (HEU) children. The most pronounced differences concerned the usage of special educational services, general learning problems, and mathematics and reading performance scores. Comparisons with both national norms and siblings/HEU children show that the differences between HIV-infected children and siblings/HEU children were less pronounced. Moreover, siblings/HEU children also reported significantly worse outcomes compared to national norms. This suggests that problems in school functioning cannot be solely attributed to the HIV-infection, but that multiple socio-economic and cultural factors may play a role herein. Conclusion Perinatally HIV-infected children seem vulnerable to problems in various areas of school functioning. Therefore, monitoring of school functioning should be an important aspect in the care for these children. A family-focused approach with special attention to a child's socio-environmental context and additional attention for siblings and HEU children, is therefore recommended.
In July 2022, the ongoing monkeypox (MPX) outbreak was declared a public health emergency of international concern. Modified vaccinia Ankara-Bavarian Nordic (MVA-BN, also known as Imvamune, JYNNEOS ...or Imvanex) is a third-generation smallpox vaccine that is authorized and in use as a vaccine against MPX. To date, there are no data showing MPX virus (MPXV)-neutralizing antibodies in vaccinated individuals nor vaccine efficacy against MPX. Here we show that MPXV-neutralizing antibodies can be detected after MPXV infection and after historic smallpox vaccination. However, a two-shot MVA-BN immunization series in non-primed individuals yields relatively low levels of MPXV-neutralizing antibodies. Dose-sparing of an MVA-based influenza vaccine leads to lower MPXV-neutralizing antibody levels, whereas a third vaccination with the same MVA-based vaccine significantly boosts the antibody response. As the role of MPXV-neutralizing antibodies as a correlate of protection against disease and transmissibility is currently unclear, we conclude that cohort studies following vaccinated individuals are necessary to assess vaccine efficacy in at-risk populations.
Abstract
Lower respiratory tract (LRT) disease induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can deteriorate to acute respiratory distress syndrome (ARDS). Because the ...release of neutrophil extracellular traps (NETs) is implicated in ARDS pathogenesis, we investigated the presence of NETs and correlates of pathogenesis in blood and LRT samples of critically ill patients with COVID-19. Plasma NET levels peaked early after intensive care unit admission and were correlated with the SARS-CoV-2 RNA load in sputum and levels of neutrophil-recruiting chemokines and inflammatory markers in plasma samples. The baseline plasma NET quantity was correlated with disease severity but was not associated with soluble markers of thrombosis or with development of thrombosis. High NET levels were present in LRT samples and persisted during the course of COVID-19, consistent with the detection of NETs in bronchi and alveolar spaces in lung tissue from deceased patient with COVID-19. Thus, NETs are produced and retained in the LRT of critically ill patients with COVID-19 and could contribute to SARS-CoV-2–induced ARDS disease.
Aberrant neutrophil extracellular trap (NET) formation is implicated in acute respiratory distress syndrome (ARDS) pathogenesis. We demonstrate that NETs are present in blood and persist at high levels in the lower respiratory tract of critically ill patients with coronavirus disease 2019 and ARDS.
Although preventable by vaccination for more than a century, rabies virus still causes numerous fatalities every year. To determine antibody levels in humans, blood collected with a finger prick and ...applied on dried blood spot (DBS) cards is an alternative for venipuncture. The use of DBS is specifically valuable in remote areas, as it is easy to perform, store and transport. Therefore, the technique is frequently used for epidemiological studies of tropical diseases. Up to present, determination of rabies virus antibody levels on human DBS has not been validated.
We evaluated the use of human DBS for rabies serology and analyzed 99 pre- or post-vaccination serum and DBS samples with a fluorescent antibody virus neutralization test (FAVNt), which is the gold standard to detect protective antibody levels, and a Bio-Rad Platelia Rabies II ELISA. Sensitivity and specificity of DBS eluates tested with the FAVNt were 97% and 92%, respectively and 87% and 96% when tested with the Platelia-II ELISA. Antibody levels measured in serum with the FAVNt, correlated best with antibody levels measured in DBS with the FAVNt (R = 0.88).
This is the first study that applies DBS for reliable detection of human antibodies against rabies virus. Both the FAVNt and Platelia-II ELISA demonstrate an acceptable performance on DBS, providing opportunities for rabies serology in remote areas. This technique could drastically ease studies evaluating (novel) rabies vaccination strategies and monitoring persisting immunity in humans at risk, living in rabies endemic regions.
Summary Background Modified vaccinia virus Ankara (MVA) is a promising viral vector platform for the development of an H5N1 influenza vaccine. Preclinical assessment of MVA-based H5N1 vaccines showed ...their immunogenicity and safety in different animal models. We aimed to assess the safety and immunogenicity of the MVA-haemagglutinin-based H5N1 vaccine MVA-H5-sfMR in healthy individuals. Methods In a single-centre, double-blind phase 1/2a study, young volunteers (aged 18–28 years) were randomly assigned with a computer-generated list in equal numbers to one of eight groups and were given one injection or two injections intramuscularly at an interval of 4 weeks of a standard dose (108 plaque forming units pfu) or a ten times lower dose (107 pfu) of the MVA-H5-sfMR (vector encoding the haemagglutinin gene of influenza A/Vietnam/1194/2004 virus H5N1 subtype) or MVA-F6-sfMR (empty vector) vaccine. Volunteers and physicians who examined and administered the vaccine were masked to vaccine assignment. Individuals who received the MVA-H5-sfMR vaccine were eligible for a booster immunisation 1 year after the first immunisation. Primary endpoint was safety. Secondary outcome was immunogenicity. The trial is registered with the Dutch Trial Register, number NTR3401. Findings 79 of 80 individuals who were enrolled completed the study. No serious adverse events were identified. 11 individuals reported severe headache and lightheadedness, erythema nodosum, respiratory illness (accompanied by influenza-like symptoms), sore throat, or injection-site reaction. Most of the volunteers had one or more local (itch, pain, redness, and swelling) and systemic reactions (rise in body temperature, headache, myalgia, arthralgia, chills, malaise, and fatigue) after the first, second, and booster immunisations. Individuals who received the 107 dose had fewer systemic reactions. The MVA-H5-sfMR vaccine at 108 pfu induced significantly higher antibody responses after one and two immunisations than did 107 pfu when assessed with haemagglutination inhibition geometric mean titre at 8 weeks against H5N1 A/Vietnam/1194/2004 (30·2 SD 3·8 vs 9·2 2·3 and 108·1 2·4 vs 15·8 3·2). 27 of 39 eligible individuals were enrolled in the booster immunisation study. A single shot of MVA-H5-sfMR 108 pfu prime immunisation resulted in higher antibody responses after the booster immunisation than did two shots of MVA-H5-sfMR at the ten times lower dose. Interpretation The MVA-based H5N1 vaccine was well tolerated and immunogenic and therefore the vaccine candidates arising from the MVA platform hold great promise for rapid development in response to a future influenza pandemic threat. However, the immunogenicity of this vaccine needs to be compared with conventional H5N1 inactivated non-adjuvanted vaccine candidates in head-to-head clinical trials. Funding European Research Council.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019 (COVID-19). Little is known about the interplay between preexisting immunity to endemic seasonal ...coronaviruses and the development of a SARS-CoV-2-specific IgG response. We investigated the kinetics, breadth, magnitude, and level of cross-reactivity of IgG antibodies against SARS-CoV-2 and heterologous seasonal and epidemic coronaviruses at the clonal level in patients with mild or severe COVID-19 as well as in disease control patients. We assessed antibody reactivity to nucleocapsid and spike antigens and correlated this IgG response to SARS-CoV-2 neutralization. Patients with COVID-19 mounted a mostly type-specific SARS-CoV-2 response. Additionally, IgG clones directed against a seasonal coronavirus were boosted in patients with severe COVID-19. These boosted clones showed limited cross-reactivity and did not neutralize SARS-CoV-2. These findings indicate a boost of poorly protective CoV-specific antibodies in patients with COVID-19 that correlated with disease severity, revealing "original antigenic sin."
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.
Abstract
Modified vaccinia virus Ankara (MVA) is used as a vaccine against monkeypox virus and as a viral vaccine vector. MVA-MERS-S is a vaccine candidate against Middle East respiratory syndrome ...(MERS)–associated coronavirus. Here, we report that cross-reactive monkeypox virus neutralizing antibodies were detectable in only a single study participant after the first dose of MVA-MERS-S vaccine, in 3 of 10 after the second dose, and in 10 of 10 after the third dose.
A modified vaccinia virus Ankara–based candidate vaccine against Middle East respiratory syndrome–associated coronavirus elicits monkeypox virus neutralizing antibodies after 3 doses in healthy clinical trial participants.
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