Elevated plasma Complement Factor H Regulating Protein 5 is associated with venous thromboembolism and COVID-19 severity

Venous thromboembolism (VTE), comprising both deep vein thrombosis (DVT) and pulmonary embolism (PE) is a common, multi-causal disease with potentially serious short- and long-term complications. In clinical practice, there is a need for improved plasma biomarker-based tools for VTE diagnosis and risk prediction. We used multiplex proteomics profiling to screen plasma from patients with suspected acute VTE, and a case-control study of patients followed up after ending anticoagulant treatment for a first VTE. With replication in 5 independent studies, together totalling 1137 patients and 1272 controls, we identify Complement Factor H Related Protein (CFHR5), a regulator of the alternative pathway of complement activation, as a novel VTE associated plasma biomarker. Using GWAS analysis of 2967 individuals we identified a genome-wide significant pQTL signal on chr1q31.3 associated with CFHR5 levels. We showed that higher CFHR5 levels are associated with increased thrombin generation in patient plasma and that recombinant CFHR5 enhances platelet activation in vitro. Thrombotic complications are a frequent feature of COVID-19; in hospitalised patients we found CFHR5 levels at baseline were associated with short-time prognosis of disease severity, defined as maximum level of respiratory support needed during hospital stay. Our results indicate a clinically important role for regulation of the alternative pathway of complement activation in the pathogenesis of VTE and pulmonary complications in acute COVID-19. Thus, CFHR5 is a potential diagnostic and/or risk predictive plasma biomarker reflecting underlying pathology in VTE and acute COVID-19.

High rate of BA.1, BA.1.1 and BA.2 in triple vaccinated

BackgroundBooster vaccine doses offer protection against severe COVID-19 caused by omicron but are less effective against infection. Characteristics such as serological correlates of protection, viral abundance, and clearance of omicron infection in triple vaccinated individuals are scarce. MethodsWe conducted a 4-week twice-weekly SARS-CoV-2 qPCR screening shortly after an mRNA vaccine booster in 368 healthcare workers. Spike-specific IgG levels and neutralization titers were determined at study start. qPCR-positive participants were sampled repeatedly for two weeks and monitored for symptoms. ResultIn total 81 (cumulative incidence 22%) omicron infections were detected, divided between BA.1, BA.1.1 and BA.2. Increasing post-booster antibody titers were protective against infection (p<0.05), linked to reduced viral load (p<0.01) and time to viral clearance (p<0.05). Only 10% of infected participants remained asymptomatic through the course of their infection. Viral load peaked at day 3 and live virus could be detected for up to 9 days after first PCR-positive sample. Presence of symptoms correlated to elevated viral load (p<0.0001), but despite resolution of symptoms most participants showed Ct levels <30 at day 9. No significant differences were observed for viral load and time to viral clearance between BA.1, BA.1.1 and BA.2 infected individuals. ConclusionWe report a high incidence of omicron infection despite recent booster vaccination in triple vaccinated individuals. Increasing levels of vaccine-induced spike-specific WT antibodies entail increased protection against infection and reduce viral load if infected. High viral load and secretion of live virus for up to nine days may facilitate transmission in a triple vaccinated population.

High prevalence of olfactory disorders 18 months after contracting COVID-19

BackgroundMore than a year after recovering from COVID-19, a large proportion of individuals still report olfactory dysfunctions. However, olfactory dysfunction was common also before the COVID-19 pandemic. To establish the prevalence of olfactory dysfunction while controlling for existing cases, we tested individuals with established COVID-19 in the first wave of the pandemic using psychophysical testing of smell functions. MethodsParticipants were regularly tested for SARS-CoV-2 IgG antibodies since the start of the pandemic. To assess normal rate of dysfunction in the population and skewed recruitment of individuals with prior olfactory dysfunction, SARS-CoV-2 IgG naive individuals were tested as a control group. ResultsOne and a half years after COVID-19, 37% of individuals who recovered from COVID-19 demonstrated a clinical reduction in their sense of smell, compared to only 20% of the control group. Critically, 51% of COVID-19-recovered individuals reported parosmia symptoms, compared to only 5% in the control group. ConclusionsIn summary, a full 65% of individuals who recovered from COVID-19 experienced some form of olfactory dysfunction 18 months later. This means that the first wave of COVID-19 increased the prevalence of a clinical reduction in the sense of smell in the population with 17 percentage points and the prevalence of any form of olfactory dysfunction with a staggering 41 percentage points when compared to individuals not infected by the virus. Given the amount of time since the initial insult to the olfactory system, it is likely that these olfactory problems are permanent in a plurality of patients.

Clinical grade ACE2 effectively inhibits SARS-CoV-2 Omicron infections

The recent emergence of the SARS-CoV-2 variant Omicron has caused considerable concern due to reduced vaccine efficacy and escape from neutralizing antibody therapeutics. Omicron is spreading rapidly around the globe and is suspected to account for most new COVID-19 cases in several countries, though the severity of Omicron-mediated disease is still under debate. It is therefore paramount to identify therapeutic strategies that inhibit the Omicron SARS-CoV-2 variant. Here we report using 3D structural modelling that Spike of Omicron can still associate with human ACE2. Sera collected after the second mRNA-vaccination did not exhibit a protective effect against Omicron while strongly neutralizing infection of VeroE6 cells with the reference Wuhan strain, confirming recent data by other groups on limited vaccine and convalescent sera neutralization efficacy against Omicron. Importantly, clinical grade recombinant human soluble ACE2, a drug candidate currently in clinical development, potently neutralized Omicron infection of VeroE6 cells with markedly enhanced potency when compared to reference SARS-CoV-2 isolates. These data show that SARS-CoV-2 variant Omicron can be readily inhibited by soluble ACE2, providing proof of principle of a viable and effective therapeutic approach against Omicron infections.

Impact of SARS-CoV-2 infection on longitudinal vaccine immune responses

People with previous SARS-CoV-2 infection mount potent immune responses to COVID-19 vaccination, but long-term effects of prior infection on these immune responses are unknown. We investigated the long-term impact of prior SARS-CoV-2 infection on humoral and cellular immune responses in healthcare workers receiving the mRNA BNT162b2 or the adenovirus vectored ChAdOx1 nCoV-19 vaccine. Vaccination with both vaccine platforms resulted in substantially enhanced T cell immune responses, antibody responses to spike and neutralizing antibodies effective against ten SARS-CoV-2 variants following SARS-CoV-2 infection, compared to in naive individuals. The enhanced immune responses sustained over seven months following vaccination. These findings imply that prior infection should be taken into consideration when planning booster doses and design of current and future COVID-19 vaccine programs. One-Sentence SummarySARS-CoV-2 infection prior to vaccination leads to substantial and durable increases in immune memory responses.

Neutralization of VOCs including Delta one year post COVID-19 or vaccine

BackgroundSARS-CoV-2 variants, such as Alpha, Beta, Gamma and Delta, are raising concern about the efficiency of neutralizing antibodies (NAb) induced by wild-type infection or vaccines based on the wild-type spike. MethodsWe determined IgG and NAb against SARS-CoV-2 variants one year following mild wild-type infection (n=104) and two-dose regimens with BNT162b2 (BNT/BNT) (n=67), ChAdOx1 (ChAd/ChAd) (n=82), or heterologous ChAdOx1 followed by BNT162b2 (ChAd/BNT) (n=116). FindingsWild type spike IgG and NAb remained detectable in 80% (83/104) of unvaccinated participants one year post mild infection. The neutralizing capacity was similar against wild type (reference), Alpha (0.95 (0.92-0.98) and Delta 1.03 (0.95-1.11) but significantly reduced against Beta (0.54 (0.48-0.60)) and Gamma 0.51 (0.44-0.61). Similarly, BNT/BNT and ChAd/ChAd elicited sustained capacity against Alpha and Delta (1.01 (0.78-1.31) and 0.85 (0.64-1.14)) and (0.96 (0.84-1.09) and 0.82 (0.61-1.10) respectively), with reduced capacity against Beta (0.67 (0.50-0.88) and 0.53 (0.40-0.71)) and Gamma (0.12 (0.06-0.27) and 0.54 (0.37-0.80)). A similar trend was found following ChAd/BNT (0.74 (0.66-0.83) and 0.70 (0.50-0.97) against Alpha and Delta and 0.29 (0.20-0.42) and 0.13 (0.08-0.20) against Beta and Gamma). InterpretationPersistent neutralization of the wide-spread Alpha and Delta variants one year after wild-type infection may aid vaccine policy makers in low-resource settings when prioritizing vaccine supply. The reduced capacity of neutralizing Beta and Gamma strains, but not the Alpha and Delta strains following both infection and three different vaccine regimens argues for caution against Beta and Gamma-exclusive mutations in the efforts to optimize next generation SARS-CoV-2 vaccines. FundingA full list of funding bodies that contributed to this study can be found in the Acknowledgements section

Antibody Responses After a Single Dose of ChAdOx1 nCoV-19 Vaccine in Healthcare Workers Previously Infected with SARS-CoV-2

BackgroundRecent reports demonstrate robust serological responses to a single dose of messenger RNA (mRNA) vaccines in individuals previously infected with SARS-CoV-2. Data on immune responses following a single-dose adenovirus-vectored vaccine expressing the SARS-CoV-2 spike protein (ChAdOx1 nCoV-19) in individuals with previous SARS-CoV-2 infection are however limited, and current guidelines recommend a two-dose regime regardless of preexisting immunity. MethodsWe compared spike-specific IgG and pseudo-neutralizing spike-ACE2 blocking antibodies against SARS-CoV-2 wild type and variants B.1.1.7, B.1.351, and P1 following two doses of the mRNA vaccine BNT162b2 and a single dose of the adenovector vaccine ChAdOx1 nCoV-19 in 232 healthcare workers with and without previous COVID-19. FindingsThe post-vaccine levels of spike-specific IgG and neutralizing antibodies against the SARS-CoV-2 wild type and all three variants of concern were similar or higher in participants receiving a single dose of ChAdOx1 nCoV-19 vaccine post SARS-CoV-2 infection (both < 11 months post infection (n=37) and [≥] 11 months infection (n=46)) compared to participants who received two doses of BNT162b2 vaccine (n=149). InterpretationOur data support that a single dose ChAdOx1 nCoV-19 vaccine serves as an effective immune booster after priming with natural SARS-CoV-2 infection up to at least 11 months post infection.

Soluble angiotensin-converting enzyme 2 is transiently elevated in COVID-19 and correlates with specific inflammatory and endothelial markers

RationaleAngiotensin-converting enzyme 2 (ACE2) is the main entry receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but how SARS-CoV-2 interactions with ACE2 influences the renin-angiotensin system (RAS) in Coronavirus disease 2019 (COVID-19) is unknown. ObjectiveTo measure circulating ACE2 and ACE levels in COVID-19 patients and investigate association with risk factors, outcome and inflammatory markers. Methods and resultsSoluble ACE2 (sACE2) and sACE concentrations were measured by ELISA in plasma samples from 114 hospital-treated COVID-19 patients and 10 healthy controls. Follow-up samples after four months were available for 58/114 patients. Von Willebrand factor (VWF), factor VIII (fVIII), D-dimer, interleukin 6 (IL-6), tumor necrosis factor and plasminogen activator inhibitor 1 (PAI-1) had previously been determined. Levels of sACE2 were higher in COVID-19 patients than in healthy controls, median 5.0 (interquartile range 2.8-11.8) ng/ml versus 1.4 (1.1-1.6) ng/ml, p < 0.0001. sACE2 was higher in men than women, but were not affected by other risk factors for severe COVID-19. sACE 2 decreased to 2.3 (1.6-3.9) ng/ml at follow-up, p < 0.0001, but remained higher than in healthy controls, p=0.012. Follow-up sACE2 levels were higher with increasing age, BMI, total number of comorbidities, for patients with diabetes and patients on RAS-inhibition. sACE was marginally lower during COVID-19 compared with at follow-up, 57 (45-70) ng/ml versus 72 (52-87) ng/ml, p=0.008. Levels of sACE2 and sACE did not differ depending on survival or disease severity (care level, respiratory support). sACE2 during COVID-19 correlated with VWF, fVIII and D-dimer, while sACE correlated with IL-6, TNF and PAI-1. ConclusionssACE2 was transiently elevated in COVID-19, likely due to increased shedding from infected cells. sACE2 and sACE during COVID-19 differed distinctly in their correlations with markers of inflammation and endothelial dysfunction, suggesting release from different cell types and/or vascular beds.

SARS-CoV-2 induces a durable and antigen specific humoral immunity after asymptomatic to mild COVID-19 infection

Current SARS-CoV-2 serological assays generate discrepant results, and the longitudinal characteristics of antibodies targeting various antigens after asymptomatic to mild COVID-19 are yet to be established. This longitudinal cohort study including 1965 healthcare workers, of which 381 participants exhibited antibodies against the SARS-CoV-2 spike antigen at study inclusion, reveal that these antibodies remain detectable in most participants, 96%, at least four months post infection, despite having had no or mild symptoms. Virus neutralization capacity was confirmed by microneutralization assay in 91% of study participants at least four months post infection. Contrary to antibodies targeting the spike protein, antibodies against the nucleocapsid protein were only detected in 80% of previously anti-nucleocapsid IgG positive healthcare workers. Both anti-spike and anti-nucleocapsid IgG levels were significantly higher in previously hospitalized COVID-19 patients four months post infection than in healthcare workers four months post infection (p=2*10-23 and 2*10-13 respectively). Although the magnitude of humoral response was associated with disease severity, our findings support a durable and functional humoral response after SARS-CoV-2 infection even after no or mild symptoms. We further demonstrate differences in antibody kinetics depending on the antigen, arguing against the use of the nucleocapsid protein as target antigen in population-based SARS-CoV-2 serological surveys.

SARS-CoV-2 exposure, symptoms and seroprevalence in health care workers

BackgroundSARS-CoV-2 may pose an occupational health risk to health care workers, but the prevalence of infections in this population is unknown. We examined the seroprevalence of SARS-CoV-2 antibodies among health care workers at a large acute care hospital in Stockholm, Sweden. We determined correlations between seroprevalence, self-reported symptoms and occupational exposure to SARS-CoV-2. Methods and findingsAll employees at Danderyd Hospital (n=4375) were invited to participate in a cross-sectional study. 2149 employees from all hospital departments were enrolled in the study between April 14th and May 8th 2020. Study participants completed a questionnaire consisting of symptoms compatible with SARS-CoV-2 infection since January 2020 and occupational exposure to patients infected with SARS-CoV-2. IgG antibodies against SARS-CoV-2 were analyzed using a multiplex assay evaluated to have 99.4% sensitivity and 99.1% specificity. The over-all seroprevalence among 2149 participants was 19.1% (n=410). There was no difference in age or sex between seropositive and seronegative participants. The symptoms with the strongest correlation to seroprevalence were anosmia and ageusia, with odds ratios of 28.4 (p=2.02*10^-120) and 19.2 (p=1.67*10^-99) respectively. Seroprevalence was strongly associated with patient-related work (OR 2.9, p=4.24*10^-8), covid-19 patient contact (OR 1.43, p=0.003), and occupation as assisting nurse (OR 3.67, p=2.16*10^-9). ConclusionThese results demonstrate that anosmia and ageusia should be included in screening guidance and in the recommendations of self-isolation to reduce further spread of SARS-CoV-2. The results furthermore imply an occupational health risk for SARS-CoV-2 infection among hospital workers. Continued measures are warranted to assure healthcare worker safety and reduce transmission from health care settings to the community during the covid-19 outbreak.