Long-term dynamics of natural, vaccine-induced, and hybrid immunity to SARS-CoV-2 in a university hospital in Colombia: A cohort study (preprint)

This prospective cohort study aimed to estimate the natural, vaccine-induced, and hybrid immunity to SARS-CoV-2, alongside the immunogenicity of the mRNA-1273 booster after the BNT162b2 primary series in healthcare workers in Colombia. IgG, IgA, and neutralizing antibodies were measured in 110 individuals with SARS-CoV-2 infection or a BNT162b2 primary series. Humoral responses and related factors were explored in a subgroup (n = 36) that received a BNT162b2 primary series followed by a mRNA-1273 booster (2BNT162b2 + 1mRNA-1273), and T-cell responses were evaluated in a subgroup of them (n = 16). For natural immunity, IgG and IgA peaked within three months, declining gradually but remaining detectable up to 283 days post-infection. Neutralizing antibody inhibition post-infection was below positive range (≥ 35%) but exceeded 97% in vaccine-induced and hybrid immunity groups. Following 2BNT162b2 + 1mRNA-1273, IgG peaked 3–4 months post-booster, gradually declining but remaining positive over 10 months, with IgA and neutralizing antibodies stable. Age and blood group were related to IgG response, while obesity and blood type to IgA response post-booster. Autoimmunity and blood type B were associated with lower neutralizing antibody inhibition. There were no differences in T-cell responses according to prior infection. These findings provide long-term insights into the immunity against SARS-CoV-2 and the immunogenicity of mRNA vaccines.

Predictors of Mortality in Hospitalized Patients with COVID-19: A One-Year Case-Control Study (preprint)

Objective: To determine the associated factors with mortality, in addition to age and sex, in a high-complexity hospital in Bogota, Colombia, during the first year of the pandemic. Design: A case-control study. Setting: High-complexity center above 2,640 meters above sea level (masl) in Colombia. Methods: A case-control study was conducted on 564 patients admitted to the hospital with confirmed COVID-19. Deceased patients (n: 282) and a control group (n: 282), matched by age, sex, and month of admission, were included. Clinical and paraclinical variables were retrospectively obtained by systematic revision of clinical records. Multiple imputations by chained equation (MICE) were implemented to account for missing variables. Classification and regression trees (CART) were estimated to evaluate the interaction of associated factors on admission and their role in predicting mortality during hospitalization. Results: Most of the patients included were males in the seventh decade of life. Most of the admissions occurred between July and August 2021. Surprisingly, recovered patients reported heterogeneous symptomatology, whereas deceased patients were most likely to present respiratory distress, dyspnea, and seizures on admission. In addition, the latter group exhibited a higher burden of comorbidities and alterations in laboratory parameters. After the imputation of datasets, CART analysis estimated 14 clinical profiles based on respiratory distress, LDH, dyspnea, hemoglobin, D-dimer, ferritin, blood urea nitrogen, C-reactive protein, PaO2/FiO2, dysgeusia, total bilirubin, platelets, and gastroesophageal reflux disease. The accuracy model for prediction was 85.6% (P < 0.0001). Conclusion: Multivariate analysis yielded a reliable model to predict mortality in COVID-19. This analysis revealed new interactions between clinical and paraclinical features in addition to age and sex. Furthermore, this predictive model could offer new clues for the personalized management of this condition in clinical settings. Keywords: SARS-CoV-2, COVID-19, Mortality, Predictors, Risk Factors

The risk of COVID-19 death is much greater and age-dependent with type I IFN autoantibodies (preprint)

SARS-CoV-2 infection fatality rate (IFR) doubles with every five years of age from childhood onward. Circulating autoantibodies neutralizing IFN-α, IFN-ω, and/or IFN-β are found in ~20% of deceased patients across age groups. In the general population, they are found in ~1% of individuals aged 20-70 years and in >4% of those >70 years old. With a sample of 1,261 deceased patients and 34,159 uninfected individuals, we estimated both IFR and relative risk of death (RRD) across age groups for individuals carrying autoantibodies neutralizing type I IFNs, relative to non-carriers. For autoantibodies neutralizing IFN-α2 or IFN-ω, the RRD was 17.0[95% CI:11.7-24.7] for individuals under 70 years old and 5.8[4.5-7.4] for individuals aged 70 and over, whereas, for autoantibodies neutralizing both molecules, the RRD was 188.3[44.8-774.4] and 7.2[5.0-10.3], respectively. IFRs increased with age, from 0.17%[0.12-0.31] for individuals <40 years old to 26.7%[20.3-35.2] for those ≥80 years old for autoantibodies neutralizing IFN-α2 or IFN-ω, and from 0.84%[0.31-8.28] to 40.5%[27.82-61.20] for the same two age groups, for autoantibodies neutralizing both molecules. Autoantibodies against type I IFNs increase IFRs, and are associated with high RRDs, particularly those neutralizing both IFN-α2 and -ω. Remarkably, IFR increases with age, whereas RRD decreases with age. Autoimmunity to type I IFNs appears to be second only to age among common predictors of COVID-19 death.

Persistent Autoimmune Activation and Proinflammatory State in Post-COVID Syndrome (preprint)

Background The immunopathological pathways enabling post-COVID syndrome (PCS) development are not entirely known. We underwent a longitudinal analysis of patients with COVID-19 who developed PCS aiming to evaluate the autoimmune and immunological status associated with this condition. Methods Thirty-three patients were included for longitudinal clinical and autoantibody analyses of whom 12 patients were assessed for cytokines and lymphocyte populations. Patients were followed during 7-11 months after acute COVID-19. Autoimmune profile and immunological status were evaluated mainly by enzyme-linked-immunosorbent assays and flow cytometry. Results Latent autoimmunity and overt autoimmunity persisted over time. A proinflammatory state was observed in patients with PCS characterized by upregulated IFN-α, TNF-α, G-CSF, IL-17A, IL-6, IL-1β, and IL-13, whereas IP-10 was decreased. In addition, PCS was characterized by increased levels of Th9, CD8+ effector T cells, naive B cells, and CD4+ effector memory T cells. Total levels of IgG S1-SARS-CoV-2 antibodies remained elevated over time. Discussion The clinical manifestations of PCS are associated with the persistence of a proinflammatory, and effector phenotype induced by SARS-CoV-2 infection. This long-term persistent immune activation may contribute to the development of latent and overt autoimmunity. Results suggest the need to evaluate the role of immunomodulation in the treatment of PCS.

Post-COVID Syndrome. A Case Series and Comprehensive Review (preprint)

The existence of a variety of symptoms with a duration beyond the acute phase of COVID-19, is referred to as post-COVID syndrome (PCS). We aimed to report a series of patients with PCS attending a Post-COVID Unit and offer a comprehensive review on the topic. Adult patients with previously confirmed SARS-CoV-2 infection were systematically assessed through a semi-structured and validated survey. Total IgG, IgA and IgM serum antibodies to SARS-CoV-2 were evaluated by an electrochemiluminescence immunoassay. A systematic review of the literature and meta-analysis were conducted, following PRISMA guidelines. Univariate and multivariate methods were used to analyze data. Out of a total of 100 consecutive patients, 53 were women, the median of age was 49 years (IQR: 37.8 to 55.3), the median of post-COVID time after the first symptoms was 219 days (IQR: 143 to 258), and 65 patients were hospitalized during acute COVID-19. Musculoskeletal, digestive (i.e., diarrhea) and neurological symptoms including depression (by Zung scale) were the most frequent observed in PCS patients. A previous hospitalization was not associated with PCS manifestation. Arthralgia and diarrhea persisted in more than 40% of PCS patients. The median of anti-SARS-CoV-2 antibodies was 866.2 U/mL (IQR: 238.2 to 1681). Despite this variability, 98 patients were seropositive. Based on autonomic symptoms (by COMPASS 31) two clusters were obtained with different clinical characteristics. Levels of anti-SARS-CoV-2 antibodies were not different between clusters. A total of 40 articles (11,196 patients) were included in the meta-analysis. Fatigue/muscle weakness, dyspnea, pain and discomfort, anxiety/depression and impaired concentration were presented in more than 20% of patients reported. In conclusion, PCS is mainly characterized by musculoskeletal, pulmonary, digestive and neurological involvement including depression. PCS is independent of severity of acute illness and humoral response. Long-term antibody responses to SARS-CoV-2 infection and a high inter-individual variability were confirmed. Future studies should evaluate the mechanisms by which SARS-CoV-2 may cause PCS and the best therapeutic options.