Detection and predictors of anti-SARS-CoV-2 antibody levels in COVID-19 patients at 8 months after symptom onset

Long-term SARS-CoV-2 neutralizing antibody level prediction using multimodal deep learning: A prospective cohort study on longitudinal data in Wuhan, China

The ongoing epidemic of SARS-CoV-2 is taking a substantial financial and health toll on people worldwide. Assessing the level and duration of SARS-CoV-2 neutralizing antibody (Nab) would provide key information for government to make sound healthcare policies. Assessed at 3-, 6-, 12-, and 18-month postdischarge, we described the temporal change of IgG levels in 450 individuals with moderate to critical COVID-19 infection. Moreover, a data imputation framework combined with a novel deep learning model was implemented to predict the long-term Nab and IgG levels in these patients. Demographic characteristics, inspection reports, and CT scans during hospitalization were used in this model. Interpretability of the model was further validated with Shapely Additive exPlanation (SHAP) and Gradient-weighted Class Activation Mapping (GradCAM). IgG levels peaked at 3 months and remained stable in 12 months postdischarge, followed by a significant decline in 18 months postdischarge. However, the Nab levels declined from 6 months postdischarge. By training on the cohort of 450 patients, our long-term antibody prediction (LTAP) model could predict long-term IgG levels with relatively high area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, and F1-score, which far exceeds the performance achievable by commonly used models. Several prognostic factors including FDP levels, the percentages of T cells, B cells and natural killer cells, older age, sex, underlying diseases, and so forth, served as important indicators for IgG prediction. Based on these top 15 prognostic factors identified in IgG prediction, a simplified LTAP model for Nab level prediction was established and achieved an AUC of 0.828, which was 8.9% higher than MLP and 6.6% higher than LSTM. The close correlation between IgG and Nab levels making it possible to predict long-term Nab levels based on the factors selected by our LTAP model. Furthermore, our model identified that coagulation disorders and excessive immune response, which indicate disease severity, are closely related to the production of IgG and Nab. This universal model can be used as routine discharge tests to identify virus-infected individuals at risk for recurrent infection and determine the optimal timing of vaccination for general populations.

Immunoglobulin G follow-up and immune response longevity analysis in SARS-CoV-2 convalescent patients and vaccinated individuals: A longitudinal analysis

BACKGROUND

Although the detection of immunoglobulin G (IgG) molecules has long been considered to be crucial for successful humoral immune defence against infections and harmful metabolites, it has become increasingly important in relation to SARS-CoV-2 research.

OBJECTIVE

To compare longitudinal changes in IgG titres in post-infection and post-vaccination Iraqi participants, and to estimate the protective benefits of the two principal vaccines used in Iraq.

METHODS

This quantitative study used samples from SARS-CoV-2 recovered patients (n= 75), those vaccinated with two doses of Pfizer or Sinopharm vaccine (n= 75), and healthy unvaccinated individuals (n= 50) who formed a control group. Participant ages (range 20-80 years) and sex (52.7% men, 47.3% females). An enzyme-linked immunosorbent assay was used to measure IgG.

RESULTS

IgG antibody levels peaked in the first month and tapered off in the following three months in both convalescent and vaccinated groups. The latter showed a significant decrease in IgG titres than in the convalescent group. Samples from the group given the mRNA vaccination that targeted spike (S) proteins might have a cross-reactivity between nucleocapsid (N) and spike (S) proteins.

CONCLUSIONS

Participants who had recovered from or who were vaccinated against SARS-CoV-2 exhibited a protective, persistent and durable humoral immune response for at least a month. This was more potent in the SARS-CoV-2 convalescent group compared to the vaccinated cohort. The IgG titres decayed faster after vaccination with Sinopharm than following the Pfizer-BioNTech vaccine.

The Levels of Anti-SARS-CoV-2 Spike Protein IgG Antibodies Before and After the Third Dose of Vaccination Against COVID-19

Purpose

The COVID-19 pandemic has been going on for almost three years, and so far, many preventive and therapeutic strategies have been developed. The issue of subsequent booster vaccinations is currently being discussed. We aimed to analyze how the third dose of vaccination against COVID-19 correlates with the dynamics of IgG anti-SARS-CoV-2 spike protein antibody levels in a group of healthy people.

Patients and Methods

The prospective study included 93 participants before and after a second booster of COVID-19 vaccination, from whom 4 blood samples were collected at intervals. The levels of IgG anti-SARS-CoV-2 in serum were identified using the chemiluminescent immunoassay specific for the receptor-binding domain (RBD) of the S1 protein. The analysis of the results was performed using appropriate statistical methods, considering p <0.05 as a statistically significant value.

Results

The IgG levels were significantly higher and less diverse after the same follow-up time from the second booster vaccination compared to the first booster. The antibody levels were positively correlated with female, healthcare workers, the elderly and participants with a negative COVID-19 history. Furthermore, the increase in IgG antibodies after the second booster vaccination correlated inversely with the baseline level of antibodies before the vaccination. The latest results showed that antibody levels dropped 1.5-fold after approx. 10 months from the second booster vaccination but still remained at a protective level.

Conclusion

Booster vaccinations seem to better stimulate immune memory, and in the case of borderline IgG level induces the greatest increase in antibodies. It is worth considering the individual parameters of patients and measuring antibodies before vaccination.

Major alterations to monocyte and dendritic cell subsets lasting more than 6 months after hospitalization for COVID-19

Introduction

After more than two years the Coronavirus disease-19 (COVID-19) pandemic continues to burden healthcare systems and economies worldwide, and it is evident that the effects on the immune system can persist for months post-infection. The activity of myeloid cells such as monocytes and dendritic cells (DC) is essential for correct mobilization of the innate and adaptive responses to a pathogen. Impaired levels and responses of monocytes and DC to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is likely to be a driving force behind the immune dysregulation that characterizes severe COVID-19.

Methods

Here, we followed a cohort of COVID-19 patients hospitalized during the early waves of the pandemic for 6-7 months. The levels and phenotypes of circulating monocyte and DC subsets were assessed to determine both the early and long-term effects of the SARS-CoV-2 infection.

Results

We found increased monocyte levels that persisted for 6-7 months, mostly attributed to elevated levels of classical monocytes. Myeloid derived suppressor cells were also elevated over this period. While most DC subsets recovered from an initial decrease, we found elevated levels of cDC2/cDC3 at the 6-7 month timepoint. Analysis of functional markers on monocytes and DC revealed sustained reduction in program death ligand 1 (PD-L1) expression but increased CD86 expression across almost all cell types examined. Finally, C-reactive protein (CRP) correlated positively to the levels of intermediate monocytes and negatively to the recovery of DC subsets.

Conclusion

By exploring the myeloid compartments, we show here that alterations in the immune landscape remain more than 6 months after severe COVID-19, which could be indicative of ongoing healing and/or persistence of viral antigens.