SARS-CoV-2 spike antigen-specific B cell and antibody responses in pre-vaccination period COVID-19 convalescent males and females with or without post-covid condition

Anti-nucleocapsid and anti-spike antibody trajectories in people with post-covid condition versus acute-only infections: a nested longitudinal case-control study within the Virus Watch prospective cohort

People with Post-Covid Condition (PCC) may demonstrate aberrant immune responses post-infection; however, serological follow-up studies are limited. We aim to compare SARS-CoV-2 serological responses to infection and vaccination in people who develop PCC versus those with an acute infection only. Participants (n = 2010) are a sub-cohort of the Virus Watch community cohort in England who provided monthly finger-prick serological samples. We compare the likelihood of post-infection seroconversion using logistic mixed models and the trajectories of anti-nucleocapsid (anti-N) and anti-spike (anti-S) antibodies using linear mixed models. Participants who developed PCC (n = 394) have 1.8x the odds of post-infection seroconversion for anti-N antibodies compared to those with an acute infection only (n = 1616) (odds ratio= 1.81 (95% confidence interval (CI) 1.16-2.90); however, these results are moderated by vaccination status and variant - with differences observed in pre-Omicron, unvaccinated participants. Anti-N levels, however, were elevated within 200 days post-infection in people with PCC compared to those without, after accounting for variant and vaccination status. Vaccination response (anti-S) pre- or post-infection did not systematically differ between groups. People with PCC demonstrate persistently higher anti-N antibody levels following primary infection compared to those with an acute infection only. These findings extend emerging evidence around infection-related immune activation and PCC.

robiotics nfluencing esponse of ntibodies over ime in eniors after VID-19 accine (PIRATES-COV): a randomised controlled trial protocol

INTRODUCTION

The elderly are particularly vulnerable to morbidity and mortality from COVID-19, the disease caused by the SARS-CoV-2. Approximately 20% of the elderly showed no antibodies 3-5 months post-second dose of the COVID-19 vaccine. As probiotics have been shown to increase influenza-specific antibody levels post-influenza vaccination, we aim to reduce the percentage of participants without antibodies against the SARS-CoV-2 spike protein receptor-binding domain (anti-S1-RBD) at 6 months post-vaccination.

METHODS AND ANALYSIS

Our study design is a double-blind randomised controlled trial, using intention-to-treat analysis. Eligible participants are a purposive sample of 688 adults aged 65-89 years, in Quebec, Canada, not diagnosed with COVID-19 in the 3 months prior to recruitment and who wish to receive a government-recommended mRNA booster (Pfizer-BioNTech, Moderna) vaccine. The intervention consists of one capsule/day of a probiotic dietary supplement of Lacticaseibacillus rhamnosus and Lacticaseibacillus casei 6×109 CFU/capsule or a placebo, for 15 days pre-booster and post-booster vaccine. All participants provide dried blood spot samples at three timepoints (inclusion, 3 and 6 months post-vaccination) and a stool sample for microbiome analysis. A subgroup of 100 participants living near Sherbrooke, Quebec, is expected to volunteer for two onsite blood-test visits (at inclusion and 6 months post-vaccination). The primary outcome is the percentage of participants without anti-S1-RBD antibodies at 6 months post-vaccination. Secondary outcomes include longitudinal analysis of anti-S1-RBD and anti-N antibodies at three timepoints. In the subgroup, serum levels of neutralising antibodies will be determined at inclusion and 6 months post-vaccination. Probiotic and vaccine side effects are monitored. At the end of the study, we expect to identify the adjuvant effect of probiotic on vaccine-induced immune response.

ETHICS AND DISSEMINATION

The study was approved by Research Ethics Board of the Centre Intégré Universitaire de Santé et des Services Sociaux de l'Estrie- Centre Hospitalier Universitaire de Sherbrooke (CIUSSS de l'Estrie-CHUS) and the CHU de Québec-Université Laval # MP-31-2022-4598 as well as Health Canada. All participants will provide informed consent. Results will be disseminated to the scientific community and to all networks related in this research.

TRIAL REGISTRATION NUMBER

NCT05195151.

Anti-SARS-CoV-2 Antibodies in Long-COVID-Markers of Protection or Elevated Risk? A Systematic Review

Long-COVID affects a significant number of COVID-19 survivors, profoundly impacting daily life and work. Although research suggests a potential link between antibody levels and long-COVID risk, findings remain inconclusive. Understanding antibody dynamics could support the identification of patients at risk, improve long-COVID diagnosis, and guide protective strategies such as vaccination. Despite growing evidence, no systematic review has yet evaluated the current literature on this topic. We therefore aimed to synthesise and evaluate existing evidence on the association between anti-SARS-CoV-2 antibody titres and long-COVID, with the goal of clarifying their potential role in predicting long-COVID risk, guiding patient management, and informing future research directions. Studies published in PubMed/Medline databases between January 2020 and October 2024 were included without language restrictions. Studies on body fluids other than serum/blood were excluded. Study selection and quality assessment was conducted independently by two researchers. After screening 949 studies, 58 studies encompassing 53,739 individuals, and 7812 long-COVID patients, were included. Evidence was highly heterogenous but most studies reported an association between anti-SARS-CoV-2-spike antibodies and long-COVID, although the nature of the association appeared to be dependent on time from acute infection. Low anti-SARS-CoV-2-spike antibodies during acute COVID-19 were associated with increased risk of long-COVID. The association between low anti-SARS-CoV-2-spike antibodies during acute COVID-19 and long-COVID suggests that maintaining sufficiently high antibody levels may be protective. However, the current evidence level is low and further studies with sufficient power are required to confirm this association and to potentially determine protective cutoffs.

Impact of a tailored exercise regimen on physical capacity and plasma proteome profile in post-COVID-19 condition

Background

Individuals affected by the post-covid condition (PCC) show an increased fatigue and the so-called post-exertion malaise (PEM) that led health professionals to advise against exercise although accumulating evidence indicates the contrary. The goal of this study is to determine the impact of a closely monitored 8-week mixed exercise program on physical capacity, symptoms, fatigue, systemic oxidative stress and plasma proteomic profiles of PCC cases.

Methods

Twenty-five women and men with PCC were assigned sequentially to exercise (n = 15) and non-exercise (n = 10) groups. Individuals with no PCC served as a control group. The exercise program included cardiovascular and resistance exercises. Physical capacity, physical activity level and the presence of common PCC symptoms were measured before and after the intervention. Fatigue was measured the day following each exercise session. Plasma and PBMC samples were collected at the beginning and end of the training program. Glutathione and deoxyguanosine levels in PBMC and plasma proteomic profiles were evaluated.

Results

Bicep Curl (+15% vs 4%; p = 0.040) and Sit-to-Stand test (STS-30 (+31% vs +11%; p = 0.043)) showed improvement in the exercise group when compared to the non-exercise group. An interaction effect was also observed for the level of physical activity (p =0.007) with a positive effect of the program on their daily functioning and without any adverse effects on general or post-effort fatigue. After exercise, glutathione levels in PBMCs increased in women but remained unchanged in men. Discernable changes were observed in the plasma proteomics profile with certain proteins involved in inflammatory response decreasing in the exercise group.

Conclusions

Supervised exercise adapted to the level of fatigue and ability is safe and effective in PCC patients in improving their general physical capacity and wellbeing. Systemic molecular markers that accompany physical improvement can be monitored by analyzing plasma proteomics and markers of oxidative stress. Large-scale studies will help identify promising molecular markers to objectively monitor patient improvement.

Lymphocyte B Subtypes in Peripheral Blood: A Prognostic Biomarker for COVID-19 Patients

BACKGROUND

In view of the scientific gap in knowledge of the involvement of the B-cell compartment and clinical prognostic in SARS-CoV-2 infection, this work aims to evaluate the B-cell subsets and the presence of specific IgM and IgG, as well as neutralizing antibodies against SARS-CoV-2, in unvaccinated patients diagnosed with COVID-19.

METHODS

This study included 133 patients with COVID-19. Cellular components were assessed by flow cytometry, and immunoglobulin levels and reactivity were measured by indirect enzyme-linked immunosorbent assay.

RESULTS

Our results showed no changes in less differentiated B cells. However, non-switched memory B cells (NS-MBCs) and class-switched memory B cells (CS-MBCs) were reduced in the patients with moderate disease. Also, plasmablasts and double-negative (DN) or "atypical" memory B cells were increased in groups of patients with moderate to critical conditions. In addition, the production of IgM, IgG, and neutralizing antibodies against SARS-CoV-2 demonstrated a positive correlation between the positivity of antibodies against SARS-CoV-2 and disease severity. Besides being related to the development of a more severe course of the disease, the increase in DN B-cell count also contributed to a poorer disease outcome in patients with a higher percentage of these cells. On the other hand, we observed an increase in the absolute number of CS-MBCs in patients with greater chances of survival.

CONCLUSIONS

This study demonstrates that the B-cell compartment may contribute to the development of clinical symptoms of COVID-19, with changes in B-cell subset counts linked to disease course and patient prognosis.