Vaccination and protective immunity to SARS-CoV-2 omicron variants in people with immunodeficiencies

Airway and Systemic Immune Responses Following the Third COVID-19 Vaccination in COPD Patients

Introduction

Booster vaccinations are required to maintain protection against COVID-19. COPD patients are at higher risk of developing severe illness following SARS-CoV-2 infection. Previous cross-sectional analysis after the second COVID-19 booster showed similar immune responses in COPD patients and controls, but pre-vaccination samples were not available. This longitudinal study evaluated systemic and airway immune responses in COPD patients using samples obtained pre- and post-third COVID-19 vaccination.

Methods

Twelve COPD patients were recruited, with plasma, nasal and sputum (n = 10) samples collected pre-vaccination and 4- and 14-weeks post vaccination. Samples were analyzed for anti-spike IgA and IgG and cellular immunity. The ability of plasma and nasal samples to block ACE2-spike protein interaction was assessed for Wild type, Delta, and Omicron spike variants.

Results

Vaccinations increased anti-spike IgG in plasma (p < 0.001), nasal (IgG p < 0.001) and sputum (p = 0.002) samples, IgA in plasma (p < 0.001) and blood cellular immunity (p = 0.001). Plasma and nasal anti-spike IgA levels correlated (rho: 0.6, p = 0.02), with similar results for IgG (rho: 0.79, p = 0.003). Post-vaccination nasal (p = 0.002) and plasma (p < 0.001) samples were less effective at blocking Omicron spike binding to ACE2 compared to the Wild type spike variant.

Discussion

Airway and systemic immune responses against SARS-CoV-2 increased in COPD patients following a third COVID-19 vaccination. Nasal and systemic responses in COPD patients were less effective against Omicron variant compared to previous variants.

The Antiviral Activity of the Lectin Griffithsin against SARS-CoV-2 Is Enhanced by the Presence of Structural Proteins

Although COVID-19 transmission has been reduced by the advent of vaccinations and a variety of rapid monitoring techniques, the SARS-CoV-2 virus itself has shown a remarkable ability to mutate and persist. With this long track record of immune escape, researchers are still exploring prophylactic treatments to curtail future SARS-CoV-2 variants. Specifically, much focus has been placed on the antiviral lectin Griffithsin in preventing spike protein-mediated infection via the hACE2 receptor (direct infection). However, an oft-overlooked aspect of SARS-CoV-2 infection is viral capture by attachment receptors such as DC-SIGN, which is thought to facilitate the initial stages of COVID-19 infection in the lung tissue (called trans-infection). In addition, while immune escape is dictated by mutations in the spike protein, coronaviral virions also incorporate M, N, and E structural proteins within the particle. In this paper, we explored how several structural facets of both the SARS-CoV-2 virion and the antiviral lectin Griffithsin can affect and attenuate the infectivity of SARS-CoV-2 pseudovirus. We found that Griffithsin was a better inhibitor of hACE2-mediated direct infection when the coronaviral M protein is present compared to when it is absent (possibly providing an explanation regarding why Griffithsin shows better inhibition against authentic SARS-CoV-2 as opposed to pseudotyped viruses, which generally do not contain M) and that Griffithsin was not an effective inhibitor of DC-SIGN-mediated trans-infection. Furthermore, we found that DC-SIGN appeared to mediate trans-infection exclusively via binding to the SARS-CoV-2 spike protein, with no significant effect observed when other viral proteins (M, N, and/or E) were present. These results provide etiological data that may help to direct the development of novel antiviral treatments, either by leveraging Griffithsin binding to the M protein as a novel strategy to prevent SARS-CoV-2 infection or by narrowing efforts to inhibit trans-infection to focus on DC-SIGN binding to SARS-CoV-2 spike protein.

A community study of neutralizing antibodies against SARS-CoV-2 in China

Background

The immune background of the overall population before and after the outbreak of SARS-CoV-2 in China remains unexplored. And the level of neutralizing antibodies is a reliable indicator of individual immunity.

Objectives

This study aimed to assess the immune levels of different population groups during a viral outbreak and identify the factors influencing these levels.

Methods

We measured the levels of neutralizing antibodies in 12,137 participants using the COVID19 Neutralizing Antibody Detection kit. The dynamics of neutralizing antibodies were analyzed using a generalized additive model, while a generalized linear model and multi-factor analysis of variance were employed to investigate the influencing factors. Additionally, statistical methods were used to compare neutralizing antibody levels among subgroups of the real-world population.

Results

Participants who received booster doses exhibited significantly higher levels of neutralizing antibodies compared to those who received only one or two doses (p<0.001). Both elderly [22.55 (5.12, 62.03) IU/mL, 55%] and minors [21.41 (8.15, 45.06) IU/mL, 56%] showed lower positivity rates and neutralizing antibody levels compared to young adults [29.30 (9.82, 188.08) IU/mL, 62%] (p<0.001). Furthermore, the HIV-positive group demonstrated a slightly lower seropositivity rate compared to the healthy group across the three vaccination time points. Notably, three months after the large-scale infection, both the neutralizing antibody level and positivity rate in real-world populations were higher than the previous record [300 (300, 300) IU/mL, 89%; 27.10 (8.77, 139.28) IU/mL, 60%], and this difference was statistically significant.

Conclusions

Increasing vaccine dosage enhances neutralizing antibody levels, resulting in greater and longer-lasting immunity. Monitoring immune levels in older individuals and those with AIDS is crucial. Additionally, the neutralizing antibodies generated from vaccination have not yet reached the threshold for achieving herd immunity, while individuals exhibit higher immune levels following a large-scale infection. These findings provide valuable insights for guiding new strategies in vaccine administration.

Real-world clinical effectiveness of Tixagevimab/Cilgavimab and Regdanvimab monoclonal antibodies for COVID-19 treatment in Omicron variant-dominant period

Several virus-neutralizing monoclonal antibodies (mAbs) have become new tools in the treatment of the coronavirus disease (COVID-19), but their effectiveness against the rapidly mutating virus is questionable. The present study investigated the effectiveness of Tixagevimab/Cilgavimab and Regdanvimab for mild and moderate COVID-19 treatment in real-world clinical practice during the Omicron variant-dominant period. Patients with known risk factors for disease progression and increasing disease severity were enrolled in the study within the first 7 days of symptom onset. Seventy-seven patients were divided into four groups: first 15 patients received 300 mg Tixagevimab/Cilgavimab intravenously (IV) and 23 patients got the same drug 300 mg intramuscularly (IM), the next 15 patients was on the same combination in dose of 600 mg IV, and 24 patients were on Regdanvimab at a dose of 40 mg/kg IV. By Day 4, 100% of Tixagevimab/Cilgavimab IV patients showed negative polymerase chain reaction results for SARS-CoV-2 Ribonucleic acid (RNA) regardless of the mAbs dose while in the Regdanvimab group 29% of the patients were positive for SARS-CoV-2 virus RNA. The testing for virus neutralizing antibodies (nAbs) to various Omicron sublineages (BA.1, BA.2, and BA.5) showed that an increase in nAb levels was detected in blood serum immediately after the drug administration only in Tixagevimab/Cilgavimab 300 mg and 600 mg IV groups. In the group of intravenous Regdanvimab, a significant increase in the level of nAbs to the Wuhan variant was detected immediately after the drug administration, while no increase in nAbs to different Omicron sublineages was observed.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT05982704.

SARS-CoV-2 Infection and Response to COVID-19 Vaccination in Patients With Primary Immunodeficiencies

Primary immunodeficiencies (PIDs) are heterogeneous, rare disorders that increase susceptibility to infection and/or immune dysregulation. Individuals with certain PIDs are at high risk of severe or fatal outcomes from SARS-CoV-2 infections (the causative agent of COVID-19), either due to the underlying PID and/or due to the presence of comorbidities such as severe lung and liver disease. Vaccination remains the primary strategy to protect individuals with PID from COVID-19. However, populations with PID exhibit variable vaccine seroresponse rates, antibody titers, and neutralization activity depending on the type of PID and/or COVID-19 vaccine, and consequently, are at an elevated risk of severe disease. In this article, we review the COVID-19 burden in patients with PIDs and focus in-depth on findings from patients with predominantly antibody deficiencies or combined immunodeficiencies. We conclude by providing COVID-19 vaccination recommendations for this population.

Differential cellular and humoral immune responses in immunocompromised individuals following multiple SARS-CoV-2 vaccinations

Introduction

The heterogeneity of the immunocompromised population means some individuals may exhibit variable, weak or reduced vaccine-induced immune responses, leaving them poorly protected from COVID-19 disease despite receiving multiple SARS-CoV-2 vaccinations. There is conflicting data on the immunogenicity elicited by multiple vaccinations in immunocompromised groups. The aim of this study was to measure both humoral and cellular vaccine-induced immunity in several immunocompromised cohorts and to compare them to immunocompetent controls.

Methods

Cytokine release in peptide-stimulated whole blood, and neutralising antibody and baseline SARS-CoV-2 spike-specific IgG levels in plasma were measured in rheumatology patients (n=29), renal transplant recipients (n=46), people living with HIV (PLWH) (n=27) and immunocompetent participants (n=64) post third or fourth vaccination from just one blood sample. Cytokines were measured by ELISA and multiplex array. Neutralising antibody levels in plasma were determined by a 50% neutralising antibody titre assay and SARS-CoV-2 spike specific IgG levels were quantified by ELISA.

Results

In infection negative donors, IFN-γ, IL-2 and neutralising antibody levels were significantly reduced in rheumatology patients (p=0.0014, p=0.0415, p=0.0319, respectively) and renal transplant recipients (p<0.0001, p=0.0005, p<0.0001, respectively) compared to immunocompetent controls, with IgG antibody responses similarly affected. Conversely, cellular and humoral immune responses were not impaired in PLWH, or between individuals from all groups with previous SARS-CoV-2 infections.

Discussion

These results suggest that specific subgroups within immunocompromised cohorts could benefit from distinct, personalised immunisation or treatment strategies. Identification of vaccine non-responders could be critical to protect those most at risk.