Previous SARS-CoV-2 Infection, Age, and Frailty Are Associated With 6-Month Vaccine-Induced Anti-Spike Antibody Titer in Nursing Home Residents

OBJECTIVES

Older nursing home residents make up the population at greatest risk of morbidity and mortality from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. No studies have examined the determinants of long-term antibody responses post vaccination in this group.

DESIGN

Longitudinal cohort study.

SETTING AND PARTICIPANTS

Residents from 5 nursing homes assessed before vaccination, and 5 weeks and 6 months post vaccination, with the BNT162b2 messenger RNA SARS-CoV-2 vaccine.

METHODS

Comprehensive clinical assessment was performed, including assessment for comorbidity, frailty, and SARS-CoV-2 infection history. Serum nucleocapsid and anti-spike receptor binding domain (RBD) antibodies were analyzed at all timepoints. An in vitro angiotensin-converting enzyme (ACE2) receptor-spike RBD neutralization assay assessed serum neutralization capacity.

RESULTS

Of 86 participants (81.1 ± 10.8 years; 65% female), just under half (45.4%; 39 of 86) had evidence of previous SARS-CoV-2 infection. All participants demonstrated a significant antibody response to vaccination at 5 weeks and a significant decline in this response by 6 months. SARS-CoV-2 infection history was the strongest predictor of antibody titer (log-transformed) at both 5 weeks [β: 3.00; 95% confidence interval (CI): 2.32-3.70; P < .001] and 6 months (β: 3.59; 95% CI: 2.89-4.28; P < .001). Independent of SARS-CoV-2 infection history, both age in years (β: -0.05; 95% CI: -0.08 to -0.02; P < .001) and frailty (β: -0.22; 95% CI: -0.33 to -0.11; P < .001) were associated with a significantly lower antibody titer at 6 months. Anti-spike antibody titers at both 5 weeks and 6 months significantly correlated with in vitro neutralization capacity.

CONCLUSIONS AND IMPLICATIONS

In older nursing home residents, SARS-CoV-2 infection history was the strongest predictor of anti-spike antibody titers at 6 months, whereas age and frailty were independently associated with lower titers at 6 months. Antibody titers significantly correlated with in vitro neutralization capacity. Although older SARS-CoV-2 naïve nursing home residents may be particularly vulnerable to breakthrough SARS-CoV-2 infection, the relationship between antibody titers, SARS-CoV-2 infection, and clinical outcomes remains to be fully elucidated in this vulnerable population.

Kinetics of the SARS-CoV-2 Antibody Avidity Response Following Infection and Vaccination

Serological assays capable of measuring antibody responses induced by previous infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been critical tools in the response to the COVID-19 pandemic. In this study, we use bead-based multiplex assays to measure IgG and IgA antibodies and IgG avidity to five SARS-CoV-2 antigens (Spike (S), receptor-binding domain (RBD), Nucleocapsid (N), S subunit 2, and Membrane-Envelope fusion (ME)). These assays were performed in several cohorts of healthcare workers and nursing home residents, who were followed for up to eleven months after SARS-CoV-2 infection or up to six months after vaccination. Our results show distinct kinetic patterns of antibody quantity (IgG and IgA) and avidity. While IgG and IgA antibody levels waned over time, with IgA antibody levels waning more rapidly, avidity increased with time after infection or vaccination. These contrasting kinetic patterns allow for the estimation of time since previous SARS-CoV-2 infection. Including avidity measurements in addition to antibody levels in a classification algorithm for estimating time since infection led to a substantial improvement in accuracy, from 62% to 78%. The inclusion of antibody avidity in panels of serological assays can yield valuable information for improving serosurveillance during SARS-CoV-2 epidemics.

Disease-Modifying Treatments for Multiple Sclerosis Affect Measures of Cellular Immune Responses to EBNA-1 Peptides

BACKGROUND AND OBJECTIVES

Epstein-Barr virus (EBV) has been strongly implicated in the pathogenesis of multiple sclerosis (MS). Despite this, there are no routinely used tests to measure cellular response to EBV. In this study, we analyzed the cellular response to EBV nuclear antigen-1 (EBNA-1) in people with MS (pwMS) using a whole blood assay.

METHODS

This cross-sectional study took place in a dedicated MS clinic in a university hospital. We recruited healthy controls, people with epilepsy (PWE), and pwMS taking a range of disease-modifying treatments (DMTs) including natalizumab, anti-CD20 monoclonal antibodies (mAbs), dimethyl fumarate (DMF), and also treatment naïve. Whole blood samples were stimulated with commercially available PepTivator EBNA1 peptides and a control virus-cytomegalovirus (CMV) peptide. We recorded the cellular response to stimulation with both interferon gamma (IFN-γ) and interleukin-2 (IL-2). We also compared the cellular responses to EBNA1 with IgG responses to EBNA1, viral capsid antigen (VCA), and EBV viral load.

RESULTS

We recruited 86 pwMS, with relapsing remitting MS, in this group, and we observed a higher level of cellular response recorded with IFN-γ (0.79 IU/mL ± 1.36) vs healthy controls (0.29 IU/mL ± 0.90, p = 0.0048) and PWE (0.17 IU/mL ± 0.33, p = 0.0088). Treatment with either anti-CD20 mAbs (0.28 IU/mL ± 0.57) or DMF (0.07 IU/mL ± 0.15) resulted in a cellular response equivalent to control levels or in PWE (p = 0.26). The results of recording IL-2 response were concordant with IFN-γ: with suppression also seen with anti-CD20 mAbs and DMF. By contrast, we did not record any differential effect of DMTs on the levels of IgG to either EBNA-1 or VCA. Nor did we observe differences in cellular response to cytomegalovirus between groups.

DISCUSSION

This study demonstrates how testing and recording the cellular response to EBNA-1 in pwMS may be beneficial. EBNA-1 stimulation of whole blood samples produced higher levels of IFN-γ and IL-2 in pwMS compared with controls and PWE. In addition, we show a differential effect of currently available DMTs on this response. The functional assay deployed uses whole blood samples with minimal preprocessing suggesting that employment as a treatment response measure in clinical trials targeting EBV may be possible.

Characterisation of the pro-inflammatory cytokine signature in severe COVID-19

Clinical outcomes from infection with SARS-CoV-2, the cause of the COVID-19 pandemic, are remarkably variable ranging from asymptomatic infection to severe pneumonia and death. One of the key drivers of this variability is differing trajectories in the immune response to SARS-CoV-2 infection. Many studies have noted markedly elevated cytokine levels in severe COVID-19, although results vary by cohort, cytokine studied and sensitivity of assay used. We assessed the immune response in acute COVID-19 by measuring 20 inflammatory markers in 118 unvaccinated patients with acute COVID-19 (median age: 70, IQR: 58-79 years; 48.3% female) recruited during the first year of the pandemic and 44 SARS-CoV-2 naïve healthy controls. Acute COVID-19 was associated with marked elevations in nearly all pro-inflammatory markers, whilst eleven markers (namely IL-1β, IL-2, IL-6, IL-10, IL-18, IL-23, IL-33, TNF-α, IP-10, G-CSF and YKL-40) were associated with disease severity. We observed significant correlations between nearly all markers elevated in those infected with SARS-CoV-2 consistent with widespread immune dysregulation. Principal component analysis highlighted a pro-inflammatory cytokine signature (with strongest contributions from IL-1β, IL-2, IL-6, IL-10, IL-33, G-CSF, TNF-α and IP-10) which was independently associated with severe COVID-19 (aOR: 1.40, 1.11-1.76, p=0.005), invasive mechanical ventilation (aOR: 1.61, 1.19-2.20, p=0.001) and mortality (aOR 1.57, 1.06-2.32, p = 0.02). Our findings demonstrate elevated cytokines and widespread immune dysregulation in severe COVID-19, adding further evidence for the role of a pro-inflammatory cytokine signature in severe and critical COVID-19.

16 SARS-COV-2 INFECTION AND VACCINATION PATTERNS DETERMINE LONG-TERM ANTIBODY RESPONSES IN NURSING HOME RESIDENTS: DATA FROM NH-COVAIR

Background

Older Nursing Home Residents (NHRs) are at greatest risk of morbidity and mortality from SARS-CoV-2, particularly in the context of both waning vaccine efficacy and the emergence of Variants-of-Concern (VOCs). However, the determinants of long-term vaccine-induced protective antibody responses are yet to be determined in this group.

Methods

NH-COVAIR recruited older NHRs for comprehensive clinical and frailty (NH-FRAIL) assessment. Blood samples were obtained pre-vaccination, at 6-weeks and 6-months following primary vaccination and 6-months following booster vaccination. Antibody titres were measured using both an electrochemiluminescence assay and a custom bead-based array (Luminex™) to measure antibody titre and avidity for Wuhan strain/major VOC antigens. Stepwise adjusted linear regression (log-transformed) assessed longitudinal determinants of vaccine-induced antibody responses.

Results

Of 86 participants (81.1 ± 10.8 years; 65% female), just under half (45.4%) had evidence of previous SARS-CoV-2 infection. All NHRs mounted a significant antibody-response to vaccination at 5 weeks followed by a significant decrease in antibody titre by 6 months. Previous SARS-CoV-2 infection was the strongest predictor of antibody waning at all timepoints (β: 3.59; 2.89, 4.28; P < 0.001 for 6-months). Independent of infection history, both age (β: –0.05; –0.08, –0.02; p<0.001) and frailty (β: –0.22; –0.33, –0.11; p<0.001) were associated with faster antibody waning at 6-months. Cross-reactivity and avidity were significantly lower for Beta (B.1.351) and Gamma (P.1) VOC strains (all p<0.001). Additionally, there was faster antibody waning and significantly reduced antibody avidity to Beta and Gamma VOCs in SARS-CoV-2 naïve NHRs.

Conclusion

Older NHRs are capable of mounting protective antibody responses to SARS-CoV-2 vaccination. Responses were more durable, with a greater cross-reactivity to and avidity for VOCs in those with previous SARS-CoV-2 infection. Increasing age and greater frailty in NHRs was associated with faster antibody waning. Our findings support ongoing serological surveillance and use of additional vaccine doses in older NHRs, particularly in those without previous SARS-CoV-2 exposure.

177 GENOME-WIDE ASSOCIATION ANALYSIS OF THE FRAILTY PHENOTYPE IN UK BIOBANK HIGHLIGHTS CARDIOMETABOLIC AND AUTOIMMUNE SIGNATURES IN AGEING

Background

Frailty is a state of advanced biological age that is characterized by multisystem physiological decline and advanced risk to adverse health outcomes. One approach to defining frailty is using the Fried frailty phenotype, a five-point list of health-related criteria used to score individuals as non-frail, pre-frail, or frail. The biological basis of frailty is not fully understood, nor why some experience frailty at younger ages. Between 30%-45% of frailty risk is estimated to be genetic. This study aimed to investigate the genetic basis of frailty phenotype risk using data from UK Biobank.

Methods

UK Biobank is a large-scale biomedical database of community dwelling adults (n = 502,529, age range: 37-73 years, 54% female). UK Biobank has genome-wide genotyping (approx. 93 million variants), health, and demographic data for all participants. A genome-wide association study (GWAS) of the frailty phenotype was performed on British and Irish adults aged 60 to 70 years (n = 157,720) to identify heritable factors which predict frailty progression in later life. Functional mapping was performed to determine genes and biological pathways enriched in GWAS results.

Results

95 single nucleotide polymorphisms (SNPs) from three independent genomic risk loci were significantly associated (p &lt; 5e-8) with the frailty phenotype in UK Biobank participants. Three genes, PPP1R3A, LONRF2, and AIF1 were statistically enriched with genetic variants. Tissue-specific expression analysis indicated genes differentially expressed in blood vessels were enriched. Linkage Disequilibrium Score Regression (lambda = 1.2005, intercept = 1.0006) indicated GWAS test statistic inflation resulting from polygenicity. SNP-based heritability was estimated to be 6.34% (SE: 0.36%).

Conclusion

SNP-based heritability of the frailty phenotype was lower than expected in comparison to previous reports of 30%-45%. Statistically significant genomic risk loci, genes, and tissue-enrichment pointed towards dysregulation of cardiometabolic, cardiovascular, and immunological processes in frailty risk, contrasting to brain pathways enriched in previous genomic analyses of the frailty index.

Immune response in vaccinated healthcare workers with frequent COVID-19 infections is characterised by blunted IFNγ and IL-2 responses to SARS-CoV-2 variants

Healthcare workers (HCWs) are at increased risk of SARS-CoV-2 infection. Despite widespread vaccination, some HCWs develop frequent symptomatic infection. We hypothesised that HCWs with frequent symptomatic COVID-19 have impaired T and B cell mediated immunity to SARS-CoV-2. Vaccinated HCWs with no prior COVID infection (n = 9), asymptomatic recent infection (n = 10), and frequent recent infection (n = 15) were recruited from a longitudinal HCW cohort study. Whole blood stimulation with SARS-CoV-2 variants (Wuhan, B.1.617, BA.2, BA.2.75, BA.4/5, XBB.1.5, BQ.1.1) was performed, with IFNγ and IL-2 responses, total IgG produced, and anti-Spike antibody neutralising capacity measured. Frequent infections had similar IFNγ and IL-2 responses to the never infected group, with significantly higher responses in the asymptomatic group. The frequent cohort had higher IgG responses to Delta and BA.4/5 and higher neutralising capacity against Omicron variants. An immune signature of blunted IL-2 and IFNγ in frequent infections may identify HCWs at increased risk of further infection.