Anti-spike IgG antibody kinetics following the second and third doses of BNT162b2 vaccine in nursing home residents

Epidemiology of COVID-19 outbreaks in aged care facilities during postvaccine period: a systematic review and meta-analysis

OBJECTIVE

We aimed to define the epidemiology of COVID-19 outbreaks in aged care facilities (ACFs) during the postvaccine period, including vaccine effectiveness (VE) for this high-risk group.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Ovid Medline, Ovid Embase, Scopus, Web of Science and Cochrane databases were searched through 1 September 2023.

ELIGIBILITY CRITERIA

Any original observational studies and trials reporting data on COVID-19 outbreaks among the partially/fully vaccinated residents from ACFs during or after the worldwide implementation of vaccine roll-out.

DATA EXTRACTION AND SYNTHESIS

We estimated the attack rate, case fatality rate, mortality rate and VE during postvaccine period. Random effect model was adopted for meta-analysis. Quality assessment on all included studies was performed using the Meta Quality Appraisal Tool.

RESULTS

38 articles were included from 12 countries reporting 79 outbreaks with 1708 confirmed cases of COVID-19 from 78 ACFs. The pooled attack rate was 28% (95% CI 20% to 37%) among the fully vaccinated residents. Two-thirds (62.5%) of the index cases were unvaccinated healthcare professionals (eg, physicians, nurses) and caregivers. Unvaccinated residents had a significantly higher rates (12%) (95% CI 7% to 19%) of mortality compared with the vaccinated residents (2%) (95% CI% 1 to 4%) and the post-COVID-19 vaccine estimates for case fatality rate (13% vs 23%) and hospitalisation rate (17% vs 37%) were substantially lower. VE in preventing disease among residents in ACFs was 73% (95% CI 49% to 86). Overall, the included studies were heterogeneous in nature, however, the risk of bias was low to moderate.

CONCLUSIONS

Our study reaffirmed the impact of vaccination as a key public health measure to minimise the burden of COVID-19 in ACFs. Facilities with higher crowding indexes should be prioritised for vaccination and should advocate for higher vaccination targets among staff and residents as a critical intervention strategy to minimise disease burden in this vulnerable population.

Impact of rituximab on humoral response to SARS-CoV-2 vaccination in previously vaccinated patients with autoimmune diseases

SARS-CoV-2 infection is more severe in patients undergoing rituximab (RTX) treatment. Humoral response to vaccination is severely impaired in patients already treated with RTX, but data on antibody persistence in patients initiating RTX are lacking. We evaluated the impact of RTX initiation on humoral response to SARS-CoV-2 vaccination in previously vaccinated patients with immune-mediated inflammatory diseases. We performed a retrospective, multicenter study evaluating the evolution of anti-spike antibodies and breakthrough infections after initiation of RTX in previously vaccinated patients with protective levels of anti-SARS-CoV-2 antibodies. Threshold for anti-S antibodies positivity and protection were 30 and 264 BAU/mL, respectively. We included 31 previously vaccinated patients initiating RTX (21 female, median age 57 years). At first RTX infusion, 12 (39%) patients had received 2 doses of vaccine, 15 (48%) had received 3 doses, and 4 (13%) had received 4 doses. The most frequent underlying diseases were ANCA-associated vasculitis (29%) and rheumatoid arthritis (23%). Median anti-S antibody titers at RTX initiation, 3 months, and 6 months were 1620 (589-2080), 1055 (467-2080), and 407 (186-659) BAU/mL, respectively. Overall, antibody titers waned by almost two-fold at 3 months and four-fold at 6 months. Median antibody titers were significantly higher in patients who received ≥3 doses compared to those who received only 2 doses. Three patients developed SARS-CoV-2 infection without any severe symptom. Anti-SARS-CoV-2 antibody titers in previously vaccinated patients decline after RTX initiation similarly to general population. Specific monitoring is useful to anticipate prophylactic strategies. Key Points • Anti-SARS-CoV-2 antibody titers in previously vaccinated patients decline after rituximab initiation similarly to the general population. • The number of dose of vaccine before rituximab initiation is associated with higher antibody titers at month 3. • Monitoring antibody levels is mandatory to initiate prophylactic strategies in this population.

A Mechanical Assay for the Quantification of Anti-RBD IgG Levels in Finger-Prick Whole Blood

A large portion of the global population has been vaccinated with various vaccines or infected with SARS-CoV-2, the virus that causes COVID-19. The resulting IgG antibodies that target the receptor binding domain (RBD) of SARS-CoV-2 play a vital role in reducing infection rates and severe disease outcomes. Different immune histories result in the production of anti-RBD IgG antibodies with different binding affinities to RBDs of different variants, and the levels of these antibodies decrease over time. Therefore, it is important to have a low-cost, rapid method for quantifying the levels of anti-RBD IgG in decentralized testing for large populations. In this study, we describe a 30 min assay that allows for the quantification of anti-RBD IgG levels in a single drop of finger-prick whole blood. This assay uses force-dependent dissociation of nonspecifically absorbed RBD-coated superparamagnetic microbeads to determine the density of specifically linked microbeads to a protein A-coated transparent surface through anti-RBD IgGs, which can be measured using a simple light microscope and a low-magnification lens. The titer of serially diluted anti-RBD IgGs can be determined without any additional sample processing steps. The limit of detection for this assay is 0.7 ± 0.1 ng/mL referenced to the CR3022 anti-RBD IgG. The limits of the technology and its potential to be further developed to meet the need for point-of-care monitoring of immune protection status are discussed.

Impact of prior SARS-COV-2 infection and vaccination on COVID-19 hospital admission and mortality amongst nursing home residents

BACKGROUND

Nursing home residents (NHRs) have experienced disproportionately high risk of severe outcomes due to COVID-19 infection.

AIM

We investigated the impact of COVID-19 vaccinations and previous SARS-CoV-2 episodes in preventing hospitalization and mortality in NHRs.

METHODS

Retrospective study of a cohort of all NHRs in our area who were alive at the start of the vaccination campaign. The first three doses of SARS-CoV-2 vaccine and prior COVID-19 infections were registered. The main outcomes were hospital admission and mortality during each follow up. Random effects time-varying Cox models adjusted for age, sex, and comorbidities were fitted to estimate hazard ratios (HRs) according to vaccination status.

RESULTS

COVID-19 hospitalization and death rates for unvaccinated NHRs were respectively 2.39 and 1.42 per 10,000 person-days, falling after administration of the second dose (0.37 and 0.34) and rising with the third dose (1.08 and 0.8). Rates were much lower amongst people who had previously had COVID-19. Adjusted HRs indicated a significant decrease in hospital admission amongst those with a two- and three-dose status; those who had had a previous COVID-19 infection had even lower hospital admission rates. Death rates decreased as NHRs received two and three doses, and the probability of death was much lower among those who had previously had the infection.

CONCLUSIONS

The effectiveness of current vaccines against severe COVID-19 disease in NHRs remains high and SARS-CoV-2 episodes prior to vaccination entail a major reduction in hospitalization and mortality rates. The protection conferred by vaccines appears to decline in the following months.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04463706.

COVID-19 therapy and vaccination: a clinical narrative review

The SARS-CoV-2 pandemic is the most globally impacting health issue our world has faced over the last century. As of January 7, 2022, around 300 million cases have been reported worldwide, with over 5 million deaths. The SARS-CoV-2 infection causes a hyperactive host immune response leading to an excessive inflammatory reaction with the release of many cytokines - cytokine storm - commonly noticed in acute respiratory distress syndrome, sepsis and fulminant multiorgan failure. Since the beginning of the pandemic, the scientific medical community has worked on therapeutic procedures that interfere with the exaggerated immune response. Thromboembolic complications are widespread in patients who are critically ill with COVID-19. Anticoagulant therapy was initially considered a cornerstone in hospitalized patients and even in the early post-discharge period; however, later trials have aborted the clinical benefits except for suspicion of or confirmed thrombosis. Immunomodulatory therapies are still crucial in moderate to severe COVID-19. Immunomodulator therapies include various medications from steroids to hydroxychloroquine, tocilizumab and Anakinra. Anti-inflammatory agents, vitamin supplements and antimicrobial therapy had initial encouraging evidence, but there are limited data to review. Convalescent plasma, immunoglobulins, eculizumab, neutralizing IgG1 monoclonal antibodies and remdesivir have positively impacted inpatient mortality and hospital length of stay. Eventually, wide population vaccination was proven to be the best tool to overcome the SARS-CoV-2 pandemic and help humanity return to regular life. Many vaccines and various strategies have been used since December 2020. This review discusses how the SARS-CoV-2 pandemic has progressed and surged, and summarizes the safety and efficacy of the most used therapies and vaccines in the light of recent evidence.

T-Cell Mediated Response after Primary and Booster SARS-CoV-2 Messenger RNA Vaccination in Nursing Home Residents

OBJECTIVES

Nursing home (NH) residents have been significantly affected by the coronavirus disease 2019 (COVID-19) pandemic. Studies addressing the immune responses induced by COVID-19 vaccines in NH residents have documented a good postvaccination antibody response and the beneficial effect of a third booster vaccine dose. Less is known about vaccine-induced activation of cell-mediated immune response in frail older individuals in the long term. The aim of the present study is to monitor messenger RNA SARS-CoV-2 vaccine-induced T-cell responses in a sample of Italian NH residents who received primary vaccine series and a third booster dose and to assess the interaction between T-cell responses and humoral immunity.

DESIGN

Longitudinal cohort study.

SETTING AND PARTICIPANTS

Thirty-four residents vaccinated with BNT162b2 messenger RNA SARS-CoV-2 vaccine between February and April 2021 and who received a third BNT162b2 booster dose between October and November 2021 were assessed for vaccine-induced immunity 6 (prebooster) and 12 (postbooster) months after the first BNT162b2 vaccine dose.

METHODS

Pre- and postbooster cell-mediated immunity was assessed by intracellular cytokine staining of peripheral blood mononuclear cells stimulated in vitro with peptides covering the immunodominant sequence of SARS-CoV-2 spike protein. The simultaneous production of interferon-γ, tumor necrosis factor-α, and interleukin-2 was measured. Humoral immunity was assessed in parallel by measuring serum concentration of antitrimeric spike IgG antibodies.

RESULTS

Before the booster vaccination, 31 out of 34 NH residents had a positive cell-mediated immunity response to spike. Postbooster, 28 out of 34 had a positive response. Residents without a previous history of SARS-CoV-2 infection, who had a lower response prior the booster administration, showed a greater increase of T-cell responses after the vaccine booster dose. Humoral and cell-mediated immunity were, in part, correlated but only before booster vaccine administration.

CONCLUSIONS AND IMPLICATIONS

The administration of the booster vaccine dose restored spike-specific T-cell responses in SARS-CoV-2 naïve residents who responded poorly to the first immunization, while a previous SARS-CoV-2 infection had an impact on the magnitude of vaccine-induced cell-mediated immunity at earlier time points. Our findings imply the need for a continuous monitoring of the immune status of frail NH residents to adapt future SARS-CoV-2 vaccination strategies.

Humoral immunity induced by mRNA COVID-19 vaccines in Nursing Home Residents previously infected with SARS-CoV-2

BACKGROUND

Nursing home (NH) residents suffered the greatest impact of the COVID-19 pandemic. Limited data are available on vaccine-induced immunity and on the protection ensured by a prior infection in this population.

AIMS

The present study aims to monitor antibody levels and their persistence over a 6-month period in NH residents according to the history of prior SARS-CoV-2 infection.

METHODS

We measured anti-trimeric Spike IgG antibody levels in a sample of 395 residents from 25 NHs in 6 Italian Regions at study enrolment (prior to the first dose of vaccine, T0) and then after 2 (T1) and 6 months (T2) following the first vaccine dose. All participants received mRNA vaccines (BNT162b2 or mRNA-1273). Analyses were performed using log-transformed values of antibody concentrations and geometric means (GM) were calculated.

RESULTS

Superior humoral immunity was induced in NH residents with previous SARS-CoV-2 infection. (T0: GM 186.6 vs. 6.1 BAU/ml, p < 0.001; T1: GM 5264.1 vs. 944.4 BAU/ml, p < 0.001; T2: GM 1473.6 vs. 128.7 BAU/ml, p < 0.001). Residents with prior SARS-CoV-2 infection receiving two vaccine doses presented significantly higher antibody concentration at T1 and T2. A longer interval between previous infection and vaccination was associated with a better antibody response over time.

DISCUSSION

In a frail sample of NH residents, prior SARS-CoV-2 infection was associated with a higher humoral response to vaccination. Number of vaccine doses and the interval between infection and vaccination are relevant parameters in determining humoral immunity.

CONCLUSIONS

These findings provide important information to plan future immunization policies and disease prevention strategies in a highly vulnerable population.