Implementation and Patient Outcomes of a Pediatric COVID-19 Monoclonal Antibody Program

BACKGROUND

The severity and reach of the COVID-19 pandemic drove the development of various therapeutic approaches to combat SARS-CoV-2, including several neutralizing monoclonal antibody (mAb) therapies. A January 2021 pediatric consensus statement opposed routine use and recommended individualized risk assessments when considering COVID-19 mAb therapies in children and adolescents due to limited data. This report describes the implementation of a mAb referral process and the clinical outcomes of patients who received a mAb infusion in a pediatric hospital.

METHODS

We developed a tiered allocation system based on underlying medical conditions and incorporated it into a standardized COVID-19 mAb referral and approval process. Demographics and clinical data were collected on all patients who received mAb therapy for treatment or post-exposure prophylaxis. Data recorded included sociodemographics, qualifying underlying medical conditions, clinical manifestations of infection, and overall course of treatment and disease.

RESULTS

A total of 182 patients ≤21 years old received a COVID-19 mAb infusion between November 27, 2020 and January 26, 2022. Patient age ranged from 10 months to 21 years, with a median age of 15 years. In total, 7 patients (4%) had suspected adverse reactions during the infusion, and 15 (8%) patients required a COVID-19-related visit within 30 days of the mAb infusion.

CONCLUSIONS

A tiered allocation process may provide the framework for the stratification and efficient distribution of mAb therapies. Future research must focus on the efficacy of these therapies in the pediatric population, standardized therapeutic prioritization, and the optimal timeframe for mAb delivery to prevent progression to severe disease.

Antibody-mediated immunity to SARS-CoV-2 spike

Despite effective spike-based vaccines and monoclonal antibodies, the SARS-CoV-2 pandemic continues more than two and a half years post-onset. Relentless investigation has outlined a causative dynamic between host-derived antibodies and reciprocal viral subversion. Integration of this paradigm into the architecture of next generation antiviral strategies, predicated on a foundational understanding of the virology and immunology of SARS-CoV-2, will be critical for success. This review aims to serve as a primer on the immunity endowed by antibodies targeting SARS-CoV-2 spike protein through a structural perspective. We begin by introducing the structure and function of spike, polyclonal immunity to SARS-CoV-2 spike, and the emergence of major SARS-CoV-2 variants that evade immunity. The remainder of the article comprises an in-depth dissection of all major epitopes on SARS-CoV-2 spike in molecular detail, with emphasis on the origins, neutralizing potency, mechanisms of action, cross-reactivity, and variant resistance of representative monoclonal antibodies to each epitope.

SARS-CoV-2 neutralizing antibodies for COVID-19: Outcomes for bamlanivimab versus bamlanivimab-etesevimab combination in a racially diverse cohort of patients with significant comorbidities

What Is Known and Objective

Anti‐spike monoclonal antibodies (MAB) including bamlanivimab (BAM) and bamlanivimab/etesevimab (BAM/E) have shown reduced hospitalization rates for non‐severe coronavirus disease 2019 (COVID‐19) in clinical trials. Recent data have provided real‐world hospitalization rates for high‐risk patients treated with BAM, however, data on a similar cohort treated with BAM/E are lacking.

Methods

This retrospective cohort study evaluated outpatients ≥18 years with laboratory‐confirmed mild/moderate COVID‐19 who received MAB from 1 December 2020 to 19 April 2021. Use of BAM monotherapy changed to BAM/E combination on 27 March 2021. Primary outcome was overall rate of COVID‐19 related‐hospitalization, including comparison of hospitalization rates between MAB‐formulation groups. Secondary outcomes were 30‐day mortality and length of stay (LOS).

Results and Discussion

The population included 643 patients (BAM and BAM/E); median age was 58 years, 43% were male, median BMI was 33 kg/m², and 24% self‐identified as Black. Patients in the BAM/E combination group were significantly younger with higher median BMI and a longer time from symptom onset to infusion. The incidence of 30‐day COVID‐19 related hospitalization was similar between patients receiving either BAM or BAM/E combination (7.8% and 7.2%, respectively).

What Is New and Conclusion

This study represents the first such publication of real‐world BAM/E hospitalization outcomes. Hospitalization rates utilizing BAM/E were comparable to BAM in our real‐world study.

Novel nanostructure-coupled biosensor platform for one-step high-throughput quantification of serum neutralizing antibody after COVID-19 vaccination

COVID-19 vaccination efficacy depends on serum levels of the neutralizing antibodies (NAs) specific to the receptor-binding domain of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Therefore, a high-throughput rapid assay capable of measuring the total SARS-CoV-2 NA level is urgently needed for COVID-19 serodiagnosis, convalescent plasma therapy, vaccine development, and assessment. Here, we developed a novel nanoplasmonic immunosorbent assay (NanoPISA) platform for one-step rapid quantification of SARS-CoV-2 NAs in clinical serum samples for high-throughput evaluation of COVID-19 vaccine effectiveness. The NanoPISA platform enhanced by the use of nanoporous hollow gold nanoparticle coupling was able to detect SARS-CoV-2 NAs with a limit of detection of 0.2 pM within 15 min without washing steps. The one-step NanoPISA for SARS-CoV-2 NA detection in clinical specimens yielded good results, comparable with those obtained in the gold-standard seroneutralization test and the surrogate virus-neutralizing enzyme-linked immunosorbent assay. Collectively, the one-step NanoPISA might be a rapid and high-throughput NA-quantification platform for evaluating the effectiveness of COVID-19 vaccines.

Disease Severity, Fever, Age, and Sex Correlate With SARS-CoV-2 Neutralizing Antibody Responses

Clinical trials on the use of COVID-19 convalescent plasma remain inconclusive. While data on safety is increasingly available, evidence for efficacy is still sparse. Subgroup analyses hint to a dose-response relationship between convalescent plasma neutralizing antibody levels and mortality. In particular, patients with primary and secondary antibody deficiency might benefit from this approach. However, testing of neutralizing antibodies is limited to specialized biosafety level 3 laboratories and is a time- and labor-intense procedure. In this single center study of 206 COVID-19 convalescent patients, clinical data, results of commercially available ELISA testing of SARS-CoV-2 spike-IgG and -IgA, and levels of neutralizing antibodies, determined by plaque reduction neutralization testing (PRNT), were analyzed. At a medium time point of 58 days after symptom onset, only 12.6% of potential plasma donors showed high levels of neutralizing antibodies (PRNT50 ≥ 1:320). Multivariable proportional odds logistic regression analysis revealed need for hospitalization due to COVID-19 (odds ratio 6.87; p-value 0.0004) and fever (odds ratio 3.00; p-value 0.0001) as leading factors affecting levels of SARS-CoV-2 neutralizing antibody titers in convalescent plasma donors. Using penalized estimation, a predictive proportional odds logistic regression model including the most important variables hospitalization, fever, age, sex, and anosmia or dysgeusia was developed. The predictive discrimination for PRNT50 ≥ 1:320 was reasonably good with AUC: 0.86 (with 95% CI: 0.79-0.92). Combining clinical and ELISA-based pre-screening, assessment of neutralizing antibodies could be spared in 75% of potential donors with a maximal loss of 10% of true positives (PRNT50 ≥ 1:320).