Driving consistency: CEPI-Centralized Laboratory Network's conversion factor initiative for SARS-CoV-2 clinical assays used for efficacy assessment of COVID vaccines

To date, thousands of SARS-CoV-2 samples from many vaccine developers have been tested within the CEPI-Centralized Laboratory Network. To convert data from each clinical assay to international standard units, the WHO international standard and the CEPI standard generated by the Medicines and Healthcare products Regulatory Agency were run in multiple facilities to determine the conversion factor for each assay. Reporting results in international units advances global understanding of SARS-CoV-2 immunity and vaccine efficacy, enhancing the quality, reliability, and utility of clinical assay data.

Standardised quantitative assays for anti-SARS-CoV-2 immune response used in vaccine clinical trials by the CEPI Centralized Laboratory Network: a qualification analysis

BACKGROUND

Accurate quantitation of immune markers is crucial for ensuring reliable assessment of vaccine efficacy against infectious diseases. This study was designed to confirm standardised performance of SARS-CoV-2 assays used to evaluate COVID-19 vaccine candidates at the initial seven laboratories (in North America, Europe, and Asia) of the Coalition for Epidemic Preparedness Innovations (CEPI) Centralized Laboratory Network (CLN).

METHODS

Three ELISAs (pre-spike protein, receptor binding domain, and nucleocapsid), a microneutralisation assay (MNA), a pseudotyped virus-based neutralisation assay (PNA), and an IFN-γ T-cell ELISpot assay were developed, validated or qualified, and transferred to participating laboratories. Immune responses were measured in ELISA laboratory units (ELU) for ELISA, 50% neuralisation dilution (ND50) for MNA, 50% neutralisation titre (NT50) for PNA, and spot-forming units for the ELISpot assay. Replicate assay results of well characterised panels and controls of blood samples from individuals with or without SARS-CoV-2 infection were evaluated by geometric mean ratios, standard deviation, linear regression, and Spearman correlation analysis for consistency, accuracy, and linearity of quantitative measurements across all laboratories.

FINDINGS

High reproducibility of results across all laboratories was demonstrated, with interlaboratory precision of 4·1-7·7% coefficient of variation for all three ELISAs, 3·8-19·5% for PNA, and 17·1-24·1% for MNA, over a linear range of 11-30 760 ELU per mL for the three ELISAs, 14-7876 NT50 per mL for PNA, and 21-25 587 ND50 per mL for MNA. The MNA was also adapted for detection of neutralising antibodies against the major SARS-CoV-2 variants of concern. The results of PNA and MNA (r=0·864) and of ELISA and PNA (r=0·928) were highly correlated. The IFN-γ ELISpot interlaboratory variability was 15·9-49·9% coefficient of variation. Sensitivity and specificity were close to 100% for all assays.

INTERPRETATION

The CEPI CLN provides accurate quantitation of anti-SARS-CoV-2 immune response across laboratories to allow direct comparisons of different vaccine formulations in different geographical areas. Lessons learned from this programme will serve as a model for faster responses to future pandemic threats and roll-out of effective vaccines.

FUNDING

CEPI.

Syrian hamster convalescence from prototype SARS-CoV-2 confers measurable protection against the attenuated disease caused by the Omicron variant

The mutation profile of the SARS-CoV-2 Omicron (lineage BA.1) variant posed a concern for naturally acquired and vaccine-induced immunity. We investigated the ability of prior infection with an early SARS-CoV-2 ancestral isolate (Australia/VIC01/2020, VIC01) to protect against disease caused by BA.1. We established that BA.1 infection in naïve Syrian hamsters resulted in a less severe disease than a comparable dose of the ancestral virus, with fewer clinical signs including less weight loss. We present data to show that these clinical observations were almost absent in convalescent hamsters challenged with the same dose of BA.1 50 days after an initial infection with ancestral virus. These data provide evidence that convalescent immunity against ancestral SARS-CoV-2 is protective against BA.1 in the Syrian hamster model of infection. Comparison with published pre-clinical and clinical data supports consistency of the model and its predictive value for the outcome in humans. Further, the ability to detect protection against the less severe disease caused by BA.1 demonstrates continued value of the Syrian hamster model for evaluation of BA.1-specific countermeasures.

Use of a Preclinical Natural Transmission Model to Study Antiviral Effects of a Carbohydrate-Binding Module Therapy against SARS-CoV-2 in Hamsters

The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV-2) and its expansion to a worldwide pandemic resulted in efforts to assess and develop interventions to reduce the disease burden. Despite the introduction of vaccine programmes against SARS-CoV-2, global incidence levels in early 2022 remained high, demonstrating a need for the development of physiologically relevant models, which are essential for the identification of alternative antiviral strategies. The hamster model of SARS-CoV-2 infection has been widely adopted due to similarities with humans in terms of host cell entry mechanism (via ACE2), and aspects of symptomology and virus shedding. We have previously described a natural transmission hamster model that better represents the natural course of infection. In the present study, we have conducted further testing of the model using the first-in-class antiviral Neumifil, which has previously shown promise against SARS-CoV-2 after a direct intranasal challenge. Neumifil is an intranasally delivered carbohydrate-binding module (CBM) which reduces the binding of viruses to their cellular receptor. By targeting the host cell, Neumifil has the potential to provide broad protection against multiple pathogens and variants. This study demonstrates that using a combination of a prophylactic and therapeutic delivery of Neumifil significantly reduces the severity of clinical signs in animals infected via a natural route of transmission and indicates a reduction of viral loads in the upper respiratory tract. Further refinements of the model are required in order to ensure the adequate transmission of the virus. However, our results provide additional data to the evidence base of Neumifil efficacy against respiratory virus infection and demonstrate that the transmission model is a potentially valuable tool for testing antiviral compounds against SARS-CoV-2.

A potent SARS-CoV-2 neutralising nanobody shows therapeutic efficacy in the Syrian golden hamster model of COVID-19

SARS-CoV-2 remains a global threat to human health particularly as escape mutants emerge. There is an unmet need for effective treatments against COVID-19 for which neutralizing single domain antibodies (nanobodies) have significant potential. Their small size and stability mean that nanobodies are compatible with respiratory administration. We report four nanobodies (C5, H3, C1, F2) engineered as homotrimers with pmolar affinity for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Crystal structures show C5 and H3 overlap the ACE2 epitope, whilst C1 and F2 bind to a different epitope. Cryo Electron Microscopy shows C5 binding results in an all down arrangement of the Spike protein. C1, H3 and C5 all neutralize the Victoria strain, and the highly transmissible Alpha (B.1.1.7 first identified in Kent, UK) strain and C1 also neutralizes the Beta (B.1.35, first identified in South Africa). Administration of C5-trimer via the respiratory route showed potent therapeutic efficacy in the Syrian hamster model of COVID-19 and separately, effective prophylaxis. The molecule was similarly potent by intraperitoneal injection.

Comparison of rhesus and cynomolgus macaques as an infection model for COVID-19

A novel coronavirus, SARS-CoV-2, has been identified as the causative agent of the current COVID-19 pandemic. Animal models, and in particular non-human primates, are essential to understand the pathogenesis of emerging diseases and to assess the safety and efficacy of novel vaccines and therapeutics. Here, we show that SARS-CoV-2 replicates in the upper and lower respiratory tract and causes pulmonary lesions in both rhesus and cynomolgus macaques. Immune responses against SARS-CoV-2 are also similar in both species and equivalent to those reported in milder infections and convalescent human patients. This finding is reiterated by our transcriptional analysis of respiratory samples revealing the global response to infection. We describe a new method for lung histopathology scoring that will provide a metric to enable clearer decision making for this key endpoint. In contrast to prior publications, in which rhesus are accepted to be the preferred study species, we provide convincing evidence that both macaque species authentically represent mild to moderate forms of COVID-19 observed in the majority of the human population and both species should be used to evaluate the safety and efficacy of interventions against SARS-CoV-2. Importantly, accessing cynomolgus macaques will greatly alleviate the pressures on current rhesus stocks.

Issues in Oncologic Surveillance of Patients with Maxillectomy Defects

Objectives:

(1) Describe locoregional and distant disease recurrence patterns among patients undergoing maxillectomy from 2001-2011 at Cleveland Clinic and UCSF Medical Center. (2) Analyze the pattern of recurrence in this cohort in order to evaluate whether microvascular reconstruction may delay clinical detection of early cancer recurrence.

Methods:

Retrospective review of patients undergoing inferior, subtotal, or total maxillectomy, with or without reconstruction, for control of malignant disease from 2001-2011 from 2 tertiary centers (Cleveland Clinic and University of California, San Francisco).

Results:

A total of 76 patients across the 2 institutions met the inclusion criteria for the study. Squamous cell carcinoma was the most prevelant pathologic diagnosis with overall disease progression of 29%. Recurrence at the skull base and regional lymphatic spread were the most common patterns identified (18 and 32%, respectively). Surveillance imaging, rather than direct observation on physical examination, raised suspicion for disease progression in the majority of cases. A total of 9 patients were found to have disease recurrence that could be surgically salvaged, with only 4 patients requiring modification to their reconstruction as part of the salvage operation.

Conclusions:

Locoregional recurrence of malignancy after partial or total maxillectomy is uncommon, and the suspicion for disease recurrence is significantly more commonly raised on surveillance imaging, rather than on physical examination. Further, locoregional recurrence is rarely amenable to successful surgical salvage. This suggests that primary microvascular reconstruction of maxillectomy defects does not delay diagnosis or treatment of disease recurrence.

Multidisciplinary management of advanced basal cell carcinoma: report of four cases

BACKGROUND

Advanced basal cell carcinomas (BCC) are neoplasms with high-risk clinical characteristics that can develop as locally advanced disease or metastasis. Treatment of advanced BCC may result in significant morbidity due to the technical challenges of size and/or location or in which surgery and radiation therapy may be contraindicated. No standard of care exists for the management of advanced BCC. As such, the difficulty in managing these tumors necessitates a multidisciplinary approach to patient care.

METHODS

We report four cases of advanced BCC that benefited from a multidisciplinary approach, as well as highlight treatment considerations and factors in the development of advanced BCC.

RESULTS

All four complex cases of advanced BCC presented to a multidisciplinary non-melanoma skin cancer tumor board with extensive tumor involvement. Treatment of disease was effective in preventing recurrence while optimizing aesthetic outcomes.

CONCLUSIONS

The multidisciplinary tumor board has a central and important role in the evaluation and management of advanced BCC.

Induced superconductivity in the three-dimensional topological insulator HgTe

A strained and undoped HgTe layer is a three-dimensional topological insulator, in which electronic transport occurs dominantly through its surface states. In this Letter, we present transport measurements on HgTe-based Josephson junctions with Nb as a superconductor. Although the Nb-HgTe interfaces have a low transparency, we observe a strong zero-bias anomaly in the differential resistance measurements. This anomaly originates from proximity-induced superconductivity in the HgTe surface states. In the most transparent junction, we observe periodic oscillations of the differential resistance as a function of an applied magnetic field, which correspond to a Fraunhofer-like pattern. This unambiguously shows that a precursor of the Josephson effect occurs in the topological surface states of HgTe.

Tyramine-Based Hyaluronan as a Tracheal Cartilage Substitute

Objective: To investigate and characterize a novel tyramine-based hyaluronan/gelatin (THA/G) composite material. First, we demonstrate the ability of THA/G to adhere and maintain respiratory epithelial cells in an in vitro model. Second, we assess the feasibility of THA/G as a biologic cartilage substitute in a rabbit model of tracheal reconstruction.

Method: Immortalized human tracheal epithelial cells were grown on various concentrations of THA/G composites in vitro. Cricotracheal resection with replacement by THA/G was performed in 4 New Zealand white rabbits with auricular cartilage as control in 2 animals. Tracheal patency, graft retention, and mucosalization were evaluated via endoscopy, imaging, and histopathology.

Results: Epithelial cell growth was demonstrated on THA/G composites in vitro. In the rabbit model, all composites remained intact within the tracheal resection. However, the limited shear strength of the THA/G posed difficulties in securing the construct. At 3 and 6 weeks postimplantation, composites revealed minimal histologic evidence of macrophage or lymphocyte infiltration and were without apparent degradation. Tracheal lumen diameter was preserved in all animals. No experimental animals had evidence of dynamic airway collapse or chondromalacia. On endoscopy, there was no evidence of tracheal inflammation or granulation. However, at 6 weeks there was limited respiratory mucosa present on histology.

Conclusion: THA/G composites are a promising material for cartilage substitution. We demonstrate an ability to support epithelial cells and maintain tracheal structure. Improvements to increase the material’s shear strength are necessary so that it may have potential as an airway cartilage substitute.

Stepped-dose protocol of cidofovir therapy in recurrent respiratory papillomatosis in children

OBJECTIVE

To evaluate a stepped-dose protocol for intralesional injection of cidofovir in children with recurrent respiratory papillomatosis (RRP).

DESIGN

Prospective, nonrandomized case series.

SETTING

Tertiary care children's hospital.

PARTICIPANTS

Eleven children undergoing evaluation for RRP from June 1, 2000, through December 31, 2001.

INTERVENTION

Intralesional injection of cidofovir was performed after microlaryngoscopy and carbon dioxide laser treatment. Patients received 4 monthly injections at a concentration of 5 mg/mL and returned 1 month after the last injection for follow-up. Patients with recurrent or recalcitrant disease then started a series of 4 monthly injections at a concentration of 10 mg/mL.

OUTCOME MEASURE

Papilloma stage (0-3) documented at multiple subsites by means of serial microlaryngoscopy. We calculated a severity score by summing the scores at all affected subsites.

RESULTS

The severity score decreased in each of the 11 patients during the course of therapy, from a mean +/- SD of 13.7 +/- 6.0 at enrollment to 2.1 +/- 3.4 at 1-month follow-up. Six patients experienced complete resolution (stage 0) and 4 others had mild disease (stage, </=5) after 4 treatments at the 5-mg/mL concentration. Five patients with residual or recurrent RRP subsequently started a series of 4 cidofovir treatments at a concentration of 10 mg/mL, with a mixed response.

CONCLUSIONS

Intralesional injection of cidofovir seems to reduce the burden of disease in children with RRP. Patients with persistent or recurrent disease may benefit from an increased cidofovir concentration of 10 mg/mL, although some aggressive papillomatous disease remains refractory to cidofovir treatment.

Attitudes of carers and the elderly occupants of residential homes to antimicrobial chewing gum as an aid to oral health

OBJECTIVE

The aim of this study was to investigate the attitudes of elderly residents to using an antimicrobial chewing gum as an aid to oral health, and the opinion of their carers on such a procedure.

DESIGN

A cross-sectional, multi-centre survey using a structured interview/questionnaire conducted with elderly residents and their carers.

SETTING

In January 1998, 9 residential/nursing homes were chosen at random from all the homes in West Hertfordshire, 207 residents were asked to chew two pieces of gum twice daily for 7 days.

SUBJECTS

The participants, 148 women and 59 men, were aged between 53-100 years (mean age 82.23 +/- 9.62 years). 47 carers, all female, were involved in distributing and collecting the gum.

RESULTS

122 residents (58.9%) were edentulous and 85 (41%) of the participants were partially dentate. Of those with teeth 23 (27%) had 21 teeth or more. 73 (35.2%) residents found that chewing the gum was difficult with 37 (17.9%) of this group being unable to chew (P < 0.0001 for those residents with no teeth/dentures or dentures unopposed by teeth or other dentures). 32 (18.6%) subjects disliked the flavour of the gum. Of the 170 residents who chewed the gum 99 (57.2%) found it reduced oral dryness and 78 (45.1%) reported it made their mouth feel healthy. 34 (53.6%) of the dentate and 47 (40.9%) of the edentate residents wished to keep using the gum (P < 0.05). 35 (74.5%) of the carers found it easy to distribute the gum and 29 (61.7%) thought that chewing gum was an acceptable method of maintaining oral health for residents.

CONCLUSION

The antimicrobial gum investigated in this study was acceptable to many elderly occupants and their carers, significantly improving perceived oral health and oral dryness of residents.

Impact of an organ donor and tissue donor advocacy program on community hospitals

A crucial shortage of organ donors exists in the United States. The majority of donor referrals come from large (greater than 500) beds) hospitals and trauma centers. To determine whether a significant number of donors who are not being recognized or referred also existed in medium-sized (300 beds) community hospitals, a Donor Advocacy Program was instituted at Francis Scott Key Medical Center in May 1987. This team developed policies and procedures to identify potential donors and conducted educational programs for physicians and nurses. A designated "Donor Advocate" made daily rounds on the inpatient units to maintain donor awareness and facilitate potential donations. After the first year, the program was evaluated. In comparison to the average of the previous three years, donor referrals increased by approximately 400 per cent and tissue donations increased over 500 per cent. Four organs were retrieved from two donors. It is concluded that an increase in referrals and tissue donations can be achieved at community hospitals through a structured donor awareness program. Recommendations are made to further examine the age group most often eligible for organ and tissue donations in community hospitals and target educational efforts accordingly. Commitment of hospital administration is vital to a positive outcome in such a program.