Real world experience of single use flexible bronchoscopy over six months in a tertiary centre

The development of single use flexible bronchoscopes (SUFBs) has accelerated in recent years, with the reduced risk of infectious transmission and reduced need for endoscopy staff particularly advantageous in the COVID-19 era. Despite complex cleaning systems for reusable flexible bronchoscopes (RFBs), disinfection is often inadequate with the consequent risk of cross infection. We trialled the routine use of The Surgical Company Bronchoflex © SUFB in a tertiary bronchoscopy service. 139 procedures were performed by five consultants from January to July 2021, with the main indications being infection (45%) and malignancy (32%). Most were performed in the endoscopy suite;eight procedures took place in the Intensive Care Unit, six at ward level and three in theatre as an adjunct to rigid bronchoscopy. SUFBs were used across a range of procedures including bronchoalveolar lavage, brushings, endobronchial biopsy, transbronchial needle aspiration, argon plasma coagulation, cryobiopsy and stent placement. 85% of procedures had no complications related to the use of a SUFB with a user satisfaction score of above 4/5 in 89% of cases (Figure 1). Issues with image quality (6%) or suction (5%) meant the reversion to reusable bronchoscope in some cases. Overall, the use of SUFBs has significant benefits in patient care with the ability to use the SUFB across a range of indications and procedures with high user satisfaction.

Continued Complexity of Mutations in Omicron Sublineages.

The latest SARS-CoV-2 variant of concern (VOC), Omicron (B.1.1.529), has diversified into more than 300 sublineages. With an expanding number of newly emerging sublineages, the mutation profile is also becoming complicated. There exist mutually exclusive and revertant mutations in different sublineages. Omicron sublineages share some common mutations with previous VOCs (Alpha, Beta, Gamma, and Delta), indicating an evolutionary relationship between these VOCs. A diverse mutation profile at the spike-antibody interface, flexibility of the regions harboring mutations, mutation types, and coexisting mutations suggest that SARS-CoV-2's evolution is far from over.

SARS-CoV2 Antibody Kinetics and Durability Three and Six Months After Two-Doses of MRNA Vaccination in Liver Transplant Recipients

Purpose: nti-spike antibody response to SARS-CoV-2 vaccination is diminished in LT recipients compared to the general population so understanding durability for those that do respond is critical to mitigating risks of infection. We measured serial antibody titers in LT recipients for 6 months after two-dose mRNA vaccine series to describe kinetics and sero-reversion rates. Method(s): LT recipients without known prior COVID-19 had anti-spike antibody testing at 1, 3, and 6 months after the second dose of mRNA vaccine (D2) using two commercial assays (Roche Elecsys anti-receptor binding domain immunoassay (EIA) [positive >=0.8 U/mL] or EUROIMMUN anti-S1 EIA [positive >=1.1 AU]). We compared titer distributions over time and identified factors associated with sero-reversion. Result(s): 180 LT recipients received BNT162b2 (48%) or mRNA-1273 (52%) 2-dose series between 1/7/2021-5/7/2021. At 1 month post-D2 (n=173), 146 (84%) had positive antibody levels at a median (IQR) of 30 (28, 32) days post-D2. At 3 months post-D2 (n=164), 149 (91%) had positive levels at a median of 92 (90, 96) days post-D2. At 6 months post-D2 (n=73), 62 (85%) had positive levels at a median of 180 (176, 185) days post-D2. Among the 66 seropositive at 1 or 3 months post-D2, 58 (88%) remained seropositive by 6 months post-D2. Neither age, years since transplant, vaccine type, nor mycophenolate (MMF) use were associated with sero-reversion, though there was a trend toward more triple immunosuppressive use (25% vs 3%, p=0.07). Of those Roche-tested, the median anti-RBD levels were >=250 U/mL (14, >=250;n=120) at 1 month post-D2, >=250 U/mL (58, >=250;n=113) at 3 months, and >=250 U/mL (30, >=250;n=49) at 6 months . Of those EUROIMMUN-tested, the median anti-S1 levels were 7.25 AU (4.31, 8.71;n=53) at 1 month, 5.71 AU (1.27, 7.90;n=51) at 3 months, and 1.73 AU (0.76, 6.01;n=25) at 6 months. Conclusion(s): Overall, most LT recipients demonstrated 6 month durability of anti-spike antibody following vaccination, but a subset did sero-revert, potentially associated with heavier immunosuppression. Further investigation into clinical consequences of waning antibody levels is key to guide timing of additional vaccine doses.

Sero-surveillance for IgG to SARS-CoV-2 at antenatal care clinics in three Kenyan referral hospitals

Introduction/ Background: The high proportion of SARS-CoV-2 infections that remain undetected presents a challenge to tracking the progress of the pandemic and implementing control measures in Kenya. Pregnant women represent a sentinel sero-surveillance population as they routinely supply blood samples at their first antenatal care visit. Methods: We determined the prevalence of IgG to SARS-CoV-2 in residual blood samples from mothers attending antenatal care services at 3 referral hospitals in Kenya (Kilifi County Hospital, Kenyatta National Hospital and Busia County Referral Hospital). We used a validated IgG ELISA for SARS-Cov-2 spike protein and adjusted the results for assay sensitivity and specificity. We then used mixture models to estimate true cumulative exposure in the context of waning IgG titres over time. Results: In Kenyatta National Hospital, Nairobi, adjusted seroprevalence in August 2020 was 50% (95% CI 42.7- 58.0) but had decreased to 32% (26.2-38.4) in February 2021. In Kilifi County Hospital, seroprevalence increased from 1% (95% CI 0.04-4.7) in September 2020 to 23% in March 2021. Only 7% of women reported past symptoms. Further results from Nairobi, Busia and Kilifi up until October 2021 and the results of the mixture modelling will be available by the 30th November 2021. Impact: Residual blood samples from antenatal care visits represent an efficient sentinel surveillance population for sero-surveillance activities. The sero-surveillance estimates from this group can be compared with those from blood donors and other sentinel populations to identify high-risk groups. Conclusion: There has been substantial, unobserved transmission of SARS-CoV-2 in parts of Nairobi, Busia and Kilifi Counties. Due to the length of time since the beginning of the pandemic, repeated cross-sectional surveys are now difficult to interpret without the use of models to account for sero-reversion.

HIV-1 DIAGNOSES in NORTH CAROLINA, 2018-21: INCIDENT INFECTIONS and DRUG RESISTANCE

Background: Knowing the true incidence of HIV-1 infections (recent infections) among people newly diagnosed is pivotal to monitoring the course of the epidemic. We have developed a Primer ID Next Gen Sequencing (PID-NGS) assay to identify recent infection by measuring within-host viral diversity over multiple regions of the HIV-1 genome. We implemented a state-wide project to identify recent infections and transmitted drug resistance mutations (DRMs) in diagnostic samples in near real time. Methods: Serum samples from individuals with newly HIV-1 diagnoses (diagnostic sample collected within 30 days of diagnosis) were sequenced. PID-NGS libraries were constructed covering the coding regions for protease, a portion of reverse transcriptase, integrase, and the env gene. The use of the PID-NGS strategy allows for significant error correction and also a definition of the sampling depth of the viral population. Recent infection was defined as within 9-month of infection. DRMs were summarized at detection sensitivities of 30%, 10% and 1% based on viral population sampling depth. Results: From Jan 2018 to Jun 2021, we successfully sequenced partial genomes from 743 individuals with new diagnoses. Year 2020 had the lowest number of new diagnoses (Fig 1a, red bar). Overall, 39.2% of samples were inferred to have represented infection within the previous 9 months. Percent of recent infection varied significantly over the years, increasing from 29.6% in late 2018 to 50.9% in early 2020, but decreasing significantly to 32.7% in 2021 (Fig 1a, blue lines). Individuals younger than 30 y/o were more likely to be identified with recent infection (p<0.01). NNRTI DRMs, especially K103N, were the most abundant DRMs. Fig 1b shows the trend of DRMs over the four years. We observed a trend of decrease in the overall NNRTI DRMs and an increase in the NRTI DRMs in the population. Further analysis suggests that the increase in NRTI DRMs were from TAMs and their revertants, while clinically important NRTI DRMs (K65R and M184) were low (<1%). Conclusion: We have demonstrated a state-wide, all-in-one platform to monitor HIV-1 recency and DRMs in new diagnoses. The number of new diagnoses decreased significantly in 2020 in concert with the COVID-19 pandemic which suggests a decrease in overall HIV testing. The decline in the percentage of recent infections in early 2021 signals a return to broader HIV-1 testing and diagnosis. The increase of other NRTI DRMs suggests ongoing evolution at these sites within the viral population.

A Humanized Antibody Targeting the CotH Invasins is Protective Against Murine Mucormycosis

Background. Despite antifungal therapy and surgical debridement, overall mortality of invasive mucormycosis is >40%. Currently the world is witnessing an explosion in mucormycosis in India among COVID-19 patients with an official count of 28,252 cases as of 06/07/2021. Thus, novel therapeutic modalities are needed. We previously reported on a mouse monoclonal antibody (C2) targeting CotH invasins being protective against mucormycosis. Here, we humanized C2 MAb and assessed its efficacy in vitro and in vivo. Methods. The C2 (IgG1) paratopes of the heavy chain and light chain were grafted on the most suitable human IgG1 with back mutations in the paratopes needed to restore binding of humanized clones to CotH3 (by biolayer interferometry using Gator). Clones were compared to C2 in their ability to prevent Rhizopus delemar-induced injury to A549 alveolar epithelial and primary human endothelial cells and for enhancing human neutrophil killing of the fungus in vitro. C2 and the humanized clones were also compared for their ability to protect neutropenic mice from mucormycosis induced by R. delemar or Mucor cicrinelloides with and without antifungal therapy. Results. Three humanized clones showed 10-fold enhanced binding affinity to CotH3 protein (~5 nM for humanized vs. ~50 nM for C2). One humanized clone (VX01) doubled the ability of neutrophils to kill R. delemar and resulted in ~50% reduction in host cell damage. A single low dose of VX01 (30 μg) given 24 h post infection resulted in comparable survival of 60-70% in mice infected intratracheally with either R. delemar or M. cicrinelloides vs. placebo mice (0% survival, P < 0.02). Importantly, VX01 acted synergistically in protecting mice when combined with liposomal amphotericin B or posaconazole in a severe model of mucormycosis with treatment starting 48 h post infection (~70% survival for combination vs. 0-20% survival for monotherapy and reduced lung fungal burden by 1.5 log, P< 0.001). GLP-tissue cross reactivity studies of VX01 showed favorable safety profiles. Conclusion. VX01 shows enhanced binding to CotH3 protein and maintained the protective features of C2 MAb against murine mucormycosis. Clinical testing of combination therapy of VX01 + antifungals is warranted. VX01 is currently in manufacturing.