Exploring adolescent girls and young women's PrEP-user profiles: qualitative insights into differentiated PrEP delivery platform selection and engagement in Cape Town, South Africa.

INTRODUCTION: Adolescent girls and young women (AGYW), a priority population for HIV prevention in Africa, show high interest but difficulty in sustained effective use of pre-exposure prophylaxis (PrEP). With ongoing PrEP scale-up focused on increasing access, it is important to understand what influences AGYW's choice of PrEP delivery platforms. METHODS: The POWER implementation study in Cape Town provided PrEP between 2017 and 2020 to AGYW (16-25 years) from four differentiated delivery platforms: mobile clinic, government facility, courier delivery or community-based youth club. Healthcare providers at government and mobile clinics provided PrEP (initiation and refills) as part of comprehensive, integrated sexual and reproductive health services. Courier and youth club platforms provided light-touch PrEP refill services incorporating rapid HIV self-testing. We conducted in-depth interviews with a purposive sample of AGYW who had ≥3 months of PrEP-use and accessed ≥2 PrEP delivery platforms. The thematic analysis explored AGYW's preferences, decision-making and habits related to PrEP access to inform market segmentation. RESULTS: We interviewed 26 AGYW (median age 20) PrEP-users between November 2020 and March 2021. AGYW PrEP-users reported accessing different services with, 24 accessing mobile clinics, 17 courier delivery, 9 government health facilities and 6 youth clubs for their PrEP refills. Qualitative findings highlighted four potential behavioural profiles. The "Social PrEP-user" preferred PrEP delivery in peer spaces, such as youth clubs or adolescent-friendly mobile clinics, seeking affirmation and social support for continued PrEP use. The "Convenient PrEP-user" favoured PrEP delivery at easily accessible locations, providing quick (courier) or integrated contraception-PrEP refill visits (mobile and government clinic). The "Independent PrEP-user" preferred PrEP delivery that offered control over delivery times that fit into their schedule, such as the courier service. The "Discreet PrEP-user" highly valued privacy regarding their PrEP use (courier delivery) and avoided delivery options where unintentional disclosure was evident (youth club). Comfort with HIV self-testing had minimal influence on PrEP delivery choice. CONCLUSIONS: Market segmentation of AGYW characterizes different types of PrEP-users and has the potential to enhance tailored messaging and campaigns to reach specific segments, with the aim of improving sustained PrEP use and HIV prevention benefits.

Macrophage-fibroblast JAK/STAT dependent crosstalk promotes liver metastatic outgrowth in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic disease for which better therapies are urgently needed. Fibroblasts and macrophages are heterogeneous cell populations able to enhance metastasis, but the role of a macrophage-fibroblast crosstalk in regulating their pro-metastatic functions remains poorly understood. Here we deconvolve how macrophages regulate metastasis-associated fibroblast (MAF) heterogeneity in the liver. We identify three functionally distinct MAF populations, among which the generation of pro-metastatic and immunoregulatory myofibroblastic-MAFs (myMAFs) critically depends on macrophages. Mechanistically, myMAFs are induced through a STAT3-dependent mechanism driven by macrophage-derived progranulin and cancer cell-secreted leukaemia inhibitory factor (LIF). In a reciprocal manner, myMAF secreted osteopontin promotes an immunosuppressive macrophage phenotype resulting in the inhibition of cytotoxic T cell functions. Pharmacological blockade of STAT3 or myMAF-specific genetic depletion of STAT3 restores an anti-tumour immune response and reduces metastases. Our findings provide molecular insights into the complex macrophage-fibroblast interactions in tumours and reveal potential targets to inhibit PDAC liver metastasis.

Targeted irradiation in an autochthonous mouse model of pancreatic cancer.

The value of radiotherapy in the treatment of pancreatic cancer has been the subject of much debate but limited preclinical research. We hypothesise that the poor translation of radiation research into clinical trials of radiotherapy in pancreatic cancer is due, in part, to inadequate preclinical study models. Here, we developed and refined methods for targeted irradiation in autochthonous mouse models of pancreatic cancer, using a small animal radiotherapy research platform. We tested and optimised strategies for administration of contrast agents, iohexol and the liver imaging agent Fenestra LC, to enable the use of computed tomography imaging in tumour localisation. We demonstrate accurate tumour targeting, negligible off-target effects and therapeutic efficacy, depending on dose, number of fractions and tumour size, and provide a proof of concept that precise radiation can be delivered effectively to mouse pancreatic tumours with a clinically relevant microenvironment. This advance will allow investigation of the radiation response in murine pancreatic cancer, discovery of mechanisms and biomarkers of radiosensitivity or resistance, and development of radiosensitising strategies to inform clinical trials for precision radiotherapy in this disease.

Efferocytosis reprograms the tumor microenvironment to promote pancreatic cancer liver metastasis.

Pancreatic ductal adenocarcinoma is a highly metastatic disease and macrophages support liver metastases. Efferocytosis, or engulfment of apoptotic cells by macrophages, is an essential process in tissue homeostasis and wound healing, but its role in metastasis is less well understood. Here, we found that the colonization of the hepatic metastatic site is accompanied by low-grade tissue injury and that efferocytosis-mediated clearance of parenchymal dead cells promotes macrophage reprogramming and liver metastasis. Mechanistically, progranulin expression in macrophages is necessary for efficient efferocytosis by controlling lysosomal acidification via cystic fibrosis transmembrane conductance regulator and the degradation of lysosomal cargo, resulting in LXRα/RXRα-mediated macrophage conversion and upregulation of arginase 1. Pharmacological blockade of efferocytosis or macrophage-specific genetic depletion of progranulin impairs macrophage conversion, improves CD8+ T cell functions, and reduces liver metastasis. Our findings reveal how hard-wired functions of macrophages in tissue repair contribute to liver metastasis and identify potential targets for prevention of pancreatic ductal adenocarcinoma liver metastasis.

KRAS allelic imbalance drives tumour initiation yet suppresses metastasis in colorectal cancer in vivo.

Oncogenic KRAS mutations are well-described functionally and are known to drive tumorigenesis. Recent reports describe a significant prevalence of KRAS allelic imbalances or gene dosage changes in human cancers, including loss of the wild-type allele in KRAS mutant cancers. However, the role of wild-type KRAS in tumorigenesis and therapeutic response remains elusive. We report an in vivo murine model of colorectal cancer featuring deletion of wild-type Kras in the context of oncogenic Kras. Deletion of wild-type Kras exacerbates oncogenic KRAS signalling through MAPK and thus drives tumour initiation. Absence of wild-type Kras potentiates the oncogenic effect of KRASG12D, while incidentally inducing sensitivity to inhibition of MEK1/2. Importantly, loss of the wild-type allele in aggressive models of KRASG12D-driven CRC significantly alters tumour progression, and suppresses metastasis through modulation of the immune microenvironment. This study highlights the critical role for wild-type Kras upon tumour initiation, progression and therapeutic response in Kras mutant CRC.

Family influences on oral PrEP use among adolescent girls and young women in Kenya and South Africa.

INTRODUCTION: Effective use of oral HIV pre-exposure prophylaxis (PrEP) has been lower among African adolescent girls and young women (AGYW) than among older women, young men who have sex with men, and serodiscordant heterosexual couples in the region. Efforts to build PrEP support have centered around peers and male partners, but the family may also play an important role. This qualitative study aimed to describe family influence on PrEP use among AGYW in in three African cities. METHODS: POWER (Prevention Options for Women Evaluation Research) was a PrEP demonstration project among 2550 AGYW (16-25 years old) in Johannesburg and Cape Town, South Africa and Kisumu, Kenya conducted from 2017 to 2020. In-depth interviews and focus group discussions were conducted with 136 AGYW participants to explore their PrEP views and experiences, including awareness and interest in PrEP; barriers and facilitators to uptake and use; the influence of family, peers, intimate partners, and community; and the key types of support for their PrEP use. Transcripts were coded and analysed thematically. RESULTS: The decision to initiate PrEP was associated with fear and anxiety linked to anticipated stigma from family members, and with family's lived HIV experience. Family disclosure, especially to mothers, was important to participants, as most lived with their families and considered it essential for them to obtain their mother's approval to use PrEP. Most family members, particularly mothers, provided instrumental, emotional, informational and appraisal support to participants using PrEP, including reminders, encouragement, and problem-solving. Participants reported that family members with insufficient information about PrEP safety and efficacy and who voiced concerns were a substantial barrier to their use. However, they often became supportive after receiving more PrEP information. CONCLUSION: Families, particularly mothers, can play an important role in supporting PrEP use. PrEP programmes should leverage family support to help with PrEP persistence by providing basic information to families about PrEP safety and efficacy. AGYW using PrEP should be encouraged to selectively disclose PrEP use to build support and counseled on how to disclose and address family concerns.

Defining the spatial distribution of extracellular adenosine revealed a myeloid-dependent immunosuppressive microenvironment in pancreatic ductal adenocarcinoma.

BACKGROUND: The prognosis for patients with pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. It has been suggested that the adenosine pathway contributes to the ability of PDAC to evade the immune system and hence, its resistance to immuno-oncology therapies (IOT), by generating extracellular adenosine (eAdo). METHODS: Using genetically engineered allograft models of PDAC in syngeneic mice with defined and different immune infiltration and response to IOT and autochthonous tumors in KPC mice we investigated the impact of the adenosine pathway on the PDAC tumor microenvironment (TME). Flow cytometry and imaging mass cytometry (IMC) were used to characterize the subpopulation frequency and spatial distribution of tumor-infiltrating immune cells. Mass spectrometry imaging (MSI) was used to visualize adenosine compartmentalization in the PDAC tumors. RNA sequencing was used to evaluate the influence of the adenosine pathway on the shaping of the immune milieu and correlate our findings to published data sets in human PDAC. RESULTS: We demonstrated high expression of adenosine pathway components in tumor-infiltrating immune cells (particularly myeloid populations) in the murine models. MSI demonstrated that extracellular adenosine distribution is heterogeneous in tumors, with high concentrations in peri-necrotic, hypoxic regions, associated with rich myeloid infiltration, demonstrated using IMC. Protumorigenic M2 macrophages express high levels of the Adora2a receptor; particularly in the IOT resistant model. Blocking the in vivo formation and function of eAdo (Adoi), using a combination of anti-CD73 antibody and an Adora2a inhibitor slowed tumor growth and reduced metastatic burden. Additionally, blocking the adenosine pathway improved the efficacy of combinations of cytotoxic agents or immunotherapy. Adoi remodeled the TME, by reducing the infiltration of M2 macrophages and regulatory T cells. RNA sequencing analysis showed that genes related to immune modulation, hypoxia and tumor stroma were downregulated following Adoi and a specific adenosine signature derived from this is associated with a poorer prognosis in patients with PDAC. CONCLUSIONS: The formation of eAdo promotes the development of the immunosuppressive TME in PDAC, contributing to its resistance to conventional and novel therapies. Therefore, inhibition of the adenosine pathway may represent a strategy to modulate the PDAC immune milieu and improve therapy response in patients with PDAC.

A decision support tool has similar high PrEP uptake and increases early PrEP persistence in adolescent girls and young women in South Africa: results from a randomized controlled trial.

INTRODUCTION: African adolescent girls and young women (AGYW) have high rates of HIV acquisition and are a priority population for HIV pre-exposure prophylaxis (PrEP). PrEP implementation has been limited by AGYW's low perceived HIV risk and provider demands. A decision support tool (DST) with information about PrEP could improve clients' risk perception, knowledge about PrEP, informed decision-making and motivation to use PrEP based on their risk, facilitating PrEP delivery in primary healthcare (PHC) clinics. METHODS: We designed MyPrEP, a client-facing DST about PrEP and HIV prevention, with youth-friendly information and images. The impact of the MyPrEP tool was assessed among HIV-negative women aged 18-25 years presenting to a PHC clinic in Johannesburg, South Africa from March 2019 to 2020. AGYW were randomized by day to the DST or a general health website as the control condition. A clinician blinded to DST versus control allocation provided standard of care counselling about PrEP, offered PrEP, administered a questionnaire and conducted sexually transmitted infection testing. The primary outcome was PrEP initiation and the secondary outcome was PrEP persistence at 1 month, determined by pharmacy dispensation records. RESULTS: Of 386 AGYW screened, 353 were randomized (DST n = 172, control n = 181) with a median age of 21 years (interquartile range [IQR] 20, 23) and 56% (199/353) attending the clinic for HIV testing, 46% (164/353) using contraception, 15% (53/353) using condoms consistently and 37% (108/353) with a curable sexually transmitted infection. PrEP was initiated by 97% in the DST group and 94% in the control group (OR 1.79; 95% confidence interval, CI = 0.79-1.53), of whom two-thirds planned to continue PrEP until they decided if they liked PrEP. At 1 month, PrEP persistence was 19% in the DST and 10% in the control group (OR 1.97, 95% CI 1.08-3.69). Ninety-nine percent randomized to the DST reported satisfaction with MyPrEP. CONCLUSIONS: Among AGYW attending a South African PHC clinic, PrEP uptake was >90% with two-fold higher PrEP persistence at 1 month in those randomized to use the MyPrEP DST. Given the need for strategies to support PrEP implementation and improve low PrEP persistence among African AGYW, a PrEP DST warrants further evaluation.

Patterns of PrEP continuation and coverage in the first year of use: a latent class analysis of a programmatic PrEP trial in Kenya.

INTRODUCTION: Effective PrEP use is critical for impact, but data are limited on common patterns of continuation and coverage among persons using PrEP in real-world settings. METHODS: Data are from the Partners Scale-Up Project, a programmatic stepped-wedge cluster-randomized trial to integrate PrEP delivery in 25 Kenyan public health facilities conducted between February 2017 and December 2021. We evaluated PrEP continuation using visit attendance and pharmacy refill records, and computed medication possession ratio to define coverage during the first year of use. Latent class mixture models were used to identify and characterize membership to different PrEP continuation patterns. Multinomial logistic regression was used to examine the association between group trajectories and demographic and behaviour characteristics. RESULTS: Overall, 4898 persons initiated PrEP, 54% (2640) were female, mean age was 33 years (standard deviation 11) and 84% (4092) had partners living with HIV. PrEP continuation was 57%, 44%, and 34% at 1, 3, and 6 months, respectively. Four unique trajectories of PrEP coverage were identified: (1) one-fourth (1154) exhibited consistent high coverage throughout the year with 93%, 94%, 96%, and 67% continuing PrEP at months 1, 3, 6, and 12, respectively; (2) 13% (682) showed high coverage trajectory throughout 6 months but coverage rapidly declined thereafter (94%, 93%, 63%, and 10% continued at months 1, 3, 6, and 12, respectively); (3) 18.9% (918) exhibited moderate coverage trajectory with 91% of clients refilling PrEP at month 1 but nearly all dropped-off thereafter (37%, 5%, and 4% continued at months 3, 6, and 12, respectively); and (4) 43.8% (2144) exhibited immediate discontinuation trajectory, in which nearly all did not have any subsequent PrEP refill. Overall, being female, older age, having partners living with HIV or of unknown HIV status were statistically associated with better PrEP continuation trajectories compared to the immediate discontinuation trajectory (p <0.05 for all). CONCLUSIONS: In this analysis of a real-world PrEP implementation programme in Kenya, we found four distinct patterns of PrEP continuation, with one-third of users exhibiting consistent high continuation throughout 12 months and two-fifths with immediate discontinuation patterns. These data may help guide tailored interventions to support PrEP continuation in this setting.

Association of sexual relationship power with PrEP persistence and other sexual health outcomes among adolescent and young women in Kenya and South Africa.

Introduction: Gendered power inequalities impact adolescent girls' and young women's (AGYW) sexual and reproductive health (SRH) outcomes. We investigated the influence of sexual relationship power on AGYW's SRH outcomes, including HIV pre-exposure prophylaxis (PrEP) persistence. Methods: The POWER study in Kisumu, Kenya, and Cape Town and Johannesburg, South Africa provided PrEP to 2,550 AGYW (aged 16-25). AGYW's perceived power in their primary sexual relationship was measured among the first 596 participants enrolled using the Sexual Relationship Power Scale's (SRPS) relationship control sub-scale. Multivariable regression was used to test for (1) key sociodemographic and relationship characteristics associated with relationship power; and (2) the association of relationship power with SRH outcomes including PrEP persistence. Results: In this cohort, the mean SRPS score was 2.56 (0.49), 542 (90.9%) initiated PrEP; 192 (35.4%) persisted with PrEP at 1 month of which 46 (24.0% of 192) persisted at 6 months. SRPS were significantly lower among AGYW who cohabited with their sex partner (-0.14, 95% CI: -0.24 to -0.04, p = 0.01), or had ≥1 sex partner (-0.10, 95% CI: -0.19 to -0.00, p = 0.05). AGYW with lower SRPS were more likely to not know their partner's HIV status (aOR 2.05, 95% CI: 1.27 to 3.33, p < 0.01), but SRPS was not associated with PrEP persistence, STI infection, condom, or hormonal contraception use. Discussion: AGYW's reasons for initiating PrEP and reasons for continuously using PrEP may be different. While low relationship power was associated with perceived HIV vulnerability, AGYW's PrEP persistence may be influenced by more than relationship power.

Monitoring AKT activity and targeting in live tissue and disease contexts using a real-time Akt-FRET biosensor mouse.

Aberrant AKT activation occurs in a number of cancers, metabolic syndrome, and immune disorders, making it an important target for the treatment of many diseases. To monitor spatial and temporal AKT activity in a live setting, we generated an Akt-FRET biosensor mouse that allows longitudinal assessment of AKT activity using intravital imaging in conjunction with image stabilization and optical window technology. We demonstrate the sensitivity of the Akt-FRET biosensor mouse using various cancer models and verify its suitability to monitor response to drug targeting in spheroid and organotypic models. We also show that the dynamics of AKT activation can be monitored in real time in diverse tissues, including in individual islets of the pancreas, in the brown and white adipose tissue, and in the skeletal muscle. Thus, the Akt-FRET biosensor mouse provides an important tool to study AKT dynamics in live tissue contexts and has broad preclinical applications.

USP9X mediates an acute adaptive response to MAPK suppression in pancreatic cancer but creates multiple actionable therapeutic vulnerabilities.

Pancreatic ductal adenocarcinomas (PDACs) frequently harbor KRAS mutations. Although MEK inhibitors represent a plausible therapeutic option, most PDACs are innately resistant to these agents. Here, we identify a critical adaptive response that mediates resistance. Specifically, we show that MEK inhibitors upregulate the anti-apoptotic protein Mcl-1 by triggering an association with its deubiquitinase, USP9X, resulting in acute Mcl-1 stabilization and protection from apoptosis. Notably, these findings contrast the canonical positive regulation of Mcl-1 by RAS/ERK. We further show that Mcl-1 inhibitors and cyclin-dependent kinase (CDK) inhibitors, which suppress Mcl-1 transcription, prevent this protective response and induce tumor regression when combined with MEK inhibitors. Finally, we identify USP9X as an additional potential therapeutic target. Together, these studies (1) demonstrate that USP9X regulates a critical mechanism of resistance in PDAC, (2) reveal an unexpected mechanism of Mcl-1 regulation in response to RAS pathway suppression, and (3) provide multiple distinct promising therapeutic strategies for this deadly malignancy.

COVID-19 Antigen Results Correlate with the Quantity of Replication-Competent SARS-CoV-2 in a Cross-Sectional Study of Ambulatory Adults during the Delta Wave.

Appropriate interpretation of various diagnostic tests for COVID-19 is critical, yet the association among rapid antigen tests, reverse transcription (RT)-PCR, and viral culture has not been fully defined. To determine whether rapid antigen testing correlates with the presence and quantity of replication-competent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in ambulatory adults, 626 adult participants were enrolled in a cross-sectional diagnostic study. Each participant had two anterior nasal swabs obtained for rapid antigen and RT-PCR testing and SARS-CoV-2 viral culture. The primary outcomes were the presence and quantification of SARS-CoV-2 growth in VeroE6-ACE2-TMPRSS2 cells in asymptomatic and symptomatic ambulatory adults. In this cross-sectional study of 626 adult outpatients, the sensitivity of a single positive antigen test to identify replication-competent SARS-CoV-2 was 63.6% in asymptomatic and 91.0% in symptomatic participants. Viral culture titers were the highest at the onset of symptoms and rapidly declined by 7 days after symptom onset. The positive agreement of the rapid antigen test with RT-PCR at a cycle threshold CT less than 30 was 66.7% in asymptomatic and 90.7% in symptomatic participants. Among symptomatic participants a with a CT less than 30, a single antigen test had a positive agreement of 90.7% (95% confidence interval [CI], 84.8% to 94.8%). There was 100% negative agreement as all 425 RT-PCR-negative participants had a negative antigen test. A positive antigen test in symptomatic adults with COVID-19 has a strong correlation with replication-competent SARS-CoV-2. Rapid antigen test results may be a suitable proxy for infectiousness. IMPORTANCE Do rapid antigen test results correlate with replication-competent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (i.e., infectious) virus? In this cross-sectional diagnostic study of 626 adults, the sensitivity of the antigen test to identify replication-competent SARS-CoV-2 was 63.6% in asymptomatic and 91.0% in symptomatic participants. Viral culture titers were the highest at the onset of symptoms and rapidly declined by 7 days after symptom onset. The positive agreement of the rapid antigen test with reverse transcription (RT)-PCR at a CT of less than 30 was 66.7% in asymptomatic participants and 90.7% in symptomatic participants. A positive antigen test may be an appropriate surrogate for identifying replication-competent virus in symptomatic individuals with COVID-19.

NUAK1 governs centrosome replication in pancreatic cancer via MYPT1/PP1ß and GSK3ß-dependent regulation of PLK4.

The AMP-activated protein kinase (AMPK)-related kinase NUAK1 (NUAK family SNF1-like kinase 1) has emerged as a potential vulnerability in MYC-dependent cancer but the biological roles of NUAK1 in different settings are poorly characterised, and the spectrum of cancer types that exhibit a requirement for NUAK1 is unknown. Unlike canonical oncogenes, NUAK1 is rarely mutated in cancer and appears to function as an obligate facilitator rather than a cancer driver per se. Although numerous groups have developed small-molecule NUAK inhibitors, the circumstances that would trigger their use and the unwanted toxicities that may arise as a consequence of on-target activity are thus undetermined. Reasoning that MYC is a key effector of RAS pathway signalling and the GTPase KRAS is almost uniformly mutated in pancreatic ductal adenocarcinoma (PDAC), we investigated whether this cancer type exhibits a functional requirement for NUAK1. Here, we show that high NUAK1 expression is associated with reduced overall survival in PDAC and that inhibition or depletion of NUAK1 suppresses growth of PDAC cells in culture. We identify a previously unknown role for NUAK1 in regulating accurate centrosome duplication and show that loss of NUAK1 triggers genomic instability. The latter activity is conserved in primary fibroblasts, raising the possibility of undesirable genotoxic effects of NUAK1 inhibition.

Duration of viral infectiousness and correlation with symptoms and diagnostic testing in non-hospitalized adults during acute SARS-CoV-2 infection: A longitudinal cohort study.

BACKGROUND: Guidelines for SARS-CoV-2 have relied on limited data on duration of viral infectiousness and correlation with COVID-19 symptoms and diagnostic testing. METHODS: We enrolled ambulatory adults with acute SARS-CoV-2 infection and performed serial measurements of COVID-19 symptoms, nasal swab viral RNA, nucleocapsid (N) and spike (S) antigens, and replication-competent SARS-CoV-2 by viral growth in culture. We determined average time from symptom onset to a first negative test result and estimated risk of infectiousness, as defined by positive viral growth in culture. RESULTS: Among 95 adults, median [interquartile range] time from symptom onset to first negative test result was 9 [5] days, 13 [6] days, 11 [4] days, and >19 days for S antigen, N antigen, culture growth, and viral RNA by RT-PCR, respectively. Beyond two weeks, virus growth and N antigen titers were rarely positive, while viral RNA remained detectable among half (26/51) of participants tested 21-30 days after symptom onset. Between 6-10 days from symptom onset, N antigen was strongly associated with culture positivity (relative risk=7.61, 95% CI: 3.01-19.22), whereas neither viral RNA nor symptoms were associated with culture positivity. During the 14 days following symptom onset, the presence of N antigen remained strongly associated (adjusted relative risk=7.66, 95% CI: 3.96-14.82) with culture positivity, regardless of COVID-19 symptoms. CONCLUSIONS: Most adults have replication-competent SARS-CoV-2 for 10-14 after symptom onset. N antigen testing is a strong predictor of viral infectiousness and may be a more suitable biomarker, rather than absence of symptoms or viral RNA, to discontinue isolation within two weeks from symptom onset.

Dynamics of SARS-CoV-2 VOC Neutralization and Novel mAb Reveal Protection against Omicron.

New variants of SARS-CoV-2 continue to emerge and evade immunity. We isolated SARS-CoV-2 temporally across the pandemic starting with the first emergence of the virus in the western hemisphere and evaluated the immune escape among variants. A clinic-to-lab viral isolation and characterization pipeline was established to rapidly isolate, sequence, and characterize SARS-CoV-2 variants. A virus neutralization assay was applied to quantitate humoral immunity from infection and/or vaccination. A panel of novel monoclonal antibodies was evaluated for antiviral efficacy. We directly compared all variants, showing that convalescence greater than 5 months post-symptom onset from ancestral virus provides little protection against SARS-CoV-2 variants. Vaccination enhances immunity against viral variants, except for Omicron BA.1, while a three-dose vaccine regimen provides over 50-fold enhanced protection against Omicron BA.1 compared to a two-dose. A novel Mab neutralizes Omicron BA.1 and BA.2 variants better than the clinically approved Mabs, although neither can neutralize Omicron BA.4 or BA.5. Thus, the need remains for continued vaccination-booster efforts, with innovation for vaccine and Mab improvement for broadly neutralizing activity. The usefulness of specific Mab applications links with the window of clinical opportunity when a cognate viral variant is present in the infected population.

Therapeutic targeting of tumour myeloid cells.

Myeloid cells are pivotal within the immunosuppressive tumour microenvironment. The accumulation of tumour-modified myeloid cells derived from monocytes or neutrophils - termed 'myeloid-derived suppressor cells' - and tumour-associated macrophages is associated with poor outcome and resistance to treatments such as chemotherapy and immune checkpoint inhibitors. Unfortunately, there has been little success in large-scale clinical trials of myeloid cell modulators, and only a few distinct strategies have been used to target suppressive myeloid cells clinically so far. Preclinical and translational studies have now elucidated specific functions for different myeloid cell subpopulations within the tumour microenvironment, revealing context-specific roles of different myeloid cell populations in disease progression and influencing response to therapy. To improve the success of myeloid cell-targeted therapies, it will be important to target tumour types and patient subsets in which myeloid cells represent the dominant driver of therapy resistance, as well as to determine the most efficacious treatment regimens and combination partners. This Review discusses what we can learn from work with the first generation of myeloid modulators and highlights recent developments in modelling context-specific roles for different myeloid cell subtypes, which can ultimately inform how to drive more successful clinical trials.

Provider perspectives on service delivery modifications to maintain access to HIV pre-exposure prophylaxis during the COVID-19 pandemic: qualitative results from a PrEP implementation project in Kenya.

INTRODUCTION: HIV pre-exposure prophylaxis (PrEP) is an essential prevention strategy being scaled up for priority populations in Kenya, including for HIV serodiscordant couples. The COVID-19 pandemic posed challenges to PrEP rollout. We conducted a qualitative study of PrEP providers to understand how clinics adjusted PrEP delivery during the COVID-19 pandemic. METHODS: Since 2017, the Partners Scale-Up Project has integrated PrEP into 25 HIV clinics in Central and Western Kenya. We conducted qualitative interviews with 40 purposively sampled clinic personnel. We interviewed personnel once during the first pandemic wave (May-Aug 2020) and again after some decline in COVID-19 rates (Nov-Jan 2021). We analysed data using inductive memo-writing and summarized data by themes along the PrEP delivery cascade, guided by the Framework for Reporting Adaptation and Modifications (FRAME). RESULTS: We interviewed 27 clinical officers, five nurses, four health records and information officers, and four counsellors from Central (n = 20) and Western (n = 20) Kenya. About half (n = 19) were female, with a median age of 32 (IQR: 29-34) and 2.3 years of experience delivering PrEP (IQR: 2-3). All participants reported clinic changes in PrEP demand creation and service delivery during the pandemic. Modifications occurred during PrEP implementation and sustainment phases, were partly reactive to the pandemic and also facilitated by interim Ministry of Health guidance on PrEP delivery during COVID, and were made by PrEP delivery teams, clients and clinic managers. Commonly reported modifications included dispensing multiple-month PrEP refills, intensifying phone-based client engagement and collaborating with other HIV clinics to ensure that clients with prolonged stays in other regions could continue to access PrEP. Some clinics also adopted practices to streamline visits, such as within clinical-room PrEP dispensing, pre-packing PrEP and task-shifting. Most providers liked these changes and hoped they would continue after the pandemic subsides. CONCLUSIONS: COVID-19 served as a catalyst for PrEP delivery innovations in Kenya. HIV clinics successfully and rapidly adapted their PrEP demand creation, refill and retention strategies to promote PrEP uptake and effective use. These modified implementation strategies highlight opportunities to streamline the delivery of PrEP, as well as other HIV and chronic care services, and strengthen engagement with populations post-pandemic.