Sri Lanka's COVID-19 response and maintaining health services: implications for future pandemics.

This study examines how Sri Lanka, a lower-middle income country, managed its COVID-19 response and maintained health services. It draws on an extensive document review, key informant interviews and a national survey of public experience and opinion to assess what Sri Lanka did, its effectiveness and why.Owing to a strong health system and luck, Sri Lanka stopped the first wave of COVID-19 infections, and it adopted a 'Zero-COVID' approach with the explicit goal of stopping outbreaks. This was initially effective. Outbreaks reduced healthcare use, but with minimal impact on health outcomes. But from end-2020, Sri Lanka switched its approach to tolerating transmission and mitigation. It took proactive actions to maintain healthcare access, and it pursued a COVID-19 vaccination effort that was successful in covering its adult population rapidly and with minimal disparities. Despite this, widespread transmission during 2021-2022 disrupted health services through the pressure on health facilities of patients with COVID-19 and infection of healthcare workers, and because COVID-19 anxiety discouraged patients from seeking healthcare. This led to substantial mortality and more than 30 000 excess deaths by 2022.We find that Sri Lanka abandoned its initially successful approach, because it failed to understand that its chosen strategy required symptomatic PCR testing in primary care. Failure to invest in testing was compounded by groupthink and a medical culture averse to testing.Sri Lanka's experience confirms that strong public health capacities, robust healthcare systems and intersectoral action are critical for pandemic response. It shows that civilian-military collaboration can be beneficial but contested, and that lack of fiscal space will undermine any response. It also demonstrates that pandemic preparedness cannot guarantee a successful pandemic response. Policy and research must pay more attention to improving decision-making processes when faced with pandemics involving novel pathogens, rapid spread, and substantial scientific uncertainty.

Factors impacting sustained coverage in the context of donor transitions: experience from Sri Lanka.

Although not reliant on donor funding for health, the external assistance that Sri Lanka receives contributes to the improvement of the health system and health outcomes. In this study, we evaluated transition experiences of the expanded programme on immunization (EPI) that received Gavi funding to expand the vaccine portfolio and the Anti-Malaria Campaign (AMC) that received funding from the Global Fund for AIDS, Tuberculosis and Malaria to scale-up interventions to target and achieve malaria elimination. We assessed if EPI and AMC programmes were able to sustain coverage of previously donor-funded interventions post-transition and explain the facilitators and barriers that contribute to this. We used a mixed methods approach using quantitative data to assess coverage indicators and the financing mix of the health programmes and qualitative analysis guided by a framework informed by the Walt and Gilson policy triangle that brought together document review and in-depth interviews to identify facilitators and barriers to transition success. The EPI programme showed sustained coverage of Gavi-funded vaccines post-transition and the funding gap was bridged by mobilizing domestic financing facilitated by the Gavi co-financing mechanism, full integration within existing service delivery structures, well-established and favourable pharmaceutical procurement processes for the public sector and stewardship and financial advocacy by technically competent managers. Although the absence of indigenous cases of malaria since 2012 suggests overall programme success, the AMC showed mixed transition success in relation to its different programme components. Donor-supported programme components requiring mobilization of operational expenses, facilitated by early financial planning, were successfully transitioned (e.g. entomological and parasitological surveillance) given COVID-19-related constraints. Other key programme components, such as research, training, education and awareness that are dependent on non-operational expenses are lagging behind. Additionally, concerns of AMC's future financial sustainability within the current structure remain in the context of low malaria burden.

De novo macrocyclic peptides for inhibiting, stabilizing, and probing the function of the retromer endosomal trafficking complex.

The retromer complex (Vps35-Vps26-Vps29) is essential for endosomal membrane trafficking and signaling. Mutation of the retromer subunit Vps35 causes late-onset Parkinson's disease, while viral and bacterial pathogens can hijack the complex during cellular infection. To modulate and probe its function, we have created a novel series of macrocyclic peptides that bind retromer with high affinity and specificity. Crystal structures show that most of the cyclic peptides bind to Vps29 via a Pro-Leu­containing sequence, structurally mimicking known interactors such as TBC1D5 and blocking their interaction with retromer in vitro and in cells. By contrast, macrocyclic peptide RT-L4 binds retromer at the Vps35-Vps26 interface and is a more effective molecular chaperone than reported small molecules, suggesting a new therapeutic avenue for targeting retromer. Last, tagged peptides can be used to probe the cellular localization of retromer and its functional interactions in cells, providing novel tools for studying retromer function.

A robust method for particulate detection of a genetic tag for 3D electron microscopy.

Genetic tags allow rapid localization of tagged proteins in cells and tissues. APEX, an ascorbate peroxidase, has proven to be one of the most versatile and robust genetic tags for ultrastructural localization by electron microscopy (EM). Here, we describe a simple method, APEX-Gold, which converts the diffuse oxidized diaminobenzidine reaction product of APEX into a silver/gold particle akin to that used for immunogold labelling. The method increases the signal-to-noise ratio for EM detection, providing unambiguous detection of the tagged protein, and creates a readily quantifiable particulate signal. We demonstrate the wide applicability of this method for detection of membrane proteins, cytoplasmic proteins, and cytoskeletal proteins. The method can be combined with different EM techniques including fast freezing and freeze substitution, focussed ion beam scanning EM, and electron tomography. Quantitation of expressed APEX-fusion proteins is achievable using membrane vesicles generated by a cell-free expression system. These membrane vesicles possess a defined quantum of signal, which can act as an internal standard for determination of the absolute density of expressed APEX-fusion proteins. Detection of fusion proteins expressed at low levels in cells from CRISPR-edited mice demonstrates the high sensitivity of the APEX-Gold method.

Increased Intensity Of PCR Testing Reduced COVID-19 Transmission Within Countries During The First Pandemic Wave.

Experts agree that reverse transcription-polymerase chain reaction (PCR) testing is critical in controlling coronavirus disease 2019 (COVID-19), but decision makers disagree on how much testing is optimal. Controlling for interventions and ecological factors, we used linear regression to quantify testing's impact on COVID-19's average reproduction number, which represents transmissibility, in 173 countries and territories (which account for 99 percent of the world's COVID-19 cases) during March-June 2020. Among interventions, PCR testing had the greatest influence: a tenfold increase in the ratio of tests to new cases reported reduced the average reproduction number by 9 percent across a range of testing levels. Our results imply that mobility reductions (for example, shelter-in-place orders) were less effective in developing countries than in developed countries. Our results help explain how some nations achieved near-elimination of COVID-19 and the failure of lockdowns to slow COVID-19 in others. Our findings suggest that the testing benchmarks used by the World Health Organization and other entities are insufficient for COVID-19 control. Increased testing and isolation may represent the most effective, least costly alternative in terms of money, economic growth, and human life for controlling COVID-19.

The role of p75NTR in cholinergic basal forebrain structure and function.

The role of the p75 neurotrophin receptor (p75(NTR)) in adult cholinergic basal forebrain (cBF) neurons is unclear due to conflicting results from previous studies and to limitations of existing p75(NTR)-knock-out mouse models. In the present study we used a novel conditional knock-out line (ChAT-cre p75(in/in)) to assess the role of p75(NTR) in the cBF by eliminating p75(NTR) in choline acetyl-transferase-expressing cells. We show that the absence of p75(NTR) results in a lasting increase in cBF cell number, cell size, and cholinergic innervation to the cortex. Analysis of adult ChAT-cre p75(in/in) mice revealed that mutant animals show a similar loss of cBF neurons with age to that observed in wild-type animals, indicating that p75(NTR) does not play a significant role in mediating this age-related decline in cBF neuronal number. However, the increased cholinergic axonal innervation of the cortex, but not the hippocampus, corresponded to alterations in idiothetic but not allothetic navigation. These findings support a role for p75(NTR)-mediated regulation of cholinergic-dependent cognitive function, and suggest that the variability in previous reports of cBF neuron number may stem from limited spatial and temporal control of p75(NTR) expression in existing knock-out models.