Antigenic cartography using sera from sequence-confirmed SARS-CoV-2 variants of concern infections reveals antigenic divergence of Omicron.

Large-scale vaccination campaigns have prevented countless hospitalizations and deaths due to COVID-19. However, the emergence of SARS-CoV-2 variants that escape from immunity challenges the effectiveness of current vaccines. Given this continuing evolution, an important question is when and how to update SARS-CoV-2 vaccines to antigenically match circulating variants, similarly to seasonal influenza viruses where antigenic drift necessitates periodic vaccine updates. Here, we studied SARS-CoV-2 antigenic drift by assessing neutralizing activity against variants of concern (VOCs) in a set of sera from patients infected with viral sequence-confirmed VOCs. Infections with D614G or Alpha strains induced the broadest immunity, whereas individuals infected with other VOCs had more strain-specific responses. Omicron BA.1 and BA.2 were substantially resistant to neutralization by sera elicited by all other variants. Antigenic cartography revealed that Omicron BA.1 and BA.2 were antigenically most distinct from D614G, associated with immune escape, and possibly will require vaccine updates to ensure vaccine effectiveness.

Men's Satisfaction with General Health Services is Associated with Future Use of HIV Testing in Malawi: A Community-Representative Survey.

Across sub-Saharan Africa, men are less likely to know their HIV status than women, leading to later treatment initiation. Little is known about how experiences with general health services affect men's use of HIV testing. We used data from a 2019 community-representative survey of men in Malawi to understand frequency and cause of men's negative health service experiences (defined as men reporting they "would not recommend" a facility) and their association with future HIV testing. We conducted univariable and multivariable logistic regressions to determine which aspects of health facility visits were associated with would-not-recommend experiences and to determine if would-not-recommend experiences 12-24 months prior to the survey were associated with HIV testing in the 12 months prior to the survey. Among 1,098 men eligible for HIV testing in the 12 months prior to the survey, median age was 34 years; 9% of men reported at least one would-not-recommend experience, which did not differ by sociodemographics, gender norm beliefs, or HIV stigma beliefs. The factors most strongly associated with would-not-recommend experiences were cost (aOR 5.8, 95%CI 2.9-11.4), cleanliness (aOR 4.2, 95%CI 1.8-9.9), medicine availability (aOR 3.3, 95%CI 1.7-6.4), and wait times (aOR 2.7, 95%CI 1.5-5.0). Reporting a would-not-recommend experience 12-24 months ago was associated with a 59% decrease in likelihood of testing for HIV in the last 12 months (aOR 0.41; 95% CI:0.17-0.96). Dissatisfaction with general health services was strongly associated with reduced HIV testing. Coverage of high-priority screening services like HIV testing may benefit from improving overall health system quality.

Strategies for Using Antigen Rapid Diagnostic Tests to Reduce Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 in Low- and Middle-Income Countries: A Mathematical Modelling Study Applied to Zambia.

BACKGROUND: Increasing the availability of antigen rapid diagnostic tests (Ag-RDTs) in low- and middle-income countries (LMICs) is key to alleviating global SARS-CoV-2 testing inequity (median testing rate in December 2021-March 2022 when the Omicron variant was spreading in multiple countries: high-income countries = 600 tests/100 000 people/day; LMICs = 14 tests/100 000 people/day). However, target testing levels and effectiveness of asymptomatic community screening to impact SARS-CoV-2 transmission in LMICs are unclear. METHODS: We used Propelling Action for Testing and Treating (PATAT), an LMIC-focused agent-based model to simulate coronavirus disease 2019 (COVID-19) epidemics, varying the amount of Ag-RDTs available for symptomatic testing at healthcare facilities and asymptomatic community testing in different social settings. We assumed that testing was a function of access to healthcare facilities and availability of Ag-RDTs. We explicitly modelled symptomatic testing demand from individuals without SARS-CoV-2 and measured impact based on the number of infections averted due to test-and-isolate. RESULTS: Testing symptomatic individuals yields greater benefits than any asymptomatic community testing strategy until most symptomatic individuals who sought testing have been tested. Meeting symptomatic testing demand likely requires at least 200-400 tests/100 000 people/day, on average, as symptomatic testing demand is highly influenced by individuals without SARS-CoV-2. After symptomatic testing demand is satisfied, excess tests to proactively screen for asymptomatic infections among household members yield the largest additional infections averted. CONCLUSIONS: Testing strategies aimed at reducing transmission should prioritize symptomatic testing and incentivizing test-positive individuals to adhere to isolation to maximize effectiveness.

Effect of index HIV self-testing for sexual partners of clients enrolled in antiretroviral therapy (ART) programs in Malawi: A randomized controlled trial.

BACKGROUND: HIV testing among the sexual partners of HIV-positive clients is critical for case identification and reduced transmission in southern and eastern Africa. HIV self-testing (HIVST) may improve uptake of HIV services among sexual partners of antiretroviral therapy (ART) clients, but the impact of HIVST on partner testing and subsequent ART initiation remains unclear. METHODS AND FINDINGS: We conducted an individually randomized, unblinded trial to assess if an index HIVST intervention targeting the partners of ART clients improves uptake of testing and treatment services in Malawi. The trial was conducted at 3 high-burden facilities in central and southern Malawi. ART clients attending HIV treatment clinics were randomized using simple randomization 1:2·5 to: (1) standard partner referral slip (PRS) whereby ART clients were given facility referral slips to distribute to their primary sexual partners; or (2) index HIVST whereby ART clients were given HIVST kits + HIVST instructions and facility referral slips to distribute to their primary sexual partners. Inclusion criteria for ART clients were: ≥15 years of age, primary partner with unknown HIV status, no history of interpersonal violence (IPV) with partner, and partner lives in facility catchment area. The primary outcome was partner testing 4-weeks after enrollment, reported by ART clients using endline surveys. Medical chart reviews and tracing activities with partners with a reactive HIV test measured ART initiation at 12 months. Analyses were conducted based on modified intention-to-treat principles, whereby we excluded individuals who did not have complete endline data (i.e., were loss to follow up from the study). Adjusted models controlled for the effects of age and marital status. A total of 4,237 ART clients were screened and 484 were eligible and enrolled (77% female) between March 28, 2018 and January 5, 2020. A total of 365 participants completed an endline survey (257/34 index HIVST arm; 107/13 PRS arm) and were included in the final analysis (78% female). Testing coverage among sexual partners was 71% (183/257) in the index HIVST arm and 25% (27/107) in the PRS arm (aRR: 2·77, 95% CI [2·56 to 3·00], p ≤ 0.001). Reported HIV positivity rates did not significantly differ by arm (16% (30/183) in HIVST versus 15% (4/27) in PRS; p = 0.99). ART initiation at 12 months was 47% (14/30) in HIVST versus 75% (3/4) in PRS arms; however, index HIVST still resulted in a 94% increase in the proportion of all partners initiating ART due to higher HIV testing rates in the HIVST arm (5% partners initiated ART in HVIST versus 3% in PRS). Adverse events including IPV and termination of the relationship did not vary by arm (IPV: 3/257 index HIVST versus 4/10 PRS; p = 0.57). Limitations include reliance on secondary report by ART clients, potential social desirability bias, and not powered for sex disaggregated analyses. CONCLUSIONS: Index HIVST significantly increased HIV testing and the absolute number of partners initiating ART in Malawi, without increased risk of adverse events. Additional research is needed to improve linkage to HIV treatment services after HIVST use. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03271307, and Pan African Clinical Trials, PACTR201711002697316.

Achieving HIV Epidemic Control and Improving Maternal Healthcare Services with Community-Based HIV Service Delivery in Zambia: Mixed-Methods Assessment of the SMACHT Project.

Novel community-based approaches are needed to achieve and sustain HIV epidemic control in Zambia. Under the Stop Mother and Child HIV Transmission (SMACHT) project, the Community HIV Epidemic Control (CHEC) differentiated service delivery model used community health workers to support HIV testing, ART linkage, viral suppression, and prevention of mother-to-child transmission (MTCT). A multi-methods assessment included programmatic data analysis from April 2015 to September 2020, and qualitative interviews from February to March 2020. CHEC provided HIV testing services to 1,379,387 clients; 46,138 were newly identified as HIV-positive (3.3% yield), with 41,366 (90%) linked to ART. By 2020, 91% (60,694/66,841) of clients on ART were virally suppressed. Qualitatively, healthcare workers and clients benefitted from CHEC, with provision of confidential services, health facility decongestion, and increased HIV care uptake and retention. Community-based models can increase uptake of HIV testing and linkage to care, and help achieve epidemic control and elimination of MTCT.

Factors associated with men's health facility attendance as clients and caregivers in Malawi: a community-representative survey.

INTRODUCTION: Men have higher rates of morbidity and mortality across nearly all top ten causes of mortality worldwide. Much of this disparity is attributed to men's lower utilization of routine health services; however, little is known about men's general healthcare utilization in sub-Saharan Africa. METHODS: We analyze the responses of 1,116 men in a community-representative survey of men drawn from a multi-staged sample of residents of 36 villages in Malawi to identify factors associated with men's facility attendance in the last 12 months, either for men's own health (client visit) or to support the health care of someone else (caregiver visit). We conducted single-variable tests of association and multivariable logistic regression with random effects to account for clustering at the village level. RESULTS: Median age of participants was 34, 74% were married, and 82% attended a health facility in the last year (63% as client, 47% as caregiver). Neither gender norm beliefs nor socioeconomic factors were independently associated with attending a client visit. Only problems with quality of health services (adjusted odds ratio [aOR] 0.294, 95% confidence interval [CI] 0.10-0.823) and good health (aOR 0.668, 95% CI 0.462-0.967) were independently associated with client visit attendance. Stronger beliefs in gender norms were associated with caregiver visits (beliefs about acceptability of violence [aOR = 0.661, 95% CI 0.488-0.896], male sexual dominance [aOR = 0.703, 95% CI 0.505-0.978], and traditional women's roles [aOR = 0.718, 95% CI 0.533-0.966]). Older age (aOR 0.542, 95% CI 0.401-0.731) and being married (aOR 2.380, 95% CI 1.196-4.737) were also independently associated with caregiver visits. CONCLUSION: Quality of services offered at local health facilities and men's health status were the only variables associated with client facility visits among men, while harmful gender norms, not being married, and being younger were negatively associated with caregiver visits.

The Role of Remdesivir in South Africa: Preventing COVID-19 Deaths Through Increasing Intensive Care Unit Capacity.

Countries such as South Africa have limited intensive care unit (ICU) capacity to handle the expected number of patients with COVID-19 requiring ICU care. Remdesivir can prevent deaths in countries such as South Africa by decreasing the number of days people spend in ICU, therefore freeing up ICU bed capacity.

Frequency of visits to health facilities and HIV services offered to men, Malawi.

OBJECTIVE: To determine how often men in Malawi attend health facilities and if testing for human immunodeficiency virus (HIV) is offered during facility visits. METHODS: We conducted a cross-sectional, community-representative survey of men (15-64 years) from 36 villages in Malawi. We excluded men who ever tested HIV-positive. Primary outcomes were: health facility visits in the past 12 months (for their own health (client visit) or to support the health services of others (guardian visit)); being offered HIV testing during facility visits; and being tested that same day. We disaggregated all results by HIV testing history: tested ≤ 12 months ago, or in need of testing (never tested or tested > 12 months before). FINDINGS: We included 1116 men in the analysis. Mean age was 34 years (standard deviation: 13.2) and 55% (617/1116) of men needed HIV testing. Regarding facility visits, 82% (920/1116) of all men and 70% (429/617) of men in need of testing made at least one facility visit in the past 12 months. Men made a total of 1973 visits (mean two visits): 39% (765/1973) were as guardians and 84% (1657/1973) were to outpatient departments. Among men needing HIV testing, only 7% (30/429) were offered testing during any visit. The most common reason for not testing was not being offered services (37%; 179/487). CONCLUSION: Men in Malawi attend health facilities regularly, but few of those in need of HIV testing are offered testing services. Health screening services should capitalize on men's routine visits to outpatient departments as clients and guardians.

Cost and Impact of Dried Blood Spot Versus Plasma Separation Card for Scale-up of Viral Load Testing in Resource-limited Settings.

BACKGROUND: Routine plasma viral load (VL) testing is recommended for monitoring human immunodeficiency virus-infected patients on antiretroviral therapy. In Zambia, VL scale-up is limited due to logistical obstacles around plasma specimen collection, storage, and transport to centralized laboratories. Dried blood spots (DBSs) could circumvent many logistical challenges at the cost of increased misclassification. Recently, plasma separation cards (PSCs) have become available and, though more expensive, have lower total misclassification than DBSs. METHODS: Using a geospatial model created for optimizing VL utilization in Zambia, we estimated the short-term cost of uptake/correct VL result using either DBSs or PSCs to increase VL access on equipment available in-country. Five scenarios were modeled: (1) plasma only (status quo); (2) plasma at high-volume sites, DBS at low-volume sites; (3) plasma at high-volume sites, PSC at low-volume sites; (4) PSC only; (5) DBS only. RESULTS: Scenario 1 resulted in 795 342 correct results due to limited patient access. When allowing for full and partial adoption of dried specimens, access increases by 19%, with scenario 3 producing the greatest number of correct results expected (929 857). The average cost per correct VL result was lowest in the plasma + DBS scenario at $30.90 compared to $31.62 in our plasma + PSC scenario. The cost per correct result of using dried specimens only was dominated in the incremental analysis, due primarily to fewer correct results. CONCLUSIONS: Adopting the partial use of dried specimens will help achieve improved VL access for patients at the lowest cost per correct result.

Cost-effectiveness and budget effect of pre-exposure prophylaxis for HIV-1 prevention in Germany from 2018 to 2058.

BackgroundPre-exposure prophylaxis (PrEP) is a highly effective HIV prevention strategy for men-who-have-sex-with-men (MSM). The high cost of PrEP has until recently been a primary barrier to its use. In 2017, generic PrEP became available, reducing the costs by 90%.AimOur objective was to assess cost-effectiveness and costs of introducing PrEP in Germany.MethodsWe calibrated a deterministic mathematical model to the human immunodeficiency virus (HIV) epidemic among MSM in Germany. PrEP was targeted to 30% of high-risk MSM. It was assumed that PrEP reduces the risk of HIV infection by 85%. Costs were calculated from a healthcare payer perspective using a 40-year time horizon starting in 2018.ResultsPrEP can avert 21,000 infections (interquartile range (IQR): 16,000-27,000) in the short run (after 2 years scale-up and 10 years full implementation). HIV care is predicted to cost EUR 36.2 billion (IQR: 32.4-40.4 billion) over the coming 40 years. PrEP can increase costs by at most EUR 150 million within the first decade after introduction. Ten years after introduction, PrEP can become cost-saving, accumulating to savings of HIV-related costs of EUR 5.1 billion (IQR: 3.5-6.9 billion) after 40 years. In a sensitivity analysis, PrEP remained cost-saving even at a 70% price reduction of antiretroviral drug treatment and a lower effectiveness of PrEP.ConclusionIntroduction of PrEP in Germany is predicted to result in substantial health benefits because of reductions in HIV infections. Short-term financial investments in providing PrEP will result in substantial cost-savings in the long term.

Cardiovascular Disease Prevention Policy in Human Immunodeficiency Virus: Recommendations From a Modeling Study.

Background: Cardiovascular disease (CVD) is expected to contribute a large noncommunicable disease burden among human immunodeficiency virus (HIV)-infected people. We quantify the impact of prevention interventions on annual CVD burden and costs among HIV-infected people in the Netherlands. Methods: We constructed an individual-based model of CVD in HIV-infected people using national ATHENA (AIDS Therapy Evaluation in The Netherlands) cohort data on 8791 patients on combination antiretroviral therapy (cART). The model follows patients as they age, develop CVD (by incorporating a CVD risk equation), and start cardiovascular medication. Four prevention interventions were evaluated: (1) increasing the rate of earlier HIV diagnosis and treatment; (2) avoiding use of cART with increased CVD risk; (3) smoking cessation; and (4) intensified monitoring and drug treatment of hypertension and dyslipidemia, quantifying annual number of averted CVDs and costs. Results: The model predicts that annual CVD incidence and costs will increase by 55% and 36% between 2015 and 2030. Traditional prevention interventions (ie, smoking cessation and intensified monitoring and treatment of hypertension and dyslipidemia) will avert the largest number of annual CVD cases (13.1% and 20.0%) compared with HIV-related interventions-that is, earlier HIV diagnosis and treatment and avoiding cART with increased CVD risk (0.8% and 3.7%, respectively)-as well as reduce cumulative CVD-related costs. Targeting high-risk patients could avert the majority of events and costs. Conclusions: Traditional CVD prevention interventions can maximize cardiovascular health and defray future costs, particularly if targeting high-risk patients. Quantifying additional public health benefits, beyond CVD, is likely to provide further evidence for policy development.

Trade-offs between clinical performance and test accessibility in tuberculosis diagnosis: a multi-country modelling approach for target product profile development.

BACKGROUND: Tuberculosis continues to be a leading cause of infectious disease mortality, and effective screening and diagnosis remains crucial. Despite progress made, diagnostic gaps remain due to poor access to diagnostic tools and testing, particularly in rural and remote areas. As such, the development of target product profiles is essential in guiding the development of new diagnostic tools, however target product profiles often lack evidence-based information and do not consider trade-offs between test accuracy and accessibility. METHODS: A simulation-based model, in the form of a decision tree, was used to map out the baseline patient tuberculosis diagnostic pathway for individuals in Kenya, South Africa, and India. The model was then used to adapt this pathway to evaluate the trade-offs between increased access to testing and varying accuracy of new tuberculosis diagnostic tools within the health-care contexts of Kenya, South Africa, and India. The model aims to support target product profile development by quantifying the impact of new diagnostics on the standard of care. The model considered three diagnostic attributes, namely sample type (sputum vs non-sputum), site of testing (point of care, near point of care, and health setting) and turnaround time. FINDINGS: Our results indicate that per sample type, novel point-of-care tests would be the most accessible and even with lower sensitivities can achieve comparable or better case detection than the current standard of care in each country. Non-sputum diagnostics also have lower sensitivity requirements. Overall, target product profile parameters with reduced sensitivities from 70% for non-sputum and 78% for sputum tests could be accepted. INTERPRETATION: Diagnostics which bring tuberculosis tests and test results closer to the patient could reduce overall diagnostic loss despite potential reductions in sensitivity. This work provides a novel framework for guiding the future development of diagnostics, with an approach towards balancing accessibility and test performance. FUNDING: The Bill and Melinda Gates Foundation (INV-045721).

Cost-effectiveness of intervention combinations towards the elimination of vertical transmission of HIV in limited-resource settings: a mathematical modelling study.

BACKGROUND: Since 2000, there has been a substantial global reduction in the vertical transmission of HIV. Despite effective interventions, gaps still remain in progress towards elimination in many low-income and middle-income countries. We developed a mathematical model to determine the most cost-effective combinations of interventions to prevent vertical transmission. METHODS: We developed a 12-month Markov model to follow a cohort of women of childbearing age (aged 15-49 years) in Zambia (n=1 107 255) who were either pregnant, in delivery, or breastfeeding; the population included in the model reflects the estimated number of pregnant women in Zambia from the 2018 Zambia Demographic and Health Survey. The model incorporated nine interventions: infant prophylaxis; three different HIV retesting schedule options; oral pre-exposure prophylaxis; maternal peer-support groups; regimen shift; tracing of loss to follow-up; and point-of-care viral load testing. We analysed incident HIV infections among mothers and infants, intervention costs, and evaluated 190 scenarios of different combinations of inventions to calculate the incremental cost-effectiveness ratios (ICERs) over 1 year. FINDINGS: Three interventions with the greatest reduction in vertical transmission, individually, were support groups for 80% of those in need (35% reduction in infant infections), HIV retesting schedules (6·5% reduction), and infant prophylaxis (4·5% reduction). Of all 190 scenarios evaluated, eight were on the cost-effectiveness frontier (ie, were considered to be cost-effective); all eight included increasing infant prophylaxis, regimen shift, and use of support groups. Excluding the highest-cost scenarios, for a 1-22% increase in total budget, 23-43% of infant infections could be prevented, producing ICERs between US$244 and $16 242. INTERPRETATION: Using the interventions modelled, it is possible to reduce vertical transmission and to cost-effectively prevent up to 1734 infant HIV infections (43% reduction) in Zambia over a period of 1 year. To optimise their effect, these interventions must be scaled with fidelity. Future work is needed to incorporate evidence on additional innovative interventions and HIV risk factors, and to apply the model to other country contexts to support targeted implementation and resource use. FUNDING: The ELMA Foundation.

Impact and cost-effectiveness of SARS-CoV-2 self-testing strategies in schools: a multicountry modelling analysis.

OBJECTIVES: To determine the most epidemiologically effective and cost-effective school-based SARS-CoV-2 antigen-detection rapid diagnostic test (Ag-RDT) self-testing strategies among teachers and students. DESIGN: Mathematical modelling and economic evaluation. SETTING AND PARTICIPANTS: Simulated school and community populations were parameterised to Brazil, Georgia and Zambia, with SARS-CoV-2 self-testing strategies targeted to teachers and students in primary and secondary schools under varying epidemic conditions. INTERVENTIONS: SARS-CoV-2 Ag-RDT self-testing strategies for only teachers or teachers and students-only symptomatically or symptomatically and asymptomatically at 5%, 10%, 40% or 100% of schools at varying frequencies. OUTCOME MEASURES: Outcomes were assessed in terms of total infections and symptomatic days among teachers and students, as well as total infections and deaths within the community under the intervention compared with baseline. The incremental cost-effectiveness ratios (ICERs) were calculated for infections prevented among teachers and students. RESULTS: With respect to both the reduction in infections and total cost, symptomatic testing of all teachers and students appears to be the most cost-effective strategy. Symptomatic testing can prevent up to 69·3%, 64·5% and 75·5% of school infections in Brazil, Georgia and Zambia, respectively, depending on the epidemic conditions, with additional reductions in community infections. ICERs for symptomatic testing range from US$2 to US$19 per additional school infection averted as compared with symptomatic testing of teachers alone. CONCLUSIONS: Symptomatic testing of teachers and students has the potential to cost-effectively reduce a substantial number of school and community infections.

Implementation research: a protocol for two three-arm pragmatic randomised controlled trials on continuous glucose monitoring devices in people with type 1 diabetes in South Africa and Kenya.

BACKGROUND: Self-monitoring of glucose is an essential component of type 1 diabetes (T1D) management. In recent years, continuous glucose monitoring (CGM) has provided an alternative to daily fingerstick testing for the optimisation of insulin dosing and general glucose management in people with T1D. While studies have been conducted to evaluate the impact of CGM on clinical outcomes in the US, Europe and Australia, there are limited data available for low- and middle-income countries (LMICs) and further empirical evidence is needed to inform policy decision around their use in these countries. METHODS: This trial was designed as a pragmatic, parallel-group, open-label, multicentre, three-arm, randomised (1:1:1) controlled trial of continuous or periodic CGM device use versus standard of care in people with T1D in South Africa and Kenya. The primary objective of this trial will be to assess the impact of continuous or periodic CGM device use on glycaemic control as measured by change from baseline glycosylated haemoglobin (HbA1c). Additional assessments will include clinical outcomes (glucose variation, time in/below/above range), safety (adverse events, hospitalisations), quality of life (EQ-5D, T1D distress score, Glucose Monitoring Satisfaction Survey for T1D), and health economic measures (incremental cost-effectiveness ratios, quality adjusted life years). DISCUSSION: This trial aims to address the substantial evidence gap on the impact of CGM device use on clinical outcomes in LMICs, specifically South Africa and Kenya. The trial results will provide evidence to inform policy and treatment decisions in these countries. TRIAL REGISTRATION: NCT05944731 (Kenya), July 6, 2023; NCT05944718 (South Africa), July 13, 2023.

Diagnostic yield as an important metric for the evaluation of novel tuberculosis tests: rationale and guidance for future research.

Better access to tuberculosis testing is a key priority for fighting tuberculosis, the leading cause of infectious disease deaths in people. Despite the roll-out of molecular WHO-recommended rapid diagnostics to replace sputum smear microscopy over the past decade, a large diagnostic gap remains. Of the estimated 10·6 million people who developed tuberculosis globally in 2022, more than 3·1 million were not diagnosed. An exclusive focus on improving tuberculosis test accuracy alone will not be sufficient to close the diagnostic gap for tuberculosis. Diagnostic yield, which we define as the proportion of people in whom a diagnostic test identifies tuberculosis among all people we attempt to test for tuberculosis, is an important metric not adequately explored. Diagnostic yield is particularly relevant for subpopulations unable to produce sputum such as young children, people living with HIV, and people with subclinical tuberculosis. As more accessible non-sputum specimens (eg, urine, oral swabs, saliva, capillary blood, and breath) are being explored for point-of-care tuberculosis testing, the concept of yield will be of growing importance. Using the example of urine lipoarabinomannan testing, we illustrate how even tests with limited sensitivity can diagnose more people with tuberculosis if they enable increased diagnostic yield. Using tongue swab-based molecular tuberculosis testing as another example, we provide definitions and guidance for the design and conduct of pragmatic studies that assess diagnostic yield. Lastly, we show how diagnostic yield and other important test characteristics, such as cost and implementation feasibility, are essential for increased effective population coverage, which is required for optimal clinical care and transmission impact. We are calling for diagnostic yield to be incorporated into tuberculosis test evaluation processes, including the WHO Grading of Recommendations, Assessment, Development, and Evaluations process, providing a crucial real-life implementation metric that complements traditional accuracy measures.

Cost of SARS-CoV-2 self-test distribution programmes by different modalities: a micro-costing study in five countries (Brazil, Georgia, Malaysia, Ethiopia and the Philippines).

OBJECTIVE: Diagnostic testing is an important tool to combat the COVID-19 pandemic, yet access to and uptake of testing vary widely 3 years into the pandemic. The WHO recommends the use of COVID-19 self-testing as an option to help expand testing access. We aimed to calculate the cost of providing COVID-19 self-testing across countries and distribution modalities. DESIGN: We estimated economic costs from the provider perspective to calculate the total cost and the cost per self-test kit distributed for three scenarios that differed by costing period (pilot, annual), the number of tests distributed (actual, planned, scaled assuming an epidemic peak) and self-test kit costs (pilot purchase price, 50% reduction). SETTING: We used data collected between August and December 2022 in Brazil, Georgia, Malaysia, Ethiopia and the Philippines from pilot implementation studies designed to provide COVID-19 self-tests in a variety of settings-namely, workplace and healthcare facilities. RESULTS: Across all five countries, 173 000 kits were distributed during pilot implementation with the cost/test distributed ranging from $2.44 to $12.78. The cost/self-test kit distributed was lowest in the scenario that assumed implementation over a longer period (year), with higher test demand (peak) and a test kit price reduction of 50% ($1.04-3.07). Across all countries and scenarios, test procurement occupied the greatest proportion of costs: 58-87% for countries with off-site self-testing (outside the workplace, for example, home) and 15-50% for countries with on-site self-testing (at the workplace). Staffing was the next key cost driver, particularly for distribution modalities that had on-site self-testing (29-35%) versus off-site self-testing (7-27%). CONCLUSIONS: Our results indicate that it is likely to cost between $2.44 and $12.78 per test to distribute COVID-19 self-tests across common settings in five heterogeneous countries. Cost-effectiveness analyses using these results will allow policymakers to make informed decisions on optimally scaling up COVID-19 self-test distribution programmes across diverse settings and evolving needs.

Determinants of epidemic size and the impacts of lulls in seasonal influenza virus circulation.

During the COVID-19 pandemic, levels of seasonal influenza virus circulation were unprecedentedly low, leading to concerns that a lack of exposure to influenza viruses, combined with waning antibody titres, could result in larger and/or more severe post-pandemic seasonal influenza epidemics. However, in most countries the first post-pandemic influenza season was not unusually large and/or severe. Here, based on an analysis of historical influenza virus epidemic patterns from 2002 to 2019, we show that historic lulls in influenza virus circulation had relatively minor impacts on subsequent epidemic size and that epidemic size was more substantially impacted by season-specific effects unrelated to the magnitude of circulation in prior seasons. From measurements of antibody levels from serum samples collected each year from 2017 to 2021, we show that the rate of waning of antibody titres against influenza virus during the pandemic was smaller than assumed in predictive models. Taken together, these results partially explain why the re-emergence of seasonal influenza virus epidemics was less dramatic than anticipated and suggest that influenza virus epidemic dynamics are not currently amenable to multi-season prediction.

A modelling framework for translating discrete choice experiment results into cost-effectiveness estimates: an application to designing tailored and scalable HIV and contraceptive services for adolescents in Gauteng, South Africa.

INTRODUCTION: South African youth and adolescents face a high burden of (Sexually Transmitted Infections) STIs, HIV and unintended pregnancies, but uptake of services remains low. To address this, tailored and scalable interventions are urgently needed. We developed a framework to fill the gap and translate the impact of facility-level attributes into a cost-effectiveness analysis for increasing HIV/contraceptive service uptake in adolescents using a discrete choice experiment (DCE). METHODS: We used a DCE (n = 805) conducted in Gauteng, South Africa, which found that staff attitude, confidentiality, Wi-Fi, subsidized food, afternoon hours and youth-only services were preferred attributes of health services. Based on this, we simulated the uptake of services adapted for these preferences. We divided preferences into modifiable attributes that could readily be adapted (e.g. Wi-Fi), and challenging to modify (more nuanced attributes that are more challenging to cost and evaluate): staff attitude and estimated the incremental change in the uptake of services using adapted services. Costs for modifiable preferences were estimated using data from two clinics in South Africa (2019 US$). We determined the incremental cost-effectiveness ratio (ICER) for additional adolescents using services of 15 intervention combinations, and report the results of interventions on the cost-effectiveness frontier. RESULTS: Greatest projected impact on uptake was from friendly and confidential services, both of which were considered challenging to modify (18.5% 95% CI: 13.0%-24.0%; 8.4% 95% CI: 3.0%-14.0%, respectively). Modifiable factors on their own resulted in only small increases in expected uptake. (Food: 2.3% 95% CI: 4.0%-9.00%; Wi-Fi: 3.0% 95% CI: -4.0% to 10.0%; Youth-only services: 0.3% 95% CI: -6.0% to 7.0%; Afternoon services: 0.8% 95% CI: -6.0% to 7.0%). The order of interventions on the cost-effectiveness frontier are Wi-Fi and youth-only services (ICER US$7.01-US$9.78 per additional adolescent utilizing HIV and contraceptive services), Wi-Fi, youth-only services and food (ICER US$9.32-US$10.45), followed by Wi-Fi, youth-only services and extended afternoon hours (ICER US$14.46-US$43.63). CONCLUSIONS: Combining DCE results and costing analyses within a modelling framework provides an innovative way to inform decisions on effective resource utilization. Modifiable preferences, such as Wi-Fi provision, youth-only services and subsidized food, have the potential to cost-effectively increase the proportion of adolescents accessing HIV and contraceptive services.

Estimating the potential impact and diagnostic requirements for SARS-CoV-2 test-and-treat programs.

Oral antivirals have the potential to reduce the public health burden of COVID-19. However, now that we have exited the emergency phase of the COVID-19 pandemic, declining SARS-CoV-2 clinical testing rates (average testing rates = ≪10 tests/100,000 people/day in low- and-middle income countries; <100 tests/100,000 people/day in high-income countries; September 2023) make the development of effective test-and-treat programs challenging. We used an agent-based model to investigate how testing rates and strategies affect the use and effectiveness of oral antiviral test-to-treat programs in four country archetypes of different income levels and demographies. We find that in the post-emergency phase of the pandemic, in countries where low testing rates are driven by limited testing capacity, significant population-level impact of test-and-treat programs can only be achieved by both increasing testing rates and prioritizing individuals with greater risk of severe disease. However, for all countries, significant reductions in severe cases with antivirals are only possible if testing rates were substantially increased with high willingness of people to seek testing. Comparing the potential population-level reductions in severe disease outcomes of test-to-treat programs and vaccination shows that test-and-treat strategies are likely substantially more resource intensive requiring very high levels of testing (>>100 tests/100,000 people/day) and antiviral use suggesting that vaccination should be a higher priority.