Estimating the effect of realistic improvements of metformin adherence on COVID-19 mortality using targeted machine learning

Background

Type 2 diabetes elevates the risk of severe outcomes in COVID-19 patients, with multiple studies reporting higher case fatality rates. Metformin is a widely used medication for glycemic management. We hypothesize that improved adherence to metformin may lower COVID-19 post-infection mortality risk in this group. Utilizing data from the Mexican Social Security Institute (IMSS), we investigate the relationship between metformin adherence and mortality following COVID-19 infection in patients with chronic metformin prescriptions.

Methods

This is a retrospective cohort study consisting of 61,180 IMSS beneficiaries who received a positive polymerase chain reaction (PCR) or rapid test for SARS-CoV-2 and had at least two consecutive months of metformin prescriptions prior to the positive test. The hypothetical intervention is improved adherence to metformin, measured by proportion of days covered (PDC), with the comparison being the observed metformin adherence values. The primary outcome is all-cause mortality following COVID-19 infection. We defined the causal parameter using shift intervention, an example of modified treatment policies. We used the targeted learning framework for estimation of the target estimand.

Findings

Among COVID-19 positive patients with chronic metformin prescriptions, we found that a 5% and 10% absolute increase in metformin adherence is associated with a respective 0.26% (95% CI: -0.28%, 0.79%) and 1.26% (95% CI: 0.72%, 1.80%) absolute decrease in mortality risk.

Interpretation

Subject to the limitations of a real-world data study, our results indicate a causal association between improved metformin adherence and reduced COVID-19 post-infection mortality risk.

Indirect vaccine effectiveness in an outbreak of Alpha B.1.1.7 variant in a California state Prison, May 2021

Incarcerated populations experienced high rates of SARS-CoV-2 infection and death during early phases of the COVID-19 pandemic. To evaluate vaccine effectiveness in the carceral context, we investigated the first outbreak of COVID-19 in a California state prison following widespread rollout of vaccines to residents in early 2021. We identified a cohort of 733 state prison residents presumed to be exposed between May 14 and June 22, 2021. 46.9 % (n = 344) were vaccinated, primarily with two doses of mRNA-1273 (n = 332, 93.6 %). In total, 92 PCR-positive cases were identified, of which 14 (14.5 %) occurred among mRNA-1273 vaccinated residents. No cases required hospitalization. All nine isolates collected belonged to the Alpha (B.1.1.7) variant. We used Cox proportional hazard regression to estimate vaccine effectiveness for at least one dose of any vaccine at the start of the outbreak. Vaccine effectiveness was 86 % (95 % CI: 75 %-97 %) against PCR-confirmed infection, with similar results for symptomatic infection. Higher rates of building-level vaccine uptake were associated with a lower overall rate of PCR-confirmed infection and symptomatic infection among unvaccinated residents. Among unvaccinated residents who lived in shared cells at the time of presumed exposure, exposure to a vaccinated cellmate was associated with a 38% (95% CI: 0.37, 1.04) lower hazard rate of PCR-confirmed infection over the study period. In this outbreak involving the Alpha SARS-CoV-2 variant, vaccination conferred direct and possibly indirect protection against SARS-CoV-2 infection and symptomatic COVID-19. Our results support the importance of vaccine uptake in mitigating outbreaks and severe disease in the prison setting and the consideration of community vaccination levels in policy and infection response.

SARS-CoV-2 infection by trimester of pregnancy and adverse perinatal outcomes: a Mexican retrospective cohort study

OBJECTIVE

Conflicting evidence for the association between COVID-19 and adverse perinatal outcomes exists. This study examined the associations between maternal COVID-19 during pregnancy and adverse perinatal outcomes including preterm birth (PTB), low birth weight (LBW), small-for-gestational age (SGA), large-for-gestational age (LGA) and fetal death; as well as whether the associations differ by trimester of infection.

DESIGN AND SETTING

The study used a retrospective Mexican birth cohort from the Instituto Mexicano del Seguro Social (IMSS), Mexico, between January 2020 and November 2021.

PARTICIPANTS

We used the social security administrative dataset from IMSS that had COVID-19 information and linked it with the IMSS routine hospitalisation dataset, to identify deliveries in the study period with a test for SARS-CoV-2 during pregnancy.

OUTCOME MEASURES

PTB, LBW, SGA, LGA and fetal death. We used targeted maximum likelihood estimators, to quantify associations (risk ratio, RR) and CIs. We fit models for the overall COVID-19 sample, and separately for those with mild or severe disease, and by trimester of infection. Additionally, we investigated potential bias induced by missing non-tested pregnancies.

RESULTS

The overall sample comprised 17 340 singleton pregnancies, of which 30% tested positive. We found that those with mild COVID-19 had an RR of 0.89 (95% CI 0.80 to 0.99) for PTB and those with severe COVID-19 had an RR of 1.53 (95% CI 1.07 to 2.19) for LGA. COVID-19 in the first trimester was associated with fetal death, RR=2.36 (95% CI 1.04, 5.36). Results also demonstrate that missing non-tested pregnancies might induce bias in the associations.

CONCLUSIONS

In the overall sample, there was no evidence of an association between COVID-19 and adverse perinatal outcomes. However, the findings suggest that severe COVID-19 may increase the risk of some perinatal outcomes, with the first trimester potentially being a high-risk period.

Recommendations for accelerating open preprint peer review to improve the culture of science

Peer review is an important part of the scientific process, but traditional peer review at journals is coming under increased scrutiny for its inefficiency and lack of transparency. As preprints become more widely used and accepted, they raise the possibility of rethinking the peer-review process. Preprints are enabling new forms of peer review that have the potential to be more thorough, inclusive, and collegial than traditional journal peer review, and to thus fundamentally shift the culture of peer review toward constructive collaboration. In this Consensus View, we make a call to action to stakeholders in the community to accelerate the growing momentum of preprint sharing and provide recommendations to empower researchers to provide open and constructive peer review for preprints.

How predictive of SARS-CoV-2 infection are clinical characteristics at presentation among individuals with COVID-like symptoms treated at the Mexican Institute of Social Security

BACKGROUND

The COVID-19 pandemic has progressed rapidly, with the emergence of new virus variants that pose challenges in treating infected individuals. In Mexico, four epidemic waves have been recorded with varying disease severity. To understand the heterogeneity in clinical presentation over time and the sensitivity and specificity of signs and symptoms in identifying COVID-19 cases, an analysis of the changes in the clinical presentation of the disease was conducted.

AIM

To analyze the changes in the clinical presentation of COVID-19 among 3.38 million individuals tested for SARS-CoV-2 at the Mexican Social Security Institute (IMSS) from March 2020 to October 2021 and evaluate the predictivity of signs and symptoms in identifying COVID-19 cases.

METHODS

A retrospective analysis of clinical presentation patterns of COVID-19 among individuals treated at IMSS was performed, contrasting the signs and symptoms among SARS-CoV-2-positive individuals with those who tested negative for the virus but had respiratory infection symptoms. The sensitivity and specificity of each sign and symptom in identifying SARS-CoV-2 infection were estimated.

RESULTS

The set of signs and symptoms reported for COVID-19-suspected patients treated at IMSS were not highly specific for SARS-CoV-2 positivity. The signs and symptoms exhibited variability based on age and epidemic wave. The area under the receiver operating characteristic (ROC) curve was 0.62 when grouping the five main symptoms (headache, dyspnea, fever, arthralgia, and cough). Most of the individual symptoms had ROC values close to 0.5 (16 out of 22 between 0.48 and 0.52), indicating non-specificity.

CONCLUSIONS

The results highlight the difficulty in making a clinical diagnosis of COVID-19 due to the lack of specificity of signs and symptoms. The variability of clinical presentation over time and among age groups highlights the need for further research to differentiate whether the changes are due to changes in the virus, who is becoming infected, or the population, particularly with respect to prior infection and vaccination status.

Group psychedelic therapy: empirical estimates of cost-savings and improved access

Objective

To compare group and individual psychedelic-assisted therapy in terms of clinician time, costs and patient access.

Methods

Using 2023 data from two group therapy trial sites, one using 3,4-Methylenedioxymethamphetamine (MDMA) to treat posttraumatic stress disorder (PTSD), and one using psilocybin to treat major depressive disorder (MDD), we compared overall variable costs, clinician costs and clinician time required by therapy protocols utilizing groups versus individual patient therapy. Using published literature, we estimated the prevalence of adults with PTSD and MDD eligible for treatment with psychedelic therapy and projected the savings in time and cost required to treat these prevalent cases.

Results

Group therapy saved 50.9% of clinician costs for MDMA-PTSD and 34.7% for psilocybin-MDD, or $3,467 and $981 per patient, respectively. To treat all eligible PTSD and MDD patients in the U.S. in 10 years with group therapy, 6,711 fewer full-time equivalent (FTE) clinicians for MDMA-PTSD and 1,159 fewer for FTE clinicians for psilocybin-MDD would be needed, saving up to $10.3 billion and $2.0 billion respectively, discounted at 3% annually.

Conclusion

Adopting group therapy protocols where feasible would significantly reduce the cost of psychedelic-assisted therapies. By enhancing the number of patients served per clinician, group therapy could also ameliorate the anticipated shortage of appropriately trained clinicians, thereby accelerating access to these promising new therapies.

Who is most at risk of dying if infected with SARS-CoV-2? A mortality risk factor analysis using machine learning of patients with COVID-19 over time: a large population-based cohort study in Mexico

OBJECTIVE

COVID-19 would kill fewer people if health programmes can predict who is at higher risk of mortality because resources can be targeted to protect those people from infection. We predict mortality in a very large population in Mexico with machine learning using demographic variables and pre-existing conditions.

DESIGN

Cohort study.

SETTING

March 2020 to November 2021 in Mexico, nationally represented.

PARTICIPANTS

1.4 million laboratory-confirmed patients with COVID-19 in Mexico at or over 20 years of age.

PRIMARY AND SECONDARY OUTCOME MEASURES

Analysis is performed on data from March 2020 to November 2021 and over three phases: (1) from March to October in 2020, (2) from November 2020 to March 2021 and (3) from April to November 2021. We predict mortality using an ensemble machine learning method, super learner, and independently estimate the adjusted mortality relative risk of each pre-existing condition using targeted maximum likelihood estimation.

RESULTS

Super learner fit has a high predictive performance (C-statistic: 0.907), where age is the most predictive factor for mortality. After adjusting for demographic factors, renal disease, hypertension, diabetes and obesity are the most impactful pre-existing conditions. Phase analysis shows that the adjusted mortality risk decreased over time while relative risk increased for each pre-existing condition.

CONCLUSIONS

While age is the most important predictor of mortality, younger individuals with hypertension, diabetes and obesity are at comparable mortality risk as individuals who are 20 years older without any of the three conditions. Our model can be continuously updated to identify individuals who should most be protected against infection as the pandemic evolves.

Changes in the epidemiological profile of SARS-CoV-2-positive individuals in Mexico across pandemic waves as an explanation of fatality reduction: a retrospective observational study

OBJECTIVES

We aim to quantify shifts in hospitalisation and mortality and how those were related to the first three phases of the epidemic and individuals' demographics and health profile among those with a positive test for SARS-CoV-2 treated at the Mexican Social Security Institute's facilities from March 2020 to October 2021.

DESIGN

Retrospective observational study using interrupted time series analysis to identify changes in hospitalisation rate and case fatality rate (CFR) by epidemic wave.

SETTING

Data from the Mexican Institute of Social Security's (IMSS) Online Influenza Epidemiological Surveillance System (SINOLAVE) that include all individuals that sought care at IMSS facilities all over Mexico.

PARTICIPANTS

All individuals included in the SINOLAVE with a positive PCR or rapid test for SARS-CoV-2.

PRIMARY AND SECONDARY OUTCOME MEASURES

Monthly test positivity rates, hospitalisation rates, CFRs and prevalence of relevant comorbidities by age group.

RESULTS

From March 2020 to October 2021, the CFR declined between 1% and 3.5%; the declines were significant for those 0-9, 20-29, 30-39, 40-49 and 70 and older. The decline was steep during the first wave and was less steep or was temporarily reversed at the beginning of the second and third waves (changes in the trend of about 0.3% and 3.8%, and between 0.7% and 3.8%, respectively, for some age groups), but then continued to the end of the analytical period. Prevalence of diabetes, hypertension and obesity among patients testing positive also declined-two for most age groups (reductions of up to 10 percentage points for diabetes, 12 percentage points for hypertension and 19 percentage points for obesity).

CONCLUSION

Data suggest that the decrease in COVID-19 fatality rate is at least partially explained by a change in the profile of those contracting the disease, that is, a falling proportion of individuals with comorbidities across all age groups.

The relationship between the gendered norm of eating last and mental health of newly married women in Nepal: A longitudinal study

Eating last is a gendered cultural norm in which the youngest daughters-in-law are expected to eat last after serving others in the household, including men and in-laws. Using women's eating last as an indicator of women's status, we studied the association between eating last and women's mental health. Using four rounds of prospective cohort data of 18-25-year-old newly married women (n = 200) cohabiting with mothers-in-law between 2018 and 2020 in the Nawalparasi district of Nepal, we examined the association between women eating last and depressive symptom severity (measured using 15-item Hopkins Symptom Checklist for Depression; HSCL-D). Twenty-five percent of women reported eating last always. The prevalence of probable depression using the established cutoff was 5.5%, consistent with the prevalence of depression in the general population. Using a hierarchical mixed-effects linear regression model, we found that women who always ate last had an expected depressive symptom severity (0-3 on HSCL-D) 0.24 points (95% confidence interval [CI]: 0.13-0.36) greater compared to women who did not eat last when adjusted for demographic variables, household food insecurity, and secular trends. Sensitivity analysis using logistic regression also suggested that women who eat last have greater odds of having probable depression (adjusted odds ratio [AOR] = 4.05; 95% CI: 1.32-12.44). We explored if the association between eating last and depressive symptom severity was moderated by household food insecurity and did not observe evidence of moderation, underscoring the significance of eating last as a woman's status indicator. Our study findings highlight that newly young married women in Nepal are a vulnerable group.

Evolution of differences in clinical presentation across epidemic waves among patients with COVID-like-symptoms who received care at the Mexican Social Security Institute

Background

Timely monitoring of SARS-CoV-2 variants is crucial to effectively managing both prevention and treatment efforts. In this paper, we aim to describe demographic and clinical patterns of individuals with COVID-19-like symptoms during the first three epidemic waves in Mexico to identify changes in those patterns that may reflect differences determined by virus variants.

Methods

We conducted a descriptive analysis of a large database containing records for all individuals who sought care at the Mexican Social Security Institute (IMSS) due to COVID-19-like symptoms from March 2020 to October 2021 (4.48 million records). We described the clinical and demographic profile of individuals tested (3.38 million, 32% with PCR and 68% with rapid test) by test result (positives and negatives) and untested, and among those tested, and the changes in those profiles across the first three epidemic waves.

Results

Individuals with COVID-19-like symptoms were older in the first wave and younger in the third one (the mean age for those positive was 46.6 in the first wave and 36.1 in the third wave; for negatives and not-tested, the mean age was 41 and 38.5 in the first wave and 34.3 and 33.5 in the third wave). As the pandemic progressed, an increasing number of individuals sought care for suspected COVID-19. The positivity rate decreased over time but remained well over the recommended 5%. The pattern of presenting symptoms changed over time, with some of those symptoms decreasing over time (dyspnea 40.6 to 14.0%, cough 80.4 to 76.2%, fever 77.5 to 65.2%, headache 80.3 to 78.5%), and some increasing (odynophagia 48.7 to 58.5%, rhinorrhea 28.6 to 47.5%, anosmia 11.8 to 23.2%, dysgeusia 11.2 to 23.2%).

Conclusion

During epidemic surges, the general consensus was that any individual presenting with respiratory symptoms was a suspected COVID-19 case. However, symptoms and signs are dynamic, with clinical patterns changing not only with the evolution of the virus but also with demographic changes in the affected population. A better understanding of these changing patterns is needed to improve preparedness for future surges and pandemics.

Reaching Adolescent Girls and Young Women With HIV Self-Testing and Contraception at Girl-Friendly Drug Shops: A Randomized Trial in Tanzania

PURPOSE

We hypothesized that an intervention designed to create girl-friendly drug shops would increase access to sexual and reproductive health products and services among adolescent girls and young women (AGYW) (ages 15-24 years) in Tanzania.

METHODS

We conducted a four-month randomized trial at 20 drug shops in Shinyanga, Tanzania from August-December 2019 to determine if the Malkia Klabu ("Queen Club") intervention increased AGYW patronage and the provision of HIV self-testing (HIVST), contraception, and health facility referrals to AGYW (primary outcomes). Drug shops were randomized 1:1 to the intervention or comparison arm. All shops were provided with OraQuick HIVST kits to give to AGYW for free. Intervention shops implemented Malkia Klabu, a loyalty program for AGYW created using human-centered design through which AGYW could also access free contraception. We compared outcomes in intention-to-treat analyses using shop observations and shopkeeper records.

RESULTS

By endline, shops implementing Malkia Klabu had higher AGYW patronage than comparison shops (rate ratio: 4.4; 95% confidence interval: 2.0, 9.8). Intervention shops distributed more HIVST kits (median per shop: 130.5 vs. 58.5, P = .02) and contraceptives (325.5 vs. 7.0, P < .01) to AGYW and provided more referrals for HIV, family planning, or pregnancy services combined (3.5 vs. 0.5, P = .02) than comparison shops.

DISCUSSION

The Malkia Klabu intervention increased AGYW patronage and the provision of HIVST kits, contraception, and referrals to AGYW at drug shops, despite HIVST kits being freely available at all participating shops. Enhancing drug shops with girl-friendly services may be an effective strategy to reach AGYW with sexual and reproductive health services.

One vaccine to counter many diseases? Modeling the economics of oral polio vaccine against child mortality and COVID-19

Introduction

Recent reviews summarize evidence that some vaccines have heterologous or non-specific effects (NSE), potentially offering protection against multiple pathogens. Numerous economic evaluations examine vaccines' pathogen-specific effects, but less than a handful focus on NSE. This paper addresses that gap by reporting economic evaluations of the NSE of oral polio vaccine (OPV) against under-five mortality and COVID-19.

Materials and methods

We studied two settings: (1) reducing child mortality in a high-mortality setting (Guinea-Bissau) and (2) preventing COVID-19 in India. In the former, the intervention involves three annual campaigns in which children receive OPV incremental to routine immunization. In the latter, a susceptible-exposed-infectious-recovered model was developed to estimate the population benefits of two scenarios, in which OPV would be co-administered alongside COVID-19 vaccines. Incremental cost-effectiveness and benefit-cost ratios were modeled for ranges of intervention effectiveness estimates to supplement the headline numbers and account for heterogeneity and uncertainty.

Results

For child mortality, headline cost-effectiveness was $650 per child death averted. For COVID-19, assuming OPV had 20% effectiveness, incremental cost per death averted was $23,000-65,000 if it were administered simultaneously with a COVID-19 vaccine <200 days into a wave of the epidemic. If the COVID-19 vaccine availability were delayed, the cost per averted death would decrease to $2600-6100. Estimated benefit-to-cost ratios vary but are consistently high.

Discussion

Economic evaluation suggests the potential of OPV to efficiently reduce child mortality in high mortality environments. Likewise, within a broad range of assumed effect sizes, OPV (or another vaccine with NSE) could play an economically attractive role against COVID-19 in countries facing COVID-19 vaccine delays.

Funding

The contribution by DTJ was supported through grants from Trond Mohn Foundation (BFS2019MT02) and Norad (RAF-18/0009) through the Bergen Center for Ethics and Priority Setting.

The Impact Of COVID-19 On The Health Of Incarcerated Older Adults In California State Prisons

The number of older adults (age fifty-five or older) incarcerated in US prisons reached an all-time high just as COVID-19 entered correctional facilities in 2020. However, little is known about COVID-19's impact on incarcerated older adults. We compared COVID-19 outcomes between older and younger adults in California state prisons from March 1, 2020, to October 9, 2021. Adjusted odds ratios (aORs) revealed an increasing risk for adverse COVID-19 outcomes among older age groups (ages 55-64, 65-74, and 75 or older) compared with younger adults, including for documented infection (aOR, 1.3, 1.4, and 1.4, respectively) and hospitalization with COVID-19 (aOR, 4.6, 8.7, and 15.1, respectively). Moreover, although accounting for 17.3 percent of the California state prison population, older adults represented 85.8 percent of this population's COVID-19-related deaths. Yet a smaller percentage of older adults than younger adults were released from prison during the pandemic. The differential rates of morbidity and mortality experienced by incarcerated older adults should be considered in future pandemic response strategies regarding prisons.

Modeling scenarios for mitigating outbreaks in congregate settings

The explosive outbreaks of COVID-19 seen in congregate settings such as prisons and nursing homes, has highlighted a critical need for effective outbreak prevention and mitigation strategies for these settings. Here we consider how different types of control interventions impact the expected number of symptomatic infections due to outbreaks. Introduction of disease into the resident population from the community is modeled as a stochastic point process coupled to a branching process, while spread between residents is modeled via a deterministic compartmental model that accounts for depletion of susceptible individuals. Control is modeled as a proportional decrease in the number of susceptible residents, the reproduction number, and/or the proportion of symptomatic infections. This permits a range of assumptions about the density dependence of transmission and modes of protection by vaccination, depopulation and other types of control. We find that vaccination or depopulation can have a greater than linear effect on the expected number of cases. For example, assuming a reproduction number of 3.0 with density-dependent transmission, we find that preemptively reducing the size of the susceptible population by 20% reduced overall disease burden by 47%. In some circumstances, it may be possible to reduce the risk and burden of disease outbreaks by optimizing the way a group of residents are apportioned into distinct residential units. The optimal apportionment may be different depending on whether the goal is to reduce the probability of an outbreak occurring, or the expected number of cases from outbreak dynamics. In other circumstances there may be an opportunity to implement reactive disease control measures in which the number of susceptible individuals is rapidly reduced once an outbreak has been detected to occur. Reactive control is most effective when the reproduction number is not too high, and there is minimal delay in implementing control. We highlight the California state prison system as an example for how these findings provide a quantitative framework for understanding disease transmission in congregate settings. Our approach and accompanying interactive website (https://phoebelu.shinyapps.io/DepopulationModels/) provides a quantitative framework to evaluate the potential impact of policy decisions governing infection control in outbreak settings.

Respiratory pandemic preparedness learnings from the June 2020 COVID-19 outbreak at San Quentin California State Prison

PURPOSE

This study aims to characterize the June 2020 COVID-19 outbreak at San Quentin California State Prison and to describe what made San Quentin so vulnerable to uncontrolled transmission.

DESIGN/METHODOLOGY/APPROACH

Since its onset, the COVID-19 pandemic has exposed and exacerbated the profound health harms of carceral settings, such that nearly half of state prisons reported COVID-19 infection rates that were four or more times (and up to 15 times) the rate found in the state's general population. Thus, addressing the public health crises and inequities of carceral settings during a respiratory pandemic requires analyzing the myriad factors shaping them. In this study, we reported observations and findings from environmental risk assessments during visits to San Quentin California State Prison. We complemented our assessments with analyses of administrative data.

FINDINGS

For future respiratory pathogens that cannot be prevented with effective vaccines, this study argues that outbreaks will no doubt occur again without robust implementation of additional levels of preparedness - improved ventilation, air filtration, decarceration with emergency evacuation planning - alongside addressing the vulnerabilities of carceral settings themselves.

ORIGINALITY/VALUE

This study addresses two critical aspects that are insufficiently covered in the literature: how to prepare processes to safely implement emergency epidemic measures when needed, such as potential evacuation, and how to address unique challenges throughout an evolving pandemic for each carceral setting.

COVID-19 outbreak in a state prison: a case study on the implementation of key public health recommendations for containment and prevention

BACKGROUND

People incarcerated in US prisons have been disproportionately harmed by the COVID-19 pandemic. That prisons are such efficient superspreading environments can be attributed to several known factors: small, communal facilities where people are confined for prolonged periods of time; poor ventilation; a lack of non-punitive areas for quarantine/medical isolation; and staggeringly high numbers of people experiencing incarceration, among others. While health organizations have issued guidance on preventing and mitigating COVID-19 infection in carceral settings, little is known about if, when, and how recommendations have been implemented. We examined factors contributing to containment of one of the first California prison COVID-19 outbreaks and remaining vulnerabilities using an adapted multi-level determinants framework to systematically assess infectious disease risk in carceral settings.

METHODS

Case study employing administrative data; observation; and informal discussions with: people incarcerated at the prison, staff, and county public health officials.

RESULTS

Outbreak mitigation efforts were characterized by pre-planning (e.g., designation of ventilated, single-occupancy quarantine) and a quickly mobilized inter-institutional response that facilitated systematic, voluntary rapid testing. However, several systemic- and institutional-level vulnerabilities were unaddressed hindering efforts and posing significant risk for future outbreaks, including insufficient decarceration, continued inter-facility transfers, incomplete staff cohorting, and incompatibility between built environment features (e.g., dense living conditions) and public health recommendations.

CONCLUSIONS

Our adapted framework facilitates systematically assessing prison-based infectious disease outbreaks and multi-level interventions. We find implementing some recommended public health strategies may have contributed to outbreak containment. However, even with a rapidly mobilized, inter-institutional response, failure to decarcerate created an overreliance on chance conditions. This left the facility vulnerable to future catastrophic outbreaks and may render standard public health strategies - including the introduction of effective vaccines - insufficient to prevent or contain those outbreaks.

Mitigating outbreaks in congregate settings by decreasing the size of the susceptible population

While many transmission models have been developed for community spread of respiratory pathogens, less attention has been given to modeling the interdependence of disease introduction and spread seen in congregate settings, such as prisons or nursing homes. As demonstrated by the explosive outbreaks of COVID-19 seen in congregate settings, the need for effective outbreak prevention and mitigation strategies for these settings is critical. Here we consider how interventions that decrease the size of the susceptible populations, such as vaccination or depopulation, impact the expected number of infections due to outbreaks. Introduction of disease into the resident population from the community is modeled as a branching process, while spread between residents is modeled via a compartmental model. Control is modeled as a proportional decrease in both the number of susceptible residents and the reproduction number. We find that vaccination or depopulation can have a greater than linear effect on anticipated infections. For example, assuming a reproduction number of 3.0 for density-dependent COVID-19 transmission, we find that reducing the size of the susceptible population by 20% reduced overall disease burden by 47%. We highlight the California state prison system as an example for how these findings provide a quantitative framework for implementing infection control in congregate settings. Additional applications of our modeling framework include optimizing the distribution of residents into independent residential units, and comparison of preemptive versus reactive vaccination strategies.

Old vaccines for new infections: Exploiting innate immunity to control COVID-19 and prevent future pandemics

The COVID-19 pandemic triggered an unparalleled pursuit of vaccines to induce specific adaptive immunity, based on virus-neutralizing antibodies and T cell responses. Although several vaccines have been developed just a year after SARS-CoV-2 emerged in late 2019, global deployment will take months or even years. Meanwhile, the virus continues to take a severe toll on human life and exact substantial economic costs. Innate immunity is fundamental to mammalian host defense capacity to combat infections. Innate immune responses, triggered by a family of pattern recognition receptors, induce interferons and other cytokines and activate both myeloid and lymphoid immune cells to provide protection against a wide range of pathogens. Epidemiological and biological evidence suggests that the live-attenuated vaccines (LAV) targeting tuberculosis, measles, and polio induce protective innate immunity by a newly described form of immunological memory termed "trained immunity." An LAV designed to induce adaptive immunity targeting a particular pathogen may also induce innate immunity that mitigates other infectious diseases, including COVID-19, as well as future pandemic threats. Deployment of existing LAVs early in pandemics could complement the development of specific vaccines, bridging the protection gap until specific vaccines arrive. The broad protection induced by LAVs would not be compromised by potential antigenic drift (immune escape) that can render viruses resistant to specific vaccines. LAVs might offer an essential tool to "bend the pandemic curve," averting the exhaustion of public health resources and preventing needless deaths and may also have therapeutic benefits if used for postexposure prophylaxis of disease.

Non-communicable diseases and inequalities increase risk of death among COVID-19 patients in Mexico

BACKGROUND

The SARS-CoV-2 pandemic compounds Mexico's pre-existing challenges: very high levels of both non-communicable diseases (NCD) and social inequity.

METHODS AND FINDINGS

Using data from national reporting of SARS-CoV-2 tested individuals, we estimated odds of hospitalization, intubation, and death based on pre-existing non-communicable diseases and socioeconomic indicators. We found that obesity, diabetes, and hypertension are positively associated with the three outcomes in a synergistic manner. The municipal poverty level is also positively associated with hospitalization and death.

CONCLUSIONS

Mexico's response to COVID-19 is complicated by a synergistic double challenge: raging NCDs and extreme social inequity. The response to the current pandemic must take both into account both to be effective and to ensure that the burden of COVID-19 not falls disproportionately on those who are already disadvantaged.

Cross-Sectional Association between Length of Incarceration and Selected Risk Factors for Non-Communicable Chronic Diseases in Two Male Prisons of Mexico City

BACKGROUND

Mexico City prisons are characterized by overcrowded facilities and poor living conditions for housed prisoners. Chronic disease profile is characterized by low prevalence of self reported hypertension (2.5%) and diabetes (1.8%) compared to general population; 9.5% of male inmates were obese. There is limited evidence regarding on the exposure to prison environment over prisoner's health status; particularly, on cardiovascular disease risk factors. The objective of this study is to assess the relationship between length of incarceration and selected risk factors for non-communicable chronic diseases (NCDs).

METHODS AND FINDINGS

We performed a cross-sectional analysis using data from two large male prisons in Mexico City (n = 14,086). Using quantile regression models we assessed the relationship between length of incarceration and selected risk factors for NCDs; stratified analysis by age at admission to prison was performed. We found a significant negative trend in BMI and WC across incarceration length quintiles. BP had a significant positive trend with a percentage change increase around 5% mmHg. The greatest increase in systolic blood pressure was observed in the older age at admission group.

CONCLUSIONS

This analysis provides insight into the relationship between length of incarceration and four selected risk factors for NCDs; screening for high blood pressure should be guarantee in order to identify at risk individuals and linked to the prison's health facility. It is important to assess prison environment features to approach potential risk for developing NCDs in this context.

A Cross-Sectional Study of Prisoners in Mexico City Comparing Prevalence of Transmissible Infections and Chronic Diseases with That in the General Population

OBJECTIVES

To describe patterns of transmissible infections, chronic illnesses, socio-demographic characteristics and risk behaviors in Mexico City prisons, including in comparison to the general population, to identify those currently needing healthcare and inform policy.

MATERIALS AND METHODS

A cross-sectional study among 17,000 prisoners at 4 Mexico City prisons (June to December 2010). Participation was voluntary, confidential and based on informed consent. Participants were tested for HIV, Hepatitis B & C, syphilis, hypertension, obesity, and, if at risk, glucose and cholesterol. A subset completed a questionnaire on socio-demographic characteristics and risk behaviors. Positive results were delivered with counseling and treatment or referral.

RESULTS

76.8% (15,517/20,196) of men and 92.9% (1,779/1,914) of women participated. Complete data sets were available for 98.8%. The following prevalence data were established for transmissible infections: HIV 0.7%; syphilis: Anti-TP+/VDRL+ 2.0%; Hepatitis B: HBcAb 2.8%, HBsAg 0.15%; Anti-HCV 3.2%. Obesity: 9.5% men, 33.8% women. Compared with national age- and sex-matched data, the relative prevalence was greater for HIV and syphilis among women, HIV and Hepatitis C in men, and all infections in younger participants. Obesity prevalence was similar for women and lower among male participants. The prevalence of previously diagnosed diabetes and hypertension was lower. Questionnaire data (1,934 men, 520 women) demonstrated lower educational levels, increased smoking and substance use compared to national data. High levels of non-sterile tattooing, physical abuse and histories of sexual violence were found.

CONCLUSION

The study identified that health screening is acceptable to Mexico City prisoners and feasible on a large-scale. It demonstrated higher prevalence of HIV and other infections compared to national data, though low rates compared to international data. Individual participants benefited from earlier diagnosis, treatment and support. The data collected will also enable the formulation of improved policy for this vulnerable group.

How the Avahan HIV prevention program transitioned from the Gates Foundation to the government of India

Developing countries face diminishing development aid and time-limited donor commitments that challenge the long-term sustainability of donor-funded programs to improve the health of local populations. Increasing country ownership of the programs is one solution. Transitioning managerial and financial responsibility for donor-funded programs to governments and local stakeholders represents a highly advanced form of country ownership, but there are few successful examples among large-scale programs. We present a transition framework and describe how it was used to transfer the Bill & Melinda Gates Foundation's HIV/AIDS prevention program, the Avahan program, to the Government of India. Essential features recommended for the transition of donor-funded programs to governments include early planning with the government, aligning donor program components with government structures and funding models prior to transition, building government capacity through active technical and management support, budgeting for adequate support during and after the transition, and dividing the transition into phases to allow time for adjustments and corrections. The transition of programs to governments is an important sustainability strategy for efforts to scale up HIV prevention programs to reach the populations most at risk.

Willingness-to-accept reductions in HIV risks: conditional economic incentives in Mexico

The objective of this study was to measure willingness-to-accept (WTA) reductions in risks for HIV and other sexually transmitted infections (STI) using conditional economic incentives (CEI) among men who have sex with men (MSM), including male sex workers (MSW) in Mexico City. A survey experiment was conducted with 1,745 MSM and MSW (18-25 years of age) who received incentive offers to decide first whether to accept monthly prevention talks and STI testing; and then a second set of offers to accept to stay free of STIs (verified by quarterly biological testing). The survey used random-starting-point and iterative offers. WTA was estimated with a maximum likelihood double-bounded dichotomous choice model. The average acceptance probabilities were: 73.9 % for the monthly model, and 80.4 % for the quarterly model. The incentive-elasticity of participation in the monthly model was 0.222, and 0.515 in the quarterly model. For a combination program with monthly prevention talks, and staying free of curable STI, the implied WTA was USD$ 288 per person per year, but it was lower for MSW: USD$ 156 per person per year. Thus, some of the populations at highest risk of HIV infection (MSM and MSW) seem well disposed to participate in a CEI program for HIV and STI prevention in Mexico. The average WTA estimate is within the range of feasible allocations for prevention in the local context. Given the potential impact, Mexico, a leader in conditional cash transfers for human development and poverty reduction, could extend that successful model to targeted HIV/STI prevention.

[Mixed design for the evaluation of the Mesoamerica Health 2015 initiative]

Since the Salud Mesoamerica 2015 initiative (SM-2015) aim is to improve health and nutrition conditions of those most vulnerable in Mesoamerica, the goal of the evaluation is to generate evidence of the joint effectiveness of a package of interventions designed to improve the health conditions. We propose a mix design for the evaluation, which will allow to know the magnitude of changes attributable to the interventions, as well as the meanings of these changes for the target population, taking into account the specificities of each country. The main axis of this design is a locality panel where information about individuals, households, and health facilities (first and second level) will also be collected. The evaluation design described in this paper was developed between June and December, 2009, and it was integrated during workshops in Cuernavaca (Mexico), Managua (Nicaragua), and San Jose (Costa Rica). The proposed design will allow to generate evidence about the joint effectiveness of the package of interventions proposed for the SM-2015. The success of this design rests on the political commitment of countries and donors.

The evolving HIV/AIDS response and the urgent tasks ahead

AIDS continues to outpace the science, financing, prevention, and treatment efforts of the past quarter-century. There have been different epochs along the evolutionary timeline of the global AIDS response, from the discovery of HIV to the threat posed by the current economic crisis. This timeline serves as a reference to how we have arrived where we are today, in the hope that understanding our past will help us set the course for a more efficient and effective future response.

Community-based prevention leads to an increase in condom use and a reduction in sexually transmitted infections (STIs) among men who have sex with men (MSM) and female sex workers (FSW): the Frontiers Prevention Project (FPP) evaluation results

Background

India has an estimated 2.0 million to 3.1 million people living with HIV; it has the highest number of HIV-positive people in Asia and ranks third in the world. The Frontiers Prevention Project (FPP) was implemented in 2002 to conduct targeted prevention intervention geared towards female sex workers (FSW) and men who have sex with men (MSM) in the state of Andhra Pradesh (AP). This paper reports the overall changes in behaviour and STI outcomes between 2003/4 and 2007 and also describes the changes attributed to the FPP.

Methods

The evaluation used two cross-sectional surveys among MSM and FSW at 24 sites in AP. Surveys were implemented using a similar methodology. Univariate analyses were conducted by comparing means: baseline vs. four-year follow-up and FPP vs. non-FPP. For both MSM and FSW, random and fixed-effects logit regression models at the site level were estimated for condom use with last partner, syphilis sero-positivity and HSV 2 sero-positivity. In addition, for FSW we estimated models for condom use with regular partner, and for MSM we estimated models for condom use with last female partner.

Results

Among MSM, fixed-effects analysis revealed that FPP was positively correlated with the probability of condom use with last female sexual partner and negatively correlated with the individual probability of sero-positivity to syphilis and HSV 2. Among FSW, the FPP intervention was significantly correlated with increased condom use with regular partners and with lower probability of STI sero-positivity.

Discussion

Important changes in behaviours related to an increase in prevention activities translated to reductions in STI sero-prevalence in AP, India. In contrast with non-FPP sites, the FPP sites experienced an intense community approach as part of the FPP intervention, and the general increase in condom use and its effect on STI sero-prevalence reflected the efficacy of these intense prevention activities focused on key populations in AP.

Adaptive vaccination strategies to mitigate pandemic influenza: Mexico as a case study

BACKGROUND

We explore vaccination strategies against pandemic influenza in Mexico using an age-structured transmission model calibrated against local epidemiological data from the Spring 2009 A(H1N1) pandemic.

METHODS AND FINDINGS

In the context of limited vaccine supplies, we evaluate age-targeted allocation strategies that either prioritize youngest children and persons over 65 years of age, as for seasonal influenza, or adaptively prioritize age groups based on the age patterns of hospitalization and death monitored in real-time during the early stages of the pandemic. Overall the adaptive vaccination strategy outperformed the seasonal influenza vaccination allocation strategy for a wide range of disease and vaccine coverage parameters.

CONCLUSIONS

This modeling approach could inform policies for Mexico and other countries with similar demographic features and vaccine resources issues, with regard to the mitigation of the S-OIV pandemic. We also discuss logistical issues associated with the implementation of adaptive vaccination strategies in the context of past and future influenza pandemics.

HIV prevention cost-effectiveness: a systematic review

Background

After more than 25 years, public health programs have not been able to sufficiently reduce the number of new HIV infections. Over 7,000 people become infected with HIV every day. Lack of convincing evidence of cost-effectiveness (CE) may be one of the reasons why implementation of effective programs is not occurring at sufficient scale. This paper identifies, summarizes and critiques the CE literature related to HIV-prevention interventions in low- and middle-income countries during 2005-2008.

Methods

Systematic identification of publications was conducted through several methods: electronic databases, internet search of international organizations and major funding/implementing agencies, and journal browsing. Inclusion criteria included: HIV prevention intervention, year for publication (2005-2008), setting (low- and middle-income countries), and CE estimation (empirical or modeling) using outcomes in terms of cost per HIV infection averted and/or cost per disability-adjusted life year (DALY) or quality-adjusted life year (QALY).

Results

We found 21 distinct studies analyzing the CE of HIV-prevention interventions published in the past four years (2005-2008). Seventeen CE studies analyzed biomedical interventions; only a few dealt with behavioral and environmental/structural interventions. Sixteen studies focused on sub-Saharan Africa, and only a handful on Asia, Latin America and Eastern Europe. Many HIV-prevention interventions are very cost effective in absolute terms (using costs per DALY averted), and also in country-specific relative terms (in cost per DALY measured as percentage of GDP per capita).

Conclusion

There are several types of interventions for which CE studies are still not available or insufficient, including surveillance, abstinence, school-based education, universal precautions, prevention for positives and most structural interventions. The sparse CE evidence available is not easily comparable; thus, not very useful for decision making. More than 25 years into the AIDS epidemic and billions of dollars of spending later, there is still much work to be done both on costs and effectiveness to adequately inform HIV prevention planning.

Severe respiratory disease concurrent with the circulation of H1N1 influenza

BACKGROUND

In the spring of 2009, an outbreak of severe pneumonia was reported in conjunction with the concurrent isolation of a novel swine-origin influenza A (H1N1) virus (S-OIV), widely known as swine flu, in Mexico. Influenza A (H1N1) subtype viruses have rarely predominated since the 1957 pandemic. The analysis of epidemic pneumonia in the absence of routine diagnostic tests can provide information about risk factors for severe disease from this virus and prospects for its control.

METHODS

From March 24 to April 29, 2009, a total of 2155 cases of severe pneumonia, involving 821 hospitalizations and 100 deaths, were reported to the Mexican Ministry of Health. During this period, of the 8817 nasopharyngeal specimens that were submitted to the National Epidemiological Reference Laboratory, 2582 were positive for S-OIV. We compared the age distribution of patients who were reported to have severe pneumonia with that during recent influenza epidemics to document an age shift in rates of death and illness.

RESULTS

During the study period, 87% of deaths and 71% of cases of severe pneumonia involved patients between the ages of 5 and 59 years, as compared with average rates of 17% and 32%, respectively, in that age group during the referent periods. Features of this epidemic were similar to those of past influenza pandemics in that circulation of the new influenza virus was associated with an off-season wave of disease affecting a younger population.

CONCLUSIONS

During the early phase of this influenza pandemic, there was a sudden increase in the rate of severe pneumonia and a shift in the age distribution of patients with such illness, which was reminiscent of past pandemics and suggested relative protection for persons who were exposed to H1N1 strains during childhood before the 1957 pandemic. If resources or vaccine supplies are limited, these findings suggest a rationale for focusing prevention efforts on younger populations.

A predictive model for the utilization of curative ambulatory health services in Mexico

OBJECTIVES

To estimate the degree to which individual and household variables jointly predict utilization of curative ambulatory services in Mexico for four types of health providers.

MATERIAL AND METHODS

Patient choice of provider (self-care, Ministry of Health, social security, or private provider) when they become ill is modeled using a nested multinomial logit model that uses household and individual variables as predictors. The data are from the Mexican National Health Survey conducted in 2000.

RESULTS

Being a social security beneficiary is one of the most important predictors of utilization. A strong positive relationship between socio-economic status (SES) and demand for services was also found, with the strongest relationship being for private providers, followed by social security. Utilization of Ministry of Health (MoH) services was negatively associated with household SES.

CONCLUSIONS

Expansion of health insurance coverage should significantly reduce health inequalities due to reduced care-seeking by non-beneficiaries.

Costing of scaling up HIV/AIDS treatment in Mexico

OBJECTIVE

To determine the net effect of introducing highly active antiretroviral treatment (HAART) in Mexico on total annual per-patient costs for HIV/AIDS care, taking into account potential savings from treatment of opportunistic infections and hospitalizations.

MATERIAL AND METHODS

A multi-center, retrospective patient chart review and collection of unit cost data were performed to describe the utilization of services and estimate costs of care for 1003 adult HIV+ patients in the public sector.

RESULTS

HAART is not cost-saving and the average annual cost per patient increases after initiation of HAART due to antiretrovirals, accounting for 90% of total costs. Hospitalizations do decrease post-HAART, but not enough to offset the increased cost.

CONCLUSIONS

Scaling up access to HAART is feasible in middle income settings. Since antiretrovirals are so costly, optimizing efficiency in procurement and prescribing is paramount. The observed adherence was low, suggesting that a proportion of these high drug costs translated into limited health benefits.

Making HIV prevention programmes work

Even after 25 years of experience, HIV prevention programming remains largely deficient. We identify four areas that managers of national HIV prevention programmes should reassess and hence refocus their efforts-improvement of targeting, selection, and delivery of prevention interventions, and optimisation of funding. Although each area is not wholly independent from one another, and because each country and epidemic context will require a different balance of time and funding allocation in each area, we present the current state of each dimension in the global HIV prevention arena and propose practical ways to remedy present deficiencies. Insufficient data for intervention effectiveness and country-specific epidemiology has meant that programme managers have operated, and continue to operate, in a fog of uncertainty. Although priority must be given to the improvement of prevention methods and the capacity for the generation and use of evidence to improve programme planning and implementation, uncertainty will remain. In the meantime, however, we argue that prevention programming can be made much more effective by use of information that is readily available.

Cost-effectiveness of introducing a rotavirus vaccine in developing countries: the case of Mexico

Background

In developing countries rotavirus is the leading cause of severe diarrhoea and diarrhoeal deaths in children under 5. Vaccination could greatly alleviate that burden, but in Mexico as in most low- and middle-income countries the decision to add rotavirus vaccine to the national immunisation program will depend heavily on its cost-effectiveness and affordability. The objective of this study was to assess the cost-effectiveness of including the pentavalent rotavirus vaccine in Mexico's national immunisation program.

Methods

A cost-effectiveness model was developed from the perspective of the health system, modelling the vaccination of a hypothetical birth cohort of 2 million children monitored from birth through 60 months of age. It compares the cost and disease burden of rotavirus in an unvaccinated cohort of children with one vaccinated as recommended at 2, 4, and 6 months.

Results

Including the pentavalent vaccine in the national immunisation program could prevent 71,464 medical visits (59%), 5,040 hospital admissions (66%), and 612 deaths from rotavirus gastroenteritis (70%). At US$10 per dose and a cost of administration of US$13.70 per 3-dose regimen, vaccination would cost US$122,058 per death prevented, US$4,383 per discounted life-year saved, at a total net cost of US$74.7 million dollars to the health care system. Key variables influencing the results were, in order of importance, case fatality, vaccine price, vaccine efficacy, serotype prevalence, and annual loss of efficacy. The results are also very sensitive to the discount rate assumed when calculated per life-year saved.

Conclusion

At prices below US $15 per dose, the cost per life-year saved is estimated to be lower than one GNP per capita and hence highly cost effective by the WHO Commission on Macroeconomics and Health criteria. The cost-effectiveness estimates are highly dependent upon the mortality in the absence of the vaccine, which suggests that the vaccine is likely to be significantly more cost-effective among poorer populations and among those with less access to prompt medical care – such that poverty reduction programs would be expected to reduce the future cost-effectiveness of the vaccine.

Cost-effectiveness of implementation methods for ELISA serology testing of Trypanosoma cruzi in California blood banks

The first U.S. ELISA test for T. cruzi antibodies was licensed by the Food and Drug Administration (FDA) on December 13, 2006. Blood banks have begun screening in absence of FDA recommendations for best implementation methods. We surveyed 2,029 blood donors at five California sites with three risk-based Chagas risk-screening questions. Semi-Markov models compared the cost-effectiveness of three testing strategies. 30% of donors screened positively. Screening all dominated doing nothing, being less costly, and saving more lives. The choice to "screen and test" compared with "testing all" varied by Chagas prevalence, "screening and testing" being cost-effective for high (0.004) and low (0.00004) prevalences, and "testing all" cost-effective for moderate risk (0.0004). It is cost-effective to screen by ELISA rather than do nothing. The best strategy depends on site-specific risk. Census estimates of Hispanics do not predict donor risk well. We suggest using our screening questions to determine risk level and most cost-effective testing strategy.

Optimizing resource allocation for HIV/AIDS prevention programmes: an analytical framework

INTRODUCTION

Although investment in HIV/AIDS prevention has increased worldwide, it remains uncertain how the additional resources can be most efficiently allocated to maximize the number of infections averted, especially at the country, regional and local levels.

METHODS

Data from developing countries in Africa, Asia and Latin America were reviewed on the allocation of HIV/AIDS prevention funds in relation to the prevalence of infection, as well as budgetary allocations for specific population groups at high risk of infection, such as sex workers, intravenous drug users and men who have sex with men. The variation in unit costs of voluntary counselling and testing in five countries was also examined.

RESULTS

Evidence was found of three distinct sources of inefficiency in the allocation of HIV/AIDS prevention resources: inefficiency in the mix of interventions selected; inefficient targeting of key populations; and technical inefficiency in the production of HIV prevention services.

CONCLUSION

A general conceptual framework for evaluating the efficiency of HIV/AIDS prevention programmes at the country, regional and local levels is proposed. This framework stresses three equally important components of programme efficiency: cost-effectiveness (the choice of the mix of interventions); targeting (the choice of the mix of target populations); and technical efficiency (the delivery of prevention services at least cost).

Improving enrollment and utilization of the Oportunidades program in Mexico could increase its effectiveness

Oportunidades, Mexico's most important antipoverty program, currently with 5 million enrolled households in all regions of the country, has been shown to significantly contribute to improving the nutrition, health, and education of the poor. Because the program has used different enrollment strategies in rural and urban areas and has both obligatory (e.g., health and nutrition education) and nonobligatory components (e.g., nutrition supplements for children younger than 2 y of age), it provides an excellent opportunity to study program enrollment and utilization of different program components. In urban areas enrollment was more complex, and hence enrollment was much lower then in rural areas where the process was quasiautomatic, and nearly all eligible households enrolled. Enrollment in urban areas was not associated with having a child younger than 2 y of age. Utilization was notably higher with the obligatory than with the nonobligatory program components, illustrated by the inadequate consumption of the nutrition program's supplement as compared with near-universal compliance with well-baby visits. Innovative approaches, some of which are currently being tested, are needed to further increase the program's impact.

The costs, benefits, and cost-effectiveness of interventions to reduce maternal morbidity and mortality in Mexico

BACKGROUND

In Mexico, the lifetime risk of dying from maternal causes is 1 in 370 compared to 1 in 2,500 in the U.S. Although national efforts have been made to improve maternal services in the last decade, it is unclear if Millennium Development Goal 5--to reduce maternal mortality by three-quarters by 2015--will be met.

METHODOLOGY/PRINCIPAL FINDINGS

We developed an empirically calibrated model that simulates the natural history of pregnancy and pregnancy-related complications in a cohort of 15-year-old women followed over their lifetime. After synthesizing national and sub-national trends in maternal mortality, the model was calibrated to current intervention-specific coverage levels and validated by comparing model-projected life expectancy, total fertility rate, crude birth rate and maternal mortality ratio with Mexico-specific data. Using both published and primary data, we assessed the comparative health and economic outcomes of alternative strategies to reduce maternal morbidity and mortality. A dual approach that increased coverage of family planning by 15%, and assured access to safe abortion for all women desiring elective termination of pregnancy, reduced mortality by 43% and was cost saving compared to current practice. The most effective strategy added a third component, enhanced access to comprehensive emergency obstetric care for at least 90% of women requiring referral. At a national level, this strategy reduced mortality by 75%, cost less than current practice, and had an incremental cost-effectiveness ratio of $300 per DALY relative to the next best strategy. Analyses conducted at the state level yielded similar results.

CONCLUSIONS/SIGNIFICANCE

Increasing the provision of family planning and assuring access to safe abortion are feasible, complementary and cost-effective strategies that would provide the greatest benefit within a short-time frame. Incremental improvements in access to high-quality intrapartum and emergency obstetric care will further reduce maternal deaths and disability.

HIV prevention costs and program scale: data from the PANCEA project in five low and middle-income countries

BACKGROUND

Economic theory and limited empirical data suggest that costs per unit of HIV prevention program output (unit costs) will initially decrease as small programs expand. Unit costs may then reach a nadir and start to increase if expansion continues beyond the economically optimal size. Information on the relationship between scale and unit costs is critical to project the cost of global HIV prevention efforts and to allocate prevention resources efficiently.

METHODS

The "Prevent AIDS: Network for Cost-Effectiveness Analysis" (PANCEA) project collected 2003 and 2004 cost and output data from 206 HIV prevention programs of six types in five countries. The association between scale and efficiency for each intervention type was examined for each country. Our team characterized the direction, shape, and strength of this association by fitting bivariate regression lines to scatter plots of output levels and unit costs. We chose the regression forms with the highest explanatory power (R2).

RESULTS

Efficiency increased with scale, across all countries and interventions. This association varied within intervention and within country, in terms of the range in scale and efficiency, the best fitting regression form, and the slope of the regression. The fraction of variation in efficiency explained by scale ranged from 26-96%. Doubling in scale resulted in reductions in unit costs averaging 34.2% (ranging from 2.4% to 58.0%). Two regression trends, in India, suggested an inflection point beyond which unit costs increased.

CONCLUSION

Unit costs decrease with scale across a wide range of service types and volumes. These country and intervention-specific findings can inform projections of the global cost of scaling up HIV prevention efforts.

Forecast of demand for antiretroviral drugs in low and middle-income countries: 2007-2008

BACKGROUND

Middle and low-income countries have scaled up HIV treatment in the past 5 years. To maintain this effort, information regarding the amounts and types of drugs is needed. Shortages or overstock of active pharmaceutical ingredients make the scale-up efforts more difficult and costly. To inform global planning and implementation, we estimate the volume of current and future demand for active pharmaceutical ingredients for first and second-line antiretroviral drugs.

METHODS

Using regression analysis and documented assumptions, we estimated the number of individuals receiving antiretroviral drugs to 2008. The volume of active pharmaceutical ingredients was calculated using two methods: a normative approach modelling implementation of country-specific guidelines, and an empirical model projecting current trends in drug use estimated by a survey of country HIV programmes.

RESULTS

The number of patients treated was estimated to reach 3.38 million by the end of 2008, of which 94.6% would be on first-line and 5.4% on second-line treatment. The largest estimated absolute demand volumes for 2008 were for nevirapine, lamivudine, and zidovudine using either approach; the largest proportional increases in 2007-2008, were observed for emtricitabine, tenofovir, indinavir, and nelfinavir. The gap between normative and empirical estimates was greatest (most positive) for tenofovir, zidovudine, didanosine, and smallest (most negative) for saquinavir and nelfinavir.

CONCLUSION

A comparison of the results from the normative and empirical demand quantities suggests that more tenofovir, zidovudine and didanosine would be required if national treatment guidelines were fully implemented, whereas the countries seem to be using more saquinavir and nelfinavir than would be required by their current guidelines.

Herpes simplex virus type 2 among Mexican high school adolescents: prevalence and association with community characteristics

BACKGROUND

We undertook this study to estimate the prevalence and correlates of herpes simplex virus type 2 (HSV-2) among Mexican adolescents in high school.

METHODS

This was a cross-sectional analysis using data that had been collected to evaluate a school-based HIV prevention intervention. As part of the final round of evaluation, capillary blood samples were taken from volunteers to test for antibodies to HSV-2. The effect of each school's seroprevalence on the probability of an individual being seropositive was estimated, and the results were grouped by town to evaluate the association between characteristics of the locality and student HSV-2 seroprevalence.

RESULTS

Dried blood spots were collected for 80% of the 1607 participants in the survey who reported that they were sexually active. Of these samples, 21% tested positive for HSV-2 antibodies, with no significant difference in prevalence between men and women. Seroprevalence among schools ranged from 0 to 57%. The number of sex workers registered in the locality was the most important covariate of seroprevalence, with each additional female sex worker (FSW) per 1000 women between 18 and 45 years of age in the town associated with an increase of 1% in the seroprevalence of HSV-2.

CONCLUSIONS

Characteristics of adolescents' micro-environments that influence their pool of potential sexual partners and the likelihood that these partners are HSV-2 positive may be more important predictors of the risk of STI infection than self-reported condom use.

Variations In Prenatal Care Quality For The Rural Poor In Mexico

Quality is high on the Mexican health policy agenda. In this paper we evaluate the quality of prenatal care for rural low-income women. Women who obtained care from private practitioners and non-MDs received fewer procedures on average. Poverty predicts poor quality; however, indigenous women in private settings received fewer procedures, after household wealth was controlled for. We recommend strengthening clinical skills and providing incentives to adhere to quality standards. Quality reporting could promote informed employer care-purchasing and individual care-seeking choices. The national health reforms should be monitored to determine their success in not only increasing access among the poor and indigenous but also ensuring that such care meets quality norms.