Chaitra Gopalappa

University of Massachusetts Amherst | UMass Amherst · Department of Mechanical and Industrial Engineering

Background As social and economic conditions are key determinants of HIV, the ‘National HIV/AIDS Strategy (NHAS)’, in addition to care and treatment metrics, aims to address mental health, unemployment, food insecurity, and housing instability, as a strategic plan for the Ending the HIV Epidemic initiative. Mechanistic models of HIV play a key role...

Introduction: Persons living with HIV have a disproportionately higher burden of HPV-related cancers. Causal factors include both behavioral and biological. While pharmaceutical and care support interventions help address biological risk of coinfection, as social conditions are common drivers of behaviors, structural interventions are key part of b...

Background The U.S. Ending the HIV epidemic (EHE) plan aims to reduce annual HIV incidence by 90% by 2030, by first focusing interventions on 57 regions (EHE jurisdictions) that contributed to more than 50% of annual HIV diagnoses. Mathematical models that project HIV incidence evaluate the impact of interventions and inform intervention decisions....

In the absence of pharmaceutical interventions, social distancing and lockdown have been key options for controlling new or reemerging respiratory infectious disease outbreaks. The timely implementation of these interventions is vital for effectively controlling and safeguarding the economy. Motivated by the COVID-19 pandemic, we evaluated whether,...

Agent-based network modeling (ABNM) simulates each person at the individual-level as agents of the simulation, and uses network generation algorithms to generate the network of contacts between individuals. ABNM are suitable for simulating individual-level dynamics of infectious diseases, especially for diseases such as HIV that spread through clos...

The 'Ending the HIV Epidemic (EHE)' national plan aims to reduce annual HIV incidence in the United States from 38,000 in 2015 to 9300 by 2025 and 3300 by 2030. Diagnosis and treatment are two most effective interventions, and thus, identifying corresponding optimal combinations of testing and retention-in-care rates would help inform implementatio...

We simulated epidemic projections of a potential COVID-19 outbreak in a residential university population in the United States under varying combinations of asymptomatic tests (5% to 33% per day), transmission rates (2.5% to 14%), and contact rates (1 to 25), to identify the contact rate threshold that, if exceeded, would lead to exponential growth...

We present the Progression and Transmission of HIV (PATH 4.0), a simulation tool for analyses of cluster detection and intervention strategies. Molecular clusters are groups of HIV infections that are genetically similar, indicating rapid HIV transmission where HIV prevention resources are needed to improve health outcomes and prevent new infection...

Background. Low-and-middle-income countries (LMICs) have higher mortality-to-incidence ratio for breast cancer compared to high-income countries (HICs) because of late-stage diagnosis. Mammography screening is recommended for early diagnosis, however, the infrastructure capacity in LMICs are far below that needed for adopting current screening guid...

Background Following the adoption of the Global Action Plan for the Prevention and Control of NCDs 2013–2020, an update to the Appendix 3 of the action plan was requested by Member States in 2016, endorsed by the Seventieth World Health Assembly in May 2017 and provides a list of recommended NCD interventions. The main contribution of this paper is...

Implementation of organized cancer screening and prevention programs in high-income countries (HICs) has considerably decreased cancer-related incidence and mortality. In low- and middle-income countries (LMICs), screening and early diagnosis programs are generally unavailable, and most cancers are diagnosed in late stages when survival is very low...

Objective: Analyzing HIV care service targets for achieving a national goal of a 25% reduction in annual HIV incidence and evaluating the use of annual HIV diagnoses to measure progress in incidence reduction. Design: Because there are considerable interactions among HIV care services, we model the dynamics of combinations of increases in HIV ca...

Background: HIV transmission is the result of complex dynamics in the risk behaviors, partnership choices, disease stage and position along the HIV care continuum-individual characteristics that themselves can change over time. Capturing these dynamics and simulating transmissions to understand the chief sources of transmission remain important fo...

Background: Mathematical models are widely used to simulate the effects of interventions to control HIV and to project future epidemiological trends and resource needs. We aimed to validate past model projections against data from a large household survey done in South Africa in 2012. Methods: We compared ten model projections of HIV prevalence, HI...

Background: The Spectrum program is used to estimate key HIV indicators for national programmes. The purpose of the study is to describe the key updates made to Spectrum in the last 2 years to produce the version used in the 2013 global estimates of HIV/AIDS. Methods: The United Nations Programme on HIV/AIDS (UNAIDS) Reference Group on Estimates,...

Background In 2011 an Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services resulting in a reduction of new HIV infections by...

In 2011 an Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services resulting in a reduction of new HIV infections by more than h...

Background New WHO guidelines recommend initiation of antiretroviral therapy for HIV-positive adults with CD4 counts of 500 cells per μL or less, a higher threshold than was previously recommended. Country decision makers have to decide whether to further expand eligibility for antiretroviral therapy accordingly. We aimed to assess the potential he...

Objectives: The present study presents estimates of the number of people who would become newly eligible for antiretroviral therapy if all countries adopted the 2013 WHO treatment guidelines. It also shows the cost and impact that would result if coverage expanded to 80% of those eligible. Methods: The AIDS Impact Model (AIM) and the Goals model...

Most countries follow WHO 2010 guidelines for the prevention of mother-to-child transmission (PMTCT) of HIV using either Option A or B for women not yet eligible for antiretroviral therapy (ART). Both of these approaches involve the use of antiretrovirals during pregnancy and breastfeeding. Some countries have adopted a new strategy, Option B+, in...

Many countries are considering expanding HIV treatment following recent findings emphasizing the effects of antiretroviral therapy (ART) on reducing HIV transmission in addition to already established survival benefits. Given the close interaction of tuberculosis (TB) and HIV epidemics, ART expansion could have important ramifications for TB burden...

Chlamydia and gonorrhea infections can lead to serious and costly sequelae in women, but sequelae in men are rare. In accordance with the Centers for Disease Control and Prevention guidelines, female jail inmates in Maricopa County (Phoenix area), Arizona, are screened for these infections. Owing to lack of evidence of screening benefits in men, ma...

Background: Lifetime costs of care and quality-of-life estimates for HIV-infected persons depend on the disease stage at which these persons are diagnosed, enter care, and start antiretroviral therapy. Updated estimates were used to analyze the effects of late versus early diagnosis/entry on US lifetime care costs, quality-of-life estimates, and H...

Purpose: Human immunodeficiency virus (HIV) lifetime treatment costs depend upon the disease stage at which HIV-infected persons are diagnosed, enter care, and start an antiretroviral therapy (ART) regimen. Clinical literature indicates that early ART initiation results in substantial benefits for the health of HIV-infected persons and reduced tran...

One of the goals of the National HIV/AIDS Strategy (NHAS) is to increase the proportion of HIV-infected individuals linked to care within 3 months of diagnosis (early linkage) from 65% to 85%. Earlier access to care, and eventually, to treatment, increases life expectancy and quality of life for HIV-infected persons. However, longer treatment is al...

According to the American Cancer Society, colorectal cancer (CRC) is the third most common cause of cancer related deaths in the United States. Experts estimate that about 85% of CRCs begin as precancerous polyps, early detection and treatment of which can significantly reduce the risk of CRC. Hence, it is imperative to develop population-wide inte...

Microarray technology for measuring gene expression values has created significant opportunities for advances in disease diagnosis and individualized treatment planning. However, the random noise introduced by the sample preparation, hybridization, and scanning stages of microarray processing creates significant inaccuracies in the gene expression...

Colorectal cancer (CRC) is the second most common cause of death in the United States. Survival depends on the stage of the cancer when diagnosed, around 90% for early stage diagnosis and declining to 15% for advanced stages [1]. Therefore, it is crucial to have effective and efficient screening policies, high compliance to screening, and adequate...

Development of approaches for early detection of cancer requires a comprehensive understanding of the cellular functions that lead to cancer, as well as implementing strategies for population-wide early detection. Cell functions are supported by proteins that are produced by active or expressed genes. Identifying cancer biomarkers, i.e., the genes...