Tetyana I. Vasylyeva

Theory, measurement and hard times: some issues for HIV/AIDS research.

Economic and political instability and related “big events” are widespread throughout the globe. Although they sometimes lead to epidemic HIV outbreaks, sometimes they do not—and we do not understand why. Current behavioural theories do not adequately address these processes, and thus cannot provide optimal guidance for effective intervention. Based in part on a critique of our prior “pathways” model of big events, we suggest that cultural–historical activity theory (CHAT) may provide a useful framework for HIV research in this area. Using CHAT concepts, we also suggest a number of areas in which new measures should be developed to make such research possible.ResumenLa inestabilidad económica y política y los “grandes eventos” asociados con ella están muy extendidas en todo el mundo. Los “grandes eventos” a veces conducen a brotes epidémicos de VIH, y a veces no, y no entendemos por qué. Las actuales teorías del comportamiento no abordan adecuadamente estos procesos, y por lo tanto no pueden proveer una óptima orientación para una efectiva intervención. Basándonos en parte en una crítica a nuestro modelo de las “vías” que se interconectan durante los grandes eventos, sugerimos que la Teoría de la Actividad Histórico-Cultural (CHAT en ingles) puede proporcionar un marco útil para la investigación del VIH en esta área. Utilizamos conceptos de CHAT y también sugerimos una serie de áreas en las que las nuevas medidas se deben desarrollar para hacer posible este tipo de investigación.

Socially-Integrated Transdisciplinary HIV Prevention

Current ideas about HIV prevention include a mixture of primarily biomedical interventions, socio-mechanical interventions such as sterile syringe and condom distribution, and behavioral interventions. This article presents a framework for socially-integrated transdisciplinary HIV prevention that may improve current prevention efforts. It first describes one socially-integrated transdisciplinary intervention project, the Transmission Reduction Intervention Project. We focus on how social aspects of the intervention integrate its component parts across disciplines and processes at different levels of analysis. We then present socially-integrated perspectives about how to improve combination antiretroviral treatment (cART) processes at the population level in order to solve the problems of the treatment cascade and make “treatment as prevention” more effective. Finally, we discuss some remaining problems and issues in such a social transdisciplinary intervention in the hope that other researchers and public health agents will develop additional socially-integrated interventions for HIV and other diseases.ResumenLas ideas actuales sobre prevención del VIH incluyen una mezcla de intervenciones biomédicas primariamente -, intervenciones socio-mecánicas tales como la distribución de jeringas estériles y preservativos e intervenciones conductuales. Este artículo presenta un marco transdisciplinario y socialmente integrado para la prevención del VIH que puede mejorar los esfuerzos de prevención actuales. En primer lugar, se describe un proyecto de intervención transdisciplinario socialmente integrado: Proyecto de Intervención para Reducción de Transmisión. Nos centramos en cómo los aspectos sociales de la intervención integran sus componentes en todas las disciplinas y los procesos en diferentes niveles de análisis. A continuación, presentamos las perspectivas socialmente integradas sobre cómo mejorar los procesos de tratamiento antirretroviral combinado (TARC) a nivel de la población con el fin de resolver los problemas de cascada de tratamiento y hacer “tratamiento como prevención” más eficaz. Finalmente, se discuten algunos problemas pendientes en la descrita intervención transdisciplinaria en la esperanza de que otros investigadores y agentes de salud pública desarrollen otras intervenciones socialmente integradas para el VIH y otras enfermedades.

A network intervention that locates and intervenes with recently HIV-infected persons: The Transmission Reduction Intervention Project (TRIP)

Early treatment, soon after infection, reduces HIV transmissions and benefits patients. The Transmission Reduction Intervention Project (TRIP) evaluated a network intervention to detect individuals recently infected (in the past 6 months). TRIP was conducted in Greece (2013–2015) and focused on drug injector networks. Based on HIV status, testing history, and the results of an assay to detect recent infections, TRIP classified drug injector “Seeds” into groups: Recent Seeds (RS), and Control Seeds with Long-term HIV infection (LCS). The network members of RS and LCS were traced for two steps. The analysis included 23 RS, 171 network members of the RS, 19 LCS, and 65 network members of the LCS. The per-seed number of recents detected in the network of RS was 5 times the number in the network of LCS (Ratio RS vs. LCS: 5.23; 95% Confidence Interval (CI): 1.54–27.61). The proportion of recents among HIV positives in the network of RS (27%) was approximately 3 times (Ratio RS vs. LCS: 3.30; 95% CI: 1.04–10.43) that in the network of LCS (8%). Strategic network tracing that starts with recently infected persons could support public health efforts to find and treat people early in their HIV infection.

The global spread of HIV-1 subtype B epidemic

Human immunodeficiency virus type 1 (HIV-1) was discovered in the early 1980s when the virus had already established a pandemic. For at least three decades the epidemic in the Western World has been dominated by subtype B infections, as part of a sub-epidemic that traveled from Africa through Haiti to United States. However, the pattern of the subsequent spread still remains poorly understood. Here we analyze a large dataset of globally representative HIV-1 subtype B strains to map their spread around the world over the last 50 years and describe significant spread patterns. We show that subtype B travelled from North America to Western Europe in different occasions, while Central/Eastern Europe remained isolated for the most part of the early epidemic. Looking with more detail in European countries we see that the United Kingdom, France and Switzerland exchanged viral isolates with non-European countries than with European ones. The observed pattern is likely to mirror geopolitical landmarks in the post-World War II era, namely the rise and the fall of the Iron Curtain and the European colonialism. In conclusion, HIV-1 spread through specific migration routes which are consistent with geopolitical factors that affected human activities during the last 50 years, such as migration, tourism and trade. Our findings support the argument that epidemic control policies should be global and incorporate political and socioeconomic factors.

Integrating molecular epidemiology and social network analysis to study infectious diseases: Towards a socio-molecular era for public health

The number of public health applications for molecular epidemiology and social network analysis has increased rapidly since the improvement in computational capacities and the development of new sequencing techniques. Currently, molecular epidemiology methods are used in a variety of settings: from infectious disease surveillance systems to the description of disease transmission pathways. The latter are of great epidemiological importance as they let us describe how a virus spreads in a community, make predictions for the further epidemic developments, and plan preventive interventions. Social network methods are used to understand how infections spread through communities and what the risk factors for this are, as well as in improved contact tracing and message-dissemination interventions. Research is needed on how to combine molecular and social network data as both include essential, but not fully sufficient information on infection transmission pathways. The main differences between the two data sources are that, firstly, social network data include uninfected individuals unlike the molecular data sampled only from infected network members. Thus, social network data include more detailed picture of a network and can improve inferences made from molecular data. Secondly, network data refer to the current state and interactions within the social network, while molecular data refer to the time points when transmissions happened, which might have happened years before the sampling date. As of today, there have been attempts to combine and compare the data obtained from the two sources. Even though there is no consensus on whether and how social and genetic data complement each other, this research might significantly improve our understanding of how viruses spread through communities.

Risk network approaches to locating undiagnosed HIV cases in Odessa, Ukraine

Providing HIV healthcare and Treatment as Prevention both depend on diagnosing HIV cases, preferably soon after initial infection. We hypothesized that tracing risk networks recruits higher proportions of undiagnosed positives than outreach‐based testing or respondent‐driven sampling (RDS) in Odessa, Ukraine.

Prevention of early HIV transmissions might be more important in emerging or generalizing epidemics

Early HIV infection accounts for up to 50% of transmission events in diverse epidemics, including those among men who have sex with men, heterosexuals, and injection drug users (IDUs). Early antiretroviral treatment initiation stops disease progression and prevents onward transmissions.

Genomic and epidemiological monitoring of yellow fever virus transmission potential

Arbovirus risk in Brazil Despite the existence of an effective vaccine for yellow fever, there are still almost 80,000 fatalities from this infection each year. Since 2016, there has been a resurgence of cases in Africa and South America—and this at a time when the vaccine is in short supply. The worry is that yellow fever will spread from the forests to the cities, because its vector, Aedes spp. mosquitoes, are globally ubiquitous. Faria et al. integrate genomic, epidemiological, and case distribution data from Brazil to estimate patterns of geographic spread, the risks of virus exposure, and the contributions of rural versus urban transmission (see the Perspective by Barrett). Currently, the yellow fever epidemic in Brazil seems to be driven by infections acquired while visiting forested areas and indicates spillover from susceptible wild primates. Science, this issue p. 894; see also p. 847 MinION genomic and case data on a recent yellow fever epidemic indicate that most infections occurred during visits to forest regions. The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian Aedes species mosquitos highlights a need to monitor the risk of reestablishment of urban YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.

Reducing HIV infection in people who inject drugs is impossible without targeting recently-infected subjects.

Objective:Although our understanding of viral transmission among people who inject drugs (PWID) has improved, we still know little about when and how many times each injector transmits HIV throughout the duration of infection. We describe HIV dynamics in PWID to evaluate which preventive strategies can be efficient. Design:Due to the notably scarce interventions, HIV-1 spread explosively in Russia and Ukraine in 1990s. By studying this epidemic between 1995 and 2005, we characterized naturally occurring transmission dynamics of HIV among PWID. Method:We combined publicly available HIV pol and env sequences with prevalence estimates from Russia and Ukraine under an evolutionary epidemiology framework to characterize HIV transmissibility between PWID. We then constructed compartmental models to simulate HIV spread among PWID. Results:In the absence of interventions, each injector transmits on average to 10 others. Half of the transmissions take place within 1 month after primary infection, suggesting that the epidemic will expand even after blocking all the post–first month transmissions. Primary prevention can realistically target the first month of infection, and we show that it is very efficient to control the spread of HIV-1 in PWID. Treating acutely infected on top of primary prevention is notably effective. Conclusion:As a large proportion of transmissions among PWID occur within 1 month after infection, reducing and delaying transmissions through scale-up of harm reduction programmes should always form the backbone of HIV control strategies in PWID. Growing PWID populations in the developing world, where primary prevention is scarce, constitutes a public health time bomb.

HIV-1 epidemic in Russia: an evolutionary epidemiology analysis

Abstract Background The emergence of HIV-1 in Russia came soon after the collapse of the Soviet Union. With more than half a million cases within 5 years, the post-soviet Russian epidemic is one of the fastest and largest HIV outbreaks ever recorded. Although driven by intravenous drug users (IDUs), why the epidemic spread so rapidly and on a large scale is unclear. One popular practice between 1990 and 2000 was to use blood as a buffer or as a purifier of homemade narcotics; this practice could account for the massive spread of HIV among Russian IDUs. We aimed to assess whether the epidemic was driven by contamination of narcotics at their source rather than by needle sharing. Methods We have previously shown that by comparing number of prevalent cases and skyline plot we can recover epidemiologically coherent combinations of transmitters and generation time. Briefly, the ratio of the number of prevalent cases divided by the skyline plot estimate (product of the effective number of infections with the generation time) is equal to the ratio of the variance of secondary infections divided by the generation time. We assume that the infected population is divided into non-transmitters and transmitters with Poisson-distributed secondary infections. We investigated the Russian epidemic using molecular sequences and number of prevalent cases that we had systematically collected from previous surveys, and analysed the variation of transmissibility. Findings We found that the scenario of point transmission is highly unlikely: if a low proportion of transmitters ( 160 per infected person) but only throughout a large time period (>6 months), rendering the epidemic a longitudinal rather than an episodic event. The most epidemiologically coherent scenario is that the generation time was contracted down to about 1 month with 30–60% transmitters and 8–27 secondary infections on average per transmitter. This finding means that most of the IDUs had transmitted HIV many times through their lifetime, at least half of which was during their primary infection. Interpretation In Russia, because of the high viral load of acute infection, the high number of contacts per IDU led to a boosting of expansion to a moderate-to-high number of transmissions (four to 14) during the first month of infection. In the absence of any prevention, there was nothing to decelerate the dispersal of blood-borne pathogens. As soon as HIV was introduced, the outbreak expanded uncontrollably. We show that such an event does not require a massive amount of centrally distributed, contaminated product, but a large number of strongly connected transmitters. Funding UK Medical Research Council, European Commission, National Institute on Drug Abuse grant DP1 DA034989 (Preventing HIV Transmission by Recently-Infected Drug Users).