Sexual behaviour patterns in South Africa and their association with the spread of HIV: insights from a mathematical model

This paper aims to quantify the effects of different types of sexual risk behaviour on the spread of HIV in South Africa. A mathematical model is developed to simulate changes in numbers of sexual partners, changes in marital status, changes in commercial sex activity and changes in the frequency of unprotected sex over the life course. This is extended to allow for the transmission of HIV, and the model is fitted to South African HIV prevalence data and sexual behaviour data. Results suggest that concurrent partnerships and other non-spousal partnerships are major drivers of the HIV/AIDS epidemic in South Africa.AIDS/HIV, sexual behavior, simulation model, South Africa

Aging with HIV: Increased risk of HIV comorbidities in older adults

With improved access to antiretroviral treatment (ART), adults with HIV live longer to reach older age. The number of older adults living with HIV is increasing steadily, giving rise to a new population of interest in HIV research and for invigorated considerations in health service delivery and policy. We analysed the profile of comorbidities in older people (50 years and older) living with HIV in South Africa. We conducted a secondary analysis of all individuals over 15 years who tested HIV positive in the Fifth South African National HIV Prevalence, Incidence, Behaviour and Communication Survey, 2017. We conducted multivariate logistic regression to determine the factors associated with having HIV comorbidity using Stata 15.0 software. We entered 3755 people living with HIV into the analysis, of whom 18.3% (n = 688) were 50 years or older

A systematic method for comparing multimorbidity in national surveys

Due to gaps in the literature, we developed a systematic method to assess multimorbidity using national surveys. The objectives of this study were thus to identify methods used to defne and measure multimorbidity, to create a pre-defned list of disease conditions, to identify potential national surveys to include, to select disease condi‑ tions for each survey, and to analyse and compare the survey fndings. We used the count method to defne multimorbidity. We created a pre-defned list of disease conditions by examining international literature and using local data on the burden of disease. We assessed national surveys, report‑ ing on more than one disease condition in people 15 years and older, for inclusion. For each survey, the prevalence of multimorbidity was calculated, the disease patterns among the multimorbid population were assessed using a latent class analysis and logistic regression was used to identify sociodemographic and behavioural factors associated with multimorbidity

HIV/AIDS mortality trends pre and post ART for 1997 - 2012 in South Africa – have we turned the tide?

Background. South Africa (SA) has one of the largest HIV/AIDS epidemics in the world and the most extensive antiretroviral therapy (ART) programme globally, which was rolled out from 2004. This paper reports the trends in HIV/AIDS mortality pre and post ART rollout in SA. Methods. Vital registration cause-of-death data from Statistics South Africa were adjusted for under-reporting of deaths using demographic methods. Misattributed HIV/AIDS deaths were identified by regressing excess mortality on a lagged indicator HIV antenatal clinic prevalence for causes found to be associated with HIV/AIDS. Background trends in the source-cause mortality rates were estimated from the trend in cause-specific mortality experienced among 75 - 84-year-olds. Mortality rates were calculated using mid-year population estimates and the World Health Organization world standard age-weights. Results. We estimated over 3 189 000 HIV/AIDS deaths for 1997 - 2012. In 1997, 60 336 (14.5%) of deaths were attributed to HIV/AIDS; this number peaked in 2006 at 283 564 (41.9%) and decreased to 153 661 (29.1%) by 2012; female mortality rates peaked in 2005 and those of males in 2006. Men aged 35 years and older had higher mortality rates than did women. While the rates at ages below 65 years in 2012 were lower than those in 2006, rates of those age 65 years and older remained unchanged. Conclusion. The number of HIV/AIDS deaths has almost halved since the ART rollout. Of concern is the high mortality in men 45 years and older and the high mortality of men compared with women in the older ages by 2012; this gap has increased with age. Treatment and prevention programmes should strategise how to target men

Bayesian modelling of population trends in alcohol consumption provides empirically based country estimates for South Africa

Background Alcohol use has widespread effects on health and contributes to over 200 detrimental conditions. Although the pattern of heavy episodic drinking independently increases the risk for injuries and transmission of some infectious diseases, long-term average consumption is the fundamental predictor of risk for most conditions. Population surveys, which are the main source of data on alcohol exposure, suffer from bias and uncertainty. This article proposes a novel triangulation method to reduce bias by rescaling consumption estimates by sex and age to match country-level consumption from administrative data. Methods We used data from 17 population surveys to estimate age- and sex-specific trends in alcohol consumption in the adult population of South Africa between 1998 and 2016. Independently for each survey, we calculated sex- and age-specific estimates of the prevalence of drinkers and the distribution of individuals across consumption categories. We used these aggregated results, together with data on alcohol production, sales and import/export, as inputs of a Bayesian model and generated yearly estimates of the prevalence of drinkers in the population and the parameters that characterise the distribution of the average consumption among drinkers. Results Among males, the prevalence of drinkers decreased between 1998 and 2009, from 56.2% (95% CI 53.7%; 58.7%) to 50.6% (49.3%; 52.0%), and increased afterwards to 53.9% (51.5%; 56.2%) in 2016. The average consumption from 52.1 g/day (49.1; 55.6) in 1998 to 42.8 g/day (40.0; 45.7) in 2016. Among females the prevalence of current drinkers rose from 19.0% (17.2%; 20.8%) in 1998 to 20.0% (18.3%; 21.7%) in 2016 while average consumption decreased from 32.7 g/day (30.2; 35.0) to 26.4 g/day (23.8; 28.9). Conclusions The methodology provides a viable alternative to current approaches to reconcile survey estimates of individual alcohol consumption patterns with aggregate administrative data. It provides sex- and age-specific estimates of prevalence of drinkers and distribution of average daily consumption among drinkers in populations. Reliance on locally sourced data instead of global and regional trend estimates better reflects local nuances and is adaptable to the inclusion of additional data. This provides a powerful tool to monitor consumption, develop burden of disease estimates and inform and evaluate public health interventions

Proteolysis of recombinant proteins in bioengineered plant cells

Plants are increasingly used as alternative expression hosts for the production of recombinant proteins offering many advantages including higher biomass and the ability to perform posttranslational modifications on complex proteins. Key challenges for optimized accumulation of recombinant proteins in a plant system still remain, including endogenous plant proteolytic activity, which may severely compromise recombinant protein stability. Several strategies have recently been applied to improve protein stability by limiting protease action such as recombinant protein production in various sub-cellular compartments or application of protease inhibitors to limit protease action. A short update on the current strategies applied is provided here, with particular focus on sub-cellular sites previously selected for recombinant protein production and the co-expression of protease inhibitors to limit protease activity.http://www.tandfonline.com/loi/kbie20hb201