Number Of Undiagnosed Infections Research Articles

Trends in undiagnosed HIV prevalence in England and implications for eliminating HIV transmission by 2030: an evidence synthesis model

SummaryBackgroundA target to eliminate HIV transmission in England by 2030 was set in early 2019. This study aimed to estimate trends from 2013 to 2019 in HIV prevalence, particularly the number of people living with undiagnosed HIV, by exposure group, ethnicity, gender, age group, and region. These estimates are essential to monitor progress towards elimination.MethodsA Bayesian synthesis of evidence from multiple surveillance, demographic, and survey datasets relevant to HIV in England was used to estimate trends in the number of people living with HIV, the proportion of people unaware of their HIV infection, and the corresponding prevalence of undiagnosed HIV. All estimates were stratified by exposure group, ethnicity, gender, age group (15–34, 35–44, 45–59, or 60–74 years), region (London, or outside of London) and year (2013–19).FindingsThe total number of people living with HIV aged 15–74 years in England increased from 83 500 (95% credible interval 80 200–89 600) in 2013 to 92 800 (91 000–95 600) in 2019. The proportion diagnosed steadily increased from 86% (80–90%) to 94% (91–95%) during the same time period, corresponding to a halving in the number of undiagnosed infections from 11 600 (8300–17 700) to 5900 (4400–8700) and in undiagnosed prevalence from 0·29 (0·21–0·44) to 0·14 (0·11–0·21) per 1000 population. Similar steep declines were estimated in all subgroups of gay, bisexual, and other men who have sex with men and in most subgroups of Black African heterosexuals. The pace of reduction was less pronounced for heterosexuals in other ethnic groups and people who inject drugs, particularly outside London; however, undiagnosed prevalence in these groups has remained very low.InterpretationThe UNAIDS target of diagnosing 90% of people living with HIV by 2020 was reached by 2016 in England, with the country on track to achieve the new target of 95% diagnosed by 2025. Reductions in transmission and undiagnosed prevalence have corresponded to large scale-up of testing in key populations and early diagnosis and treatment. Additional and intensified prevention measures are required to eliminate transmission of HIV among the communities that have experienced slower declines than other subgroups, despite having very low prevalences of HIV.FundingUK Medical Research Council and Public Health England.

Tracking elimination of HIV transmission in men who have sex with men in England: a modelling study

SummaryBackgroundTo manage the HIV epidemic among men who have sex with men (MSM) in England, treatment as prevention strategies based on test and treat were strengthened between 2011 and 2015, and supplemented from 2015 by scale-up of pre-exposure prophylaxis (PrEP). We examined the effect of these interventions on HIV incidence and investigated whether internationally agreed targets for HIV control and elimination of HIV transmission by 2030 might be within reach among MSM in England.MethodsWe used a novel, age-stratified, CD4-staged Bayesian back-calculation model to estimate HIV incidence and undiagnosed infections among adult MSM (age ≥15 years) during the 10-year period between 2009 and 2018. The model used data on HIV and AIDS diagnoses routinely collected via the national HIV and AIDS Reporting System in England, and knowledge on the progression of HIV through CD4-defined disease stages. Estimated incidence trends were extrapolated, assuming a constant MSM population from 2018 onwards, to quantify the likelihood of achieving elimination of HIV transmission, defined as less than one newly aquired infection per 10 000 MSM per year, by 2030.FindingsThe peak in HIV incidence in MSM in England was estimated with 80% certainty to have occurred in 2012 or 2013, at least 1 year before the observed peak in new diagnoses in 2014. Results indicated a steep decrease in the annual number of new infections among MSM, from 2770 (95% credible interval 2490–3040) in 2013 to 1740 (1500–2010) in 2015, followed by a steadier decrease from 2016, down to 854 (441–1540) infections in 2018. A decline in new infections was consistently estimated in all age groups, and was particularly marked in MSM aged 25–34 years, and slowest in those aged 45 years or older. Similar trends were estimated in the number of undiagnosed infections, with the greatest decrease after 2013 in the 25–34 years age group. Under extrapolation assumptions, we calculated a 40% probability of achieving the defined target elimination threshold by 2030.InterpretationThe sharp decrease in HIV incidence, estimated to have begun before the scale up of PrEP, indicates the success of strengthening treatment as prevention measures among MSM in England. To achieve the 2030 elimination threshold, targeted policies might be required to reach those aged 45 years or older, in whom incidence is decreasing at the slowest rate.FundingUK Medical Research Council, UK National Institute of Health Research Health Protection Unit in Behavioural Science and Evaluation, and Public Health England.

Using CD4 Data to Estimate HIV Incidence, Prevalence, and Percent of Undiagnosed Infections in the United States.

The incidence and prevalence of HIV infection are important measures of HIV trends; however, they are difficult to estimate because of the long incubation period between infection and symptom development and the relative infrequency of HIV screening. A new method is introduced to estimate HIV incidence, prevalence, and the number of undiagnosed infections in the United States using data from the HIV case surveillance system and CD4 test results. Persons with HIV diagnosed during 2006-2013 and their CD4 test results were used to estimate the distribution of diagnosis delay from HIV infection to diagnosis based on a well-characterized CD4 depletion model. This distribution was then used to estimate HIV incidence, prevalence, and the number of undiagnosed infections. Applying this method, we estimated that the annual number of new HIV infections decreased after 2007, from 48,300 (95% confidence interval [CI]: 47,300 to 49,400) to 39,000 (95% CI: 36,600 to 41,400) in 2013. Prevalence increased from 923,200 (95% CI: 914,500 to 931,800) in 2006 to 1,104,600 (95% CI: 1,084,300 to 1,124,900) in 2013, whereas the proportion of undiagnosed infections decreased from 21.0% in 2006 (95% CI: 20.2% to 21.7%) to 16.4% (95% CI: 15.7% to 17.2%) in 2013. HIV incidence, prevalence, and undiagnosed infections can be estimated using HIV case surveillance data and information on first CD4 test result after diagnosis. Similar to earlier findings, the decreases in incidence and undiagnosed infections are encouraging but intensified efforts for HIV testing and treatment are needed to meet the goals of the National HIV/AIDS Strategy.

Increasing Knowledge of HIV Infection Status through Opt-Out Testing

The diagnosis of HIV infection is the point of entry for treatment and prevention services, yet many infected persons in both developed and developing countries remain undiagnosed. To reduce the number of undiagnosed infections, a variety of expanded testing policies have been recommended, including opt-out testing. This testing model assumes that in populations of increased HIV prevalence, voluntary testing should be offered to all patients seen in healthcare settings and performed unless patients specifically decline. While this approach raises ethical issues concerning “voluntariness”, access to care, and stigma, the potential benefits of opt-out testing far outweigh its potential adverse effects.

Cost-Effectiveness of Finding New HIV Diagnoses Using Rapid HIV Testing in Community-Based Organizations

We assessed the cost-effectiveness of determining new human immunodeficiency virus (HIV) diagnoses using rapid HIV testing performed by community-based organizations (CBOs) in Kansas City, Missouri, and Detroit, Michigan. The CBOs performed rapid HIV testing during April 2004 through March 2006. In Kansas City, testing was performed in a clinic and in outreach settings. In Detroit, testing was performed in outreach settings only. Both CBOs used mobile testing vans. Measures of effectiveness were the number of HIV tests performed and the number of people notified of new HIV diagnoses, based on rapid tests. We retrospectively collected program costs, including those for personnel, test kits, mobile vans, and facility space. The CBO in Kansas City tested a mean of 855 people a year in its clinic and 703 people a year in outreach settings. The number of people notified of new HIV diagnoses was 19 (2.2%) in the clinic and five (0.7%) in outreach settings. The CBO in Detroit tested 976 people a year in outreach settings, and the number notified of new HIV diagnoses was 15 (1.5%). In Kansas City, the cost per person notified of a new HIV diagnosis was $3,637 in the clinic and $16,985 in outreach settings. In the Detroit outreach settings, the cost per notification was $13,448. The cost of providing a new HIV diagnosis was considerably higher in the outreach settings than in the clinic. The variation can be largely explained by differences in the number of undiagnosed infections among the people tested and by the costs of purchasing and operating a mobile van.