Estimates Of Human Immunodeficiency Virus Incidence Research Articles

Recent HIV Infection: Diagnosis and Public Health Implications.

The early period of infection with human immunodeficiency virus (HIV) has been associated with higher infectiousness and, consequently, with more transmission events. Over the last 30 years, assays have been developed that can detect viral and immune biomarkers during the first months of HIV infection. Some of them depend on the functional properties of antibodies including their changing titers or the increasing strength of binding with antigens over time. There have been efforts to estimate HIV incidence using antibody-based assays that detect recent HIV infection along with other laboratory and clinical information. Moreover, some interventions are based on the identification of people who were recently infected by HIV. This review summarizes the evolution of efforts to develop assays for the detection of recent HIV infection and to use these assays for the cross-sectional estimation of HIV incidence or for prevention purposes.

Investigation of the Proportion of Diagnosed People Living with HIV/AIDS among Foreign Residents in Japan.

Foreign residents represent an increasing proportion of newly diagnosed human immunodeficiency virus (HIV) infections and acquired immunodeficiency syndrome (AIDS) cases in Japan, though scant research has addressed this. This study aimed to estimate the diagnosed proportion of people living with HIV/AIDS (PLWHA) among foreign residents in Japan, covering 1990–2017 and stratifying by geographic region of the country of origin. A balance equation model was employed to statistically estimate the diagnosed proportion as a single parameter. This used published estimates of HIV incidence and prevalence, population size, visit duration, travel volume, as well as surveillance data on HIV/AIDS in Japan. The proportion varied widely by region: People from Western Europe, East Asia and the Pacific, Australia and New Zealand, and North America were underdiagnosed, while those from sub-Saharan Africa, South and South-East Asia, and Latin America were more frequently diagnosed. Overall, the diagnosed proportion of PLWHA among foreign residents in Japan has increased, but the latest estimate in 2017 was as low as 55.3%; lower than the estimate among Japanese on the order of 80% and far below the quoted goal of 90%. This finding indicates a critical need to investigate the underlying mechanisms, including disparate access to HIV testing.

Cluster of HIV Infections Attributed to Unsafe Injection Practices--Cambodia, December 1, 2014-February 28, 2015.

In December 2014, local health authorities in Battambang province in northwest Cambodia reported 30 cases of human immunodeficiency virus (HIV) infection in a rural commune (district subdivision) where only four cases had been reported during the preceding year. The majority of cases occurred in residents of Roka commune. The Cambodian National Center for HIV/AIDS (acquired immunodeficiency syndrome), Dermatology and Sexually Transmitted Diseases (NCHADS) investigated the outbreak in collaboration with the University of Health Sciences in Phnom Penh and members of the Roka Cluster Investigation Team. By February 28, 2015, NCHADS had confirmed 242 cases of HIV infection among the 8,893 commune residents, an infection rate of 2.7%. Molecular investigation of the HIV strains present in this outbreak indicated that the majority of cases were linked to a single HIV strain that spread quickly within this community. An NCHADS case-control study identified medical injections and infusions as the most likely modes of transmission. In response to this outbreak, the Government of Cambodia has taken measures to encourage safe injection practices by licensed medical professionals, ban unlicensed medical practitioners, increase local capacity for HIV testing and counseling, and expand access to HIV treatment in Battambang province. Measures to reduce the demand for unnecessary medical injections and the provision of unsafe injections are needed. Estimates of national HIV incidence and prevalence might need to be adjusted to account for unsafe injection as a risk exposure.

Estimation of HIV Incidence Using Multiple Biomarkers

The incidence of human immunodeficiency virus (HIV) is the rate at which new HIV infections occur in populations. The development of accurate, practical, and cost-effective approaches to estimation of HIV incidence is a priority among researchers in HIV surveillance because of limitations with existing methods. In this paper, we develop methods for estimating HIV incidence rates using multiple biomarkers in biological samples collected from a cross-sectional survey. An advantage of the method is that it does not require longitudinal follow-up of individuals. We use assays for BED, avidity, viral load, and CD4 cell count data from clade B samples collected in several US epidemiologic cohorts between 1987 and 2010. Considering issues of accuracy, cost, and implementation, we identify optimal multiassay algorithms for estimating incidence. We find that the multiple-biomarker approach to cross-sectional HIV incidence estimation corrects the significant deficiencies of currently available approaches and is a potentially powerful and practical tool for HIV surveillance.

Statewide Estimation of Racial/Ethnic Populations of Men Who Have Sex with Men in the U.S.

Men who have sex with men (MSM) bear the greatest burden of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in every state in the U.S., but their populations are poorly defined. We estimated and compared populations of MSM in 2007 by region, state, and race/ethnicity. We averaged findings from two statistical models we had previously developed to estimate the total state-specific percentage and number of males who were MSM. The models were based, respectively, on state-specific rural/ suburban/urban characteristics and an index using state-specific household census data on same-sex male unmarried partners. A third model, based on racial/ethnic ratios from a nationally representative behavioral survey, partitioned these statewide numbers by race/ethnicity. Of an estimated 7.1 million MSM residing in the U.S. in 2007, 71.4% (5.1 million) were white, 15.9% (1.1 million) were Hispanic, 8.9% (635,000) were black, 2.7% (191,000) were Asian, 0.4% (26,000) were American Indian/Alaska Native, 0.1% (6,000) were Native Hawaiian/other Pacific Islander, and 0.6% (41,000) were of multiple/unknown race/ethnicity. The overall U.S. percentage of males who were MSM (6.4%) varied from 3.3% in South Dakota to 13.2% in the District of Columbia, which we treated as a state. Estimated numbers of MSM ranged from 9,612 in Wyoming to 1,104,805 in California. Plausible estimates of MSM populations by state and race/ethnicity can inform and guide HIV/AIDS surveillance, allocation of resources, and advocacy. They can help in the planning, implementation, and evaluation of HIV prevention programs and other services. Using MSM numbers as denominators, estimates of population-based MSM HIV incidence, prevalence, and mortality rates could help clarify national and state-level epidemic dynamics. Until corroborated by other modeling and/or empirical research, these estimates should be used with caution.

HIV decline in Zimbabwe due to reductions in risky sex? Evidence from a comprehensive epidemiological review.

Background Recent data from antenatal clinic (ANC) surveillance and general population surveys suggest substantial declines in human immunodeficiency virus (HIV) prevalence in Zimbabwe. We assessed the contributions of rising mortality, falling HIV incidence and sexual behaviour change to the decline in HIV prevalence.Methods Comprehensive review and secondary analysis of national and local sources on trends in HIV prevalence, HIV incidence, mortality and sexual behaviour covering the period 1985–2007.Results HIV prevalence fell in Zimbabwe over the past decade (national estimates: from 29.3% in 1997 to 15.6% in 2007). National census and survey estimates, vital registration data from Harare and Bulawayo, and prospective local population survey data from eastern Zimbabwe showed substantial rises in mortality during the 1990s levelling off after 2000. Direct estimates of HIV incidence in male factory workers and women attending pre- and post-natal clinics, trends in HIV prevalence in 15–24-year-olds, and back-calculation estimates based on the vital registration data from Harare indicated that HIV incidence may have peaked in the early 1990s and fallen during the 1990s. Household survey data showed reductions in numbers reporting casual partners from the late 1990s and high condom use in non-regular partnerships between 1998 and 2007.Conclusions These findings provide the first convincing evidence of an HIV decline accelerated by changes in sexual behaviour in a southern African country. However, in 2007, one in every seven adults in Zimbabwe was still infected with a life-threatening virus and mortality rates remained at crisis level.

Estimation of HIV Incidence in the United States

Incidence of human immunodeficiency virus (HIV) in the United States has not been directly measured. New assays that differentiate recent vs long-standing HIV infections allow improved estimation of HIV incidence. To estimate HIV incidence in the United States. Remnant diagnostic serum specimens from patients 13 years or older and newly diagnosed with HIV during 2006 in 22 states were tested with the BED HIV-1 capture enzyme immunoassay to classify infections as recent or long-standing. Information on HIV cases was reported to the Centers for Disease Control and Prevention through June 2007. Incidence of HIV in the 22 states during 2006 was estimated using a statistical approach with adjustment for testing frequency and extrapolated to the United States. Results were corroborated with back-calculation of HIV incidence for 1977-2006 based on HIV diagnoses from 40 states and AIDS incidence from 50 states and the District of Columbia. Estimated HIV incidence. An estimated 39,400 persons were diagnosed with HIV in 2006 in the 22 states. Of 6864 diagnostic specimens tested using the BED assay, 2133 (31%) were classified as recent infections. Based on extrapolations from these data, the estimated number of new infections for the United States in 2006 was 56,300 (95% confidence interval [CI], 48,200-64,500); the estimated incidence rate was 22.8 per 100,000 population (95% CI, 19.5-26.1). Forty-five percent of infections were among black individuals and 53% among men who have sex with men. The back-calculation (n = 1.230 million HIV/AIDS cases reported by the end of 2006) yielded an estimate of 55,400 (95% CI, 50,000-60,800) new infections per year for 2003-2006 and indicated that HIV incidence increased in the mid-1990s, then slightly declined after 1999 and has been stable thereafter. This study provides the first direct estimates of HIV incidence in the United States using laboratory technologies previously implemented only in clinic-based settings. New HIV infections in the United States remain concentrated among men who have sex with men and among black individuals.

HIV prevalence for New York State using Newborn Seroprevalence and AIDS Surveillance Data

The objective of this work is to estimate human immunodeficiency virus (HIV) prevalence in the adult populations of New York City, and of New York State (NYS) excluding New York City. Evidence is presented that not all HIV-infected persons live long enough to satisfy an acquired immunodeficiency syndrome (AIDS) diagnosis. The term preAIDS mortality refers to the mortality of HIV-infected persons, due to any cause, before they can be diagnosed with AIDS. The effect of preAIDS mortality on the estimate of HIV incidence, using back calculation of AIDS Surveillance Data, is to produce low-biased estimates of HIV incidence and prevalence. Estimates of HIV prevalence in women of childbearing age were obtained from the Newborn Seroprevalence Survey [Lessner L. The estimation of HIV prevalence for women of childbearing age in New York City, presently under review]. HIV-positive women in this population typically do not have an opportunistic infection. Thus estimates of HIV prevalence in this population occurred earlier in the spectrum of HIV disease then when they finally satisfied the definition of AIDS that depends on incidence of an opportunistic disease. These earlier estimates of HIV prevalence in women were found to be substantially larger then those obtained from back calculation using female AIDS Surveillance Data. This comparison was used to obtain a quantitative measure R of the effect of preAIDS mortality on HIV prevalence: where 1/ R equals the proportion of HIV-infected intravenous drug users that become AIDS cases The preAIDS mortality adjustment factor R was used in the estimation of HIV prevalence and incidence for NYS. We believe that the use of the adjustment factor resulted in more accurate estimates. Using this factor, our estimated HIV incidence for New York City in 1991 was nearly 26% larger than without the adjustment while projected HIV prevalence for 1996 was nearly 27% larger. The paper estimates HIV prevalence. The AIDS Surveillance operation uses AIDS cases to back calculate HIV incidence and prevalence. Since many HIV-infected intravenous drug using (IDU) population die before they become an AIDS case, the estimates from the back calculation are low biased. Low biased because there were many HIV-infected people who died before they ever satisfied the AIDS protocol. The totals presented here adjust for preAIDS mortality and are necessarily larger than what was recorded by the NYS Dept. of Health. After the change in the definition of AIDS to simply HIV prevalence and the change to electronic reporting, the totals were mostly HIV cases reported in the given year and not AIDS. Thus there is no comparison. This paper represents the last best look at the natural history of AIDS in NYS.

Validating marker-based incidence estimates in repeatedly screened populations.

Disease incidence (new cases of disease per person per year) is usually measured by using longitudinal data. However, several recent proposals for measuring the incidence of human immunodeficiency virus (HIV) rely on cross-sectional data only. These methods assume each person is only sampled once; however, in some instances, it is necessary to consider these cross-sectional methods when individuals are represented more than once in the survey sample. We derive an extension of the cross-sectional incidence estimator that is valid for data from repeatedly screened populations and show under what conditions our new estimator reduces to the old estimator. An example involving estimation of HIV incidence among repeat blood donors is presented.

Measuring HIV-1 Incidence in Northern Thailand: Prospective Cohort Results and Estimates Based on Early Diagnostic Tests

Measuring the incidence of the human immunodeficiency virus (HIV) is of vital importance but can be difficult and costly. We compared HIV-1 incidence measured directly from prospective cohort studies with rates derived from a method using the prevalence of HIV-1 antibody-negative, p24-antigen-positive individuals. Male and female commercial sex workers (CSWs) were enrolled and followed in separate cohort studies in northern Thailand between 1989 and 1994, and HIV incidence was measured by prospective follow-up of individuals seronegative at baseline. In 1991-1992 cross-sectional serosurveys were done among male and female CSWs in the same region; all HIV-1 antibody-negative subjects in these surveys were tested for p24 antigenemia. HIV incidence was estimated using the prevalence of p24 antigen and a model based on the mean duration of p24 antigenemia before HIV antibody detection. The cohort studies showed high initial incidence rates-23.8/100 person-years (PY) among female CSWs and 11.9/100 PY among male CSWs-but poor compliance with prospective follow-up. Subjects lost to follow-up appeared to be at greater risk of HIV seroconversion than those retained. The p24 antigen method estimate among female CSWs, 25.4%/year, was quite similar to the initial incidence rate found in the cohort. The estimate by the p24 antigen method was higher, 19.9%/year, among male CSWs than that measured prospectively. In populations with high rates of HIV transmission and in whom long-term follow-up is incomplete, estimates of incidence using p24 antigen prevalence among antibody-negative subjects can give useful and economical estimates of HIV incidence and allow for estimates of whether the incidence rates are similar in subjects successfully followed and those lost to follow-up.

Estimation of cumulative HIV incidence in Australia, based on national case reporting

It has been recognised that the Australian National HIV Database may contain multiple reports for some individuals, mainly because of incomplete or inaccurate recording of name codes. The number of distinct individuals diagnosed with human immunodeficiency virus (HIV) was estimated from the dates of birth of cases of HIV infection reported to the database. There were 18,787 cases of HIV infection diagnosed by the end of 1994 and reported to the database by the end of April 1995. Based on the reported dates of birth, the total number of individuals was estimated to lie in the range 13,600 to 15,300. Corresponding analyses by state (or territory) estimated the total number of individuals diagnosed with HIV to lie in the ranges 8360 to 9760 in New South Wales, 1490 to 1540 in Queensland, 3010 to 3180 in Victoria and 1530 to 1600 in other states and territories combined. It was estimated that 5 per cent of individuals were diagnosed with HIV infection in more than one state. Allowing for people with HIV infection who have not yet been tested for HIV antibody and reported, the total number of people to have acquired HIV in Australia by the end of 1994 was estimated to lie in the range 15,500 to 17,700. This is consistent with back-projection estimates.

Back-projection and sensitivity analysis of the HIV-AIDS epidemic in the Caribbean.

In this study we estimated past human immunodeficiency virus (HIV) incidence in 19 nations in the primarily English-speaking Caribbean and projected the course of the epidemic to the year 1999. We compared the results obtained from several different models of HIV incidence and different assumed incubation distributions. Linear and nonlinear optimization methods were used to fit several models (power, logistic, spline, and step) to adult (age 15 years or older) AIDS incidence data derived from our existing surveillance system. All four models tested gave good fits to the data, with estimates of cumulative HIV incidence in 1993 ranging from 16,504 to 21,732. An increase in the assumed median of the AIDS incubation distribution by one year increased the estimates of current cumulative adult HIV incidence by approximately 12%; these estimates varied by as much as 6% between models. An adjustment of the data for possible reporting delay increased the estimates by approximately 7% and for underreporting by 25%. Despite their sensitivity to underlying assumptions, back-projection estimates provide useful insights into the patterns of HIV and AIDS incidence. The models indicate that HIV and AIDS incidences in the English-speaking Caribbean have been rising steadily, with adult HIV prevalence in the general population still less than 1%.

Assessing the extent of the Australian HIV epidemic from AIDS surveillance data

Current knowledge about human immunodeficiency virus (HIV) disease is used to assess past and future trends in Australian HIV/AIDS (acquired immune deficiency syndrome) incidence, focusing on the precision with which such assessments can be made. The statistical method of back-projection is applied to reconstruct the past pattern of HIV incidence from surveillance data on AIDS incidence to June 1992. The results indicate that HIV incidence rose rapidly in the early 1980s to peak in 1983-1984, followed by a sharp decline. This finding is insensitive to plausible variations from the assumptions made, and is consistent with both success in preventive strategies and high levels of infection in a subgroup having a high probability of exposure. Cumulative HIV incidence to the end of 1987 is estimated with a 90 per cent confidence interval from 9,350 to 10,350. Estimation of the cumulative HIV incidence to June 1992 is less precise, with a 90 per cent confidence interval of 12,900 to 17,800. After adjustment for underreporting the incidence could be as high as 22,000, but only if recent infection rates, which cannot be quantified accurately, were very high. Based on data to June 1992, the estimated trend in AIDS incidence indicates 680 new cases in 1993, rising gradually to 695 in 1995. The estimated rate of increase in AIDS incidence over the recent past and near future is significantly less than that observed earlier in the epidemic. This is a consequence of both the earlier peak in HIV incidence and the effect of therapy.

HIV Prevalence Among Washington, DC, Residents Having Abortions

<h3>To the Editor.</h3> —In their recent article, Rosenberg et al¹used backcalculation methods to reconstruct human immunodeficiency virus (HIV) incidence from acquired immunodeficiency syndrome (AIDS) incidence in subgroups of the population, and then compared the results with directly measured seroprevalence in selected sentinel populations. In this context, it should be noted that both techniques, ie, backcalculation and direct serosurveys, have different shortcomings. These must be addressed before comparing results of the techniques for the purpose of cross-validation. Forecasts based exclusively on AIDS incidence data cannot produce good estimates of recent HIV incidence because of the virus' long and variable incubation period. On the other hand, direct serosurveys based on unlinked testing allow the assessing of trends in recent HIV prevalence but are restricted to readily accessible sentinel populations, which may be subject to selection bias (eg, patients of sexually transmitted disease clinics, pregnant women, or hospitalized patients). Rosenberg et