HIV incidence estimate combining HIV/AIDS surveillance, testing history information and HIV test to identify recent infections in Lazio, Italy

Use of HIV Recency Assays for HIV Incidence Estimation and Other Surveillance Use Cases: Systematic Review

BACKGROUND

HIV assays designed to detect recent infection, also known as "recency assays," are often used to estimate HIV incidence in a specific country, region, or subpopulation, alone or as part of recent infection testing algorithms (RITAs). Recently, many countries and organizations have become interested in using recency assays within case surveillance systems and routine HIV testing services to measure other indicators beyond incidence, generally referred to as "non-incidence surveillance use cases."

OBJECTIVE

This review aims to identify published evidence that can be used to validate methodological approaches to recency-based incidence estimation and non-incidence use cases. The evidence identified through this review will be used in the forthcoming technical guidance by the World Health Organization (WHO) and United Nations Programme on HIV/AIDS (UNAIDS) on the use of HIV recency assays for identification of epidemic trends, whether for HIV incidence estimation or non-incidence indicators of recency.

METHODS

To identify the best methodological and field implementation practices for the use of recency assays to estimate HIV incidence and trends in recent infections for specific populations or geographic areas, we conducted a systematic review of the literature to (1) understand the use of recency testing for surveillance in programmatic and laboratory settings, (2) review methodologies for implementing recency testing for both incidence estimation and non-incidence use cases, and (3) assess the field performance characteristics of commercially available recency assays.

RESULTS

Among the 167 documents included in the final review, 91 (54.5%) focused on assay or algorithm performance or methodological descriptions, with high-quality evidence of accurate age- and sex-disaggregated HIV incidence estimation at national or regional levels in general population settings, but not at finer geographic levels for prevention prioritization. The remaining 76 (45.5%) described the field use of incidence assays including field-derived incidence (n=45), non-incidence (n=25), and both incidence and non-incidence use cases (n=6). The field use of incidence assays included integrating RITAs into routine surveillance and assisting with molecular genetic analyses, but evidence was generally weaker or only reported on what was done, without validation data or findings related to effectiveness of using non-incidence indicators calculated through the use of recency assays as a proxy for HIV incidence.

CONCLUSIONS

HIV recency assays have been widely validated for estimating HIV incidence in age- and sex-specific populations at national and subnational regional levels; however, there is a lack of evidence validating the accuracy and effectiveness of using recency assays to identify epidemic trends in non-incidence surveillance use cases. More research is needed to validate the use of recency assays within HIV testing services, to ensure findings can be accurately interpreted to guide prioritization of public health programming.

HIV incidence among sexual health clinic attendees in England: First estimates for black African heterosexuals using a biomarker, 2009-2013

Introduction

The HIV epidemic in England is largely concentrated among heterosexuals who are predominately black African and men who have sex with men (MSM). We present for the first time trends in annual HIV incidence for adults attending sexual health clinics, where 80% of all HIV diagnoses are made.

Methods

We identified newly diagnosed incident HIV using a recent infection testing algorithm (RITA) consisting of a biomarker (AxSYM assay, modified to determine antibody avidity), epidemiological and clinical information. We estimated HIV incidence using the WHO RITA formula for cross-sectional studies, with HIV testing data from sexual health clinics as the denominator.

Results

From 2009 to 2013, each year, between 9,700 and 26,000 black African heterosexuals (of between 161,000 and 231,000 heterosexuals overall) were included in analyses. For the same period, annually between 19,000 and 55,000 MSM were included. Estimates of HIV incidence among black Africans increased slightly (although non-significantly) from 0.15% (95% C.I.0.05%-0.26%) in 2009 to 0.19% (95% C.I.0.04%-0.34%) in 2013 and was 4-5-fold higher than among all heterosexuals among which it remained stable between 0.03% (95% C.I.0.02%-0.05%) and 0.05% (95% C.I.0.03%-0.07%) over the period. Among MSM incidence was highest and increased (non-significantly) from 1.24% (95%C.I 0.96–1.52%) to 1.46% (95% C.I 1.23%-1.70%) after a peak of 1.52% (95%C.I 1.30%-1.75%) in 2012.

Conclusion

These are the first nationwide estimates for trends in HIV incidence among black African and heterosexual populations in England which show black Africans, alongside MSM, remain disproportionately at risk of infection. Although people attending sexual health clinics may not be representative of the general population, nearly half of black Africans and MSM had attended in the previous 5 years. Timely and accurate incidence estimates will be critical in monitoring the impact of the reconfiguration of sexual health services in England, and any prevention programmes such as pre-exposure prophylaxis.

Epidemiological HIV infection surveillance among subjects with risk behaviours in the city of Messina (Sicily) from 1992 to 2015

INTRODUCTION

Epidemiological studies are a key element in determining the evolution and spread of HIV infection among the world population. Knowledge of the epidemiological dynamics improves strategies for prevention and monitoring.

METHODS

We examined 2,272 subjects who voluntarily underwent HIV testing from January 1992 to December 2015. For each subject, an anonymous form was completed to obtain information on personal data, sexual habits and exposure to risk factors.

RESULTS

The number of subjects undergoing the screening test has increased over the years and the average age of the tested subjects has decreased over time. The main motivation for undergoing HIV testing is unprotected sex. Although heterosexual subjects taking the test were more numerous than homosexuals in this study, an increase in the latter over time should be highlighted.

CONCLUSIONS

Although the number of tests performed has increased over the years, the persistence of unprotected sex shows an inadequate perception of risk. Therefore, it is necessary to implement programmes to increase the general awareness of HIV infection. It is also essential to undertake constant monitoring of behaviour, risk perception and the application of the screening test via surveillance systems in order to implement effective and efficient prevention.

HIV incidence in the Estonian population in 2013 determined using the HIV-1 limiting antigen avidity assay

OBJECTIVES

Estonia has one the highest number of new HIV diagnoses in the European Union, mainly among injecting drug users and heterosexuals. Little is known of HIV incidence, which is crucial for limiting the epidemic. Using a recent HIV infection testing algorithm (RITA) assay, we aimed to estimate HIV incidence in 2013.

METHODS

All individuals aged ≥18 years newly-diagnosed with HIV in Estonia January- December 2013, except blood donors and those undergoing antenatal screening, were included. Demographic and clinical data were obtained from the Estonian Health Board and the Estonian HIV-positive patient database. Serum samples were tested for recent infection using the LAg-avidity EIA assay. HIV incidence was estimated based on previously published methods.

RESULTS

Of 69,115 tested subjects, 286 (0.41%) were newly-diagnosed with HIV with median age of 33 years (IQR: 28-42) and 65% male. Self-reported routes of HIV transmission were mostly heterosexual contact (n = 157, 53%) and injecting drug use (n = 62, 21%); 64 (22%) were with unknown risk group. Eighty two (36%) were assigned recent, resulting in estimated HIV incidence of 0.06%, corresponding to 642 new infections in 2013 among the non-screened population. Incidence was highest (1.48%) among people who inject drugs.

CONCLUSIONS

These high HIV incidence estimates in Estonia call for urgent action of renewed targeted public health promotion and HIV testing campaigns.

Tackling the Hepatitis C Disease Burden in Punjab, India

Hepatitis C virus (HCV) is a globally prevalent pathogen and is a major cause of healthcare burden in India. HCV poses a significant problem in the state of Punjab, India owing to the higher prevalence of risk factors like unsafe medical practices (including unsafe injections and dental procedures) and intravenous drug use. The reported prevalence of HCV in this part of the country was 5.2% in 2012, while a recent study has shown the prevalence to be 3.2% in 2016. Similar to the other geographic belts in India, genotype 3 predominates in the state of Punjab. Control of HCV infection in Punjab requires focusing on several strategies. There is a need to formulate a health educational curriculum targeting not only the high-risk population but also the general population regarding the transmission of HCV. Training of family physicians who form the first link to patients in the community is imperative in the success of healthcare programmes. Adopting the dual approach of treating the old cases (decreasing the reservoir pool of HCV) and decreasing the incidence of new ones would help curtail the disease and decrease liver related mortality. A commendable initiative has been launched by the Punjab state government to eliminate HCV from Punjab. However, besides the initiative by the government, a concerted effort by all other stakeholders in managing the HCV burden in India, namely the doctors, the drug companies and the non-government organizations is required for control of HCV.

HIV Incidence Estimates Using the Limiting Antigen Avidity EIA Assay at Testing Sites in Kiev City, Ukraine: 2013-2014

Objective

To estimate HIV incidence and highlight the characteristics of persons at greatest risk of HIV in the Ukraine capital, Kiev.

Method

Residual samples from newly-diagnosed persons attending the Kiev City AIDS Centre were tested for evidence of recent HIV infection using an avidity assay. Questions on possible risk factors for HIV acquisition and testing history were introduced. All persons (≥16yrs) presenting for an HIV test April’13–March’14 were included. Rates per 100,000 population were calculated using region-specific denominators.

Results

During the study period 6370 individuals tested for HIV. Of the 467 individuals newly-diagnosed with HIV, 21 had insufficient samples for LAg testing. Of the remaining 446, 39 (8.7%) were classified as recent with an avidity index <1.5ODn, 10 were reclassified as long-standing as their viral load was <1000 copies/mL, resulting in 29 (6.5%) recent HIV infections. The only independent predictor for a recent infection was probable route of exposure, with MSM more likely to present with a recent infection compared with heterosexual contact [Odds Ratio 8.86; 95%CI 2.65–29.60]. We estimated HIV incidence at 21.5 per 100,000 population, corresponding to 466 new infections. Using population estimates for MSM and PWID, incidence was estimated to be between 2289.6 and 6868.7/100,000 MSM, and 350.4 for PWID.

Conclusion

A high proportion of persons newly-infected remain undiagnosed, with MSM disproportionally affected with one in four newly-HIV-diagnosed and one in three recently-HIV-infected. Our findings should be used for targeted public health interventions and health promotion.

Methods for using clinical laboratory test results as baseline confounders in multi-site observational database studies when missing data are expected

PURPOSE

Our purpose was to quantify missing baseline laboratory results, assess predictors of missingness, and examine performance of missing data methods.

METHODS

Using the Mini-Sentinel Distributed Database from three sites, we selected three exposure-outcome scenarios with laboratory results as baseline confounders. We compared hazard ratios (HRs) or risk differences (RDs) and 95% confidence intervals (CIs) from models that omitted laboratory results, included only available results (complete cases), and included results after applying missing data methods (multiple imputation [MI] regression, MI predictive mean matching [PMM] indicator).

RESULTS

Scenario 1 considered glucose among second-generation antipsychotic users and diabetes. Across sites, glucose was available for 27.7-58.9%. Results differed between complete case and missing data models (e.g., olanzapine: HR 0.92 [CI 0.73, 1.12] vs 1.02 [0.90, 1.16]). Across-site models employing different MI approaches provided similar HR and CI; site-specific models provided differing estimates. Scenario 2 evaluated creatinine among individuals starting high versus low dose lisinopril and hyperkalemia. Creatinine availability: 44.5-79.0%. Results differed between complete case and missing data models (e.g., HR 0.84 [CI 0.77, 0.92] vs. 0.88 [0.83, 0.94]). HR and CI were identical across MI methods. Scenario 3 examined international normalized ratio (INR) among warfarin users starting interacting versus noninteracting antimicrobials and bleeding. INR availability: 20.0-92.9%. Results differed between ignoring INR versus including INR using missing data methods (e.g., RD 0.05 [CI -0.03, 0.13] vs 0.09 [0.00, 0.18]). Indicator and PMM methods gave similar estimates.

CONCLUSION

Multi-site studies must consider site variability in missing data. Different missing data methods performed similarly. Copyright © 2016 John Wiley & Sons, Ltd.

How many people are living with undiagnosed HIV infection? An estimate for Italy, based on surveillance data

Objective:

To estimate the size and characteristics of the undiagnosed HIV population in Italy in 2012 applying a method that does not require surveillance data from the beginning of the HIV epidemic.

Methods:

We adapted the method known as ‘London method 2’; the undiagnosed population is estimated as the ratio between the estimated annual number of simultaneous HIV/clinical AIDS diagnoses and the expected annual progression rate to clinical AIDS in the undiagnosed HIV population; the latter is estimated using the CD4⁺ cell count distribution of asymptomatic patients reported to surveillance. Under-reporting/ascertainment of new diagnoses was also considered. Also, the total number of people living with HIV was estimated.

Results:

The undiagnosed HIV population in 2012 was 13 729 (95% confidence interval: 12 152–15 592), 15 102 (13 366–17 151) and 16 475 (14 581–18 710), assuming no under-reporting/ascertainment, 10 and 20% of under-reporting/ascertainment, respectively. The percentage of undiagnosed cases was higher among HIV people aged below 25 years (25–28%), MSM (16–19%) and people born abroad (16–19%), whereas it was small among injection drug users (3%).

Conclusion:

The estimate of people in Italy with undiagnosed HIV in 2012 was in a plausible range of 12 000–18 000 cases, corresponding to 11–13% of the overall prevalence. The method is straightforward to implement only requiring annual information from the HIV surveillance system about CD4⁺ cell count and clinical stage at HIV diagnosis. Thus, it could be used to monitor if a certain prevention initiative lead to the reduction of the undiagnosed HIV population over time. It can also be easily implemented in other countries collecting the same basic information from the HIV surveillance system.

Continuous increase in HIV-1 incidence after the year 2000 among men who have sex with men in Rome: insights from a 25-year retrospective cohort study

To assess trends in HIV-1 incidence and risk factors for seroconversion among men who have sex with men (MSM) resident in Rome, Italy, a retrospective longitudinal cohort study was conducted over 25 years. Incidence rates and trends were modelled using Poisson regression and risk factors were assessed by multivariate Cox models. Of 1,862 HIV-1-negative individuals, 347 seroconverted during follow-up. HIV-1 incidence rates increased from 5.2/100 persons/year (p/y) in 1986 (95% confidence interval (CI): 2.3–11.5) to 9.2/00 p/y in 1992 (95% CI: 6.4–13.0), decreased to 1.3/100 p/y in 2001 and increased until 2009 (11.7/100 p/y; 95% CI: 7.4–18.6). The risk of HIV-1 seroconversion increased during the study period in younger MSM (incidence rate ratio (IRR) = 17.18; 95% CI: 9.74–30.32 in 16–32 year-olds and IRR = 5.09; 95% CI: 2.92–8.87 in 33–41 year-olds) and in those who acquired syphilis (IRR = 7.71; 95% CI: 5.00–11.88). In contrast, the risk of seroconversion decreased among highly educated MSM (IRR = 0.54; 95% CI: 0.35–0.82) and those without Italian citizenship (IRR = 0.45; 95% CI: 0.28–0.71). The HIV epidemic in MSM living in Rome continues to expand. Targeted prevention programmes against sexually transmitted infections to enhance knowledge transfer and behavioural skills are urgently required.

Antiretroviral treatment-based cost saving interventions may offset expenses for new patients and earlier treatment start

OBJECTIVES

Combination antiretroviral therapy (cART) has become the main driver of total costs of caring for persons living with HIV (PLHIV). The present study estimated the short/medium-term cost trends in response to the recent evolution of national guidelines and regional therapeutic protocols for cART in Italy.

METHODS

We developed a deterministic mathematical model that was calibrated using epidemic data for Lazio, a region located in central Italy with about six million inhabitants.

RESULTS

In the Base Case Scenario, the estimated number of PLHIV in the Lazio region increased over the period 2012-2016 from 14 414 to 17 179. Over the same period, the average projected annual cost for treating the HIV-infected population was €147.0 million. An earlier cART initiation resulted in a rise of 2.3% in the average estimated annual cost, whereas an increase from 27% to 50% in the proportion of naïve subjects starting cART with a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen resulted in a reduction of 0.3%. Simplification strategies based on NNRTIs co-formulated in a single tablet regimen and protease inhibitor/ritonavir-boosted monotherapy produced an overall reduction in average annual costs of 1.5%. A further average saving of 3.3% resulted from the introduction of generic antiretroviral drugs.

CONCLUSIONS

In the medium term, cost saving interventions could finance the increase in costs resulting from the inertial growth in the number of patients requiring treatment and from the earlier treatment initiation recommended in recent guidelines.

The potential impact of routine testing of individuals with HIV indicator diseases in order to prevent late HIV diagnosis

Background

The aim of our work was to evaluate the potential impact of the European policy of testing for HIV all individuals presenting with an indicator disease, to prevent late diagnosis of HIV. We report on a retrospective analysis among individuals diagnosed with HIV to assess whether a history of certain diseases prior to HIV diagnosis was associated with the chance of presenting late for care, and to estimate the proportion of individuals presenting late who could have been diagnosed earlier if tested when the indicator disease was diagnosed.

Methods

We studied a large cohort of individuals newly diagnosed with HIV infection in 13 counselling and testing sites in the Lazio Region, Italy (01/01/2004-30/04/2009). Considered indicator diseases were: viral hepatitis infection (HBV/HCV), sexually transmitted infections, seborrhoeic dermatitis and tuberculosis. Logistic regression analysis was performed to estimate association of occurrence of at least one indicator disease with late HIV diagnosis.

Results

In our analysis, the prevalence of late HIV diagnosis was 51.3% (890/1735). Individuals reporting at least one indicator disease before HIV diagnosis (29% of the study population) had a lower risk of late diagnosis (OR = 0.7; 95%CI: 0.5-0.8) compared to those who did not report a previous indicator disease. 52/890 (5.8%) late presenters were probably already infected at the time the indicator disease was diagnosed, a median of 22.6 months before HIV diagnosis.

Conclusions

Our data suggest that testing for HIV following diagnosis of an indicator disease significantly decreases the probability of late HIV diagnosis. Moreover, for 5.5% of late HIV presenters, diagnosis could have been anticipated if they had been tested when an HIV indicator disease was diagnosed.

However, this strategy for enhancing early HIV diagnosis needs to be complemented by client-centred interventions that aim to increase awareness in people who do not perceive themselves as being at risk for HIV.

Attitude towards antiretroviral Pre-Exposure Prophylaxis (PrEP) prescription among HIV specialists

BACKGROUND

To investigate perceptions and attitude to prescribe Pre-Exposure Prophylaxis (PrEP) among HIV specialists.

METHODS

A questionnaire developed through a Focus Group and literature review was administered to a convenience sample of HIV specialists during educational courses in two Regions and an online survey in February-May 2012. Participants were classified as having a positive or negative attitude according to their willingness to prescribe PrEP. Demographic and working information, experience with HIV-infected patients, information and provision of antiretrovirals to uninfected persons, self-reported knowledge, perceptions and concerns regarding PrEP were assessed. The association between a different attitude towards PrEP prescription and selected characteristics was assessed through univariate and multivariate regression analysis.

RESULTS

Of 311 specialists, 70% would prescribe PrEP, mainly to serodiscordant partners (64%) but also to people at ongoing, high risk of HIV infection (56%); 66% advocated public support of costs. A negative attitude towards PrEP was significantly associated with lack of provision of information on, and prescription of, antiretroviral post-exposure prophylaxis; specialists with a negative attitude believed behavioural interventions to be more effective than PrEP and were more concerned about toxicity. Overall, 90% of specialists disagreed regarding a lack of time for engaging in prevention counselling and PrEP monitoring; 79% would welcome formal guidelines, while those with a negative attitude did not consider this advisable.

CONCLUSIONS

Although conflicting attitudes appear evident, most specialists seem to be willing, with guidance from normative bodies, to promote PrEP within multiple prevention strategies among vulnerable populations. More scientific evidence regarding effectiveness could overcome resistance.