Evaluation of an HIV recent infection testing algorithm with serological assays among men who have sex with men in Mexico.

BACKGROUND: Human immunodeficiency virus (HIV) incidence should be calculated in cross-sectional studies using recent infection testing algorithms (RITA) that consider clinical variables and serological test results such as enzyme-linked immunosorbent assay (ELISA) and dried blood spot (DBS) analysis. METHODS: The correlation between serum samples and DBS was evaluated using two commercial ELISA kits: SediaTM BED HIV-1 Incidence EIA (BED-Sedia) and Maxim HIV-1 Limiting Antigen Avidity (LAg-Avidity). Eight different RITAs were developed; all of them included serological assays. A combination of the variables viral load, antiretroviral therapy (ART) and CD4 count was used to build the RITAs. The sensitivity, specificity, Youden index, predictive positive value, predictive negative value, false recent rate (FRR) and false long-term rate were evaluated. RESULTS: The correlations between serum samples and DBS were 0.990 and 0.867 for BED-Sedia and LAg-avidity, respectively. Using only serological assays, the Youden index was higher for LAg-avidity than BED-Sedia (82.1-83.0% versus 69.2-69.6%). The best RITA was ART-serology, which showed a Youden index of 91.2-93.9% and FRR of 1.8-2.2%. CONCLUSIONS: Using DBS samples to determine HIV incidence is a good tool for epidemiological surveillance. The RITA that included ART and serological tests (BED-Sedia or LAg-avidity) showed the highest sensitivity and specificity and a low FRR.

HIV serology false positivity among expatriates from Africa: a screening dilemma.

HIV prevalence in Oman is low (<5 %); however, 45 % of the population are expatriates, including a portion originating from countries with high HIV prevalence (>5 %). HIV screening is performed at regional public health laboratories as part of a medical fitness programme for residency applicants. We conducted a retrospective evaluation of indeterminate serology results from 11 females of African origin, aged 21-43 years. Serology testing for HIV was conducted according to the national Oman algorithm: fourth-generation immunoassays (Bio-Rad GS HIV Combo Ag/Ab EIA, Siemens Enzygnost HIV Integral 4, Abbott ARCHITECT HIV Ag/Ab Combo, Roche Elecsys HIV Combi PT, bioMérieux VIDAS HIV DUO QUICK), confirmatory assays (Geenius HIV 1/2 Confirmatory, INNO-LIA HIV I/II Score) and PCR testing. Confirmatory testing to resolve indeterminate results was conducted with available samples for five patients using a combination of immunoassays, confirmatory assays, PCR/PERT and pro-viral DNA levels, at three external laboratories; Roche Diagnostics (Germany), Swiss National Laboratory (Switzerland) and Barts Health NHS Trust (UK). Nineteen serum, 15 plasma and two whole-blood samples were analysed. Nine of ten patients analysed on Bio-Rad and Siemens immunoassays were highly reactive; seven were highly reactive on the Abbott assay. Eight of nine patients tested with the Roche assay were negative. Three of four patients tested on the bioMérieux assay were negative. Five patients underwent confirmatory testing at external laboratories; all were negative by HIV-RNA or pro-viral DNA testing. In conclusion, HIV-RNA and pro-viral DNA testing is recommended for HIV screening of individuals from high-prevalence regions coming to low-prevalence regions.

HIV testing history and access to treatment among migrants living with HIV in Europe.

INTRODUCTION: Migrants are overrepresented in the European HIV epidemic. We aimed to understand the barriers and facilitators to HIV testing and current treatment and healthcare needs of migrants living with HIV in Europe. METHODS: A cross-sectional study was conducted in 57 HIV clinics in nine countries (Belgium, Germany, Greece, Italy, The Netherlands, Portugal, Spain, Switzerland and United Kingdom), July 2013 to July 2015. HIV-positive patients were eligible for inclusion if they were as follows: 18 years or older; foreign-born residents and diagnosed within five years of recruitment. Questionnaires were completed electronically in one of 15 languages and linked to clinical records. Primary outcomes were access to primary care and previous negative HIV test. Data were analysed using random effects logistic regression. Outcomes of interest are presented for women, heterosexual men and gay/bisexual men. RESULTS: A total of 2093 respondents (658 women, 446 heterosexual men and 989 gay/bisexual men) were included. The prevalence of a previous negative HIV test was 46.7%, 43.4% and 82.0% for women, heterosexual and gay/bisexual men respectively. In multivariable analysis previous testing was positively associated with: receipt of post-migration antenatal care among women, permanent residency among heterosexual men and identifying as gay rather than bisexual among gay/bisexual men. Access to primary care was found to be high (>83%) in all groups and was strongly associated with country of residence. Late diagnosis was common for women and heterosexual men (60.8% and 67.1%, respectively) despite utilization of health services prior to diagnosis. Across all groups almost three-quarters of people on antiretrovirals had an HIV viral load <50 copies/mL. CONCLUSIONS: Migrants access healthcare in Europe and while many migrants had previously tested for HIV, that they went on to test positive at a later date suggests that opportunities for HIV prevention are being missed. Expansion of testing beyond sexual health and antenatal settings is still required and testing opportunities should be linked with combination prevention measures such as access to PrEP and treatment as prevention.

Perceived risk and decisional balance to HIV testing in men who have sex with men from Monterrey, Mexico. / Riesgo percibido y balance decisional hacia la prueba del VIH en hombres que tienen sexo con hombres de Monterrey, México.

The perceived risk to HIV and the decisional balance (pros and cons) towards HIV testing are fundamental aspects for understanding the motivation of men who have sex with men to engage in behaviours that reduce or increase the risk of infection with the virus. OBJECTIVES: To describe the perceived risk of HIV and the decisional balance towards HIV testing and determine the association between perceived risk and the decisional balance towards HIV testing of men who have sex with men. METHOD: Descriptive correlational design, we used respondent-driven sampling, with which we recruited 202 men who have sex with men. RESULTS: Mean age of 27.79 (SD=8.13), 66.3% reported low perceived risk to HIV. The most significant pros were: "If I had HIV I would not want to infect anyone else" (95%) and "I would like to be sure I did not have HIV to tell my sexual partner" (90.6%). The most significant cons were: "I am afraid of the needle used for the HIV test" (53%), "people could reject me if they had HIV" (78.7%). Finally, there was a correlation between the perceived risk and the decisional balance towards HIV testing (rs=.759, p<.001). CONCLUSIONS: Given such data, in future interventions it is important to consider information about the importance of HIV testing on a regular basis, as well as actions to increase the perception of vulnerability to HIV in this population.

Birth conditions of children of women living with HIV

The objective was to identify the conditions of birth of children of women living with HIV in the period between 2009 and 2019, at the Regional Maternal and Child Hospital of Imperatriz (MA). Cross-sectional, quantitative, documentary study, with descriptive analysis of the data and carried out in a reference maternity hospital between August 2020 and July 2021. Information from the medical records of HIV-positive pregnant women and their newborn children was included. The results collected 314 medical records, of which 195 were eligible. Regarding the birth conditions of the newborns, in 56.41% the rapid test was negative; 72.82% used post-birth prophylaxis; 75.38% did not receive breast milk; 68.2% received vaccines at birth; 40.51% did not use any medication. 20.51% of the mothers were between 36 and 40 years old; 59.48% did not live in the municipality surveyed; 23.6% were housewives; 65.64 were multipara women; 46.15% were diagnosed with HIV during pregnancy; 67.17% had no coinfections; 82.05% underwent prenatal care; 60.51% used intrapartum prophylaxis; and 77.43% underwent cesarean section. The prenatal and childbirth follow-up of most of these women living with HIV reflected positively on the conditions of birth of their children, being an important strategy, aiming at the non-vertical transmission and prevention of the disease in children (AU).

Objetivou-se identificar as condições de nascimento de filhos de mulheres vivendo com HIV no período compreendido entre 2009 e 2019, no Hospital Regional Materno Infantil de Imperatriz (MA). Estudo transversal, quantitativo, documental, com análise descritiva dos dados e realizado em maternidade de referência entre os meses de agosto de 2020 e julho de 2021. Incluíram-se informações dos prontuários das gestantes soropositivas para HIV e de seus filhos recém-nascidos. Os resultados levantaram 314 prontuários, destes, 195 eram elegíveis. Sobre as condições de nascimento dos recém-nascidos, em 56,41% o teste rápido foi negativo; 72,82% usaram profilaxia pós-nascimento; 75,38% não receberam leite materno; 68,2% receberam vacinas logo ao nascer; 40,51% não faziam uso de nenhuma medicação; 20,51% das mães tinham entre 36 a 40 anos; 59,48% não residiam no município pesquisado; 23,6% eram donas de casa; 65,64 eram multigestas; 46,15% receberam o diagnóstico de HIV na gestação; 67,17% não tinham coinfecções; 82,05% realizaram o pré-natal; 60,51% fizeram uso da profilaxia intraparto; e 77,43% fizeram cesariana. O acompanhamento no pré-natal e parto da maioria dessas mulheres vivendo com HIV refletiu positivamente nas condições de nascimento de seus filhos, sendo uma importante estratégia, visando a não transmissão vertical e prevenção da doença nas crianças (AU).

Factors Associated With Access to HIV Testing and Primary Care Among Migrants Living in Europe: Cross-Sectional Survey.

BACKGROUND: There is a heavy and disproportionate burden of human immunodeficiency virus (HIV) infection among migrant communities living in Europe. Despite this, the published evidence related to HIV testing, prevention, and treatment needs for migrants is sparse. OBJECTIVE: The aim of this study was to identify the factors associated with access to primary care and HIV testing among migrant groups living in Europe. METHODS: A Web-based survey (available in 14 languages) was open to all people aged 18 years and older, living outside their country of birth in the World Health Organization (WHO) European area. Community organizations in 9 countries promoted the survey to migrant groups, focusing on those at a higher risk of HIV (sub-Saharan Africans, Latin Americans, gay or bisexual men, and people who inject drugs). Multivariable analysis examined factors associated with access to primary care and previous history of an HIV test. RESULTS: In total, 559 women, 395 heterosexual men, and 674 gay or bisexual men were included in the analysis, and 68.1% (359/527) of women, 59.5% (220/371) of heterosexual men, and 89.6% (596/664) of gay or bisexual men had tested for HIV. Low perceived risk was the reason given for not testing by 62.3% (43/69) of gay or bisexual men and 83.3% (140/168) of women and heterosexual men who reported never having tested for HIV. Access to primary care was >60% in all groups. Access to primary care was strongly positively associated with living in Northern Europe compared with Southern Europe (women: adjusted odds ratio, aOR 34.56 [95% CI 11.58-101]; heterosexual men: aOR 6.93 [95% CI 2.49-19.35], and gay or bisexual men: aOR 2.53 [95% CI 1.23-5.19]), whereas those with temporary residency permits were less likely to have access to primary care (women: aOR 0.41 [95% CI 0.21-0.80] and heterosexual men: aOR 0.24 [95% CI 0.10-0.54] only). Women who had experience of forced sex (aOR 3.53 [95% CI 1.39-9.00]) or postmigration antenatal care (aOR 3.07 [95% CI 1.55-6.07]) were more likely to have tested for HIV as were heterosexual men who had access to primary care (aOR 3.13 [95% CI 1.58-6.13]) or reported "Good" health status (aOR 2.94 [95% CI 1.41-5.88]). CONCLUSIONS: Access to primary care is limited by structural determinants such as immigration and health care policy, which varies across Europe. For those migrants who can access primary care and other health services, missed opportunities for HIV testing remain a barrier to earlier testing and diagnosis for migrants in Europe. Clinicians should be aware of these potential structural barriers to HIV testing as well as low perception of HIV risk in migrant groups.

Meningitis aséptica por varicela zóster sin rash vesicular previo en paciente VIH positivo. Presentación de caso / Varicella Zoster aseptic meningitis without previous vesicular rash in VIH positive patient. Case report

Resumen Un cuadro de meningitis aséptica, en el contexto de un paciente inmunosuprimido con diagnóstico de infección por Virus de Inmunodeficiencia Humana (VIH), debe llevar a pensar en múltiples diagnósticos diferenciales. Entre estos, se incluye el virus varicela zóster (VVZ) como uno de los principales agentes causales de meningitis a líquido cefalorraquídeo claro. Su reactivación da lugar a múltiples manifestaciones neurológicas potencialmente mortales en las que se consideraba al rash vesicular, o exantema pápulo/vesículo/ costroso como un signo fundamental para su diagnóstico. No obstante, las lesiones cutáneas están ausentes en más de un tercio de los pacientes con compromiso del sistema nervioso central. A continuación, se presenta el caso de un paciente con infección por VIH que presenta cefalea más fiebre, con hallazgos en líquido cefalorraquídeo de pleocitosis neutrofílica y una prueba molecular confirmatoria para virus varicela zóster, en ausencia de rash vesicular previo que guiara hacia este diagnóstico. MÉD.UIS.2021;34(1): 91-9.

Abstract The clinical presentation of aseptic meningitis in the context of an immunosuppressed patient with a diagnosis of Human Immunodeficiency Virus (HIV) infection, should lead us to consider multiple differential diagnoses. Among these, the Varicella Zoster Virus (VZV) has been found as one of the main causative agents of clear cerebrospinal fluid meningitis. Its reactivation gives rise to multiple life-threatening neurological manifestations in which vesicular rash, or papule / vesicular / crusted rash was considered a fundamental sign for its diagnosis. However, skin lesions are absent in more than a third of patients with central nervous system involvement. Herein, we report a case of an HIV-infected patient with headache, fever and neutrophilic pleocytosis with FilmArray that confirms Varicella Zoster virus infection in an immunocompromised patient in the absence of vesicular rash. MÉD.UIS.2021;34(1): 91-9.

Optimizing Human Immunodeficiency Virus Testing Interventions for Men Who Have Sex With Men in the United States: A Modeling Study.

Background. In the United States, public health recommendations for men who have sex with men (MSM) include testing for human immunodeficiency virus (HIV) at least annually. We model the impact of different possible HIV testing policies on HIV incidence in a simulated population parameterized to represent US MSM. Methods. We used exponential random graph models to explore, among MSM, the short-term impact on baseline (under current HIV testing practices and care linkage) HIV incidence of the following: (1) increasing frequency of testing; (2) increasing the proportion who ever test; (3) increasing test sensitivity; (4) increasing the proportion of the diagnosed population achieving viral suppression; and combinations of 1-4. We simulated each scenario 20 times and calculated the median and interquartile range of 3-year cumulative incidence of HIV infection. Results. The only intervention that reduced HIV incidence on its own was increasing the proportion of the diagnosed population achieving viral suppression; increasing frequency of testing, the proportion that ever test or test sensitivity did not appreciably reduce estimated incidence. However, in an optimal scenario in which viral suppression improved to 100%, HIV incidence could be reduced by an additional 17% compared with baseline by increasing testing frequency to every 90 days and test sensitivity to 22 days postinfection. Conclusions. Increased frequency, coverage, or sensitivity of HIV testing among MSM is unlikely to result in reduced HIV incidence unless men diagnosed through enhanced testing programs are also engaged in effective HIV care resulting in viral suppression at higher rates than currently observed.

Laboratory diagnosis of HIV-1 and HIV-2 in Africa.

PIP: It is well accepted that HIV is the cause of AIDS and that the virus is distributed widely throughout the world. Being able to diagnose infection with HIV through laboratory tests has done much to facilitate the early recognition of the severity and extent of the AIDS pandemic. Many laboratory techniques exist to detect infection with HIV-1 and HIV-2. In recent years, however, African countries have found it difficult to implement such diagnostic tests because the tests have been either ill-suited or too expensive for the developing country setting. This paper describes many of the HIV laboratory diagnostic techniques currently used in both diagnostic and research settings. The review of techniques is, however, neither all-inclusive nor globally applicable, but intended to be simply a view of available techniques from the African perspective. The opening general section on the detection of HIV-1 and HIV-2 is followed by discussion of screening tests, rapid tests, and confirmatory tests to detect HIV antibodies. Techniques to detect virus include viral isolation, the detection of viral antigen, and PCR. HIV testing algorithms are discussed. The authors stress in closing the importance of the effective laboratory diagnosis of HIV in the prevention and control of HIV/AIDS. Laboratory personnel must be trained, cost-effective laboratory techniques made available for the African setting, and test systems chosen which are best adapted to the prevailing epidemiologic, socioeconomic, and cultural contexts. These latter systems often will differ from the types of diagnostic tests and testing algorithms used in more developed countries.^ieng

Sensitivity of HIV-antibody assays determined by seroconversion panels.

OBJECTIVES: To determine the sensitivity of HIV-antibody assays for detecting low levels of HIV antibody using seroconversion and other panels containing plasma of varying titres. METHODS: Eight HIV-antibody assays, available under the World Health Organization bulk-procurement agreement, were evaluated on sets of sequential plasma samples derived from 11 individuals who had recently become HIV-infected (seroconversion panels). In addition, two non-seroconversion panels, consisting of low performance (titre) and mixed titre samples were used to further define the sensitivity of the assays. The eight assays included two rapid tests, one simple test, and five enzyme-linked immunosorbent assays (ELISA). RESULTS: On average, the eight assays detected antibody 0.5-4.8 days later than the reference test (Abbott HIV-1/HIV-2 3rd generation ELISA); these differences were statistically significant for six of the eight tests. All tests performed well on the low performance and mixed titre panels. All eight assays also had comparable sensitivity to that of the reference test on a large panel of known positive plasma. The additional risk of missing an infectious unit of blood during seroconversion by using the least sensitive rather than the reference test was estimated to be 1 in 7600 and 1 in 76 million at annual HIV incidence rates of 1 and 0.0001%, respectively. The cost of eliminating this additional risk by using the reference test is between US$ 15,150 and 151 million per unit detected at the above incidence rates. CONCLUSIONS: Although there are differences in sensitivity between the assays when used to test blood from individuals during the course of seroconversion, the differences are small, and all eight tests are appropriate for use as screening tests.

Reasons for the wide variation in reported rates of mother-to-child transmission of HIV-1.

PIP: The explanation of marked global variation (between 12 and 65%) in the rate of mother-to-child transmission (MCT) of HIV-1 both in developed and developing countries is inadequate. The risk of MCT ranges from one in eight to one in 1.5 pregnancies. There are marked methodological differences in the case definitions, study designs and diagnostic criteria in the various MCT investigations. Although most HIV-1 MCT appears to occur in the peripartum period, it can also occur in the intrauterine phase or immediately postpartum requiring diagnostic techniques that are not often available. Polymerase chain reaction or in situ hybridization tests for early diagnosis of MCT have been found to lack specificity for both HIV-infected and uninfected infants who are born to HIV-infected mothers and who remain HIV-seropositive during their first year of life. A second explanation for the wide variability derives from the varying case mix of any given maternal cohort. HIV infection during pregnancy and pregnant women with advanced HIV-induced immunosuppression are particularly infectious to their children. A third source of MCT variation results from selection bias in many MCT studies. It is not known whether the only mechanism of transmission in the perinatal period is transplacental or transmission occurs during delivery. Data suggest that delivery via Caesarean section halves the risk of MCT. Antiretroviral treatment (zidovudine) for HIV-infected mothers in the immediate prepartum and intrapartum period, followed by postpartum administration to their infants has reduced these infants' chance of MCT by as much as 50%. A recent study from Malawi demonstrated that HIV-1-seropositive women with vitamin A deficiency had a twofold greater risk of transmitting HIV-1 infection to their infants. The many biologic reasons for the wide variation in MCT make it unlikely that prevention will be possible through a single biologic and/or pharmacologic approach.^ieng

Simultaneous introduction of distinct HIV-1 subtypes into different risk groups in Russia, Byelorussia and Lithuania.

OBJECTIVE: To investigate genotypes and serotypes of HIV-1 variants in Russia, Byelorussia and Lithuania. PATIENTS AND METHODS: Sera from 20 HIV-1-infected individuals were tested in an enzyme-linked immunosorbent assay (ELISA) with 19 V3 synthetic peptides, and serum HIV-1 V3 RNA was amplified and sequenced. RESULTS: Sequence comparison of the envelope V3 region among specimens tested revealed a 2-29% range nucleotide divergence, with a mean of 19%. Phylogenetic analysis from the homosexual men were shown to belong to subtype B, and all of the heterosexually infected individuals to subtype C. Sequences from the parenterally infected individuals were more heterogeneous. IOn the peptide ELISA three reactivity patterns were found. Serum samples from six out of seven homosexual men showed reactivity to peptides p108 or p110 representing V3 amino-acid sequences found in US/West European HIV-1 isolates. Serum samples from six of seven individuals who had acquired HIV-1 through heterosexual contacts were reactive to peptide p169. Four out of six parenterally infected patients had peak reactivity to p168. CONCLUSION: Distinct HIV-1 variants were found in Russia, Byelorussia and Lithuania, which were introduced simultaneously in the mid-1980s. This diversity was shown to be associated with the route of transmission. Homosexual men appeared to be infected with subtype B and heterosexually infected individuals with subtype C HIV-1 variants. HIV-1 subtypes A, C, D and G were found among parenterally infected individuals.

PIP: HIV-1 variants show a relatively high level of genomic and antigenic diversity. This heterogeneity is particularly high in the V3 domain of envelope glycoprotein gp120, which is implicated in a number of biological properties of HIV-1, including cell tropism, infectivity, and cytopathogenicity; it is also a target for both humoral and cellular immune response. At least nine subtypes of HIV-1 have been identified. Subtypes A-H are phylogenetically equidistant and shown to be geographically associated with different subcontinents. Subtype B is most prevalent in North and South America and western Europe. Subtypes A, C, D, G, and H are found frequently in sub-Saharan countries, while subtype C is also found in India. Subtype E sequences have been found in patients from Thailand and Central Africa, and subtype F has been described in Romania and Brazil. This study reports findings from an investigation of genotypes and serotypes of HIV-1 variants in Russia, Byelorussia, and Lithuania. Sera from 15 HIV-1-infected men and 5 HIV-1-infected females were tested by ELISA with 19 V3 synthetic peptides with amplified and sequenced serum HIV-1 V3 RNA. Sequence comparison of the envelope V3 region among specimens tested revealed a 2-29% range of nucleotide divergence, with a mean of 19%. Distinct variants of HIV-1 were found in Russia, Byelorussia, and Lithuania, which were introduced simultaneously in the mid-1980s. The diversity was shown to be associated with the route of transmission. Homosexual men appeared to be infected with subtype B compared to heterosexually infected individuals with subtype C HIV-1 variants. HIV-1 subtypes A, C, D, and G were found among parenterally-infected individuals. These findings are based upon the three peptide reactivity patterns identified by ELISA. Serum samples from six out of seven homosexual men showed reactivity to peptides p108 or p110 representing V3 amino-acid sequences found in US/West European HIV-1 isolates. Serum samples from six out of seven individuals who had acquired HIV-1 through heterosexual contacts were reactive to peptide p169, and four out of six parenterally infected patients had peak reactivity to p168.

Saliva-based HIV-antibody testing in Thailand.

OBJECTIVE: To determine whether saliva could serve as an alternative to serum for HIV-antibody testing in an ongoing sentinel surveillance program in Thailand. METHODS: Serum and saliva specimens were collected from 1955 individuals in four of the 73 sentinel sites of the national surveillance program in Thailand. Intravenous drug users, female prostitutes, and men attending sexually transmitted disease clinics were included as participants. All specimens were collected and tested anonymously. Saliva was gathered with the Omni-Sal collection device and analyzed for the presence of HIV antibodies using the immunoglobulin G antibody-capture enzyme-linked immunosorbent assay (GACELISA) laboratory test, specially designed for low concentration body fluids. Our gold standard was serum, collected and analyzed independently from the saliva specimens, using an ELISA test for screening and Western blot for confirmation. Linkage between serum and saliva was blind to the laboratory. A set of HIV-positive and HIV-negative quality assurance samples for both serum and saliva were also analyzed blind. RESULTS: Findings are presented as observed in the field, and as quality assurance samples after the correction of various field and laboratory errors. The sensitivity of the GACELISA with saliva was 98.0% in the field (298 HIV-positive specimens), 100% after correction of errors (300 HIV-positive specimens), and 100% among the quality assurance samples (95 HIV-positive specimens). The specificity of the GACELISA was 99.4% in the field (1653 HIV-negative specimens), 99.6% after correction of errors (1654 HIV-negative specimens), and 100% among the quality assurance samples (96 HIV-negative specimens). CONCLUSION: Our findings support other published studies that also featured the GACELISA. We conclude that saliva is comparable to serum for assessing HIV antibodies in individuals for surveillance and screening purposes.

Antigenic variation of the dominant gp41 epitope in Africa.

OBJECTIVE: To determine the value of (combinations of) synthetic peptides representing immunodominant sites on HIV-1/HIV-2 transmembrane proteins for the detection and discrimination between HIV-1 and HIV-2 infection in various populations. DESIGN AND METHODS: Two 24-mer synthetic peptides derived from immunodominant sites on the HIV-1 and HIV-2 transmembrane proteins were used separately, in combination (env 1/2), and in combination with recombinant p24 (p24/env) in enzyme-linked immunosorbent assays. RESULTS: Positive reactions with env-1 were found in 150 out of 150 (100%) samples from Dutch AIDS patients, 60 out of 60 (100%) samples from Dutch homosexual men obtained 1 year after HIV-1-antibody seroconversion, 29 out of 30 (96.7%) samples from these men obtained at the time of HIV-1-antibody seroconversion, 40 out of 41 (97.6%) samples from East Africans with AIDS-related symptoms, and three out of 29 (10.3%) samples from West Africans with HIV-2 infection (including a sample from an individual infected with both HIV-1 and HIV-2). Positive reactions with env-2 in these study populations were 11 out of 150 (7.3%), nine out of 60 (15%), none out of 30 (0%), 25 out of 41 (60.9%) and 29 out of 29 (100%), respectively. In the samples with dual reactivity, true versus cross-reactivity could generally be differentiated on the basis of large differences in optical density values in the respective assays. All samples reacted positively with p24/env; 308 out of 310 (99.3%) were positive in the env 1/2 assay. Four East African samples that had negative or only weakly positive reactions with env-1 showed a noticeably stronger reaction with variant peptides derived from Central African isolate sequences. In all samples from HIV-1-infected Dutch homosexual men, the strongest signal was detected using the env-1 peptide sequence, which is derived from European and American isolates. CONCLUSIONS: Small peptide antigens may permit the detection of strain-specific antibodies, allowing serological characterization of HIV isolates.

Field evaluation of alternative testing strategies for diagnosis and differentiation of HIV-1 and HIV-2 infections in an HIV-1 and HIV-2-prevalent area.

OBJECTIVE: To identify cost-efficient alternative antibody testing strategies for screening, confirmation and discrimination of HIV-1 and HIV-2 infections, including rapid simple tests (RST) as well as enzyme-linked immunosorbent assays (ELISA), in a HIV-1 and HIV-2-prevalent area. DESIGN: Evaluation and comparison of anti-HIV-1/2 assays, adhering to the World Health Organization recommendations for alternative confirmatory strategies, using banked and prospectively collected specimens in Guinea-Bissau. METHODS: A total of 1110 consecutive sera from Bissau were included in the first phase, of which 198 (17.8%) were HIV-seropositive: 52 (4.7%) HIV-1, 120 (10.8%) HIV-2, and 26 (2.3%) HIV-1/HIV-2 dually reactive. In addition, 95 selected HIV-positive specimens were included for study of sensitivity and cross-reactivity between HIV-1 and HIV-2. Western blot was used as a gold standard for confirming the reactivity of the specimens. All specimens were screened by two assays. Enzygnost ELISA and Capillus RST. Samples reactive by any of the screening assays were further tested by assays chosen for confirmation: UBI ELISA, Innotest ELISA Recombigen RST, Multispot RST and Immunocomb RST. The confirmatory RST as well as Wellcozyme Recombinant HIV-1 ELISA, PEPTI-LAV and INNO-LIA were also used to study differentiation between HIV-1 and HIV-2. RESULTS: The sensitivities of all assays were 100%. The specificities of the screening assays at initial and repeated testing were 98.0 and 99.7%, respectively, for Enzygnost and 99.8 and 99.9%, respectively, for Capillus. The various combinations of two or three assays showed specificities of 99.2-100%. Several possible combinations of assays were identified where a specificity of 100% and good differentiation between HIV-1 and HIV-2 was achieved. Significant differences in the capacity to discriminate were noted; Immunocomb and PEPTI-LAV had the lowest number of dual-reactive results. A follow-up study of 1501 consecutive samples tested with the strategy chosen for routine use showed a sensitivity and specificity comparable to ELISA and Western blot. CONCLUSION: High sensitivities and specificities were obtained with various combinations of assays including RST as well as ELISA, and these procedures are well suited for field use in Africa. Serodiagnostic strategies for HIV can be based on RST alone and differentiation between HIV-1 and HIV-2 can be achieved as part of these strategies. Large differences in the capacity of individual assays to discriminate between HIV-1 and HIV-2 were observed.

PIP: Western blot (WB) is the most widely used serological confirmatory test of ELISA and rapid simple tests (RST) to detect infection with HIV. WB tests, however, are expensive, time-consuming, and have technical disadvantages. The authors therefore conducted a study to identify cost-efficient alternative strategies for HIV-antibody screening, confirmation, and discrimination of HIV-1 and HIV-2 infections in a HIV-1 and HIV-2 prevalent area. 1110 consecutively collected blood sera from Guinea-Bissau were included in the first phase of the study, of which 198 (17.8%) were known to be HIV-seropositive; 52 with HIV-1, 120 with HIV-2, and 26 being HIV-1/HIV-2 dually reactive. 95 selected HIV-positive specimens were included for study of sensitivity and cross-reactivity between HIV-1 and HIV-2, with WB used to confirm specimen reactivity. All specimens were screened by Enzygnost ELISA and Capillus RST, with reactive samples further tested by the following assays for confirmation: UBI ELISA, Innotest ELISA, Recombigen RST, Multispot RST, and Immunocomb RST. The confirmatory RST, Wellcozyme Recombinant HIV-1 ELISA, PEPTI-LAV, and INNO-LIA were also used to study differentiation between HIV-1 and HIV-2. All assays were 100% sensitive. The specificities of the screening assays at initial and repeated testing were 98.0% and 99.7%, respectively, for Enzygnost and 99.8% and 99.9%, respectively, for Capillus. Various combinations of 2-3 assays yielded specificities of 99.2-100%. Screening with Enzygnost ELISA and confirmation and differentiation between HIV-1 and HIV-2 with Capillus RST and Multispot RST was adopted for routine use at Guinea-Bissau's National Public Health Laboratory. A field trial of the approach conducted in 1996 involving 1501 sera found a sensitivity and specificity comparable to ELISA and WB.

Algorithms for detecting antibodies to HIV-1: results from a rural Ugandan cohort.

OBJECTIVE: To evaluate an algorithm using two enzyme immunoassays (EIA) for anti-HIV-1 antibodies in a rural African population and to assess alternative simplified algorithms. METHODS: Sera obtained from 7895 individuals in a rural population survey were tested using an algorithm based on two different EIA systems: Recombigen HIV-1 EIA and Wellcozyme HIV-1 Recombinant. Alternative algorithms were assessed using negative or confirmed positive sera. RESULTS: None of the 227 sera classified as unequivocably negative by the two assays were positive by Western blot. Of 192 sera unequivocably positive by both assays, four were seronegative by Western blot. The possibility of technical error cannot be ruled out in three of these. One of the alternative algorithms assessed classified all borderline or discordant assay results as negative had a specificity of 100% and a sensitivity of 98.4%. The cost of this algorithm is one-third that of the conventional algorithm. CONCLUSIONS: Our evaluation suggests that high specificity and sensitivity can be obtained without using Western blot and at a considerable reduction in cost.

PIP: Although the Western blot test is widely used to confirm HIV-1 serostatus, concerns over its additional cost have prompted review of the need for supplementary testing and the evaluation of alternative test algorithms. Serostatus tends to be confirmed with this additional test especially when tested individuals will be informed of their serostatus or when results will be used for research purposes. The confirmation procedure has been adopted as a means of securing suitably high levels of specificity and sensitivity. With the goal of exploring potential alternatives to Western blot confirmation, the authors describe the use of parallel testing with a competitive and an indirect enzyme immunoassay with and without supplementary Western blots. Sera were obtained from 7895 people in the rural population survey and tested with an algorithm based on the Recombigen HIV-1 EIA and Wellcozyme HIV-1 Recombinant; alternative algorithms were assessed on negative or confirmed positive sera. None of the 227 sera classified as negative by the 2 assays were positive by Western blot. Of the 192 identified ass positive by both assays, 4 were found to be seronegative with Western blot. The possibility of technical error does, however, exist for 3 of these latter cases. One of the alternative algorithms assessed classified all borderline or discordant assay results as negative with 100% specificity and 98.4% sensitivity. This particular algorithm costs only one-third the price of the conventional algorithm. These results therefore suggest that high specificity and sensitivity may be obtained without using Western blot and at a considerable reduction in cost.

Highly specific V3 peptide enzyme immunoassay for serotyping HIV-1 specimens from Thailand.

OBJECTIVE: To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale serotyping of HIV-1 specimens from Thailand. DESIGN: Serologic reactivities with synthetic peptides derived from the V3 loop of gp120 were used for typing HIV-1 specimens. METHODS: Synthetic peptides PND-A and PND-B, derived from the consensus amino-acid sequences of the V3 loop of gp120 from two major genomic variants of HIV-1 in Thailand (A and B), were evaluated in an EIA on 61 Thai HIV-1 sera for which genotypes had been determined by polymerase chain reaction. The peptide EIA was then applied to sera from 188 HIV-1-infected patients, selected in non-random, convenience samples of known risk groups from four geographic regions of Thailand. RESULTS: The sensitivities and specificities of PND-A and PND-B were 86% (30 out of 35) and 96% (25 out of 26) and 92% (24 out of 26) and 94% (33 out of 35), respectively, with 100% predictive values of a monoreactive positive test for both peptides. The assay classified 101 specimens as serotype A, 39 as serotype B, eight as serotype AB (dually reactive), and 40 as untypable (non-reactive). Excluding dual reactors and non-reactors, 92% (77 out of 84) of specimens from patients probably infected by sexual contact were serotype A; conversely, 76% (28 out of 37) of injecting drug users were serotype B. CONCLUSION: The serologic results corroborated previous findings, in a smaller subset of samples, of an apparent segregation of viral subtypes by mode of transmission, suggesting two separate HIV-1 epidemics in Thailand. This peptide EIA could be a valuable epidemiologic tool in determining the dynamics of the rapid spread of HIV-1 in Thailand.

PIP: A simple synthetic enzyme immunoassay (EIA) for serotyping HIV-1 specimens from Thailand, based on gp120 V3 loop peptide, was developed and tested on 188 sera from 4 regions of the country. There are 2 major known gene variants of HIV-1 in Thailand designated genotype A and B. The peptide EIA was tested on 61 sera that had been characterized by polymerase chain reaction and DNA sequencing. The EIA was then tested on 188 sera from high risk groups collected in the northern, northeastern, central and southern regions in mid-1991. The PND-A assay was 86% sensitive and 96% specific; the PND-B assay was 96% sensitive and 92% specific. The EIAs showed 100% predictive values when sera known to be reactive to only HIV A or B were tested. In the series there were also 8 sera reactive to both A and B and 40 not reactive to either variant. Excluding dual and non-reactors, 92% of patients with sexual high risk factors had HIV-1 type A and 76% of those with IV drug use history had type B. The results suggest that 2 HIV-1 epidemics have occurred in Thailand, an initial wave in 1988 among IV drug users and a later wave centered among prostitutes and their clients.

Seroincidence of HIV-1 infection in African women of reproductive age: a prospective cohort study in Kigali, Rwanda, 1988-1992.

OBJECTIVE: To estimate the seroincidence of HIV-1 infection among women of reproductive age in Kigali, Rwanda. DESIGN: Fixed prospective cohort followed for 36 months between November 1988 and June 1992, as part of an ongoing study of mother-to-child transmission of HIV-1. SETTING: Centre Hospitalier, Kigali, Rwanda. SUBJECTS: A total of 216 HIV-seronegative women were enrolled at delivery between November 1988 and June 1989. METHODS: A blood sample was obtained at delivery to test for HIV antibodies (by enzyme-linked immunosorbent assay and Western blot). Serum was tested every 3 months during follow-up. Incidence density rates of HIV seroconversion were estimated. RESULTS: The follow-up rate after 3 years was 89%, assessed by the maximum person-years method. The seroincidence density rate was 3.5 per 100 women-years (95% confidence interval, 1.9-5.0). It decreased linearly from 7.6 during the first 6-months postpartum to 2.5 per 100 women-years during the last 6 months of the third year of follow-up. Maternal age did not affect HIV incidence rates. We examined the role of the cohort, counselling, and the first 6-month postpartum effects on this estimate. CONCLUSION: This fixed cohort provided an overall estimation of the HIV infection incidence rate and its dynamics. These figures could be used for programming future HIV preventive vaccine efficacy trials in Rwanda.

PIP: The objective was to estimate the seroincidence of HIV-1 infection among women of reproductive age in Kigali, Rwanda. A fixed prospective cohort followed a total of 216 HIV-seronegative women for 36 months between November 1988 and June 1992 at Centre Hospitalier, Kigali, Rwanda. A study of mother-to-child transmission of HIV-1 has been going on at the Centre Hospitalier de Kigali since November 1988. A group of HIV-seronegative women matched by maternal age and parity was consecutively selected as a comparison group. The mean maternal age was 25.1 years (SD, 4.5 years), and the total number of pregnancies was 2.7 (SD, 1.8). A blood sample was obtained at delivery to test for HIV antibodies (by enzyme-linked immunosorbent assay and Western blot). Serum was tested every 3 months during follow-up. The follow-up rate after 3 years was 89.2% (577/646.75), assessed by the maximum person-years method. 20 seroconversions were documented during the first 36 months of follow-up among the 216 women seronegative at inclusion, yielding a cumulative incidence of 11.2%. The largest number of seroconversions (8/20; 40%) was observed in the first 6 months of the postpartum period. The seroincidence density rate was 3.5/100 women-years (95% confidence interval, 1.9-5.0). It decreased linearly from 7.6 during the first 6-months postpartum to 2.5 per 100 women-years during the last 6 months of the third year of follow-up (P = 0.01). Maternal age did not affect HIV incidence rates. We examined the role of the cohort, counseling, and the first 6-month postpartum effects on this estimate. The study confirms that pregnant women may represent a population in which the HIV seroincidence is high and concentrated in the immediate postpartum period. Pregnant women should become a potential target group for future large scale vaccination trials and programs with adequate follow-up. These figures could be used for programming future HIV preventive vaccine efficacy trials in Rwanda.

Accurate detection of maternal antibodies to HIV in newborn whole blood dried on filter paper.

OBJECTIVE: The testing of neonatal blood specimens dried on filter paper for maternal HIV antibodies, using an enzyme immunoassay (EIA) with confirmation of repeatedly reactive specimens by immunoblot (IB), was first described in 1987. It has been used to conduct large, unlinked, anonymous HIV seroprevalence surveys for surveillance of HIV in child-bearing women in several countries. We directly assessed the sensitivity and specificity of this combination of tests to detect maternal HIV antibodies. SETTING: Serum samples obtained from mothers delivering at a major hospital in Kinshasa, Zaire were screened for HIV antibody using the rapid assay HIVCHEK. DESIGN: Plasma from HIVCHEK-positive women and age-matched negative controls were tested by enzyme-linked immunosorbent assay (ELISA); repeatedly reactive specimens were confirmed by Western blot (WB). Two days after delivery, whole blood was obtained from each newborn by heel-stick, dried on filter paper, and tested by EIA. Repeatedly reactive specimens were confirmed by IB. MAIN OUTCOME MEASURE: The serologic status of neonatal filter-paper specimens was compared with that of corresponding maternal plasma. RESULTS: The testing of neonatal filter-paper specimens using EIA, with confirmatory testing of repeatedly reactive specimens using IB, was 100.0% sensitive [of the 192 ELISA-positive and WB-positive maternal plasma specimens, 192 of the corresponding newborn filter-paper specimens were EIA-positive and IB-positive; 95% confidence interval (CI), 98.1-100]. The detection of maternal HIV antibodies was 99.6% specific using this combination of tests (of the 281 ELISA-negative or ELISA-positive but WB-negative maternal plasma samples, 280 of the corresponding newborn filter-paper specimens were EIA-negative or EIA-positive but IB-negative; 95% CI, 98.0-100). CONCLUSIONS: Maternal HIV antibodies can be detected accurately by testing neonatal blood dried on filter paper, using EIA with confirmation of repeatedly reactive specimens by IB. This approach can facilitate the determination of HIV seroprevalence in child-bearing women in countries with neonatal screening programs, or where serum or plasma is difficult to obtain.

PIP: Neonatal blood specimens dried on filter paper have been tested for maternal HIV antibodies in large, unlinked, anonymous HIV seroprevalence surveys toward the surveillance of HIV in child-bearing women in several countries. This study assesses the sensitivity and specificity of this combination of tests. The standard approach involves first testing the sample via an enzyme immunoassay (EIA), then confirming repeatedly reactive specimens through immunoblot (IB). To test this methodology, serum samples were obtained from mothers delivering at a major hospital in Kinshasa, Zaire, and screened with rapid assay HIVCHEK for antibody to HIV. Plasma from HIVCHEK-positive women and age-matched negative controls were then subjected to ELISA, with repeatedly reactive samples confirmed with Western blot. Whole blood was later obtained by heel-stick from each newborn 2 days after delivery, dried on filter paper, and tested by EIA and IB for confirmation. The serologic statuses of neonatal filter-paper specimens were then compared with those of corresponding maternal plasma. 100% sensitivity was achieved by testing neonatal filter-paper specimens with EIA and confirming with IB. The combination of tests also proved 99.6% specific for detecting maternal HIV antibodies; both results are at 95% confidence intervals. These results demonstrate that maternal HIV antibodies can therefore be detected accurately by testing neonatal blood dried on filter paper, using EIA, then confirming repeatedly reactive specimens via IB. This approach may help determine HIV seroprevalence in childbearing women in countries with neonatal screening programs or where serum or plasma is difficult to obtain.