摘要:

Objective:To describe persons with HIV infection and AIDS but with persistently negative HIV antibody enzyme immunoassay (EIA) results.Design:Surveillance for persons meeting a case definition for HIV-1-seronegative AIDS.Setting:United States and Canada.Patients:A total of eight patients with seronegative AIDS identified from July 1995 through September 1997.Main outcome measures:Clinical history of HIV disease, history of HIV test results, and CD4 cell counts from medical record review; results of testing with a panel of EIA for antibodies to HIV-1, and HIV-1 p24 antigen; and viral subtype.Results:Negative HIV EIA results occurred at CD4 cell counts of 0-230×106/l, and at HIV RNA concentrations of 105000-7943000 copies/ml. Using a panel of HIV EIA on sera from three patients, none of the HIV EIA detected infection with HIV-1, and signal-to-cut-off ratios were ≤0.8 for all test kits evaluated. Sera from five patients showed weak reactivity in some HIV EIA, but were non-reactive in other HIV EIA. All patients were infected with HIV-1 subtype B.Conclusions:Rarely, results of EIA tests for antibodies to HIV-1 may be persistently negative in some HIV-1 subtype B-infected persons with AIDS. Physicians treating patients with illnesses or CD4 cell counts suggestive of HIV infection, but for whom results of HIV EIA are negative, should consider p24 antigen, nucleic acid amplification, or viral culture testing to document the presence of HIV.

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To compare three possible therapeutic strategies for the treatment of patients with an intermediate risk of HIV disease progression.Design:Mathematical modeling based on assumptions derived from published data.Methods:A parametric survival model was fitted to empirical data to describe the survival trajectory of untreated individuals. It was assumed that successful treatment decreases the risk of disease progression during the first year after its introduction by a constant that is dependent on the magnitude of the initial drop in HIV viral load. Thereafter, individual members of the treatment cohort follow different pathways, depending on the duration of the initial response or, in case of virologic failure, the response to a new drug regimen.Results:Sub-groups of patients starting therapy with two nucleoside reverse transcriptase inhibitors (NRTI) or two NRTI and a protease inhibitor had the highest instantaneous risk of disease progression at the end of the 5-year follow-up period. Patients who started therapy with two NRTI and a non-NRTI had the lowest likelihood of progression to AIDS or death at 5 years of follow-up. This is because, in the case of the subgroup whose initial treatment included a protease inhibitor, failure rates due to non-adherence to therapy are high and response to salvage therapy is limited by past protease inhibitor experience.Conclusions:Despite the superior virologic potency of the protease inhibitor-containing regimens, in this analysis other strategies performed equally well or even better. In the absence of solid empirical data and until the advent of antiretroviral regimens that are shown to be safe, simple to take, and maximally suppress viral load, caution may be required in selecting the long-term therapy for patients with less advanced HIV disease.

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background:A marked decline in the number of reported AIDS cases has been observed in the United Kingdom, as in many industrialized countries, in 1996 and 1997. In England and Wales, a large reduction in AIDS cases has been recorded among homosexual and bisexual men.Objectives:To investigate, using data from the homosexuals and bisexuals in England and Wales as an example, possible explanations for the above decline such as the effects of new anti-retroviral therapies, or a decrease in the incidence of HIV in recent years.Methods:A multistage model of HIV infection, HIV diagnosis, treatment and of AIDS diagnosis has been used to represent the pattern of HIV and AIDS incidence in homosexual and bisexual men in England and Wales up to the end of 1995. Scenarios for the post-1995 period were examined under different assumptions about changes in HIV incidence in recent years and treatment uptake and efficacy.Results:The fall in the incidence of AIDS is unlikely to be the result of a reduction in HIV transmission during the 1990s. The most plausible explanation for this fall is the effect of new, more effective, anti-retroviral therapies. As a consequence, the number of individuals on treatment is likely to increase by 50 to 100% compared with the pre-1996 levels by the year 2001. Also, if the effect of the new therapies has a limited duration, or the use of such therapies is not well tolerated, the incidence of AIDS will rise again in the near future.Conclusions:These findings indicate that a substantial workload increase is under way for the healthcare system, and reiterate the need for measures to reduce HIV transmission as a means of bringing about a sustainable change in the incidence of AIDS.

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To evaluate HIV serologic testing algorithms based on a combination of three enzyme linked immunosorbent assays (ELISA) for the confirmation of HIV infection in Abidjan, Côte d′Ivoire, where HIV-2 and HIV-1 non-B subtypes are prevalent.Methods:A total of 1069 human sera with known serologic status, in addition to a seroconversion and low titer antibody panel were initially tested by six ELISA to determine the sensitivity, specificity and &dgr; values of the assays. On the basis of the performance of the assays, three ELISA (Enzygnost, ICE 1.0.2, and Vironostika) were selected for use in a parallel and serial testing algorithm in analyzing 8283 consecutively collected sera. In the parallel testing algorithm, sera concordantly reactive or non-reactive by Enzygnost and ICE 1.0.2 were considered as true positive or true negative, respectively. In the serial algorithm, sera reactive by Enzygnost were retested by ICE 1.0.2. Sera with discordant results were tested by Vironostika, and the results was considered definitive. All reactive sera, plus a random sample of negative sera were tested for confirmation by Peptilav. In addition, a random sample of reactive sera was tested by Western blot.Results:All ELISA had 100% sensitivity; specificities ranged from 96.8 to 100%. Positive and negative &dgr; values of the ELISA were high (range, 6.89 to 46.07 and -2.05 to -5.75, respectively). Of the 8283 sera, 2054 were considered true positives and were correctly classified by the parallel testing algorithm (sensitivity, 100%). Of the 6229 true negative sera, 6226 were negative by the parallel testing algorithm (specificity, 99.95%). The sensitivity of the serial algorithm was 99.96%, and specificity was 99.95%. None of the 250 concordant ELISA-negative sera in the algorithm that were randomly tested in Peptilav was positive; similarly, all of the 103 concordant ELISA-positive sera were confirmed by Western blot. The three-ELISA algorithm resulted in reagent cost-savings of at least 50% compared with the Peptilav-based algorithm.Conclusion:These resultssuggest that a combination of ELISA using different principles or antigens in a serial or parallel algorithm is an efficient and cost-effective alternative to the standard algorithm in areas where HIV-1 and HIV-2 are prevalent.

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:Prophylactic zidovudine during pregnancy and labour reduces maternal viral load and, with neonatal therapy, has been shown to reduce vertical transmission. However, zidovudine may have additional effects. Advanced HIV disease is associated with premature delivery, which in turn results in increased vertical transmission. Data from the European Collaborative Study (ECS) were analysed to investigate whether zidovudine could be associated with decreased prematurity risk and/or with a reduced frequency of low birthweight.Methods:HIV-infected pregnant women enrolled in the ECS were followed prospectively according to a standard protocol. Gestational age was assessed by ultrasound, prematurity was defined as delivery before 37 weeks and the cut-off for low birthweight was 2500g. We calculated odds ratios (OR) to estimate the effect of zidovudine on the risk of premature or low birthweight delivery.Results:In 2299 mothers, zidovudine taken to reduce the risk of vertical transmission decreased the odds of premature delivery by a quarter (OR= 0.76, 95% confidence interval (CI) 0.53-1.09), and the odds of low birthweight by nearly half (OR= 0.55, 95% CI 0.39-0.79). Allowing for CD4 count and mode of delivery did not greatly alter these OR values. A multivariate analysis suggested that prophylactic zidovudine and prematurity were independently associated with risk of transmission.Conclusion:Our findings suggest an additional health benefit of zidovudine. Even if most vertical transmission occurs around the time of delivery, therapy earlier in pregnancy could have an indirect effect on transmission rates through delaying delivery. This hypothesis needs to be confirmed or refuted by more appropriate studies.

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To assess whether the custom of prolonged post-partum sexual abstinence in Benin is associated with an increased incidence of extra-marital sexual contacts by husbands.Design:Cross-sectional survey of adult men and women.Methods:Data obtained from men on their extra-marital sexual behaviour in the past 12 months were linked to data on post-partum abstinence over the same time interval reported by wives. Multivariate analysis was applied to assess the association between conjugal abstinence and husband′s extra-marital sex, net of the effects of possible confounders.Results:Approximately half of married men experienced post-partum abstinence in the past 12 months. In this group, 32% reported one or more extra-marital sexual contacts compared with 20% among those who experienced no abstinence (OR=1.8,P<0.001). This association is essentially unchanged after controlling for marriage type, age, education, urban-rural residence, income and household wealth. Age, income and wealth are also significant predictors of the probability of extra-marital sex. The effects of income and wealth largely disappear when attention is restricted to extra-marital sex without using a condom on the most recent occasion.Conclusions:The potentially protective effect of prolonged abstinence after childbirth in Benin (and probably in much of West Africa) is offset by an increased probability that husbands will seek extra-marital partners without using condoms. Although not quantifiable, the enhanced longer-term risks of sexually transmitted diseases/HIV infection for wives probably outweigh the short-term benefits. Family planning practitioners in this region should not hesitate to recommend the early resumption of sex and suitable methods of post-partum contraception for women who express concern or uncertainty about their husband′s behaviour.

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0269-9370    

出版商:OVID    

年代:1999

数据来源: OVID