Socioeconomic geographical links to human immunodeficiency virus seroprevalence among childbearing women in Montreal, 1989-1993.

BACKGROUND: To describe the socioeconomic profiles of geographical areas on Montreal Island in which human immunodeficiency virus (HIV) seropositive women delivering live births between 1989 and 1993 reside. METHODS: Leftover dried blood spot filter paper specimens collected from newborns were irretrievably unlinked from identifying information prior to testing. Seroprevalence estimates were calculated based on Western blot confirmed positive samples. Using data from the Canadian census, Revenue Canada, and provincial birth records, the socioeconomic characteristics of postal zones in which seropositive mothers reside were described. RESULTS: Montreal Island had an overall 5-year HIV seroprevalence rate estimate of 16.6 (95% CI: 14.1-19.3) per 10000 childbearing women. Areas in which at least one seropositive woman gave birth had lower mean infant birthweights and higher percentages of single mothers and single-parent families. The HIV-positive neonatal blood specimens were more likely to originate from areas where a higher proportion of residents reported less education, greater unemployment, and lower income. CONCLUSIONS: Higher HIV infection rates were found among childbearing women from lower socioeconomic areas of Montreal. Increased understanding of the relationship between socioeconomic status and HIV acquisition and transmission is required to inform the development of targeted HIV prevention programmes.

Prevalence and risk behaviours for HIV infection among inmates of a provincial prison in Quebec City.

OBJECTIVE: To assess HIV prevalence and related risk factors among inmates at the Quebec Detention Centre (QDC). DESIGN: Cross-sectional prevalence study. METHODS: Inmates incarcerated at the QDC in September 1994 were asked to participate in an anonymous survey concerning HIV infection. Volunteers answered a questionnaire and provided a saliva sample during a meeting with an interviewer. RESULTS: The overall participation rate was 95% (618 out of 651). HIV prevalence was 2% (11 out of 499) in men. All HIV-infected men were injecting drug users (IDU) with an HIV prevalence of 9% (11 out of 129) in this group. HIV prevalence was 14% (9/63) among male IDU admitting previous needle-sharing and 3% (two out of 66) among the other IDU (odds ratio, 5.3; P = 0.028). Twelve male inmates admitted injecting drugs during imprisonment, of whom 11 shared needles and three were HIV-positive. HIV prevalence in men reporting sexual intercourse with men prior to incarceration was 10% (five out of 52). Nine of the 119 women were HIV-infected (8%), seven of whom were IDU (prevalence of 16% in female IDU). One of the two non-IDU had sexual contacts with male IDU, and the other with men who had sex with men. Tattooing was not associated with HIV infection in either men or women. CONCLUSIONS: Prisoners constitute a group at high risk of HIV infection mainly because of the high proportion of them who are IDU. Imprisonment offers a good opportunity to provide education and preventive programs to this specific group that might otherwise be difficult to reach.

Combining pooling and alternative algorithms in seroprevalence studies.

Data from two seroprevalence studies and one comparative study of confirmatory algorithms were used to compare the costs and sensitivities of six algorithms for determining seropositivity to human immunodeficiency virus (HIV). We evaluated confirmatory strategies by using the CBC Recombigen HIV enzyme immunoassay (EIA; Cambridge BioScience, Worcester, Mass.) and immunoblotting followed by radioimmunoprecipitation assay to confirm indeterminate immunoblotting results with and without pooling of samples during screening. The least expensive algorithm was that in which sera were pooled during screening and EIA was used to confirm positive test results. The cost savings associated with this confirmatory test were greater when the prevalence of HIV infection was higher. Savings from pooling of sera for screen testing diminished as HIV prevalence increased. The sensitivity and specificity of EIA with respect to immunoblotting and radioimmunoprecipitation assay were estimated to be 0.9992 and 0.9977, respectively. We found that the implementation of pooling during screening and the use of EIA as the confirmatory test do not affect the statistical reliability of estimates of seropositivity but do result in considerable cost savings.

Evaluation of a human immunodeficiency virus test algorithm utilizing a recombinant protein enzyme immunoassay.

Many truly human immunodeficiency virus (HIV) antibody-negative serum samples may be unnecessarily subjected to costly and time-consuming Western blots (immunoblots). An investigation was undertaken to evaluate the efficiency of using a recombinant protein-based enzyme immunosorbent assay (EIA; Cambridge BioScience [CBC] Recombigen HIV EIA) as an adjunct to whole viral lysate EIA. A total of 2,212 serum samples which had been screened by viral lysate EIA were tested by CBC EIA in parallel with the Western blot. The sensitivity and specificity of the CBC kit were 99.9 and 99.7%, respectively. Positive and negative predictive values were 99.7 and 99.9%, respectively. The high sensitivity of this kit and its high negative predictive value make it an attractive addition to an HIV testing algorithm by reducing the number of Western blot tests on truly antibody negative serum samples.

Laboratory evidence of active HIV-1 infection in Canadians with hemophilia associated with administration of heat-treated factor VIII.

Heat-treated factor VIII has been implicated in the transmission of HIV to hemophiliacs. Previously, evidence has been limited to documenting cases of seroconversion following administration of heat-treated factor VIII. Here, we present evidence of active HIV infection, i.e., infected and not merely sensitized following factor VIII injections. Six Canadians with hemophilia had seroconverted during a longitudinal study of their HIV immune status. Two of the three patients tested by this method demonstrated HIV gag-specific sequences upon amplification by polymerase chain reaction. In addition, HIV-1 virus was isolated from peripheral blood lymphocytes of one of these two persons as shown by reverse transcriptase activity of culture supernatants as well as neutralizable p24 antigen. This, we believe, is the first evidence of active HIV infection following administration of 60 degrees C, 30 h heat-treated factor VIII.

Laboratory diagnosis of the first cases of HIV-2 infection in Canada.

Until recently the geographic distribution of infection due to human immunodeficiency virus type 2 (HIV-2) had excluded North America. We report the first two cases of such infection in Canada. Both people came from endemic areas of western Africa and were asymptomatic. The results of a commercial enzyme immunoassay specific for HIV-1 antibody were positive in both cases, but those of the Western blot technique were indeterminate. The Western blot technique specific for HIV-2 antibody and the indirect fluorescent antibody test were used to verify the presence of HIV-2 antibody.