Serious infections during pregnancy among women with advanced human immunodeficiency virus infection

Fifty-six human immunodeficiency virus seropositive-women and 76 human immunodeficiency virus seronegative-women had known CD4 cell values and were followed up throughout pregnancy. The women with seronegative results and the 40 with seropositive results and CD4 (helper cell) counts consistently greater than 300 cells/mm3 had no serious infections during pregnancy. Among the 16 with seropositive results and counts that fell below 300 cells/mm3, three developed opportunistic infections, one had pneumonia, and one had a post-cesarean-section abscess. Human immunodeficiency virus seropositive-women with low CD4 counts are at markedly increased risk of serious infections during pregnancy. The consequences of this for fetal health, pregnancy management, maternal well-being, and human immunodeficiency virus testing policies are discussed.

Mother-to-infant transmission of human immunodeficiency virus type 1: association with prematurity or low anti-gp120

In a prospective study of pregnant women infected with human immunodeficiency virus type 1 (HIV-1) in Brooklyn, New York, USA, 16 (29%) of 55 evaluable infants were infected with HIV-1. 9 infants had paediatric acquired immunodeficiency syndrome, 6 had less severe clinical manifestations of HIV-1 infection, and 1 was symptom-free but was seropositive for HIV-1 beyond 15 months of age. The 10 infants born at 37 weeks of gestation or earlier were at higher risk of HIV-1 infection than infants born at 38 weeks of gestation or later (60% vs 22%) but the median age at appearance of disease was approximately 5 months in both groups. The HIV-1 transmission rate was not associated with predelivery levels of maternal T cells, anti-p24, or neutralising antibodies but it was higher, among full-term infants, for those with mothers in the lowest third of the distribution of anti-gp120 levels (53%). On immunoblot, transmitting mothers lacked a gp120 band but not other bands. Protection was not associated with antibody to recombinant peptides from the hypervariable region of the major neutralising gp120 epitope, and the anti-gp120 endpoint dilution titre was similar in transmitting and non-transmitting mothers. Mothers of uninfected full-term infants appear to confer immunological protection against HIV-1 infection of their offspring by way of a high-affinity antibody to a gp120 epitope, whose specificity has importance for vaccine development and possibly perinatal immunotherapy.

Urinary neopterin concentrations vs total neopterins for clinical utility

Neopterin measurements are especially useful as an early marker in (e.g.) allograft rejections and in patients infected with human immunodeficiency virus type 1 (HIV-1). An increased concentration of total neopterins (neopterin + dihydroneopterin) is also a significant marker in patients with HIV-1 infection. In this study we compared concentrations of neopterin and total neopterins in urine samples from 77 homosexual men with and 73 without established HIV-1 infection. HIV-1-seropositive homosexual men had higher concentrations of neopterin and total neopterins (and 7,8-dihydroneopterin) in their urine than did those who were HIV-1-seronegative, and there was a close correlation between neopterin and total neopterins. Both neopterin variables correlated inversely with CD4+ T-cell counts and CD4+/CD8+ T-cell ratios but not with CD8+ T-cell counts in the HIV-1-seropositive men. Our data indicate that measurements of neopterin and total neopterins are of almost equal potential for clinical diagnosis. However, when measuring total neopterins, which includes oxidation of 7,8-dihydroneopterin to neopterin, more strict requirements of sample collection and handling are necessary to avoid degradation of the 7,8-dihydro derivative.

Urinary neopterin concentrations vs total neopterins for clinical utility

Neopterin measurements are especially useful as an early marker in (e.g.) allograft rejections and in patients infected with human immunodeficiency virus type 1 (HIV-1). An increased concentration of total neopterins (neopterin + dihydroneopterin) is also a significant marker in patients with HIV-1 infection. In this study we compared concentrations of neopterin and total neopterins in urine samples from 77 homosexual men with and 73 without established HIV-1 infection. HIV-1-seropositive homosexual men had higher concentrations of neopterin and total neopterins (and 7,8-dihydroneopterin) in their urine than did those who were HIV-1-seronegative, and there was a close correlation between neopterin and total neopterins. Both neopterin variables correlated inversely with CD4+ T-cell counts and CD4+/CD8+ T-cell ratios but not with CD8+ T-cell counts in the HIV-1-seropositive men. Our data indicate that measurements of neopterin and total neopterins are of almost equal potential for clinical diagnosis. However, when measuring total neopterins, which includes oxidation of 7,8-dihydroneopterin to neopterin, more strict requirements of sample collection and handling are necessary to avoid degradation of the 7,8-dihydro derivative.

Immunosuppression in pregnant women infected with human immunodeficiency virus

One hundred two pregnant women at high risk of infection with the human immunodeficiency virus (62 who were drug abusers and 40 of Haitian origin) were prospectively examined for immunologic changes during and after pregnancy. Among the 63 human immunodeficiency virus-negative women, levels of CD4+ (helper) cells fell to a nadir at 8 weeks before delivery and rose rapidly just before delivery. The level of CD8+ (cytotoxic/suppressor) cells rose slowly from midpregnancy to delivery. Among the 37 human immunodeficiency virus-positive pregnant women, levels of CD4+ cells fell during pregnancy (except for a transient weak increase just before delivery) and did not recover in the postpartum period. Levels of CD8+ cells were consistently higher in human immunodeficiency virus-positive than human immunodeficiency virus-negative women. Post partum the CD8+ cells in human immunodeficiency virus-negative women stabilized at delivery levels, whereas they increased greatly in human immunodeficiency virus-positive women. The loss of CD4+ cells in human immunodeficiency virus-positive women appeared to be faster during pregnancy than in the postpartum period. These data support the hypothesis that pregnancy may accelerate human immunodeficiency virus-induced depletion of CD4+ cells and increase the risk of acquired immunodeficiency syndrome.

A prospective study of human immunodeficiency virus type 1 infection and the development of AIDS in subjects with hemophilia

We evaluated a multicenter cohort of 1219 subjects with hemophilia or related disorders prospectively, focusing on 319 subjects with documented dates of seroconversion to human immunodeficiency virus type 1 (HIV-1). The incidence rate of the acquired immunodeficiency syndrome (AIDS) after seroconversion was 2.67 per 100 person-years and was directly related to age (from 0.83 in persons 1 to 11 years old up to 5.66 in persons 35 to 70 years old; Ptrend = 0.00003). The annual incidence of AIDS ranged from zero during the first year after seroconversion to 7 percent during the eighth year, with eight-year cumulative rates (+/- SE) of 13.3 +/- 5.3 percent for ages 1 to 17, 26.8 +/- 6.4 percent for ages 18 to 34, and 43.7 +/- 16.4 percent for ages 35 to 70. Serial immunologic and virologic markers (total numbers of CD4 lymphocytes, presence of serum interferon or HIV-1 p24 antigen, and low or absent serum levels of anti-p24 or anti-gp120) predicted a high risk for the subsequent development of AIDS. Adults 35 to 70 years old had a higher incidence of low CD4 counts than younger subjects (P less than or equal to 0.005), whereas adolescents had a low rate of anti-p24 loss (P = 0.0007) and subjects 1 to 17 years old had a lower incidence of AIDS after loss of anti-p24 (P = 0.03). These findings not only demonstrate that the risk of AIDS is related directly to age but also suggest that older adults are disproportionately affected during the earlier phases of HIV disease, that adolescents may have a low replication rate of HIV, and that children and adolescents may tolerate severe immunodeficiency better because they have fewer other infections or because of some unmeasured, age-dependent cofactor or immune alteration in the later phase of HIV disease.

Predictive markers for the acquired immunodeficiency syndrome (AIDS) in hemophiliacs: persistence of p24 antigen and low T4 cell count

STUDY OBJECTIVE

To investigate the predictive value of assays for human immunodeficiency virus (HIV) p24 antigen, p24 antibody, and gp120 antibody compared with T4 cell counts.

DESIGN

Prospective cohort selected from persons who had HIV-antibody seroconversion.

PATIENTS

Eighty-seven persons with hemophilia with an actuarial cumulative acquired immunodeficiency syndrome (AIDS) incidence of 26% (CI, 12% to 40%), 8 years after HIV-antibody seroconversion.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Human immunodeficiency virus p24 antigen was detected in 8 of 74 (11%) of the patients without AIDS and 7 of 13 (54%) of the patients with AIDS. The 2-year actuarial incidence of AIDS was 24% (CI, 0% to 48%) after detection of p24 antigen, 16% (CI, 0% to 34%) after loss of p24 antibody, 20% (CI, 0% to 45%) after loss of gp120 antibody, 31% (CI, 15% to 47%) after a T4 count of less than 200 cells/microL, and 67% (CI, 31% to 100%) after a T4 count of less than 200 cells/microL among those patients positive for p24 antigen. Very low numbers of T4 and T8 lymphocytes, presence of p24 antigen in serum, and absence of p24 antibody all had some predictive value. However, only p24 antigen (relative hazard 6.0, P = 0.008) and T4 counts (relative hazard 5.3, P = 0.002 with T4 count less than 200 cells/microL) independently predicted AIDS up to 12 months before diagnosis.

CONCLUSIONS

Strong predictors of AIDS are p24 antigenemia or low T4 counts. Detection of p24 antigen is highly specific and complementary to the greater sensitivity of low T4 counts. These findings have important implications regarding prognosis, counseling, and the planning of clinical trials.

A method for the rapid screening of human blood samples for the presence of HIV-1 sequences: the probe-shift assay

In theory, screening directly for the human immunodeficiency virus (HIV) DNA has advantages over screening for HIV-related antibodies; however, the HIV genome appears to be present only in a small fraction of peripheral blood cells from infected individuals. The polymerase chain reaction (PCR) specifically amplifies defined DNA segments, permitting the identification of specific DNA segments even if they are present in a fraction of cells. HIV-derived PCR-amplified segments have been detected by Southern transfer, "dot-blot" hybridization, and digestion with restriction endonucleases. Unfortunately, PCR may amplify not only the single segment of interest but also irrelevant segments, which can be incorrectly identified as HIV related. We describe here an alternative approach to specific detection of PCR-amplified DNA segments, the probe-shift assay, that is simpler, faster, and less subject to erroneous identification than the previously described techniques. The probe-shift assay relies on the hybridization of an appropriately labeled oligonucleotide probe to the amplified segment in solution. The hemiduplex formed between the amplified DNA and the probe is detected following fractionation on nondenaturing gels. This procedure is sufficiently sensitive to detect a single infected cell in the presence of more than 10(5) uninfected cells and has been applied directly to clinical samples.

Censoring in an epidemic with an application to hemophilia-associated AIDS

In epidemiologic studies of infectious diseases, the times of infection may be known only up to an interval. A two-stage parametric regression model is proposed for the analysis of cohort studies during an epidemic in which the exact times of infection cannot be ascertained. The methods permit joint estimation of the effects of covariates both on the risk of infection and the risk of progression to clinical disease once infected. The methodology is applied to a cohort of hemophiliacs who were at risk of infection with the AIDS virus. It was found that hemophiliacs with severe Type A hemophilia were at highest risk of infection, and the risk of infection increased sharply in the early 1980s. Hemophiliacs who were over the age of 20 at infection were at higher risk of progression to AIDS than hemophiliacs who were under age 20. The estimate of the cumulative probability of developing AIDS within t years of infection (the incubation period distribution) for hemophiliacs over age 20 was 1 - exp(-.0021t2.516). Since follow-up in this cohort was restricted to about 10 years from infection, estimates of the incubation period distribution beyond 10 years depend on model extrapolation and should be interpreted cautiously.

Modelling the risk of adult T-cell leukemia/lymphoma in persons infected with human T-lymphotropic virus type I

Adult T-cell leukemia/lymphoma (ATL), a malignancy of mature CD4-positive lymphocytes, has been etiologically linked to the human retrovirus HTLV-I. Although a long latent period is suggested from migrant studies, little prospective information on the risk of developing ATL among persons with HTLV-I infection is available. We present here a model for ATL risk based upon age- and sex-specific HTLV-I seroprevalence data from a cross-sectional survey of 13,000 Jamaicans and ATL incidence data from a 2 1/2-year case-control study. By examining the age-specific incidence of ATL relative to both adult and childhood-acquired seropositivity versus childhood-acquired seropositivity alone, we provide evidence in support of the hypothesis that childhood infection with HTLV-I is important to the development of ATL. Using this model, the cumulative lifetime risk of ATL for those infected before age 20 is estimated to be 4.0% for males and 4.2% for females. Under this hypothesis, HTLV-I-associated diseases with shorter latent periods, such as tropical spastic paraparesis, should have a higher incidence in adult females than in adult males.

Spectrum of HIV-1 neutralizing antibodies in a cohort of homosexual men: results of a 6 year prospective study

Serum samples collected prospectively between 1982 and 1987 from a cohort of homosexual men were analyzed for HIV-1 neutralizing antibodies. Seven seroconverters who became infected between 1982 and 1984 and 12 seroprevalents who were already seropositive in 1982 remained free of AIDS. During the 6 year period, 1 seroconverter and 14 seroprevalents developed AIDS. Healthy seroconverters developed neutralizing antibodies slowly and reached moderate geometric mean titers (GMT) of 1:100 within 3 years of seroconversion. Healthy seroprevalents already had moderate titers in 1982, which increased markedly in 1985-1986 (GMT greater than 1:200) and subsequently returned to the previous level in 1987. Neutralizing antibody titers declined 3 years prior to diagnosis in men who developed AIDS and reached levels significantly lower than those of healthy counterparts 2 years before diagnosis. Analysis of neutralizing antibody activity to several HIV-1 isolates indicated that the lower titers of men who developed AIDS were not due to diminished group-specific reactivity. Thus, high neutralizing antibody titers correlated with better clinical outcome, and low or decreasing neutralizing antibody titer signaled poor prognosis. Although naturally developing neutralizing antibodies may ultimately be inadequate in controlling disease progression, measures able to boost the neutralizing antibody titer of individuals already infected with the virus or to elicit high-titer neutralizing antibodies in individuals at risk may yet prove beneficial in controlling viral spread in vivo or in preventing new infection, presumably in concert with cellular immunity.

A method for predicting individual HIV infection status in the absence of clinical information

Latent structure analysis can be used to determine sensitivity and specificity rates of human immunodeficiency virus antibody assays in the absence of previous clinical or laboratory results. The technique was applied to the analysis of data obtained when a panel of serum samples, collected as part of a large-scale screening project, were subjected to four conventional bioassays (ag121, p24, gp120, and an enzyme-linked immunosorbent assay). To determine the accuracy of this statistical approach, the results of latent structure analysis were compared with the known clinical diagnoses of patients from whom the samples were taken, and nearly 100% agreement was obtained. Although a two-class latent structure model had some predictive value, a three-class model more adequately explained assay patterns. The use of the four standard assays in conjunction with the statistical methods described here would largely reduce the need for confirmatory Western blot assays in analyses of large panels of samples.

Risk of human immunodeficiency virus (HIV-1) infection among laboratory workers

In a prospective cohort study of 265 laboratory and affiliated workers, one individual with no recognized risk factors for human immunodeficiency virus type 1 (HIV-1) infection was HIV-1 seropositive at the time of entry into the study. Molecular analyses of two HIV-1 isolates derived in two independent laboratories from a blood sample from this worker showed that the isolates were indistinguishable from a genotypic form of HIV-1 present in the H9/HTLV-IIIB cell line. Exposure to this strain of virus most probably occurred during work with concentrated virus or culture fluids from virus-producing cell lines under standard Biosafety Level 3 containment. Although no specific incident leading to this infection has been identified, undetected skin contact with virus culture supernatant might have occurred. This worker was the only one found to be positive among the subgroup of 99 workers who shared a work environment involving exposure to concentrated virus. The incidence rate of 0.48 per 100 person-years exposure indicates that prolonged laboratory exposure to concentrated virus is associated with some risk of HIV-1 infection, which is comparable to the risk for health care workers experiencing a needle stick exposure. While none of the ten workers with parenteral exposure to HIV-1 in this cohort became infected, a worker in another laboratory did seroconvert following an injury with a potentially contaminated needle. Strict Biosafety Level 3 containment and practices should be followed when working with concentrated HIV-1 preparations, and further refinement of the procedures may be necessary.

Cancer in a group at risk of acquired immunodeficiency syndrome (AIDS) through 1984

Using a proportional morbidity analysis method, the authors examined changes in the risk of malignancy among never-married men 20-49 years old (a surrogate population for homosexual men) in a high AIDS-risk area (City of San Francisco) and other lower AIDS-risk areas. This approach easily detected increases in Kaposi's sarcoma (odds ratio (OR) comparing 1973-1978 to 1984: 2,479-fold, proportional increase = 99.9%) and in non-Hodgkin's lymphomas (OR = 4.2-fold in 1984, p for trend less than 0.0001, proportional increase = 70%) in the City of San Francisco, with excesses especially in the Burkitt-like lymphomas and immunoblastic lymphomas. Extranodal lymphomas of the brain, but not other sites, were especially prominent (proportional increase = 96%). In addition, nonsignificant increases were seen for Hodgkin's disease (p for trend = 0.13) and for hepatoma (p for trend = 0.08). A posteriori, the authors noted increases in urinary tract tumors and acute lymphoblastic leukemia which warrant monitoring. Other tumors suggested to be AIDS-associated did not occur excessively in this population. Among single young men outside of San Francisco, Kaposi's sarcoma also increased significantly (OR = 182 in 1984), suggesting a lag of about three years behind the increases in the City of San Francisco. Some tumors may require a longer latent period before an association becomes manifest. In the meantime, however, these data indicate that the increases in AIDS-related cancers are limited to only a few malignancies.

Natural history of human immunodeficiency virus infections in hemophiliacs: effects of T-cell subsets, platelet counts, and age

Serial T-cell subsets and platelet counts were determined in a cohort of 84 hemophiliacs in whom time of seroconversion for human immunodeficiency virus (HIV) antibody could be ascertained. An abrupt decrease in the number of T-helper (T4) cells was seen in 9 patients 12 to 24 months before the acquired immunodeficiency syndrome (AIDS) was diagnosed (p = 0.0007 compared with those who did not develop AIDS). Thrombocytopenia also was associated with an increased risk for AIDS (p = 0.02), as was older age at the time of seroconversion (p = 0.03). Ten patients developed AIDS at 24 to 95 months after seroconversion, for a cumulative incidence (+/- SE) of 18.0% +/- 7.1% at 6 years. Hemophiliacs who had T4 cell counts of less than 200 cells/microL had a 50% +/- 16% cumulative incidence of AIDS within 2 years, indicating that decreasing or very low T4 cell counts have predictive value for the development of AIDS. Furthermore, the data suggest that thrombocytopenia and older age may be markers for a cofactor that increases the risk for AIDS in hemophiliacs.

What is safe sex? Suggested standards linked to testing for human immunodeficiency virus

Because of the lethality of the HIV epidemic, rational and scientifically defined standards of sex that preclude the spread of sexually transmitted diseases are required. In the context of an HIV-antibody test that has been documented to be extremely sensitive and specific, standards for truly safe sex can be defined. HIV testing can be used as a powerful tool for defining a series of standards for sexual partners that eliminates, with reasonable certainty, the further spread of HIV. Such standards provide a defined benchmark for future research aimed at evaluating the effectiveness of public health measures in arresting the spread of the virus. The fact that at least 10 million American blood donors and some 2 million Americans applying for or in the armed forces have been tested demonstrates that the adverse consequences of testing can be limited. Now is the time to minimize the fear and eliminate the risk of transmitting HIV to loved ones by urging widespread voluntary testing of sexually active adults and by developing standards for safe sex.

Risk of AIDS after herpes zoster

In a closed internal medicine practice for homosexual men in Central Manhattan herpes zoster developed in 112 men between 1980 and mid-1986. In these patients the incidence of acquired immunodeficiency syndrome (AIDS) was high: Kaplan-Meier survival analysis indicated cumulative incidences of AIDS of 22.8% within 2 years after herpes zoster, 45.5% within 4 years, and an estimated 72.8% after 6 years. Severity of zoster (relative risk, RR = 4.6), degree of pain (RR = 3.4), and zoster of the cranial or cervical dermatomes (RR = 2.2) were all associated with a poor outcome. Oral thrush, oral hairy leucoplakia, amoebiasis, and superficial (tinea) fungal infections also indicated an increased risk of AIDS among zoster patients. Oral thrush and oral hairy leucoplakia manifestations were diagnosed an average of 1.2 and 1.1 years, respectively, after the diagnosis of herpes zoster; thus zoster is an early indicator of an impaired immunity. Herpes zoster can be used as a predictor of AIDS and in AIDS risk groups should be regarded as a poor prognostic sign.

Antiviral antibodies in the sera of homosexual men: correlation with their lifestyle and drug usage

Healthy homosexual men between the ages of 21 and 65 years, from the Washington, DC (n = 162), and New York City (n = 89) areas, were studied for antibodies in the serum against cytomegalovirus (CMV), herpes simplex virus (HSV) types 1 and 2, and Epstein Barr virus (EBV) viral capsid antigen (VCA). CMV-specific antibodies were assayed by enzyme-linked immunosorbent assay (ELISA), anti-HSV-1 and -2 antibodies were measured by indirect hemagglutination (IHA), and antibodies to EBV VCA were measured by the immunofluorescence assay. Antibodies to human T lymphotrophic virus III (HTLV-III) were detected by ELISA and Western blot procedures. T lymphocytes were enumerated using OKT4 monoclonal antibody. Healthy male volunteer blood donors (n = 90) matched for age range and race proportions were used as controls. The percentage of seropositive individuals in the homosexual group was higher (90-98%) for all the viruses tested than in the control group (47-87%). Comparisons of the geometric mean titers, expressed as reciprocal serum dilutions, of seropositive individuals in homosexual (H) vs control (C) group were as follows: CMV-IgG (ELISA) H = 1:794, C = 1:68; HSV-1 (IHA) H = 1:248, C = 1:14; HSV-2 (IHA) H = 1:56, C = 1:17; EBV-VCA (IFA) H = 1:385, C = 1:131. The homosexual group also showed a higher frequency of individuals with elevated titers than the control group. The CMV IgM antibody was prevalent in 17.7% of the homosexual group and 5% of the control group; arithmetic means for ELISA values for CMV IgM were 0.207 for the homosexual group and 0.05 for the control group. In the homosexual group, the anti-CMV antibody titers increased with age (P = 0.01) and with numbers of sex partners (P = 0.06). Both anti-HSV-1 and anti-HSV-2 antibodies correlated with the number of sex partners (P = 0.04 and P = 0.05, respectively). Neither age nor partner number correlated with response to EBV, and no particular sex act was related to the EBV VCA titer level. HTLV-III seropositivity was associated with higher herpes virus group antibody titers, probably because of life style cofactors. Among the HTLV-III-seropositive subjects, those with less than or equal to 400 T-helper lymphocytes/mm3 had lower antibody titers than those with greater than 400 T-helper lymphocytes/mm3 counts, suggesting an impaired immune response secondary to immunosuppression.

Effect of T4 count and cofactors on the incidence of AIDS in homosexual men infected with human immunodeficiency virus

We prospectively evaluated potential markers and cofactors for the acquired immunodeficiency syndrome (AIDS) in 86 homosexual men who were seropositive for human immunodeficiency virus antibodies. During three years of follow-up, 19 men developed AIDS. Risk of AIDS was clearly predicted by the total number of circulating OKT4-positive lymphocytes (T4 count) at enrollment, while the corresponding T8 count was unrelated to subsequent AIDS development. Subjects in Manhattan had a higher risk of Kaposi's sarcoma than did subjects in Washington, DC, and the risk of AIDS tended to increase with numerous homosexual partners. Several of 40 potential cofactors defined ex post facto, including receptive fellatio, enemas, methaqualone use, and high levels of antibody to hepatitis B surface antigen, appeared to be associated with Kaposi's sarcoma but not with Pneumocystis pneumonia. Our data suggest that potent cofactors for Pneumocystis pneumonia were not prominent, pointing to the need for effective drug therapies, particularly to reduce the high AIDS risk of persons with human immunodeficiency virus infection and low T4 counts.

Heterosexual transmission of human immunodeficiency virus: association with severe depletion of T-helper lymphocytes in men with hemophilia

We evaluated risk factors for human immunodeficiency virus (HIV) seropositivity in the wives/female sexual partners of hemophiliacs. One of the 6 seropositive women has developed the acquired immunodeficiency syndrome (AIDS). At least three of the others seroconverted during 1985-86, after more than four years of regular sexual contact with a seropositive hemophiliac. HIV seropositivity was present in at least 5 (50%) of the 10 female partners of hemophiliacs with severe depletion of T-helper cells (less than 100/microliters), including 3 (43%) of the 7 female partners of hemophiliacs with AIDS. All 4 HIV seropositive women with available data had vaginal intercourse without a condom, but risk of seropositivity did not appear to be affected by the frequency of vaginal intercourse or by hysterectomy. Other sexually transmitted diseases, anal intercourse, or vaginal intercourse during menstrual periods were not necessary for HIV infection. These data suggest that heterosexual transmission of HIV can occur during routine vaginal intercourse but that it usually does not occur until the hemophiliac has severe immune deficiency late in the course of HIV infection.