Thymic dysfunction and time of infection predict mortality in human immunodeficiency virus-infected infants. CDC Perinatal AIDS Collaborative Transmission Study Group

The effect of human immunodeficiency virus (HIV)-induced thymic dysfunction (TD) on mortality was studied in 265 infected infants in the CDC Perinatal AIDS Collaborative Transmission Study. TD was defined as both CD4 and CD8 T cell counts below the 5th percentile of joint distribution for uninfected infants within 6 months of life. The 40 HIV-infected infants with TD (15%) had a significantly greater mortality than did the 225 children without TD (44% vs. 9% within 2 years). Infants with TD infected in utero had higher mortality than did those infected intrapartum (70% vs. 37% within 2 years), while no significant difference was noted between infants without TD with either mode of transmission. The TD profile was independent of plasma virus load. Virus-induced TD by particular HIV strains and the time of transmission are likely to explain the variation in pathogenesis and patterns of disease progression and suggest the need for early aggressive therapies for HIV-infected infants with TD.

International multicentre pooled analysis of late postnatal mother-to-child transmission of HIV-1 infection. Ghent International Working Group on Mother-to-Child Transmission of HIV

BACKGROUND

An understanding of the risk and timing of mother-to-child transmission of HIV-1 in the postnatal period is important for the development of public-health strategies. We aimed to estimate the rate and timing of late postnatal transmission of HIV-1.

METHODS

We did an international multicentre pooled analysis of individual data from prospective cohort studies of children followed-up from birth born to HIV-1-infected mothers. We enrolled all uninfected children confirmed by HIV-1-DNA PCR, HIV-1 serology, or both. Late postnatal transmission was taken to have occurred if a child later became infected. We calculated duration of follow-up for non-infected children from the time of negative diagnosis to the date of the last laboratory follow-up, or for infected children to the mid-point between the date of last negative and first positive results. We stratified the analysis for breastfeeding.

FINDINGS

Less than 5% of the 2807 children in four studies from industrialised countries (USA, Switzerland, France, and Europe) were breastfed and no HIV-1 infection was diagnosed. By contrast, late postnatal transmission occurred in 49 (5%) of 902 children in four cohorts from developing countries, in which breastfeeding was the norm (Rwanda [Butare and Kigali], Ivory Coast, Kenya), with an overall estimated risk of 3.2 per 100 child-years of breastfeeding follow-up (95% CI 3.1-3.8), with similar estimates in individual studies (p=0.10). Exact information on timing of infection and duration of breastfeeding was available for 20 of the 49 children with late postnatal transmission. We took transmission to have occurred midway between last negative and first positive HIV-1 tests. If breastfeeding had stopped at age 4 months transmission would have occurred in no infants, and in three if it had stopped at 6 months.

INTERPRETATION

Risk of late postnatal transmission is consistently shown to be substantial for breastfed children born to HIV-1-positive mothers. This risk should be balanced against the effect of early weaning on infant mortality and morbidity and maternal fertility.

Sensitivity and specificity of a qualitative RNA detection assay to diagnose HIV infection in young infants. Perinatal AIDS Collaborative Transmission Study

OBJECTIVE

To evaluate the sensitivity and specificity of an RNA detection assay for diagnosing perinatal HIV infection.

METHODS

Plasma and serum specimens taken during the first 3 months of life from HIV-infected and uninfected children enrolled in a cohort study were assayed for HIV RNA using the qualitative nucleic acid sequence-based amplification (NASBA) kit. Sensitivity, specificity, and predictive values were calculated. NASBA results from infected children were compared with DNA PCR results from the same blood samples. Autoantibody patterns of suspected false-positive specimens were compared with those of subsequent specimens from the same child to exclude specimen labelling errors.

RESULTS

Amongst 131 specimens from 105 HIV-infected children, the sensitivity of the qualitative NASBA assay was 13 out of 34 [38%; 95% confidence interval (CI), 22-56] at < 7 days, 56 out of 58 (97%; 95% CI, 88-100) at 7-41 days, and 37 out of 39 (95%; 95% CI, 83-99) at 42-93 days of life. Of 252 specimens from 206 uninfected children, six tested positive and one tested indeterminate by NASBA. Four of these positive specimens had discordant autoantibody patterns suggesting mislabelling; excluding these, the test specificity was 245 out of 248 (99%; 95% CI, 97-100). Amongst 128 paired specimens from infected children, NASBA results were more often positive than those from DNA PCR (103 versus 92; P=0.01). Amongst infants with specimens drawn in the first week of life, the proportion born after > 4 h of membrane rupture was greater amongst those testing negative (81%) than those testing positive (46%; P=0.05).

CONCLUSIONS

The qualitative NASBA RNA assay is highly specific and more sensitive than DNA PCR. Qualitative RNA assays may be useful for diagnosing and excluding perinatal HIV infection in children after the first week of life for such purposes as initiating antiretroviral therapy and other treatment, resolving parental uncertainty, determining timing of transmission, and providing endpoints for intervention trials.

Impact of zidovudine use on risk and risk factors for perinatal transmission of HIV. Perinatal AIDS Collaborative Transmission Studies

OBJECTIVES

To evaluate the impact of perinatal zidovudine use on the risk of perinatal transmission of HIV and to determine risk factors for transmission among women using perinatal zidovudine.

DESIGN

Prospective cohort study of 1533 children born to HIV-infected women between 1985 and 1995 in four US cities.

METHODS

The association of potential risk factors with perinatal HIV transmission was assessed with univariate and multivariate statistics.

RESULTS

The overall transmission risk was 18% [95% confidence interval (CI), 16-21]. Factors associated with transmission included membrane rupture > 4 h before delivery [relative risk (RR), 2.1; 95% CI, 1.6-2.7], gestational age < 37 weeks (RR, 1.8; 95% CI, 1.4-2.2), maternal CD4+ lymphocyte count < 500 x 10(6) cells/l (RR, 1.7; 95% CI, 1.3-2.2), birthweight < 2500 g (RR, 1.7; 95% CI, 1.3-2.1), and antenatal and neonatal zidovudine use (RR, 0.6; 95% CI, 0.4-0.9). For infants exposed to zidovudine antenatally and neonatally, the transmission risk was 13% overall but was significantly lower following shorter duration of membrane rupture (7%) and term delivery (9%). The transmission risk declined from 22% before 1992 to 11% in 1995 (P < 0.001) in association with increasing zidovudine use and changes in other risk factors.

CONCLUSIONS

Perinatal HIV transmission risk has declined with increasing perinatal zidovudine use and changes in other factors. Further reduction in transmission for women taking zidovudine may be possible by reducing the incidence of other potentially modifiable risk factors, such as long duration of membrane rupture and prematurity.

Diagnosis of perinatal human immunodeficiency virus infection by polymerase chain reaction and p24 antigen detection after immune complex dissociation in an urban community hospital

Results of polymerase chain reaction (PCR) and p24 antigen detection after immune complex dissociation (p24-ICD) were compared with antibody results after 18 months of age for human immunodeficiency virus (HIV) diagnosis in 345 prospectively followed, perinatally exposed infants. Of 59 infected and 286 uninfected infants tested at 1-6 months of age, sensitivity and specificity were, respectively, 100% and > 97% for PCR and 90% and > 97% for p24-ICD. Testing was done on > or = 2 occasions in the first 6 months of life in 43 infected infants; 77% had > or = 2 positive results with the same test. Of these infants, 68% had 2 positive p24-ICD tests. In uninfected infants, 96% had only negative tests; none had > 1 positive. By 6 months, all uninfected infants with > or = 2 PCR results could have been diagnosed. HIV status can be determined by PCR by age 6 months in most HIV-exposed infants. p24-ICD should not be used alone, because of its lower sensitivity, but may be useful in areas without advanced laboratory support.

Attitudes, practices, and infection risks of hemophilia treatment center nurses who teach infection control for the home

OBJECTIVE

To examine the practices toward infection control training and to assess the attitudes about, and risks for, exposures to blood among hemophilia treatment center (HTC) nurses who teach home infusion therapy (HIT).

DESIGN AND POPULATION

Written and telephone interview surveys of the 153 nurses who teach HIT at federally funded HTCs.

MAIN OUTCOME MEASURES

Hemophilia treatment center nurses' teaching practices and infection control messages taught, and frequency of exposures to blood.

RESULTS

The response rate to the written nurses' survey was 60% and to the telephone interview 88%. Nurses taught patients a median of three HIT sessions totaling 4 hours of instruction. Reevaluation of patients' HIT practices took place every 6 months by 22% and every 12 months by 59% of nurses. Nurses frequently reported teaching proper use of a sharps disposal container (99%) and gloves (93%), but less often reported teaching patients to wash hands after infusions (26%) and to report needlestick injuries to HTCs (11%). The respondents identified several barriers to effective infection control as it is practiced in the home by patients. Although at least 30% of HTC nurses recalled having had percutaneous exposure to blood, they considered their risk for hepatitis B infection low but greater than for infection with the human immunodeficiency virus (HIV).

CONCLUSIONS

While some important infection control messages are stressed during HIT teaching, others may be underemphasized. Failure to instruct patients about all infection control precautions may be related to nurse educators' perception of low to moderate personal risk for hepatitis B and HIV infection. Patients receiving HIT, and those who assist them, need to be fully aware of, and to have reinforced periodically, universal infection control strategies in the home.

Infection control practices in the home: a survey of households of HIV-infected persons with hemophilia

OBJECTIVE

To assess infection control practices and risk for human immunodeficiency virus (HIV) transmission in households where home infusion for hemophilia is used.

DESIGN

Cross-sectional prospective survey from 1992 through 1994.

SETTING

Hemophilia treatment centers.

PARTICIPANTS

Human immunodeficiency virus (HIV)-infected persons with hemophilia who receive home infusions of clotting factor concentrate and their household members.

MAIN OUTCOME MEASURES

Frequency of specific infection control practices in the home and the risk of HIV transmission to household members.

RESULTS

We surveyed 235 persons from 75 families (79 HIV-infected persons with hemophilia and 156 household members) about infection control practices in the home. Forty-eight percent of household members surveyed helped with the infusion process. Of 74 members who assisted with infusion, 13 (18%) had sustained a needlestick injury, 11 of whom were injured during the past year. One hundred fifty household members tested for antibody to HIV were antibody negative. These household members had a total of 903 person-years of contact after HIV was diagnosed in the index case. Household members' adherence to recommended infection control measures was highest for washing hands after cleaning up infusion equipment and waste, and for using sharps disposal containers. Adherence was lowest for wearing gloves when helping with infusions and proper disposal of bloody waste from the infusion.

CONCLUSIONS

No HIV transmission was found among persons living with HIV-infected persons with hemophilia, although there was a high rate of needlestick injuries during home infusion. Because persons who assisted with infusions often did not wear gloves and many households did not dispose of bloody waste properly, hemophilia treatment center personnel should emphasize these areas when training for home infusion. Adherence to appropriate infection control practices should help to keep the risk of HIV transmission in households extremely low.

Lack of increased risk for perinatal human immunodeficiency virus transmission to subsequent children born to infected women

BACKGROUND

Little is known about whether a woman's risk of transmitting HIV perinatally increases over time and whether the infection outcome of a previous child affects the risk of transmitting HIV to subsequent children.

METHODS

We analyzed data from 114 prospectively followed women who gave birth to at least 2 children after becoming infected with HIV to determine the risk for perinatal HIV transmission to these sibling pairs.

RESULTS

The median interval between sibling births was 19 months. HIV infection occurred in 19 (17%) older siblings and 20 (18%) younger siblings (P = 0.87). Two (11%) of the 19 children with infected older siblings were infected compared with 18 (19%) of the 95 children with uninfected older siblings (P = 0.86). The risk for transmission to younger siblings was not associated with the interval between deliveries of the two siblings.

CONCLUSIONS

These data do not demonstrate that an HIV-infected woman's risk of transmitting HIV perinatally increases with time, although the observed interpregnancy interval was relatively short. The risk for perinatal transmission does not appear to be affected by the infection outcome of previous children. These findings may be useful for counseling HIV-infected women about their risk of transmitting HIV perinatally.

Estimating the timing of mother-to-child transmission of human immunodeficiency virus in a breast-feeding population in Kinshasa, Zaire

Breast-fed infants born to human immunodeficiency virus (HIV)-infected mothers in Kinshasa, Zaire, were monitored a mean of 18 months. HIV infection in infants was determined by polymerase chain reaction (PCR), HIV culture, or ELISA. PCR test results for HIV DNA on venous blood drawn from children ages 0-2 days and 3-5 months were used to estimate proportions of mother-to-child transmission and transmission risks during the intrauterine, intrapartum/early postpartum, and late postpartum periods. Among 69 HIV-infected children (26% of the cohort), 23% (95% confidence interval [CI], 14%-35%) were estimated to have had intrauterine, 65% (CI, 53%-76%) intrapartum/early postpartum, and 12% (CI, 5%-22%) late postpartum transmission. The estimated risks for intrauterine, intrapartum/early postpartum, and late postpartum infection, respectively, were 6% (16/261; CI, 4%-10%), 18% (45/245; CI, 14%-24%), and 4% (8/189; CI, 2%-8%). These results support earlier studies indicating that most transmission occurs during labor and delivery or in the early postpartum period and that the risk of HIV transmission through breast-feeding during the postpartum period is substantial.

Cost-effectiveness of short-course zidovudine to prevent perinatal HIV type 1 infection in a sub-Saharan African Developing country setting

OBJECTIVE

To evaluate the cost-effectiveness of a short-course zidovudine program to prevent perinatal transmission of human immunodeficiency virus (HIV) type 1 in sub-Saharan African country settings.

DESIGN AND SETTING

Several clinical trials of short-course zidovudine during pregnancy for prevention of perinatal transmission of HIV are under way in developing countries in sub-Saharan Africa. A decision model was used to examine the cost-effectiveness of zidovudine programs in a hypothetical 1-year birth cohort in a sub-Saharan African setting from the perspective of the health care system and of society. A completed short course of zidovudine was assumed to reduce perinatal HIV transmission from 25% to 16.5%, approximately one half of the effect of the longer-course zidovudine. Estimates of program costs, lifetime HIV-related health care costs, and lost productivity costs were derived from the published literature and from preliminary data available from sites of planned clinical trials. Sensitivity analyses were conducted on all relevant parameters.

MAIN OUTCOME MEASURES

Medical costs, lost productivity costs, program costs, cost savings, and incremental cost-effectiveness, expressed as cost per infant HIV infection prevented.

RESULTS

The model estimated that a national zidovudine program in a setting with 12.5% HIV seroprevalence would reduce perinatal HIV incidence by 12% (4.9 infections per 1000 births). The costs to the health care system would be $3748 per infant HIV infection prevented. When productivity losses were included in the model, the cost decreases to $1115 per infant HIV infection prevented. The cost to implement a national zidovudine program including the cost of counseling, testing, and drugs, would be $2 million per 100,000 births or $20 per pregnant woman. In the base case, decreases in the cost of counseling and testing and increases in maternal HIV prevalence, zidovudine efficacy, and medical and lost productivity costs improved cost-effectiveness of the zidovudine program.

CONCLUSIONS

Assuming demonstrable efficacy of short-course zidovudine prevention of perinatal HIV, a national perinatal HIV prevention program with zidovudine in most sub-Saharan African country settings would reduce the incidence of infant HIV infection and, in some settings, provide societal savings; however, substantial initial investment in such programs will be required. Where health care resources are limited, as in these regions, allocation of resources to a perinatal zidovudine program will need to be considered in the context of resources required for other pressing medical care needs.

Preventing perinatal transmission of HIV--costs and effectiveness of a recommended intervention

OBJECTIVE

To calculate the national costs of reducing perinatal transmission of human immunodeficiency virus through counseling and voluntary testing of pregnant women and zidovudine treatment of infected women and their infants, as recommended by the Public Health Service, and to compare these costs with the savings from reducing the number of pediatric infections.

METHOD

The authors analyzed the estimated costs of the intervention and the estimated cost savings from reducing the number of pediatric infections. The outcome measures are the number of infections prevented by the intervention and the net cost (cost of intervention minus the savings from a reduced number of pediatric HIV infections). The base model assumed that intervention participation and outcomes would resemble those found in the AIDS Clinical Trials Group Protocol 076. Assumptions were varied regarding maternal seroprevalence, participation by HIV-infected women, the proportion of infected women who accepted and completed the treatment, and the efficacy of zidovudine to illustrate the effect of these assumptions on infections prevented and net cost.

RESULTS

Without the intervention, a perinatal HIV transmission rate of 25% would result in 1750 HIV-infected infants born annually in the United States, with lifetime medical-care costs estimated at $282 million. The cost of the intervention (counseling, testing, and zidovudine treatment) was estimated to be $ 67.6 million. In the base model, the intervention would prevent 656 pediatric HIV infections with a medical care cost saving of $105.6 million. The net cost saving of the intervention was $38.1 million.

CONCLUSION

Voluntary HIV screening of pregnant women and ziovudine treatment for infected women and their infants resulted in cost savings under most of the assumptions used in this analysis. These results strongly support implementation of the Public Health Service recommendations for this intervention.

Preventing Pneumocystis carinii pneumonia in persons infected with human immunodeficiency virus

Although the incidence of Pneumocystis carinii pneumonia (PCP) among adults infected with human immunodeficiency virus (HIV) has declined, no decline in PCP incidence has been observed among HIV-infected children, and PCP remains the most common serious opportunistic infection among both adults and children in the United States. Some evidence of airborne transmission of P. carinii exists, and some clusters of cases of PCP have been reported; however, data are insufficient to recommend that persons with PCP be separated from immunosuppressed persons as a standard practice. The incidence of PCP can be reduced substantially if persons at risk for PCP are identified and receive adequate chemoprophylaxis. Several drugs and drug combinations are highly effective in preventing PCP. For both adults and children, oral trimethoprim-sulfamethoxazole (TMP-SMZ) is the preferred form of prophylaxis. Adverse effects are commonly associated with the use of TMP-SMZ and in some cases may necessitate withdrawal of the drug until the effects resolve. However, reintroduction at the same dose or at a lower and gradually increasing dose will often permit the continued use of TMP-SMZ. For persons intolerant of TMP-SMZ, dapsone alone and dapsone plus pyrimethamine are effective alternatives. A third alternative is aerosolized pentamidine. Additional drugs of unproven efficacy but of potential use in exceptional cases are available.

Prophylaxis against Pneumocystis carinii pneumonia among children with perinatally acquired human immunodeficiency virus infection in the United States. Pneumocystis carinii Pneumonia Prophylaxis Evaluation Working Group

BACKGROUND

Pneumocystis carinii pneumonia (PCP) remains a common and often fatal opportunistic infection among children infected with the human immunodeficiency virus (HIV). HIV-infected infants between three and six months of age are particularly vulnerable. Current guidelines recommend prophylaxis in children from birth to 11 months old who have CD4+ counts below 1500 cells per cubic millimeter.

METHODS

We used national surveillance data to estimate the annual incidence of PCP among children less than one year old. We reviewed the medical records of 300 children given a diagnosis of PCP between January 1991 and June 1993 to determine why treatment according to the 1991 guidelines for prophylaxis against PCP either was not given or failed to prevent the disease.

RESULTS

In our study the incidence of PCP in the first year of life among infants born to HIV-infected mothers changed little between 1989 and 1992. Among 7080 children born to HIV-infected mothers in 1992, PCP developed in 2.4 percent. Of 300 children with PCP diagnosed from January 1991 through June 1993, 199 (66 percent) had never received prophylaxis, and for 118 of those children (59 percent) exposure to HIV was first identified 30 days or less before the diagnosis of PCP. Among 129 children less than one year old, the CD4+ count declined by an estimated 967 cells per cubic millimeter (95 percent confidence interval, 724 to 1210 cells per cubic millimeter) during the three months before the diagnosis of PCP. Among infants in whom CD4+ counts were determined within one month of the diagnosis of PCP, 18 percent (20 of 113) had at least 1500 cells per cubic millimeter, a level higher than the currently recommended threshold for prophylaxis.

CONCLUSIONS

In the United States the incidence of PCP among HIV-infected infants has not declined. If this infection is to be prevented, infants exposed to HIV must be identified earlier, and prophylaxis must be offered to more children than the guidelines currently recommend.