Immunogenicity of Licensed Influenza A (H1N1) 2009 Monovalent Vaccines in HIV-Infected Children and Youth.

BACKGROUND: With the emergence of pandemic influenza A (pH1N1) in 2009, children and youth infected with human immunodeficiency virus (HIV) were vulnerable because of immunologic impairment and the greater virulence of this infection in young persons. METHODS: A multicenter study of the immunogenicity of 3 licensed influenza A (H1N1) monovalent vaccines (1 live attenuated and 2 inactivated) was conducted in children and youth with perinatal HIV infection, most of whom were receiving ≥3 antiretroviral drugs, had CD4% ≥15, and plasma HIV RNA levels <400 copies/mL. Serum hemagglutinin inhibition assay (HAI) antibody levels were measured and correlated with baseline demographic and clinical variables. RESULTS: One hundred forty-nine subjects were enrolled at 26 sites in the United States and Puerto Rico. Over 40% had baseline HAI titers ≥40. For subjects aged 6 months to <10 years, 79% and 68%, respectively, achieved a ≥40- and ≥4-fold rise in HAI titers after the second dose of vaccine. Three weeks after a single immunization with an inactivated vaccine, similar immunogenicity results were achieved in youth aged 10-24 years. With multivariable analysis, only Hispanic ethnicity and CD4% ≥15 were associated with achieving both HAI titer ≥40- and ≥4-fold rise in titer. CONCLUSIONS: Although licensed pH1N1 vaccines produced HAI titers that were considered to be protective in the majority of HIV-infected children and youth, the proportion with titers ≥40- and ≥4-fold rise in titer was lower than expected for children without HIV infection. Vaccine immunogenicity was lower in HIV-infected children and youth with evidence of immune suppression.

Safety and infectivity of two doses of live-attenuated recombinant cold-passaged human parainfluenza type 3 virus vaccine rHPIV3cp45 in HPIV3-seronegative young children.

BACKGROUND: Human parainfluenza virus type 3 (HPIV3) is a common cause of upper and lower respiratory tract illness in infants and young children. Live-attenuated cold-adapted HPIV3 vaccines have been evaluated in infants but a suitable interval for administration of a second dose of vaccine has not been defined. METHODS: HPIV3-seronegative children between the ages of 6 and 36 months were randomized 2:1 in a blinded study to receive two doses of 105 TCID50 (50% tissue culture infectious dose) of live-attenuated, recombinant cold-passaged human PIV3 vaccine (rHPIV3cp45) or placebo 6 months apart. Serum antibody levels were assessed prior to and approximately 4-6 weeks after each dose. Vaccine virus infectivity, defined as detection of vaccine-HPIV3 in nasal wash and/or a≥4-fold rise in serum antibody titer, and reactogenicity were assessed on days 3, 7, and 14 following immunization. RESULTS: Forty HPIV3-seronegative children (median age 13 months; range 6-35 months) were enrolled; 27 (68%) received vaccine and 13 (32%) received placebo. Infectivity was detected in 25 (96%) of 26 evaluable vaccinees following doses 1 and 9 of 26 subject (35%) following dose 2. Among those who shed virus, the median duration of viral shedding was 12 days (range 6-15 days) after dose 1 and 6 days (range 3-8 days) after dose 2, with a mean peak log10 viral titer of 3.4 PFU/mL (SD: 1.0) after dose 1 compared to 1.5 PFU/mL (SD: 0.92) after dose 2. Overall, reactogenicity was mild, with no difference in rates of fever and upper respiratory infection symptoms between vaccine and placebo groups. CONCLUSION: rHPIV3cp45 was immunogenic and well-tolerated in seronegative young children. A second dose administered 6 months after the initial dose was restricted in those previously infected with vaccine virus; however, the second dose boosted antibody responses and induced antibody responses in two previously uninfected children.

Evaluation of tuberculosis diagnostics in children: 1. Proposed clinical case definitions for classification of intrathoracic tuberculosis disease. Consensus from an expert panel.

There is a critical need for improved diagnosis of tuberculosis in children, particularly in young children with intrathoracic disease as this represents the most common type of tuberculosis in children and the greatest diagnostic challenge. There is also a need for standardized clinical case definitions for the evaluation of diagnostics in prospective clinical research studies that include children in whom tuberculosis is suspected but not confirmed by culture of Mycobacterium tuberculosis. A panel representing a wide range of expertise and child tuberculosis research experience aimed to develop standardized clinical research case definitions for intrathoracic tuberculosis in children to enable harmonized evaluation of new tuberculosis diagnostic technologies in pediatric populations. Draft definitions and statements were proposed and circulated widely for feedback. An expert panel then considered each of the proposed definitions and statements relating to clinical definitions. Formal group consensus rules were established and consensus was reached for each statement. The definitions presented in this article are intended for use in clinical research to evaluate diagnostic assays and not for individual patient diagnosis or treatment decisions. A complementary article addresses methodological issues to consider for research of diagnostics in children with suspected tuberculosis.

Introduction: Paving the way for biomedical HIV prevention interventions in youth.

The HIV epidemic among youth continues to grow at alarming proportions throughout the world. Efficacious and comprehensive biomedical prevention interventions are desperately needed for this vulnerable population if a reduction in global HIV incidence is to be achieved. To succeed at enrolling youth in studies of such modalities, communities whose youth will be participating must be highly engaged throughout the spectrum of research concept development to implementation and later translation into programs. In this process, there are numerous challenges, both intrinsic and extrinsic to the youth themselves. Intrinsic ones include developmental considerations in physiology, pharmacology, and behavior; extrinsic considerations are those in the community, ethical, legal, and regulatory arenas and those in designing clinical trials for youth to feasibly participate. We convened a consultative meeting to deliberate over these considerations among a variety of experts representing youth and their community, advocacy groups, academia, industry, regulators, and others in the federal government. Broad recommendations aimed at many stakeholders in the adolescent HIV prevention research agenda were made and were to improve the timely inclusion of youth in this research to ensure that prevention agents can be used safely by youth as soon as they become available to adults.

Assessment of birth defects according to maternal therapy among infants in the Women and Infants Transmission Study.

BACKGROUND: To evaluate rate and types of birth defects according to timing of antiretroviral exposure among babies born to HIV-infected women. METHODS: Anomalies identified during the prenatal, neonatal, or follow-up period were classified using criteria of the Antiretroviral Pregnancy Registry. Antiretroviral use was classified as none, second or third trimester only, or first trimester. RESULTS: From January 1, 1990 through June 30, 2004, 2527 live births (LBs) occurred to 2353 women. Defects were identified in 90 babies for a rate of 3.56 defects per 100 LBs. The rate of defects was 3.19 per 100 LBs (24 of 752 LBs) with first-trimester antiretroviral exposure, 3.54 per 100 LBs (41 of 1158 LBs) with exposure later in pregnancy, and 4.05 of 100 LBs (25 of 617 LBs) with no antiretroviral use. Only genital abnormalities, specifically hypospadias, were significantly increased among babies born to women with first-trimester exposure to antiretrovirals (7 of 382 male LBs) compared with the 2 other groups (2 of 892 male LBs; P = 0.007). On logistic regression, use of zidovudine in the first trimester was associated with hypospadias (adjusted odds ratio = 10.68, 95% confidence interval: 2.11 to 54.13; P = 0.004). CONCLUSIONS: In general, data were reassuring, although the frequency of exposure to newer agents was limited. The increased risk of hypospadias after first-trimester exposure must be explored, because this association has not been detected previously.

Gender differences in lymphocyte populations, plasma HIV RNA levels, and disease progression in a cohort of children born to women infected with HIV.

OBJECTIVE: We sought to document gender differences in lymphocyte subsets and plasma RNA levels in a pediatric cohort with presumed minimal hormonal differences (on the basis of age). METHODS: Blood samples from antiretroviral therapy-treated, HIV-infected children (n = 158) and HIV-uninfected children (n = 1801) who were enrolled in the Women and Infants Transmission Study were analyzed at specified study intervals with consensus protocols, and various parameters were compared. RESULTS: Antiretroviral therapy-treated, HIV-infected female children had, on average, 0.38 log10 copies per mL lower plasma RNA levels than did their male counterparts, but lymphocyte differences were not noted in this cohort. Despite their higher plasma RNA level, a greater proportion of male children survived through 8 years of age. There were no gender differences with respect to the age of diagnosis of HIV, time to antiretroviral therapy after diagnosis of HIV, or type of antiretroviral therapy. Lymphocyte differences were noted for uninfected children. CONCLUSIONS: Plasma RNA levels differed among antiretroviral therapy-treated, HIV-infected children according to gender, in a manner similar to that noted in previous pediatric and adult studies. Lymphocyte subsets varied according to gender in a cohort of HIV-exposed but uninfected children. Most importantly, overall mortality rates for this cohort differed according to gender.

Hepatitis C virus coinfection and HIV load, CD4+ cell percentage, and clinical progression to AIDS or death among HIV-infected women: Women and Infants Transmission Study.

BACKGROUND: Despite previous study, it remains unclear whether hepatitis C virus (HCV) coinfection affects the progression of human immunodeficiency virus (HIV) type 1 infection. The Women and Infants Transmission Study provided an opportunity to assess this issue. METHODS: Longitudinal data on 652 HIV-1-infected women enrolled in the study before the availability of highly active antiretroviral therapy (HAART; 1989-1995) were analyzed. Random effects models were used to determine whether HCV coinfection was associated with different CD4+ cell percentages and HIV-1 RNA levels over time, and Cox proportional hazards models were used to compare the rates of clinical progression to acquired immunodeficiency syndrome (AIDS) or death. RESULTS: Of 652 women, 190 (29%) were HCV infected. During follow-up, 19% of women were exposed to HAART. After controlling for indicators of disease progression (CD4+ cell percentages and HIV-1 RNA levels determined closest to the time of delivery in pregnant women), ongoing drug use, receipt of antiretroviral therapy, and other important covariates, no differences were detected in the HIV-1 RNA levels, but the CD4+ cell percentages were slightly higher in HCV-infected women than in HCV-uninfected women. During follow-up, 48 women had progression to a first clinical AIDS-defining illness (ADI), and 26 died with no documented antecedent ADI. In multivariable analyses, HCV-infected participants did not have faster progression to a first class C AIDS-defining event or death (relative hazard, 0.75; 95% confidence interval, 0.37-1.53). CONCLUSIONS: In this cohort, the rate of clinical progression of HIV-1 infection was not greater for HCV-infected women.