Vaccination Of HIV-infected Children Research Articles

Three vs Four Dose Schedule of Hepatitis-B Vaccine in HIV-infected Children

Three vs Four Dose Schedule of Hepatitis-B Vaccine in HIV-infected Children

Three vs Four Dose Schedule of Double Strength Recombinant Hepatitis-B Vaccine in HIV-infected Children: A Randomized Controlled Trial

To compare seroprotection rates and the anti-HBs titers following primary immunization with double strength (20 µg) recombinant hepatitis B virus (rHBV) vaccine administered intramuscularly (IM) in a 3-dose (0, 1 and 6 months) vs 4-dose (0, 1, 2 and 6 months) schedule in HIV-infected children receiving antiretroviral therapy (ART). An accelerated 3-dose schedule (0, 1, 2 months) within the 4-dose group was also compared. Randomized controlled trial. Pediatric ART clinic of a tertiary hospital in Delhi from November, 2017 to April, 2019. Fifty (25 per group) HIV-infected children aged 18 months - 12 years receiving ART for at least 6 months who had not received any prior dose of HBV vaccine, and were anti-HBs negative. Group 1 received 20 µg of rHBV vaccine IM (in deltoid muscle) at 0, 1, and 6 months, and group 2 received 20 µg the same vaccine at 0, 1, 2 and 6 months. Anti-HBs titers and proportion of responders in 3-dose vs 4-dose group at seventh and twelfth month and at third month after an accelerated 3-dose schedule. Median (IQR) anti-HBs titers at the seventh month were significantly higher in group 2 [225.7 (151-300) IU/L] compared to group 1 [138.2 (35.2-250) IU/L], but were comparable at the 12th month. Seroprotection rates were comparable between group 2 and group 1 at 7th month (96% vs 80%; P=0.19) and 12th month (96% vs 88%; P=0.61). The proportion of good responders were also comparable between the groups at 7th month and 12th month (both P=0.29). Accelerated 3-dose schedule achieved comparable anti-HBs titers [179.9 (130.6-250) IU/L] and seroprotection rate (92%) one month after completion of schedule to the standard 3-dose + schedule. A 3-dose double strength recombinant HBV vaccine schedule offers comparable seroprotection to 4-dose schedule for HIV-infected children receiving ART.

Detection of immunoglobulin G levels produced by oral polio vaccine in HIV infected children in Jos, Plateau State, Nigeria.

IntroductionDisease eradication requires a long time and efficient management as compared to disease control program. After successful small pox eradication, polio virus causing poliomyelitis is choice for next eradication. The corner stone of the global polio eradication initiative is the immunization of children with multiple doses of Oral Polio Vaccine (OPV) through both Routine Immunization (RI) and Supplemental Immunization Activities (SIAs). This informed our design of this prospective study. Objective is to determine levels of Immunoglobulin G antibodies produced in HIV infected children aged (one to ten years) vaccinated with Oral Polio Vaccine (OPV) in Jos, Plateau State, Nigeria.MethodsOne hundred and eighty-two children infected with HIV who had received Oral Polio Vaccine (OPV) at least four times had their blood samples collected and assayed for the presence of Polio Specific IgG antibodies using IgG ELISA test kit (DEMEDITEC Diagnostic GmbH, Germany). Three millilitre (3ml) of venous blood samples were collected aseptically by venepuncture. Sera obtained were assayed using Enzyme immunoassay detection and quantitative determination of human IgG antibodies against poliomyelitis virus in serum and plasma (Demeditic Poliomyelitis Virus IgG ELISA DEPOL01-Germany).ResultsThe result showed that 95.6% (174/182) of the tested children had detectable IgG antibodies against polio virus. The high proportion of 95.6% recorded in this study indicates HIV infected children responded effectively to the Oral Polio Vaccine (OPV) being used in the ongoing polio eradication initiative. In this study, 4.4% (8/182) of the HIV infected children were not producing detectable amount of antibodies that could protect them from exposure to wild type of polio virus.ConclusionThis study shows that HIV infected children had detectable antibodies (Immunoglobulin G) against polio virus. Despite the overall progress recorded in the fight against poliomyelitis in Nigeria, a lot needs to be done to further strengthen the fight against poliomyelitis in Nigeria.

Immunogenicity and Safety of the Measles Vaccine in HIV-Infected Children: An Updated Systematic Review

Children infected with human immunodeficiency virus (HIV) are at increased risk of measles morbidity and mortality. We searched abstracts from the PubMed, Embase, and Latin American and Caribbean Center on Health Sciences Information databases for articles published from the earliest date available through September 26, 2017. The primary outcome of interest was serological responses to measles vaccine, stratified by HIV infection status. A total of 2,858 potentially eligible articles were identified, and the final review included 12 studies published between 1992 and 2013, 9 of which reported data on vaccine safety. The studies we included represented 3,573 children, of whom at least 335 were infected with HIV, 788 were HIV-exposed but not infected, and 1,478 were unexposed to HIV. Four of the 12 studies found statistically significant reductions in seropositivity among HIV-infected children compared with HIV-uninfected children within 4 months of vaccination (prevalence ratio range, 0.44-0.70), and forest plots provided visual trends of decreasing immunity over time among HIV-infected children in 2 additional studies. No vaccine-related deaths or serious adverse events were reported. This updated review demonstrated limitations of the existing published literature but supported evidence of reduced immunogenicity of measles vaccine among HIV-infected children, supporting the World Health Organization recommendation to revaccinate HIV-infected children against measles following immune reconstitution with combination antiretroviral therapy.

Seroprevalence of measles vaccine antibody response in vertically HIV-infected children, in Morocco

BackgroundThe widespread use of an effective and safe vaccine to measles has substantially decreased morbidity and mortality from this epidemic. Nevertheless, HIV-infected children vaccinated against measles may develop an impaired vaccine response and remain susceptible to this disease. In Morocco, infants are routinely vaccinated against measles, regardless of their HIV serostatus. An evaluation of the immunization of these children may be of paramount importance to implement timely measures aimed at preventing measles transmission.MethodsIn this study, we have enrolled 114 children vaccinated against measles, 50 children prenatally infected with HIV and 64 HIV-uninfected children. For all children, blood samples were taken to measure anti-measles IgG by EIA and CD4 count by flow cytometry. Additionally, HIV viral load was determined by automated real time PCR, for HIV-infected children.ResultsThe seroprotective rate of IgG anti-measles antibodies was significantly lower among HIV-infected children (26%) compared with HIV-uninfected children (73%) (p < 0.001). Within HIV-infected children group, the comparison of variables between children without seroprotective seroconversion to measles and those with seroprotective immunity, displayed that sex and age were not statistically different, p > 0.999 and p = 0.730, respectively. However, CD4 count was lower among children with negative serostatus to measles (23% versus 32%, p < 0.001). Furthermore, viral load was higher, with 2.91 log10 ± 2.24 versus 1.7 log10 ± 1.5 (p = 0.042). Finally, 62% of children with a negative vaccine response to measles were under HAART therapy, versus 92% (p = 0.008).ConclusionThe majority of HIV-infected children vaccinated against measles develop a suboptimal seroprotective titer, and therefore remain at risk for this highly infectious disease. These data in combination with international recommendations, including recent WHO guidance on vaccination of HIV-infected children, suggest there is a need for national measures to prevent these children from measles.

Persistence of memory B-cell and T-cell responses to the quadrivalent HPV vaccine in HIV-infected children.

To determine the magnitude and persistence of quadrivalent human papillomavirus (HPV)16 and HPV18 B-cell and T-cell memory after three or four doses of quadrivalent HPV vaccine (QHPV) in HIV-infected children. Seventy-four HIV-infected children immunized with four doses and 23 with three doses of QHPV had HPV16 and HPV18 IgG B-cell and IFNγ and IL2 T-cell ELISPOT performed at 2, 3.5 and 4-5 years after the last dose. HPV16 and HPV18 T-cell responses were similar in both treatment groups, with higher responses to HPV16 vs. HPV18. These HPV T-cell responses correlated with HIV disease characteristics at the study visits. Global T-cell function declined over time as measured by nonspecific mitogenic stimulation. B-cell memory was similar across treatment groups and HPV genotypes. There was a decline in HPV-specific B-cell memory over time that reached statistical significance for HPV16 in the four-dose group. B-cell and T-cell memory did not significantly differ after either three or four doses of QHPV in HIV-infected children. The clinical consequences of decreasing global T-cell function and HPV B-cell memory over time in HIV-infected children requires further investigation.

Humoral and cell-mediated immune responses after a booster dose of HBV vaccine in HIV-infected children, adolescents and young adults.

ObjectiveHBV vaccine induces protective antibodies only in 23–56% of HIV-infected children. The aim of our study is to evaluate the immunologic effects of a booster dose of HBV vaccine in HIV-infected youth.Design53 young HIV-infected patients in whom HBV vaccination did not elicit protective Ab titers were enrolled. All patients were on ART with optimal immunological and viral response.MethodAll patients received a booster dose of HBV vaccine (HBVAXPRO 10 μg i.m.). HBV-specific Ab titer, viral load and CD4+ T cells were measured at baseline (T0), T1, T6 and T12 months. In a subgroup of 16 patients HBV-specific cell mediated immune responses were evaluated at baseline, at T1 and T6.ResultsThe booster dose induced seroconversion in 51% of patients at T1, 57% at T6, and49% at T12; seroconversion rate was significantly correlated with CD4+T cells at T0 and to the CD4 nadir. The booster dose induced HBV-specific cell mediated immunity at T6 mainly in Responders (Rs): Effector Memory CD8+T cells, HBV-specific TNFα-, IFNγ-, granzyme secreting CD8+ T cells and IL2-secreting CD4+ T cells were significantly increased in Rs compared to T0. In Non Responders (NRs), HBV-specific IL2-secreting CD4+ T cells, Central and Effector Memory CD8+ T cells were the only parameters modified at T6.ConclusionsSeroconversion induced by a booster dose of vaccine correlates with the development of T cell immunological memory in HIV-infected patients who did not respond to the standard immunization. Alternate immunization schedules need to be considered in NRs.

Safety and immune response after two-dose meningococcal C conjugate immunization in HIV-infected children and adolescents in Rio de Janeiro, Brazil.

2-18 years old HIV-infected subjects with CD4+ T-lymphocyte cell (CD4) ≥15%, without active infection or antibiotic use, were enrolled to receive 2 doses of conjugated meningococcal C oligosaccharide-CRM197 12-18 months apart. All patients were evaluated before and 1-2 months after immunization for seroprotection [defined as human serum bactericidal activity (hSBA) titer ≥1:4]. AEs were assessed at 20 min, 3 and 7 days after each dose. Factors independently associated with seroprotection were studied. 156 subjects were enrolled and 137 received a booster MCC dose. 55% were female, and median age was 12 years. Eight-nine percent were receiving combined antiretroviral therapy (cART) at the booster visit (median duration of 7.7 years), 59.9% had undetectable viral load (VL) at baseline, and 56.2% at the booster visit. Seroprotection was achieved in 78.8% (108/137) subjects, with a significantly higher GMT than after the priming dose (p < 0.01). Mild AEs were experienced after a second MCC dose (38%). In logistic regression, undetectable viral load at entry [odds ratio (OR) = 7.1, 95% confidence interval (95%CI): 2.14-23.37], and probably higher CD4 percent at the booster immunization visit (OR): 1.1, 95%CI: 1.01-1.17 were associated with seroprotection after a booster dose of MCC. A booster dose of MCC was safe and induced high seroprotection rate even 12-18 months after priming. MCC should be administered after maximum virologic suppression has been achieved. These results support the recommendation of 2-dose of MCC for primary immunization in HIV-infected children and adolescents with restored immune function.

Double Dose Versus Standard Dose Hepatitis B Vaccine in HIV-infected Children: A Randomized Controlled Trial.

To compare the efficacy of double dose (20 µg) with standard dose (10 µg) of hepatitis B vaccine in HIV-infected children. Unvaccinated HIV-infected children were randomized to receive 3 doses of double dose (N=27) or standard dose (N=28) of recombinant Hepatitis B vaccine. Anti-HBs antibody titres were measured 3 mo after the last dose. An antibody titre ≥10 mIU/mL 12 weaks after the third dose was considered as serporotection. Seroprotection was achieved by 17 (60.7%) children in standard dose group against 20 (74%) in the double dose group [RR (95%CI) 0.8 (0.17-1.7); P=0.29]. CD4 count < 500 cells/mm3 was significantly associated with lower rates of seroprotection. Double dose of hepatitis B vaccine does not seem to provide any advantage when compared to standard dose in HIV-infected children.

Four-year persistence of type-specific immunity after quadrivalent human papillomavirus vaccination in HIV-infected children: Effect of a fourth dose of vaccine

ObjectiveAlthough HIV-infected children are recommended to receive quadrivalent human papillomavirus vaccine (QHPV) there is limited information on their response to QHPV. This study in HIV-infected children, evaluated the magnitude and duration of immune responses to QHPV. This report describes type-specific serum antibody responses over a 4-to-5year period after either 3 or 4 doses of QHPV. Design/methodsHIV-infected children, ages 7-to-11years, received 3 doses of QHPV (n=96) or placebo (n=30). At 72weeks QHPV recipients received a fourth dose (n=84), while placebo recipients began the 3-dose QHPV schedule (n=27). HPV serotype-specific antibody was determined, by competitive Luminex immunoassay (cLIA) and IgG Luminex immunoassay, at 2, 3.5, and 4-to-5years after the last dose of QHPV in each treatment arm. ResultsAt 4-to-5years after the last dose of QHPV, antibody titers were significantly higher in 4-dose than in 3-dose group. However, the proportion of vaccinees with a seroresponse in the cLIA assay was not different between the two groups (86–93% for HPV types 6, 11, and 16, and 64% for HPV type 18). These results were very similar to the seroresponse rate in these HIV-infected children at 1month after completing vaccination. ConclusionsChildren with well-controlled HIV infection who receive 3 doses of the QHPV vaccine maintain seropositivity and antibody levels that are generally similar to children of the same age who are not HIV-infected. Antibody titer correlated strongly with low log HIV RNA, low CD8%, and high CD4%. Additionally, a fourth dose of vaccine in HIV-infected children produces a marked rise in antibody characteristic of an anamnestic response and persistence of high antibody levels.Study identification: IMPAACT P1085 (V501-021). CLINICALTRIALS.GOV identifier: NCT01206556.

Evaluation of the efficiency of antituberculosis vaccination in children born to HIV-infected women

The key epidemiological indicators were investigated over time forthe bacilli Calmette-Guerin (BCG) (BCG-M) vaccination of HIV-infected children. BCG-induced immunity and vaccination safety were studied in 376 children, including 131 with an established diagnosis of HIV infection, 141 with a perinatal HIV infection contact, and 104 children born to HIV-negative women. There were 60 cases of tuberculosis among the vaccinated. BCG vaccination of children born to HIV-infected women, but to HIV-uninfected ones was ascertained to show a 4-fold decrease in the risk of tuberculosis at an early age and in that of disseminated tuberculosis (including meningitis) (OR= 3.78; p0.05). BCG vaccination of the HIV-infected children did not reduce the risk of disseminated processes: their proportion among the vaccinated and the unvaccinated was 28.9 and 20.3%, respectively (p>0.05). BCG postvaccination immunity was determined in only one third (29.7%) of the vaccinated in the presence of a small scar in 76.9% of cases.

Evaluation of immune responses to combined hepatitis A and B vaccine in HIV-infected children and children on immunosuppressive medication

ObjectiveA phase IV interventional study with a combined hepatitis A and B vaccine was conducted in HIV-infected children and children receiving immunosuppressive medication for treatment of rheumatic diseases to evaluate immune responses. MethodsBoth groups (1–16 years of age) received combined (inactivated) HAV and (rDNA) HBV vaccine Ambirix® at months 0 and 6. Serum samples were taken at four time points and tested for anti-HAV and anti-HBs antibodies. Anti-HAV concentrations ≥20mIU/mL or anti-HBs concentrations ≥10mIU/mL were considered protective. Seropositivity percentages were calculated and geometric mean concentrations (GMCs) were compared by nonparametric Mann–Whitney U-test or Kruskal–Wallis one-way-analysis-of-variance. ResultsOf 80 HIV-infected children who completed the study, 67 were HAV-susceptible and 68 HBV-susceptible at enrolment. Of 80 children with rheumatic diseases who completed the study, 65 were HAV-susceptible and 74 HBV-susceptible at enrolment. Immune responses to HAV after first dose of vaccine in both study groups were low: 71% and 55% respectively, whereas immune responses after the second dose were 99% and 100% respectively. Immune response to HBV after first dose of vaccine in both groups was also low: 27% and 17% respectively. Immune responses after the second dose were 97% and 93%, respectively. A larger proportion of children on combination antiretroviral therapy (cART) and of children with viral load <50copies/mL responded to HBV, and also showed a significantly higher GMC. ConclusionsAlthough immune response after full series of combined HAV and HBV vaccine in both groups was excellent and comparable to healthy children, a substantial proportion of both groups was not protected for HAV after first dose of vaccine. This protection gap is especially important for HAV in travel health and postexposure prophylactic treatment: both groups of children should be serologically tested for anti-HAV prior to travel to ensure protection if there is no time to await second dose of vaccine.

High proportions of regulatory B and T cells are associated with decreased cellular responses to pH1N1 influenza vaccine in HIV-infected children and youth (IMPAACT P1088)

HIV-infected individuals have poor responses to inactivated influenza vaccines. To evaluate the potential role of regulatory T (Treg) and B cells (Breg), we analyzed their correlation with humoral and cell-mediated immune (CMI) responses to pandemic influenza (pH1N1) monovalent vaccine in HIV-infected children and youth. Seventy-four HIV-infected, 4- to 25-y old participants in a 2-dose pH1N1 vaccine study had circulating and pH1N1-stimulated Treg and Breg measured by flow cytometry at baseline, post-dose 1 and post-dose 2. Concomitantly, CMI was measured by ELISPOT and flow cytometry; and antibodies by hemagglutination inhibition (HAI). At baseline, most of the participants had pH1N1-specific IFNγ ELISPOT responses, whose magnitude positively correlated with the baseline pH1N1, but not with seasonal H1N1 HAI titers. pH1N1-specific IFNγ ELISPOT responses did not change post-dose 1 and significantly decreased post-dose 2. In contrast, circulating CD4+CD25+% and CD4+FOXP3+% Treg increased after vaccination. The decrease in IFNγ ELISPOT results was marginally associated with higher pH1N1-specific CD19+FOXP3+ and CD4+TGFβ+% Breg and Treg, respectively. In contrast, increases in HAI titers post-dose 1 were associated with significantly higher circulating CD19+CD25+% post-dose 1, whereas increases in IFNγ ELISPOT results post-dose 1 were associated with higher circulating CD4+/C8+CD25+FOXP3+%. In conclusion, in HIV-infected children and youth, influenza-specific Treg and Breg may contribute to poor responses to vaccination. However, robust humoral and CMI responses to vaccination may result in increased circulating Treg and/or Breg, establishing a feed-back mechanism.

Efficacy and immunogenicity of influenza vaccine in HIV-infected children

HIV-infected children are at heightened risk for severe influenza illness; however, there is no study on the efficacy or effectiveness of influenza vaccine in these children. We evaluated the safety, immunogenicity, and efficacy of nonadjuvanted, trivalent inactivated influenza vaccine (TIV) against confirmed seasonal influenza virus illness in HIV-infected children. A double-blind, placebo-controlled trial was undertaken in Johannesburg in 2009. Four hundred and ten children were randomized to two doses of TIV or placebo 1 month apart. Nasopharyngeal aspirates obtained at respiratory illness visits were tested by influenza-specific reverse transcriptase-PCR (RT-PCR). Vaccine immunogenicity was evaluated by hemagglutinin inhibition (HAI) assay. Influenza isolates were sequenced and evaluated in maximum likelihood phylogenetic analysis. Overall, the median age of participants was 23.8 months and their median CD4% was 33.5. Ninety-two percent of enrolees were on antiretroviral therapy. Among children receiving both doses of vaccine/placebo, confirmed seasonal influenza illness occurred in 13 (all H3N2) of 205 TIV recipients and 17 (15 H3N2 and two influenza B) of 200 placebo recipients with vaccine efficacy of 17.7% (95% confidence interval <0-62.4%). The proportion of TIV recipients who seroconverted after second dose against vaccine strains of H1N1, H3N2, and influenza B were 47.5, 50.0, and 40.0%, compared to 4.7, 11.6, and 0%, respectively among placebo recipients. There were no TIV-related serious adverse events. Sequence analysis of wild-type H3N2 strains indicated drift from the H3N2 vaccine strain. Poor immunogenicity of TIV, coupled with drift of circulating H3N2 wild-type compared to vaccine strain, may explain the lack of efficacy of TIV in young HIV-infected children. Alternate TIV vaccine schedules or formulations warrant evaluation for efficacy in HIV-infected children.

Immune Activation and Viral Replication after Vaccination with an Influenza A H1N1 2009 Vaccine in HIV-Infected Children Receiving Antiretroviral Therapy

Immunization with a pandemic influenza A H1N1 2009 was recommended for HIV-infected patients. However, there is limited information concerning the impact of immunization with this vaccine on immune activation and HIV viral replication. In this study, 45 HIV-infected children and adolescents receiving antiretroviral therapy were immunized with a 2-dose series of nonadjuvated monovalent influenza A H1N1 2009 vaccine upon enrollment and approximately 1 month later. Immunogenicity was determined by haemagglutination inhibition assay. The level of immune activation was determined by identification of CD38 and HLA-DR on CD8+ T cells. Patients were divided into 2 groups which include patients who had an undetectable HIV viral load (HIV detectable group) and patients who show virological failure (HIV nondetectable group). The results showed seroconversion rate of 55.2% in HIV nondetectable group, whereas 31.3% was found in HIV detectable group. Both groups of patients showed no major increase in immune activation after immunization. Interestingly, a decrease in the frequency of CD8+ T cells that coexpressed CD38 and HLA-DR was observed after immunization in both groups of patients. We suggested that immunization with influenza A H1N1 2009 vaccine can induce immune response to the pandemic virus without major impact on HIV viral replication and immune activation.

Immunogenicity of a meningococcal serogroup C conjugate vaccine in HIV-infected children, adolescents, and young adults

Children and adolescents infected with HIV typically have a lower response to immunization than do those in the general population. In most developed countries, meningococcal serogroup C conjugate vaccine is one of the recommended vaccines for such individuals. However, there have been no studies evaluating the antibody response to this vaccine in HIV-infected children, adolescents or young adults. In this study, we evaluated that response using serum bactericidal antibody (SBA) and enzyme-linked immunosorbent assay, comparing HIV-infected with non-HIV-infected patients, as well as analysing the occurrence of side effects. In non-responders, we assessed the antibody response to revaccination. This clinical trial involved 92 patients between 10 and 20years of age: 43 HIV-infected patients (HIV+ group) and 49 non-HIV-infected patients (HIV− group). After one dose of the vaccine, 72.1% of the HIV+ group patients and 100% of the HIV− group patients were considered protected. Of the HIV+ group patients who received a second dose of the vaccine, only 40% acquired protection. Overall, 81.4% of the HIV+ group patients acquired protection (after one or two doses of the vaccine). Side effects occurred in 16.3% and 44% of the HIV+ group and HIV− group patients, respectively. Therefore, the meningococcal serogroup C conjugate vaccine proved to be safe and effective for use in HIV-infected children, adolescents, and young adults, although their antibody response was weaker than that shown by non-HIV-infected patients. This indicates the need to discuss changes to the immunization schedule for children, adolescents, and young adults infected with HIV, in order to ensure more effective protection against meningococcal disease.

Guidance on vaccination of HIV‐infected children in Europe

Guidance on vaccination of <scp>HIV</scp>‐infected children in <scp>E</scp>urope

Safety and immunogenicity of a monovalent MF59®-adjuvanted A/H1N1 vaccine in HIV-infected children and young adults

BackgroundThis Phase IV study evaluated the safety and immunogenicity of a two-dose, MF59®-adjuvanted (Novartis Vaccines, Marburg, Germany), monovalent, A/H1N1 pandemic influenza vaccination schedule in Human Immunodeficiency Virus (HIV) positive children and young adults. MethodsA total of 83 children infected with HIV-1, and 37 non-immunocompromised, age-matched controls were enrolled. All participants received two vaccine doses administered three weeks apart. Antibody responses were assessed by haemagglutination assay at baseline, three weeks after each vaccine dose, and six months after immunization. Vaccines were evaluated according to European influenza vaccine licensure criteria. ResultsThe investigational vaccine was well tolerated. After the first vaccine dose, seroconversion rates were significantly lower in HIV-positive patients (60%) than controls (82%), with GMTs of 419 and 600, respectively. No significant differences in seroconversion rates were observed between the two study groups in response to the second vaccine dose. Persisting antibody titers were similar for both HIV-positive and non-infected controls, six months after immunization. ConclusionOne dose of MF59-adjuvanted vaccine was sufficient to provide adequate levels of seroprotection against A/H1N1 influenza disease in HIV-positive children. However, a two-dose vaccination schedule may be optimal for this population.

Immunogenicity and safety of monovalent influenza A (H1N1) 2009 in HIV-infected Thai children

To evaluate the immunogenicity and safety of the monovalent pandemic influenza A (H1N1) 2009 (pH1N1) vaccine in HIV-infected Thai children, 2 doses, 28days apart, of non-adjuvant monovalent pH1N1 vaccine (Panenza(®) by Sanofi Pasteur, 15μg/dose) provided by the National Health Promotion Program of the Thai Ministry of Public Health were given to HIV-infected children. Immunogenicity was measured by hemagglutination inhibition test (HAI) using two antigens, pH1N1 (A/Thailand/104/09) and seasonal influenza A H1N1 (A/Brisbane/59/07-like), at baseline, and 28days after each dose. Serologic response was defined as four-fold rising of HAI titer or HAI titer ≥1:40 for those with baseline titer ≤1:10. Adverse events were recorded for 7days after each vaccination. Of the 119 HIV-infected children enrolled, 60 (50.4%) were female with a median (IQR) age of 10.4 (7.2-13.7)years. All but 2 (98.3%) children were receiving antiretroviral therapy. At baseline, the median CD4 cell count was 782 (570-1149)cells/mm(3), 91 (80.5%) children had HIV RNA level <40copies/ml. The baseline HAI titer ≥1:40 for pH1N1 and seasonal H1N1 were 45.4%, and 39.5%, respectively. At 28 days after doses 1 and 2, the serologic response rates for pH1N1 were 54.2% and 67.8% with the geometric mean titer of 109.9 and 141.8; and serologic response rate when tested with seasonal H1N1 were 2.5% and 3.5%, respectively. The presence of baseline HAI titer for pH1N1 or seasonal H1N1 was found to be associated with serologic response. The vaccine was well tolerated. The results suggested that monovalent pH1N1 vaccine was immunogenic and safe in well controlled HIV-infected children with low level of cross reacting antibody to seasonal H1N1.

Long-Term Immunogenicity after One and Two Doses of a Monovalent MF59-Adjuvanted A/H1N1 Influenza Virus Vaccine Coadministered with the Seasonal 2009-2010 Nonadjuvanted Influenza Virus Vaccine in HIV-Infected Children, Adolescents, and Young Adults in a Randomized Controlled Trial

Few data are available on the safety and long-term immunogenicity of A/H1N1 pandemic influenza vaccines for HIV-infected pediatric patients. We performed a randomized controlled trial to evaluate the safety and long-term immunogenicity of 1 versus 2 doses of the 2009 monovalent pandemic influenza A/H1N1 MF59-adjuvanted vaccine (PV) coadministered with the seasonal 2009-2010 trivalent nonadjuvanted influenza vaccine (SV) to HIV-infected children, adolescents, and young adults. A total of 66 HIV-infected patients aged 9 to 26 years were randomized to receive one (group 1) or two (group 2) doses of PV coadministered with 1 dose of SV. The main outcome was the seroconversion rate for PV at 1 month. Secondary outcomes were the geometric mean titer ratios and the seroprotection rates at 1 month for all vaccines, seroconversion rates at 1 month for SV, and longitudinal changes of antibody titers (ABTs) at 1, 2, 6, and 12 months for all vaccines. Groups 1 and 2 had similar CD4 counts and HIV RNA levels during the study. The seroconversion rate for PV was 100% at 1 month in both groups. ABTs for PV were high during the first 6 months and declined below seroprotection levels thereafter. Longitudinal changes in ABTs were similar in groups 1 and 2 for both PV and SV. The side effects of vaccination were mild and mostly local. In HIV-infected children, adolescents, and young adults, the immune response triggered by a single dose of PV was similar to that obtained with a double dose and was associated with long-term antibody response.