Pneumococcal and influenza immunization and human immunodeficiency virus load in children

No changes on viral load and CD4+ T-cell counts following immunization with 7-valent pneumococcal conjugate vaccine among HIV-infected adults in Malawi

Vaccination has been associated with a transient increase in viremia in HIV-infected individuals, although contradicting evidence persist in the literature. As part of a randomized placebo-controlled efficacy trial of the PCV7 in Malawi, we collected viral load and CD4+ T-cell counts from 237 adults who received two doses of vaccine or placebo, administered 4 weeks apart. Analyses were conducted separately for cART and non-cART users. Our analysis show no difference in viral loads between vaccine and placebo groups, regardless of cART use. Viremia decreased from 4.1 to 2.9 log₁₀ copies/mL (p < 0.0001) among those using cART, consistent vaccine and placebo groups, but no changes were seen among the non-cART cohort. CD4+ T-cell counts remained unchanged regardless of cART use, or allocation to vaccine or placebo. We concluded that there was no evidence of detrimental effects of PCV7 administration on viral load or CD4+ T-cell counts six months after vaccination with PCV7.

Sublingual allergen immunotherapy in HIV-positive patients

HIV infection is a relative contraindication for allergic immunotherapy (AIT). In the last decade, highly active antiretroviral therapy (HAART) has improved the immune function and life expectancy in HIV-infected patients whose respiratory allergic incidence is similar to the general population. We evaluated the safety and clinical effectiveness of sublingual immunotherapy in a group of grass pollen-allergic HAART-treated HIV-positive patients. Thirteen patients received sublingual immunotherapy (SLIT) tablet (Oralair, Stallergenes©) and symptomatic therapy and were compared with nine patients receiving symptomatic therapy alone. Clinical benefits were evaluated by the analysis of total combined score (TCS), sum of symptom-medication score, and a quality of life (QoL) questionnaire. HIV viral load and peripheral TCD4 lymphocytes were analyzed at the beginning and at the end of the study. Clinical efficacy data showed a significant improvement in SLIT-treated patients compared to controls (TCS: P = 0.0001; QoL: P = 0.03). We did not observe any significant alteration of TCD4 cell counts and viral load (VL) in both groups. Our preliminary data showed that SLIT therapy in viro-immunological controlled HAART treated HIV positive patients was efficacious, safe and well tolerated.

HIV: practical implications for the practicing allergist-immunologist

OBJECTIVES

To review the effects of human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) on allergic diseases and discuss the clinical, pathophysiologic, diagnostic, and therapeutic challenges unique to HIV-infected patients receiving highly active antiretroviral therapy (HAART).

DATA SOURCES

The MEDLINE and OVID databases were searched to identify pertinent articles using the following keywords: HIV, AIDS, IgE, allergic rhinitis, adverse drug reaction, asthma, chronic obstructive pulmonary disease, food allergy, and immunization. References from the chosen articles were also examined.

STUDY SELECTION

Articles were selected based on their relevance to the subject matter and currency.

RESULTS

Human immunodeficiency virus infection causes immunologic alterations that ultimately lead to cell-mediated immune deficiency. In addition, the immune dysfunction caused by HIV also increases the likelihood of developing allergic and other immune-mediated diseases in many patients. HAART is associated with reconstitution of immune system function. While offering protection against infection, immune reconstitution also can provoke immunopathologic conditions. Patients infected with HIV show an increased prevalence of allergic rhinitis, adverse drug reactions, and noninfectious pulmonary complications. The pathophysiology of HIV infection is associated with unique clinical, diagnostic, and therapeutic considerations when treating allergic diseases in HIV-infected patients.

CONCLUSIONS

With the use of HAART and the subsequent decrease in infectious complications, HIV-infected patients now live longer and experience common chronic diseases. Evaluation of HIV-infected patients with rhinitis, asthma, and adverse drug reactions may become more frequent as HAART continues to extend the life expectancy of patients living with HIV. Understanding the interactions between HIV and these conditions can facilitate a knowledgeable approach to treating an HIV-infected patient.

The immunogenicity of a novel A (H1N1) vaccine in HIV-infected children

BACKGROUND

In October 2009, the United Kingdom Department of Health recommended vaccination of high-risk groups, including children with HIV, with a novel, oil-in-water AS03(B) adjuvanted Influenza A (H1N1) vaccine (Pandemrix). There were no published data available regarding the immunogenicity of this vaccine in such children.

OBJECTIVES

This study evaluated the immunogenicity of the adjuvanted Influenza A (H1N1) vaccine in HIV-infected children immunised according to national recommendations and assessed the impact of vaccination on individual CD4 counts and HIV viral loads.

METHODS

HIV-infected children attending outpatient appointments between 01 November and 31 December 2009 were offered two doses of H1N1 vaccine three weeks apart and a blood test before and 3 weeks after the second dose of vaccine. Serum antibody responses were determined by a haemagglutination inhibition (HAI) assay using standard methods.

RESULTS

Of the 39 children recruited for vaccination, 31 (median age 11.2, range 3.0-17.9 years) received both doses of vaccine and provided pre- and post-vaccination blood samples. Eight children (26%) had baseline HAI titres ≥ 1:32. After vaccination, 29 children (94%, 95% CI, 78.6-99.2%) had HAI titres ≥ 1:32 (seroprotection), of whom 27 (87.1%, 95% CI, 70.1-96.4%) had also had a four-fold rise in titres (seroconversion). In the univariate analysis, post-vaccination geometric mean titres (GMTs) were higher among the 21 children receiving highly active anti-retroviral therapy compared with the 10 treatment-naïve children (GMT 406 [95% CI 218-757] vs. 128 [49-336]; P=0.035), but this was no longer statistically significant when adjusted for prevaccine GMTs. There was no significant impact of vaccination on CD4+ T cell count or HIV viral load.

CONCLUSION

The AS03(B)-adjuvanted pandemic Influenza A (H1N1) vaccine is highly immunogenic and appears to be safe in HIV-infected children.

T cell responses of HIV-infected children after administration of inactivated or live attenuated influenza vaccines

Live-attenuated influenza vaccine (LAIV) prevents significantly more cases of influenza in immune-competent children than the trivalent inactivated vaccine (TIV). We compared the T cell responses to LAIV or TIV in HIV-infected children. IFN-gamma-ELISPOT for the three vaccine-contained influenza strains, two mismatched strains, and phytohemagglutinin (PHA), was performed at 0, 4, and 24 weeks postimmunization in 175 HIV-infected children randomly assigned to LAIV or TIV. The contribution of CD8 T cells to the influenza-specific response (CD8-ELISPOT) was evaluated by CD8-cell depletion. CD8 T cells accounted for > or =87% of the total influenza-ELISPOT. At baseline, total influenza-ELISPOT and CD8-ELISPOT values were similar or higher in TIV compared with LAIV recipients. Four and 24 weeks after TIV, total influenza-ELISPOT and CD8-ELISPOT results were significantly lower than baseline results (p < or = 0.001). Responses to PHA also tended to decrease at 4 weeks after TIV (p = 0.06), but rebounded to baseline levels at 24 weeks. Four weeks after LAIV, total influenza-ELISPOT responses to vaccine-contained strains A H3N2 and B significantly decreased. Other ELISPOT values at 4 weeks and all values at 24 weeks were similar to the baseline values. At 4 and 24 weeks, TIV compared to LAIV administration resulted in a significantly greater decrease in influenza-specific ELISPOT values for vaccine-contained influenza A strains (p < or = 0.02). Responses to PHA also tended to decrease more in TIV recipients (p = 0.07). HIV-infected children immunized with TIV had significant and persistent decreases in ELISPOT responses to influenza. LAIV administration suppressed ELISPOT responses less. The clinical significance of these findings deserves further study.

Prophylaxis and therapy for Chikungunya virus infection

BackgroundChikungunya virus (CHIKV) is a recently reemerged arbovirus responsible for a massive outbreak of infection in the Indian Ocean region and India that has a very significant potential to spread globally because of the worldwide distribution of its mosquito vectors. CHIKV induces a usually self-limited disease in humans that is characterized by fever, arthralgia, myalgia, and rash; however, cases of severe CHIKV infection have recently been described, particularly in adults with underlying condition and neonates born to viremic mothers

MethodsHuman polyvalent immunoglobulins were purified from plasma samples obtained from donors in the convalescent phase of CHIKV infection, and the preventive and curative effects of these immunoglobulins were investigated in 2 mouse models of CHIKV infection that we developed

ResultsCHIKV immunoglobulins contain anti-CHIKV antibodies and exhibit a high in vitro neutralizing activity and a powerful prophylactic and therapeutic efficacy against CHIKV infection in vivo, including in the neonate

ConclusionsAdministration of CHIKV immunoglobulins may constitute a safe and efficacious prevention strategy and treatment for individuals exposed to CHIKV who are at risk of severe infection, such as neonates born to viremic mothers and adults with underlying conditions. These results provide a proof-of-concept for purifying human immunoglobulins from plasma samples from patients in the convalescent phase of an emerging infectious disease for which neither prevention nor treatment is available

Immunogenicity of 23-valent pneumococcal polysaccharide vaccine in HIV-infected pregnant women and kinetics of passively acquired antibodies in young infants

Whether gestational immunization of HIV-infected mothers with the 23-valent pneumococcal polysaccharide vaccine (PPV) confers maternal and infant early life, passive protection is not known. We evaluated safety, immunogenicity and placental transfer of antibodies in 44 HIV-infected women. Pneumococcal IgG antibodies against serotypes 1, 3, 5, 6B, 9V, and 14 were measured in mothers (pre-vaccination and at delivery), and infants (at birth, 1, 2, 3, and 6 months). PPV was safe and immunogenic in mothers. Newborns received 46-72% of maternal antibody titers. Overall, infants had antibody levels lower than protective by 2 months of age. Alternative pneumococcal vaccination of HIV-infected pregnant women should be explored with the aim of prolonging passive protection in their infants.

Abnormal humoral immune response to influenza vaccination in pediatric type-1 human immunodeficiency virus infected patients receiving highly active antiretroviral therapy

Given that highly active antiretroviral therapy (HAART) has been demonstrated useful to restore immune competence in type-1 human immunodeficiency virus (HIV-1)-infected subjects, we evaluated the specific antibody response to influenza vaccine in a cohort of HIV-1-infected children on HAART so as to analyze the quality of this immune response in patients under antiretroviral therapy. Sixteen HIV-1-infected children and 10 HIV-1 seronegative controls were immunized with a commercially available trivalent inactivated influenza vaccine containing the strains A/H1N1, A/H3N2, and B. Serum hemagglutinin inhibition (HI) antibody titers were determined for the three viral strains at the time of vaccination and 1 month later. Immunization induced a significantly increased humoral response against the three influenza virus strains in controls, and only against A/H3N2 in HIV-1-infected children. The comparison of post-vaccination HI titers between HIV-1+ patients and HIV-1 negative controls showed significantly higher HI titers against the three strains in controls. In addition, post vaccination protective HI titers (defined as equal to or higher than 1:40) against the strains A/H3N2 and B were observed in a lower proportion of HIV-1+ children than in controls, while a similar proportion of individuals from each group achieved protective HI titers against the A/H1N1 strain. The CD4+ T cell count, CD4/CD8 T cells ratio, and serum viral load were not affected by influenza virus vaccination when pre- vs post-vaccination values were compared. These findings suggest that despite the fact that HAART is efficient in controlling HIV-1 replication and in increasing CD4+ T cell count in HIV-1-infected children, restoration of immune competence and response to cognate antigens remain incomplete, indicating that additional therapeutic strategies are required to achieve a full reconstitution of immune functions.

Response to Measles, Mumps, and Rubella Revaccination in HIV-Infected Children with Immune Recovery after Highly Active Antiretroviral Therapy

BACKGROUND

The low prevalence of measles antibody in human immunodeficiency virus (HIV)-infected children after immune recovery as a result of highly active antiretroviral therapy increases the risk of morbidity and mortality from disease. The objective of our study was to evaluate the efficacy and safety of revaccination with measles, mumps, and rubella (MMR) vaccine in HIV-infected children with immune recovery.

METHODS

Inclusion criteria were (1) HIV-infected children aged >5 years, (2) a nadir CD4 lymphocyte percentage <or=15%, (3) immune recovery (defined as a CD4 lymphocyte percentage >15% for >or=3 months after highly active antiretroviral therapy), and (4) no protective antibody against measles. Each child received 1 dose of MMR vaccine, and antibodies were measured at 4 and 24 weeks after vaccination. Protective antibodies were defined as an antimeasles immunoglobulin G (IgG) level >or=320 mIU/mL, an antimumps IgG titer >1:500, and an antirubella IgG level >10 IU/mL.

RESULTS

There were 51 participants. The mean age (+/- standard deviation) was 10.2 +/- 2.5 years. Prior to revaccination, 28 participants (55%) had baseline protective antibody to mumps, and 11 (20%) had baseline protective antibody to rubella. The prevalence of protective antibody at 4 weeks was 90%, 100%, and 78% for measles, rubella, and mumps, respectively, and then slightly decreased to 80%, 94%, and 61%, respectively, at 24 weeks after revaccination. No serious adverse reactions were attributed to revaccination.

CONCLUSIONS

The majority of HIV-infected children with immune recovery can develop protective antibodies after MMR revaccination. Revaccination with MMR vaccine in HIV-infected children with immune recovery should be considered to ensure individual immunity and limit the spread of disease.

Allergen immunotherapy in a patient with human immunodeficiency virus: effect on T-cell activation and viral replication

BACKGROUND

Allergen immunotherapy is a major therapeutic modality in the treatment of allergic rhinitis. However, with T-cell activation potential, its role in patients with human immunodeficiency virus (HIV) was theoretically limited.

OBJECTIVE

To report the results of allergen immunotherapy in a patient with HIV treated with highly active antiretroviral therapy (HAART).

METHODS

A 44-year-old man with a history of HIV did not respond to medical therapy for allergic rhinitis. His HIV status was well controlled with HAART. Owing to the severity of his allergic rhinitis symptoms, he accepted the risk of allergy immunotherapy despite the unknown effect of immunotherapy in patients with HIV.

RESULTS

After 6 weeks of weekly immunotherapy injections, his viral load remained undetectable and his CD4 cell count changed from 540 to 570 cells/microL. After 16 weeks of weekly immunotherapy, his viral load increased to 10,900 copies/mL, and his CD4 cell count increased to 665 cells/microL. After 24 weeks of weekly immunotherapy, his viral load returned to an undetectable level, and his CD4 cell count stabilized at 356 cells/microL. Despite his notable change in HIV status, he continues to receive the same HAART. He currently continues en route to maintenance immunotherapy.

CONCLUSIONS

The effect of allergen immunotherapy on HIV infection has not been previously reported. A concern remains that any form of immunotherapy may negatively affect HIV disease progression. This case illustrates that weekly allergen immunotherapy may have induced limited T-cell proliferation and a modest increase in RNA viral load, which resolved with continuation of HAART.

Immunogenicity and effect of a virosomal influenza vaccine on viral replication and T-cell activation in HIV-infected children receiving highly active antiretroviral therapy

In order to evaluate the immunogenicity and the effect of a virosomal influenza vaccine on viral replication and T-cell activation in HIV-infected children receiving highly active antiretroviral therapy (HAART), 29 children infected with HIV-1 vertically (19 primed with a previous influenza vaccination and 10 who were not been immunized against influenza) were immunized with an intramuscular virosome-adjuvanted influenza vaccine. According to the European Agency for Evaluation of Medical Products (EMEA) criteria, the immunogenicity of the vaccine was adequate against all three influenza strains (A H1N1, A H3N2, and B) in the primed children, and against A H1N1 and A H3N2 in the unprimed children. After in vitro stimulation with vaccine antigens, the IFN-gamma levels in the peripheral blood mononuclear cells cultures increased significantly from a baseline level of 103.0 +/- 229.8 pg/ml to a 30-day level of 390.7 +/- 606.3 pg/ml (P < 0.05), with concentrations significantly higher (P < 0.05) in the primed children than in the unprimed children. No increase in plasma HIV-1 RNA or HIV-1 proviral DNA was observed in either subgroup, and the immunophenotype analyses demonstrated that the CD4+ cell counts and percentages, the CD4/CD8 ratio and activated lymphocytes remained stable in either group from baseline to 1 month after each vaccine dose. This study showed that the virosomal influenza vaccine does seem to be immunogenic in the majority of HIV-infected children receiving HAART and does not induce viral replication or T-cell activation. Given the possible influenza-related complications in children infected with HIV, these results support the use of this influenza vaccine in such patients.

Effect of influenza virus vaccine on the expression of human immunodeficiency virus co-receptor CCR5

BACKGROUND

Administration of influenza vaccine to human immunodeficiency virus (HIV)-infected children can lead to increased viral load. CCR5 and CXCR4 are known to play an important role in HIV cell entry and viral replication.

OBJECTIVE

To determine the effects of influenza vaccine on chemokine receptors and on viral load in HIV-infected children.

METHODS

Eight HIV-infected children receiving stable therapy and 11 healthy adults were enrolled. Chemokine expression and immune activation were determined before and 48 hours after influenza vaccination. CCR5 and beta-chemokine gene expression were analyzed using real-time polymerase chain reaction. Viral load was measured at baseline, 48 hours, and 6 to 12 weeks.

RESULTS

Forty-eight hours after influenza vaccination, mean CCR5 expression was significantly decreased on the CD3 (21.1% vs 11.3% in HIV-infected children; P = .02; and 18.3% vs 10.7% in controls; P = .008) and CD4 (13.0% vs 3.6% in the HIV group; P = .04; and 13.6% vs 6.5% in controls; P = .02) lymphocytes. This was observed in conjunction with an increase in HLA-DR expression on T lymphocytes in HIV-infected children (P = .046). No significant changes were observed in HIV viral load, CD3 and CD8 lymphocyte counts, expression of interleukin 2 receptor and CXCR4, or gene expression of CCR5 and beta-chemokines 48 hours after vaccination.

CONCLUSIONS

Influenza virus vaccine markedly decreased chemokine receptor CCR5 expression on CD4 T lymphocytes. However, this immunomodulatory effect does not seem to affect overall viral replication in HIV-infected children who received highly active antiretroviral therapy.

Pneumococcal conjugate vaccines for preventing vaccine-type invasive pneumococcal disease and pneumonia with consolidation on x-ray in children under two years of age

BACKGROUND

Pneumonia, most commonly caused by Streptococcus pneumoniae (Pnc), is a major cause of morbidity and mortality among young children especially in developing countries. Recently, the prevalence of antibiotic-resistant Pnc has increased worldwide such that the effectiveness of preventive strategies, like the new pneumococcal conjugate vaccines (PCV) on rates of invasive pneumococcal disease (IPD) and pneumonia, needs to be evaluated.

OBJECTIVES

To determine the efficacy of PCV in reducing the incidence of IPD due to vaccine serotypes (VT) and x-ray confirmed pneumonia with consolidation of unspecified etiology in children who received PCV before 12 months of age.

SEARCH STRATEGY

We searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2004), MEDLINE (1990 to March 2004) and EMBASE (1990 to December 2003). Reference list of articles, and books of abstracts of relevant symposia, were hand searched. Researchers in the field were also contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing PCV with placebo, or another vaccine, among children below two years with IPD and clinical/radiographic pneumonia as outcomes.

DATA COLLECTION AND ANALYSIS

Two reviewers independently identified eligible studies, assessed trial quality, and extracted data. Differences were resolved by discussion. The inverse variance method was used to pool effect sizes.

MAIN RESULTS

We identified four trials assessing the efficacy of PCV in reducing the incidence of IPD, two on x-ray confirmed pneumonia as outcome, and one on clinical pneumonia, with or without x-ray confirmation. Results from pooling HIV-1 negative children from the South African study with the other studies were as follows: the pooled vaccine efficacy (VE) for vaccine-type IPD was 88% (95% confidence interval (CI) 73% to 94%; fixed effect and random effects models), the effect measure was statistically significant (p <0.00001) and there was no heterogeneity (p = 0.77I2 0%); the pooled VE for all-serotype IPD was 66% (95% CI 46% to 79%; fixed effect model), the effect measure was statistically significant (p <0.00001) and there was no statistical heterogeneity (p = 0.09, I2 51%); the pooled VE for x-ray confirmed pneumonia was 22% (95% CI 11% to 31%; both fixed effect and random effects models) and there was no statistical heterogeneity (p = 0.80, I2 0%). Analyses that included all the children in the South African study (HIV-1 negative and HIV-1 positive children) and pooled with data from the other studies gave very similar results.

REVIEWERS' CONCLUSIONS

PCV is effective in reducing the incidence of IPD from all serotypes but exerts a greater effect in reducing VT IPD. Although PCV is also effective in reducing the incidence of x-ray confirmed pneumonia, there are still uncertainties about the definition of this outcome. Additional randomised controlled trials are currently in progress.

Immunogenicity and efficacy of childhood vaccines in HIV-1-infected children

Children infected by HIV-1 are particularly vulnerable to severe, recurrent, or unusual infections by vaccine-preventable pathogens. Routine immunisations seem to be generally safe for HIV-1-infected children, but responses may be suboptimal. Early HIV-1-induced immune attrition associated with viral replication may particularly interfere with the development of memory responses. In high HIV-1 prevalence regions, the accumulation of susceptible hosts may compromise disease-control efforts. Although early control of viral replication through treatment with highly active therapy may preserve immune function and responses to routine childhood vaccines, availability is limited in the areas most affected. In this review, we provide an overview of the immunogenicity and efficacy of childhood vaccines in HIV-1-infected children. The possible immunological bases for defective responses are discussed; unanswered questions and the need for further research are delineated.

Safety and immunogenicity of influenza vaccination in individuals infected with HIV

Influenza can cause severe complications in HIV infected individuals leading to increases in hospitalisation and mortality. Vaccination is recommended for such individuals, but some studies reported that immunisation against influenza may stimulate an increase of HIV viral load and decrease of CD4+ cells count. A review of published studies, including our study carried out in HIV former drug addicts, indicates that vaccination against influenza is well tolerated in both children and adult individuals with HIV, but response to vaccination is lower than that observed in immunocompetent individuals. Most studies, including our own, show that vaccination does not induce significant changes in viral load and CD4+ cell counts. In studies reporting modifications of such parameters there is a general agreement that the increased viral replication is usually transient and unable to determine a clear, measurable progression of the underlying HIV disease. Therefore, vaccination against influenza can be safely administered to HIV infected people.

Viral load response to a pneumococcal conjugate vaccine, polysaccharide vaccine or placebo among HIV-infected patients

We determined the HIV viral load in 66 adults randomly assigned to receive pneumococcal immunization with one or two doses of protein conjugate vaccine, one dose of polysaccharide vaccine, one dose of each, or placebo. Second doses were given 8 weeks after the first. Mean baseline viral load and CD4 cell count were 3.41 copies/ml (log10) and 457 cells/microl, respectively. We found no change in viral load during 24 weeks of follow-up for any vaccine or combination of vaccines or placebo.

Immunization of HIV-infected children with varicella vaccine

OBJECTIVE

To determine the safety and immunogenicity of varicella vaccine in children with human immunodeficiency virus (HIV) infection. Children (n = 41) who were mildly affected by HIV (Centers for Disease Control and Prevention stage N1 or A1) and had no history or serum antibody indicative of prior varicella infection were immunized with two doses of live attenuated varicella vaccine.

RESULTS

A minority of the vaccine recipients had mild local or systemic reactions. Vaccination had no effect on the clinical stage of HIV or the HIV RNA plasma load. CD4 cell percentage and CD4 cell count were marginally decreased at week 4 after the first vaccination; this effect was no longer present at week 8 after vaccination. Two months after the second dose of vaccine, 60% of vaccine recipients had anti-varicella antibody in their serum, and 83% had a positive lymphocyte proliferation assay response to varicella antigen.

CONCLUSION

On the basis of its safety and immunogenicity, varicella vaccine should be considered in the childhood vaccines given to mildly affected HIV-infected children.