Immunogenicity and safety of meningococcal C conjugate vaccine in children and adolescents infected and uninfected with HIV in Rio de Janeiro, Brazil

Longevity of serologic responses following a single dose of typhoid conjugate vaccine among children living with HIV in Pakistan: A prospective cohort study

BACKGROUND

This study aimed to assess the longevity of serologic response and seroconversion rates at several time points following TCV vaccination among children living with HIV aged 6 months to 15 years in Pakistan.

METHODS

From November 20, 2020, to January 2, 2021; 336 children were enrolled and followed up prospectively for 12 months. Blood samples were collected before the administration of TCV and at 4-6 weeks, 6 months, and 1 year after administration of a single dose (0.5 ml) of intramuscular Typbar TCV®. Samples were analyzed for anti-Vi-IgG antibodies using ELISA. Geometric mean titers (GMTs), seroconversion rates (fourfold rise in anti-Vi-IgG from baseline) were assessed, and factors associated with sustained seroconversion at 1 year were evaluated using generalized linear mixed models.

FINDINGS

The seroconversion rates were significantly lower in children aged 6 months to 5 years compared to children > 5 years; (127/216 (58·8%)) versus (81/111 (73·0%)) at 6 months and (110/217 (50·7%)) versus (78/109 (71·6%)) at 1 year, only two-third; 188/326 (57·7%) remained seroconverted at 1 year. The GMTs (95 % CI) were significantly lower in children aged 6 months to 5 years compared to children > 5 years, 9·6 (7·6, 12·0) versus 28·9 (20·2, 41·4) at 6 months, and 6·6 (5·4, 8·0) versus 23·1 (16·4, 32·5) at 1 year time point. The odds of sustained seroconversion significantly decreased with time (adjusted odds ratio (aOR): 0.23; 95 % CI: 0.14, 0.40). The odds of sustained seroconversion following 1 year of TCV vaccination were significantly higher among children with non-severe HIV clinical disease (aOR: 10·61; 95% CI: 1·52, 73·98) and children in elder age group (aOR: 7·45; 95% CI: 1·18, 47·03).

CONCLUSIONS

A significant decrease in seroconversion rates was observed among children living with HIV following one year of TCV administration. The decline was significantly higher in children with severe or advanced HIV clinical disease and children younger than five years of age.

Propositive follow-up: Long-term immune responses to the 4CMenB and MenACWY vaccines in people living with HIV

BACKGROUND

People living with HIV have an increased risk of meningococcal disease. The Propositive trial evaluated co-administration of two doses of a four-component recombinant protein-based MenB vaccine (4CMenB) and a quadrivalent conjugate polysaccharide MenACWY vaccine (MenACWY-CRM197) given 1 month apart in people with HIV. The follow-up trial assessed the immunogenicity of these vaccines at 1.5 and 2.5 years after primary vaccination.

METHODS

Participants who completed the parent Propositive trial were invited to the follow-up study. Immunogenicity analysis was performed at 18 and 30 months after primary vaccination. Primary outcome measures were serum bactericidal antibody (SBA) geometric mean titres (GMTs) against three MenB reference strains and the proportion of participants maintaining a protective SBA titre of ≥4 at 18 and 30 months. Secondary outcome measures were SBA GMTs against MenA, C, W, and Y serogroups and the proportion of participants maintaining a protective SBA titre of ≥8 at 18 and 30 months. The trial is registered with Clinicaltrials.gov (NCT042394300).

RESULTS

A total of 40 participants aged 22-47 years were enrolled. Geometric mean titres waned by 18 and 30 months but remained higher than pre-vaccination for all MenB strains and MenA, C, W, and Y. In total, 75%-85% of participants retained protective SBA titres by 30 months against individual MenB strains, whereas 68.8% of patients retained protective antibody titres against all three MenB strains. Antibodies against MenC waned more rapidly than did those against MenA, W, and Y. The proportion of participants with protective titres against MenC at 30 months was also lower (46.9%) than that with protective titres against MenA (87.5%), W (78.1%), and Y (87.5%).

CONCLUSIONS

Immune responses against MenB in our cohort of people living with HIV at 2.5 years of follow-up were reassuring, with 68.8% of participants retaining protection against all three reference strains. However, responses against MenC were lower than those against MenA, W, and Y serogroups.

Immunogenicity of the Conjugate Meningococcal ACWY-TT Vaccine in Children and Adolescents Living with HIV

BACKGROUND

Children and adolescents living with HIV (CALHIV) are at high risk of meningococcal infections and may present lower immune responses to vaccines. The objectives of this study were to assess the immunogenicity of the quadrivalent Men ACWY-TT vaccine (Nimenrix®) in CALHIV after a two-dose schedule and to describe possible HIV-related factors that may affect the immunogenic response.

METHODS

A multicenter prospective study was designed, including CALHIV followed in five hospitals in Madrid, between 2019 and 2021. Two doses of the Men ACWY-TT vaccine were administered. Serum bactericidal antibody (SBA) assays using rabbit complement (rSBA) against serogroups C, W, and Y were used to determine seroprotection and vaccine response (the proportion achieving a putative protective titer of ≥eight or a ≥four-fold rise in titer from baseline). Serum was collected at baseline, and at 3 and 12 months after vaccination.

RESULTS

There were 29 CALHIV included, 76% of whom were perinatally infected. All were receiving TAR and presented a good immunovirological and clinical status overall. At baseline, 45% of CALHIV had seroprotective titers to at least one serogroup, with individual seroprotection rates of 24%, 28%, and 32% against C, W, and Y, respectively. After a two-dose schedule, vaccine response was 83% for each serogroup, eliciting a vaccine response to all serogroups in 69% of them. One year after vaccination, 75% of CALHIV maintained seroprotective titers against the C serogroup, and 96% against W and Y. None of the HIV-related characteristics analyzed could predict vaccine response or antibody duration.

CONCLUSIONS

CALHIV who received effective TAR and presented a good immuno-virological situation achieved an appropriate vaccine response after two doses of the Men ACWY-TT vaccine, and antibody-mediated protection against serogroups C, W, and Y was maintained in more than 70% of the patients one year after vaccination.

The propositive study: Immunogenicity and safety of a four-component recombinant protein-based vaccine against MenB and a quadrivalent conjugate MenACWY vaccine in people living with HIV

BACKGROUND

People living with HIV have been shown to have an increased risk of invasive meningococcal disease. In some countries, meningococcal vaccines are now routinely recommended to all people living with HIV, but no study has yet assessed the immunogenicity and safety of a meningococcal serogroup B vaccine or the co-administration of a MenB and MenACWY vaccine in people living with HIV.

METHODS

This phase IV open-label clinical trial investigated the immunogenicity and safety of two doses of a four-component recombinant protein-based MenB vaccine (4CMenB) and a quadrivalent conjugate polysaccharide MenACWY vaccine (MenACWY-CRM197) given 1 month apart in a population of people living with HIV. Immunogenicity analysis was performed before vaccination and 1 month after the second doses of 4CMenB and MenACWY. Primary outcome measures were serum bactericidal assay geometric mean titres against three MenB reference strains at baseline and 1 month post vaccination, the proportion of participants achieving a putative protective titre of ≥4, and the proportion of participants with a ≥4-fold rise in titre from baseline. Secondary outcome measures were serum bactericidal assay geometric mean titres against MenA, C, W, and Y reference strains at baseline and 1 month post vaccination, the proportion achieving a putative protective titre of ≥8, and the proportion with a ≥4-fold rise in titre from baseline. Safety outcomes were solicited and unsolicited adverse events in the 7 days following vaccination. The trial was registered with clinicaltrials.gov (NCT03682939).

FINDINGS

In total, 55 participants aged 20-45 years were enrolled. All participants (100%; 95% confidence interval [CI] 93-100) achieved putative protective titres for two of the three MenB strains and for MenA, W, and Y. A total of 98% (95% CI 89-100) achieved a protective titre for the third MenB strain and 94% (95% CI 83-99) for MenC. No serious adverse events were reported.

INTERPRETATION

4CMenB and MenACWY were immunogenic and well-tolerated in a population of people living with HIV 1 month after two doses.

Immunogenicity, effectiveness, and safety of SARS-CoV-2 vaccination in people with HIV

OBJECTIVES

People with HIV (PWH) experience a greater risk of morbidity and mortality following COVID-19 infection, and poorer immunological responses to several vaccines. We explored existing evidence regarding the immunogenicity, effectiveness, and safety of SARS-CoV-2 vaccines in PWH compared with controls.

METHODS

We conducted a systematic search of electronic databases from January 2020 until June 2022, in addition to conference databases, to identify studies comparing clinical, immunogenicity, and safety in PWH and controls. We compared results between those with low (<350 cells/μl) and high (>350 cells/μl) CD4 + T-cell counts where possible. We performed a meta-analysis of seroconversion and neutralization responses to calculate a pooled risk ratio as the measure of effect.

RESULTS

We identified 30 studies, including four reporting clinical effectiveness, 27 immunogenicity, and 12 reporting safety outcomes. PWH were 3% [risk ratio 0.97, 95% confidence interval (95% CI) 0.95-0.99] less likely to seroconvert and 5% less likely to demonstrate neutralization responses (risk ratio 0.95, 95% CI 0.91-0.99) following a primary vaccine schedule. Having a CD4 + T-cell count less than 350 cells/μl (risk ratio 0.91, 95% CI 0.83-0.99) compared with a CD4 + T-cell count more than 350 cells/μl, and receipt of a non-mRNA vaccine in PWH compared with controls (risk ratio 0.86, 95% CI 0.77-0.96) were associated with reduced seroconversion. Two studies reported worse clinical outcomes in PWH.

CONCLUSION

Although vaccines appear well tolerated in PWH, this group experience poorer immunological responses following vaccination than controls, particularly with non-mRNA vaccines and low CD4 + T-cell counts. PWH should be prioritized for mRNA COVID-19 vaccines, especially PWH with more advanced immunodeficiency.

Living with HIV and Getting Vaccinated: A Narrative Review

After 40 years of its appearance, human immunodeficiency virus (HIV) infection remains a leading public health challenge worldwide. Since the introduction of antiretroviral treatment (ART), HIV infection has become a chronic condition, and people living with HIV could have life expectancies close to those of the general population. People with HIV often have an increased risk of infection or experience more severe morbidity following exposure to vaccine-preventable diseases. Nowadays, several vaccines are available against bacteria and viruses. However, national and international vaccination guidelines for people with HIV are heterogeneous, and not every vaccine is included. For these reasons, we aimed to perform a narrative review about the vaccinations available for adults living with HIV, reporting the most updated studies performed for each vaccine among this population. We performed a comprehensive literature search through electronic databases (Pubmed-MEDLINE and Embase) and search engines (Google Scholar). We included English peer-reviewed publications (articles and reviews) on HIV and vaccination. Despite widespread use and guideline recommendations, few vaccine trials have been conducted in people with HIV. In addition, not all vaccines are recommended for people with HIV, especially for those with low CD4 cells count. Clinicians should carefully collect the history of vaccinations and patients' acceptance and preferences and regularly check the presence of antibodies for vaccine-preventable pathogens.

Expression of TIGIT, PD-1 and HLA-DR/CD38 markers on CD8-T cells of children and adolescents infected with HIV and uninfected controls

Immune exhaustion and senescence are scarcely studied in HIV-pediatric patients. We studied the circulatory CD8 T cells activation/exhaustion and senescent phenotype of children and adolescents vertically infected with HIV or uninfected controls based on the expression of human leukocyte antigen (HLA-DR), CD38, T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), programmed death 1 (PD-1) and CD57 by flow cytometry, during approximately one year. Eleven HIV-infected (HI) and nine HIV-uninfected (HU) children/adolescents who received two doses or one dose of meningococcal C conjugate vaccine (MenC), respectively, were involved in this study. Blood samples were collected before the immunization (T0), 1-2 months after the first dose (T1), and 1-2 months after the second dose (T2), which was administered approximately one year after the first one. HI patients not receiving combined antiretroviral therapy (cART) showed a higher frequency of CD8 T cells TIGIT+, PD-1+ or CD57+, as well as a higher frequency of CD8 T cells co-expressing CD38/HLA-DR/TIGIT or CD38/HLA-DR/PD-1 when compared to HI treated or HU individuals, at all times that they were assessed. CD8 T cells co-expressing CD38/DR/TIGIT were inversely correlated with the CD4/CD8 ratio but positively associated with viral load. The co-expression of CD38/DR/TIGIT or CD38/DR/PD-1 on CD8 T cells was also inversely associated with the CD4 T cells expressing co-stimulatory molecules CD127/CD28. The results showed a higher expression of exhaustion/senescence markers on CD8 T cells of untreated HI children/adolescents and its correlations with viral load.

National and regional differences in meningococcal vaccine recommendations for individuals at an increased risk of meningococcal disease

INTRODUCTION

Invasive meningococcal disease (IMD) is a severe, life-threatening condition caused by infection with Neisseria meningitidis. Currently available vaccines offer protection against the five most common meningococcal disease-causing serogroups and include monovalent and quadrivalent conjugate vaccines (MenA, MenC, MenACWY vaccines) and outer membrane vesicle- and/or recombinant protein-based vaccines (MenB vaccines).

AREAS COVERED

Country and regional immunization programs target populations susceptible to IMD and typically emphasize the highest-risk age groups (i.e., infants, adolescents/young adults, and the elderly); however, additional groups are also considered at an elevated risk and are the focus of the current review. Specific increased-risk groups include individuals with underlying immunocompromising medical conditions, university/college students, Indigenous people, laboratory workers, military personnel, men who have sex with men, and travelers to areas with hyperendemic IMD. This review compares established meningococcal vaccination recommendations for these vulnerable groups in Europe, the United States, Australia, New Zealand, Israel, Brazil, and Turkey.

EXPERT OPINION

Recommendations should be standardized to cover all groups at increased risk of IMD.

Association between circulating exhausted CD4+ T cells with poor meningococcal C conjugate vaccine antibody response in HIV-infected children and adolescents

OBJECTIVES

To investigate the expression levels of surface markers of activation (CD38 and HLA-DR), inhibition (PD-1, TIGIT and CD57) and co-stimulation (CD28 and CD127) on CD4+ T cells of children/adolescents with vertical HIV infection (HI patients) and HIV-uninfected (HU) controls vaccinated with the meningococcal C conjugate vaccine (MCC).

METHODS

HI patients (n=12), aged 8-17 years, were immunized with two MCC injections, while HU controls (n=9), aged 5.3-10.7 years, received a single MCC dose (as per national recommendation at the time of this study, a single MCC vaccine dose should be given for healthy children and youth aged 1-18 years). The HI patients were categorized according to the combined antiretroviral therapy (cART) treatment. Blood samples were obtained before vaccination, after priming, and after the administration of a booster dose of vaccine to determine the serum bactericidal antibody (SBA) titers and the expression levels of surface markers on CD4+ T cells by flow cytometry. The levels of serum cytokines, IL-4 and CXCL-13 were also measured using Luminex kits.

RESULTS

The co-expression of the TIGIT-HLA-DR-CD38 molecules increased in the CD4+ T cells of HI patients/no-cART who also showed a lower frequency of CD127+CD28+ CD4+ T cells than HI patients/cART and HU group subjects. There were significant negative correlations between the frequency of exhausted CD4+ T cells and the SBA response. IL-4 levels were higher in HI patients/cART and positively correlated with SBA titers but negatively associated with the expression of exhaustion markers. Moreover, the CXCL-13 levels were positively correlated with the exhausted CD4+ T cells.

CONCLUSION

The results of our study suggest that the co-expression of exhaustion markers and/or loss of co-stimulatory molecules influence the SBA response in HI patients.

Meningococcal Vaccination: Recommendations of the Advisory Committee on Immunization Practices, United States, 2020

This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) for use of meningococcal vaccines in the United States. As a comprehensive summary and update of previously published recommendations, it replaces all previously published reports and policy notes. This report also contains new recommendations for administration of booster doses of serogroup B meningococcal (MenB) vaccine for persons at increased risk for serogroup B meningococcal disease. These guidelines will be updated as needed on the basis of availability of new data or licensure of new meningococcal vaccines. ACIP recommends routine vaccination with a quadrivalent meningococcal conjugate vaccine (MenACWY) for adolescents aged 11 or 12 years, with a booster dose at age 16 years. ACIP also recommends routine vaccination with MenACWY for persons aged ≥2 months at increased risk for meningococcal disease caused by serogroups A, C, W, or Y, including persons who have persistent complement component deficiencies; persons receiving a complement inhibitor (e.g., eculizumab [Soliris] or ravulizumab [Ultomiris]); persons who have anatomic or functional asplenia; persons with human immunodeficiency virus infection; microbiologists routinely exposed to isolates of Neisseria meningitidis; persons identified to be at increased risk because of a meningococcal disease outbreak caused by serogroups A, C, W, or Y; persons who travel to or live in areas in which meningococcal disease is hyperendemic or epidemic; unvaccinated or incompletely vaccinated first-year college students living in residence halls; and military recruits. ACIP recommends MenACWY booster doses for previously vaccinated persons who become or remain at increased risk.In addition, ACIP recommends routine use of MenB vaccine series among persons aged ≥10 years who are at increased risk for serogroup B meningococcal disease, including persons who have persistent complement component deficiencies; persons receiving a complement inhibitor; persons who have anatomic or functional asplenia; microbiologists who are routinely exposed to isolates of N. meningitidis; and persons identified to be at increased risk because of a meningococcal disease outbreak caused by serogroup B. ACIP recommends MenB booster doses for previously vaccinated persons who become or remain at increased risk. In addition, ACIP recommends a MenB series for adolescents and young adults aged 16-23 years on the basis of shared clinical decision-making to provide short-term protection against disease caused by most strains of serogroup B N. meningitidis.

Baseline Circulating Activated TFH and Tissue-Like Exhausted B Cells Negatively Correlate With Meningococcal C Conjugate Vaccine Induced Antibodies in HIV-Infected Individuals

Since 2006, meningococcal serogroup C (MenC) conjugate (MCC) vaccines have been supplied by the Brazilian government for HIV-infected children under 13 years old. For measuring protection against MenC, the serum bactericidal antibody (SBA) assay is the method of choice. The characterization of T follicular helper cells (TFH) cells has been an area of intensive study because of their significance in multiple human diseases and in vaccinology. The objective of this study was to characterize the phenotype of peripheral TFH cells and B cells and how they associated with each other and with SBA levels induced by vaccination as well as with serum cytokine levels of HIV-infected and non-infected children and adolescents. We found that CD27⁻IgD⁻CD21⁻CD38⁺ (exhausted B cells) as well as short-lived plasmablasts (CD27⁺IgD⁻CD21⁻CD38⁺) are increased in cART treated HIV patients and negatively associated with MCC vaccine induced SBA levels. Baseline frequency of activated peripheral TFH cells was a negative correlate for SBA response to MCC vaccine but positively correlated with circulating plasmablast frequency. Baseline IL4-levels positively associated with SBA response but showed a negative correlation with activated peripheral TFH cells frequency. The increased frequency of activated peripheral TFH cells found in non-responders to the vaccine implies that higher activation/differentiation of CD4 T cells within the lymph node is not necessarily associated with induction of vaccine responses.

Immunogenicity and safety of the quadrivalent meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) in splenectomized or hyposplenic children and adolescents: Results of a phase III, open, non-randomized study

BACKGROUND

Individuals with functional or anatomic asplenia are at high risk for meningococcal disease. We evaluated the immunogenicity and safety of 1 and 2 doses of the quadrivalent meningococcal serogroups A, C, W, Y tetanus toxoid-conjugate vaccine (MenACWY-TT) in this high-risk population.

METHODS

This phase III, open-label, controlled, non-randomized study (NCT01641042) enrolled 1-17-year-olds with impaired splenic activity (high-risk group) and age-matched healthy controls (control group). We measured immune responses to MenACWY-TT by serum bactericidal activity assays using rabbit (rSBA) and human (hSBA) complement and in terms of antibodies against polysaccharides of the 4 vaccine serogroups. We evaluated vaccine response rates (VRRs) as 4-fold increases from pre-vaccination levels or titers ≥1:32 (rSBA)/≥1:8 (hSBA). We recorded solicited and unsolicited adverse events (AEs) during 4 and 31 days post-vaccination, and serious AEs (SAEs) and new onset of chronic illnesses (NOCIs) throughout the study.

RESULTS

The according-to-protocol cohort for immunogenicity included 40 participants per group. In both groups, the first MenACWY-TT dose induced rSBA VRRs of 92.5-100% and hSBA VRRs of 55.6-77.1% across vaccine serogroups. Following the second MenACWY-TT dose, all participants had high responses, with rSBA and hSBA VRRs of 73.0-100% across vaccine serogroups. rSBA and hSBA geometric mean titers for each serogroup increased in both groups (with different magnitudes, but ≥13.1-fold) compared with baseline levels. Polysaccharide antibody concentrations ≥2.0 μg/ml were detected in ≥84.4% of participants and were similar between groups. Incidences of solicited and unsolicited AEs were comparable between groups. We recorded SAEs in 4/43 participants in the high-risk group and 1/43 participants in the control group (none vaccine-related). No NOCIs were reported.

CONCLUSION

In this descriptive study, MenACWY-TT induced similar functional and humoral immune responses and had a clinically acceptable safety profile in children and adolescents with impaired splenic activity and in healthy controls.

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

We aimed to evaluate immunogenicity and adverse events (AEs) after a booster dose of Meningococcal C conjugated (MCC) vaccine in HIV-infected children and adolescents, who had a previous low seroconversion rate after priming with MCC, at a reference HIV-care center in Rio de Janeiro.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Antibody persistence following meningococcal C conjugate vaccination in children and adolescents infected with human immunodeficiency virus

OBJECTIVE

HIV-infected individuals (HIVI) are threatened by meningococcal infection and presented lower response to vaccines. Data are scarce on long-term persistence of human serum bactericidal antibody (hSBA) after a meningococcal C conjugate (MCC) vaccine in HIVI youth; the authors aimed to describe this persistence in HIVI.

METHODS

HIVI and HIV uninfected individuals (HIVU), aged 2-18 years, CD4 >15% were recruited. Seroprotection (hSBA ≥1:4) at baseline and at 12-18 months after immunization was evaluated and the association of the different factors with the long-term persistence was calculated using logistic regression.

RESULTS

A total of 145 HIVI, 50 HIVU were recruited and immunized, and their median age was 11 years (median age in HIVI group was 12 years, and 10 years in HIVU group, p-value=0.02). 85 HIVI (44%) had undetectable viral load (UVL). Seroprotection rate was 27.2%: 24.1% in HIVI and 36% in HIVU 12-18 months after immunization (p=0.14). Baseline immunity (odds ratio [OR]=70.70, 95% CI: 65.2-766.6); UVL at entry (OR: 2.87, 95% CI: 0.96-8.62) and lower family income (OR: 0.09, 95% CI: 0.01-0.69) were associated with seroprotection among HIVI.

CONCLUSION

Seroprotection at 12-18 months after single dose of MCC was low for both groups, and higher among individuals who presented baseline immunity. Among HIVI, vaccine should be administered after UVL is achieved.

A cross-reacting material CRM197 conjugate vaccine induces diphtheria toxin neutralizing antibody response in children and adolescents infected or not with HIV

Anti-diphtheria antibody levels decrease with aging, and frequent booster vaccinations are required to maintain herd immunity. We analyzed the diphtheria toxin neutralizing antibody (DT-Nab) response induced by a conjugate vaccine (meningococcal C polysaccharide-CRM₁₉₇) in HIV-vertically infected (HI) children and adolescents and healthy controls (HC) with matched age. We report the association of DT-Nab with the bactericidal antibodies to serogroup C meningococcus (MenC). Before vaccination, 21 HI patients (50%) had no protection against diphtheria (≤0.01IU/ml of antibody) and only 8 (19%) showed complete protection (≥0.1IU/ml). About half of the HC (56%) had complete protection before immunization and 6 subjects (12%) had no protection against diphtheria. After one and two vaccine injections, 96% of HC and 64% of HI vaccinees, respectively, showed full protection against diphtheria. These data indicate that CRM₁₉₇ was able to induce primary and/or booster response in both groups of individuals.

Association of serum bactericidal antibody and opsonic antibody levels after Neisseria meningitidis serogroup C conjugate vaccine in Brazilian children and adolescents infected or not infected with HIV

Neisseria meningitidis serogroup C (MenC) is the main causative agent of meningitis in Brazil. HIV infection affects the quality of the immune system. HIV⁺ children have an increased risk of infection to encapsulated bacteria such as N. meningitidis. We evaluated the opsonic antibody (OPA) levels and its correlation with serum bactericidal antibody (SBA) levels induced by one and two doses of a MenC conjugate vaccine in children and adolescents HIV⁺ and HIV-exposed but uninfected children (HEU) group. Overall the data show the importance of two doses of vaccine for HIV⁺ individuals. About 79% and 58% of HIV⁺ patients showed SBA and OPA positive response after two doses of vaccine, respectively. For HEU group, 62% and 41% of patients showed SBA and OPA positive response after one dose of vaccine, respectively. A positive and significant association between SBA and OPA levels was seen after two doses of vaccine in HIV⁺ patients.

Immunization of HIV-infected adult patients - French recommendations

Human immunodeficiency virus (HIV)-infected patients remain at increased risk of infection including vaccine-preventable diseases. Vaccines are therefore critical components in the protection of HIV-infected patients from an increasing number of preventable diseases. However, missed opportunities for vaccination among HIV-infected patients persist and vaccine coverage in this population could be improved. This article presents the French recommendations regarding immunization of HIV-infected adults in the light of the evidence-based literature on the benefits and the potential risks of vaccines among this vulnerable population.

Bacterial agents causing meningitis during 2013-2014 in Turkey: A multi-center hospital-based prospective surveillance study

This is an observational epidemiological study to describe causes of bacterial meningitis among persons between 1 month and 18 y of age who are hospitalized with suspected bacterial meningitis in 7 Turkish regions. covering 32% of the entire population of Turkey. We present here the results from 2013 and 2014. A clinical case with meningitis was defined according to followings: any sign of meningitis including fever, vomiting, headache, and meningeal irritation in children above one year of age and fever without any documented source, impaired consciousness, prostration and seizures in those < 1 y of age. Single tube multiplex PCR assay was performed for the simultaneous identification of bacterial agents. The specific gene targets were ctrA, bex, and ply for N. meningitidis, Hib, and S. pneumoniae, respectively. PCR positive samples were recorded as laboratory-confirmed acute bacterial meningitis. A total of 665 children were hospitalized for suspected acute meningitis. The annual incidences of acute laboratory-confirmed bacterial meningitis were 0.3 cases / 100,000 population in 2013 and 0.9 cases/100,000 in 2014. Of the 94 diagnosed cases of bacterial meningitis by PCR, 85 (90.4%) were meningococcal and 9 (9.6%) were pneumococcal. Hib was not detected in any of the patients. Among meningococcal meningitis, cases of serogroup Y, A, B and W-135 were 2.4% (n = 2), 3.5% (n = 3), 32.9% (n = 28), and 42.4% (n = 36). No serogroup C was detected among meningococcal cases. Successful vaccination policies for protection from bacterial meningitis are dependent on accurate determination of the etiology of bacterial meningitis. Additionally, the epidemiology of meningococcal disease is dynamic and close monitoring of serogroup distribution is comprehensively needed to assess the benefit of adding meningococcal vaccines to the routine immunization program.

Risk of invasive meningococcal disease in children and adults with HIV in England: a population-based cohort study

BACKGROUND

Recent studies have identified HIV infection as a potential risk factor for invasive meningococcal disease (IMD), suggesting that HIV-infected individuals could benefit from meningococcal vaccination to reduce their risk of this rare, but severe and potentially fatal infection. In the United Kingdom, as in most industrialised countries, HIV is not considered a risk factor for IMD.

METHODS

IMD incidence and relative risk by age group and meningococcal capsular group in HIV-positive compared with HIV-uninfected individuals was estimated through data linkage of national datasets in England between 2011 and 2013.

RESULTS

IMD incidence among persons diagnosed with HIV was 6.6 per 100,000 compared to 1.5 per 100,000 among HIV-negative individuals, with a relative risk of 4.5 (95 % CI, 2.7-7.5). All but one case occurred in adults aged 16-64 years, who had a 22.7-fold (95 % CI, 12.4-41.6; P <0.001) increased risk compared with the HIV-negative adults. IMD risk by capsular group varied with age. HIV-positive children and adolescents had a higher risk of meningococcal group B disease, while adults were at increased risk of groups C, W and Y disease. Most HIV-positive individuals had been born in Africa, had acquired HIV through heterosexual contact, and were known to be HIV-positive and receiving antiretroviral treatment at IMD diagnosis. The most common clinical presentation was septicemia and, although intensive care admission was common, none died of IMD.

CONCLUSIONS

HIV-positive children and adults are at significantly increased risk of IMD, providing an evidence base for policy makers to consider HIV as a risk factor for meningococcal vaccination.

Subsets of memory CD4+ T cell and bactericidal antibody response to Neisseria meningitidis serogroup C after immunization of HIV-infected children and adolescents

Meningococcal disease is endemic in Brazil, with periodic outbreaks and case fatality rates reach as high as 18 to 20% of cases. Conjugate vaccines against meningococci are immunogenic in healthy children. However, we have previously shown a poor bactericidal antibody response to a Men C conjugate vaccine in Brazilian HIV-infected children and adolescents after a single vaccine administration. The goal of the present work was to investigate associations between bactericidal antibody response induced by MenC vaccine and the frequency and activation profile (expression of CD38, HLA-DR and CCR5 molecules) of total CD4+ memory T cell sub-populations in HIV-1-infected children and adolescents. Responders to vaccination against MenC had a predominance (about 44%) of CD4+ TINTERMEDIATE subset followed by TTRANSITIONAL memory subset (23 to 26%). Importantly, CD4+ TINT frequency was positively associated with bactericidal antibody response induced by vaccination. The positive correlation persisted despite the observation that the frequency TINT CD38+HLA-DR+ was higher in responders. In contrast, CD4+ TCENTRAL MEMORY (TCM) subset negatively correlated with bactericidal antibodies. In conclusion, these data indicate that less differentiated CD+ T cells, like TCM may be constantly differentiating into intermediate and later differentiated CD4+ T cell subsets. These include CD4 TINT subset which showed a positive association with bactericidal antibodies.