Evaluation of Immune Response to Measles Component of MMR Vaccine in Children with HIV Infection Receiving Antiretroviral Therapy

Nutritional Supplementation to Increase Influenza Vaccine Response in Children Living With HIV: A Pilot Clinical Trial

AIMS

Vaccine response is poor among children living with HIV. The gut microbiota has been identified as a potential target to improve vaccine immunogenicity, but data are scarce in the context of HIV infection.

METHODS

Pilot, double-blind, randomized placebo-controlled trial in which 24 HIV-infected children were randomized to receive a mixture of symbiotics, omega-3/6 fatty acids, and amino acids or placebo for 4 weeks, each in combination with ART, and were then immunized against influenza. Vaccine response and safety of the nutritional supplementation were the primary outcomes.

RESULTS

Eighteen HIV-infected children completed the follow-up period (mean age 11.5 ± 4.14 years, 61% female). The nutritional supplement was safe but did not enhance the response to the influenza vaccine. A 4-fold rise in antibody titers was obtained in only 37.5% of participants in the intervention arm vs. 40% in the placebo. No immunological or inflammatory predictors of vaccine response were identified.

CONCLUSIONS

In this exploratory study, a 4-week course of symbiotics did not increase influenza vaccine immunogenicity in HIV-infected children. Larger studies are warranted to address the potential of modulating the microbiome in children living with HIV.

Immune function in childhood cancer survivors: a Children's Oncology Group review

Childhood cancer and its treatment often impact the haematopoietic and lymphatic systems, with immunological consequences. Immunological assessments are not routinely included in surveillance guidelines for most survivors of childhood cancer, although a robust body of literature describes immunological outcomes, testing recommendations, and revaccination guidelines after allogeneic haematopoietic cell transplantation. Survivorship care providers might not fully consider the impaired recovery of a child's immune system after cancer treatment if the child has not undergone haematopoietic cell transplantation. We did a scoping review to collate the existing literature describing immune function after childhood cancer therapy, including both standard-dose chemotherapy and high-dose chemotherapy with haematopoietic cell rescue. This Review aims to summarise: the principles of immunology and testing of immune function; the body of literature describing immunological outcomes after childhood cancer therapy, with an emphasis on the risk of infection, when is testing indicated, and preventive strategies; and knowledge gaps and opportunities for future research.

Safety and Immunogenicity of Measles Vaccination in HIV-Infected and HIV-Exposed Uninfected Children: A Systematic Review and Meta-Analysis

BACKGROUND

HIV-infected and HIV-exposed uninfected (HEU) children have an increased risk of measles that may be due to altered immune responses or suboptimal timing of measles vaccination. We aimed to evaluate the safety and immunogenicity of measles vaccination in HIV-infected and HEU children.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Embase, Cochrane Library, CINAHL, Global Health Library and IndMED on May 9, 2018. Studies were included if they reported on safety or seroresponse (either seroprotection/seropositivity/seroconversion) after measles vaccination in HIV-infected or HEU children. We calculated pooled estimates to compare immunogenicity outcomes between HIV-infected, HEU and HIV-unexposed children, using risk ratios [RRs] (with 95%CIs). PROSPERO registration number: CRD42017057411.

FINDINGS

Seventy-one studies met the inclusion criteria (15,363 children). Twenty-eight studies reported on safety; vaccine-associated adverse events and deaths were uncommon. Sixty-two studies reported on immunogenicity, 27 were included in the meta-analysis. HIV-infected children had lower seroresponse rates after primary vaccination compared with HIV-unexposed (RR 0.74; 95%CI: 0.61-0.90, I 2  = 85.9%) and HEU children (0.78; 0.69-0.88, I 2  = 77.1%), which was mitigated by antiretroviral therapy and time interval between vaccination and serology. HEU and HIV-unexposed children had similar seroresponses. Vaccination at 6-months resulted in similar proportions of HIV-infected children having seroresponse compared with HIV-unexposed (0.96; 0.77-1.19) and HEU children (1.00; 0.73-1.37, I 2  = 63.7%).

INTERPRETATION

Primary measles vaccination at 6-months of age may provide protection against measles during early infancy in settings with high prevalence of maternal HIV-infection, however, further studies are needed to evaluate this strategy in HEU children and HIV-infected children receiving antiretroviral therapy.

FUNDING

South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation in Vaccine Preventable Diseases; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit.

Seroprevalence of transplacentally acquired measles antibodies in HIV-exposed versus HIV-unexposed infants at six months of age

BACKGROUND & OBJECTIVES

Measles infection is reported to be more severe, prolonged and associated with a higher complication rate in children with HIV infection. Reports indicate that infants born to HIV-infected women [HIV exposed infants (HEI)] may be more vulnerable to measles. The World Health Organization recommends measles vaccination starting at six months of age in these infants who may be HIV-infected themselves. However, in India, they are given measles vaccination at nine months of age like all other infants. In this study, the seroprevalence of transplacentally acquired measles antibodies was compared in HEI and unexposed infants (HUnI) at six months of age and the proportion of HEI undergoing seroconversion after immunization with measles vaccine was assessed.

METHODS

In this prospective longitudinal study, measles IgG antibodies were estimated in serum of 49 HEI and 50 HUnI aged 6-7 months. Measles vaccine was then administered to HEI. Assessment for measles IgG antibodies was repeated 8-12 wk post-immunization.

RESULTS

Measles IgG antibodies were detected in two of 49 (4.1%) HEI and 16 of 50 (32%) HUnI. HEI were 11 times more likely to lack measles antibodies as compared to HUnI (odds ratio=11.05, 95% confidence interval=2.989-40.908). Post-vaccination, seroprevalence of measles antibodies increased to 38.5 per cent (PInterpretation & conclusions: Most HEI lacked measles antibodies at six months age and were, therefore, more vulnerable to measles than HUnI. Seroconversion in response to a single dose of measles vaccine administered at six months age was low in these infants, signifying the need of additional dose(s) of measles/measles-containing vaccine.

Immunisation of the immunocompromised child

Immunocompromised children have a higher risk of developing infections and associated higher rates of mortality and morbidity. Although this group could benefit the most from vaccine administration, specific considerations regarding immunisations are required. This review is a summary of the vaccines that are relevant to the immunocompromised host, covering both live and non-live vaccines. The burden of disease, safety, immunogenicity/effectiveness and specific recommendations for each vaccine are described as well as specific guidelines from different organisations.