Immunization practice and vaccine safety perception in centres caring for children with prenatally acquired HIV: results from the Pediatric European Network for Treatment of AIDS survey

Abstract

Introduction: Perinatally HIV-infected children are more susceptible to vaccine preventable infections and vaccine induced immunity is less robust than in healthy children because of precocious waning of protective immunity. For this high risk population it is important to design specific vaccine schedules to define correct dosing and to set accurate correlates of protection. This survey was performed to give an overview of current vaccinations practice among paediatricians looking after vertically HIV-infected children. Methods: An online questionnaire regarding vaccination practices in HIV-infected children was completed by investigators from the PENTA network. Data were collected between November 2013 and March 2014. Results: A total of 88 experts in the management of paediatric HIVinfection from 46 different units looking after 2465 patients completed the questionnaire.The majority of units (72%) did not perform routine childhood immunizations in HIV centres. Vaccination histories were incomplete for 40% of the studied population. Influenza, pneumococcal conjugate vaccine and human papilloma vaccine immunizations are widely administered (93, 89 and 83% of units, respectively).Varicella and Rotavirus vaccinations are less recommended (61 and 24% of the units, respectively). Monitoring of vaccine responses is employed in 72% of centres. Serology appears to be the most feasible assay among the different centres (90%), mostly performed with immune-enzymatic assays. Conclusions: Vaccination practices for perinatally HIV-infected children still vary widely between countries. A crucial issue is the incomplete adherence to varicella vaccine. Indeed only in few countries varicella vaccination is universally recommended for children at national. More efforts should be made to standardize mandatory and recommended vaccinations, as well as to guide timing of serological assays. The majority of units carry out immuno-enzymatic tests to evaluate specific antibody levels. However, methods vary with different cut-offs of protection and units of measurement employed. Moreover, especially in high risk groups (e.g. children who started late HAART or performed vaccinations before treatment), researches on the development of novel methods to assess protective immunity and accurate correlates of protection are needed. The ultimate goal will be to design individualized vaccine schedules, developed on therapeutic and immunological features of individual patients, optimizing the chances of them gaining robust long-termvaccine induced protection.