This monocenter, descriptive, prospective, non-interventional study evaluated the long-term immune responses following routine vaccination with one or 2 doses of a licensed inactivated hepatitis A (HA) vaccine (Avaxim® 80U Pediatric) at age 11–23 months in a cohort of children from Mendoza, Argentina. Antibodies to hepatitis A virus (anti-HAV) were quantified annually up to Y5, and at Y7. Children whose titer decreased to below the seroprotection threshold (defined as an anti-HAV antibody concentration of ≥ 10 mIU/mL in a microparticle enzyme immunoassay up to Y5, or ≥ 3 mIU/mL in an electrochemiluminescence immunoassay at Y7) received a routine booster dose of the same HA vaccine. This report summarizes the data at 7 year after the first vaccination. Of 546 participants initially included, 264 participants remained at Y7 and provided blood samples. Of these, 204 having received one HA primary dose as a toddler were still seroprotected at Y7; titers for a further 7 also having received one HA dose as a toddler fell to below the seroprotection threshold and they therefore received a booster; all 53 having received 2 HA doses as a toddler and still present at Y7 remained seroprotected at Y7. One or 2 primary doses of this HA vaccine in toddlers result in very good persistence of anti-HAV up to 7 year post-first vaccination.

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MenACYW-TT (MenQuadfi®) is a quadrivalent meningococcal tetanus toxoid conjugate vaccine licensed in Europe for use in individuals ≥12 months. This study assessed whether serogroup C immune responses with MenACYW-TT were at least non-inferior, or superior, to those of quadrivalent meningococcal ACWY (MCV4-TT; Nimenrix®) and monovalent meningococcal C (MenC-TT; NeisVac-C®) vaccines in toddlers (12–23 months). In this modified, double-blind Phase III study (NCT03890367), 701 toddlers received one dose of MenACYW-TT (n = 230), MCV4-TT (n = 232) or MenC-TT (n = 239). Serum bactericidal assays with human (hSBA) and baby rabbit (rSBA) complement were used to measure anti-meningococcal serogroup C antibodies at baseline and 30 days post-vaccination. A sequential statistical approach was used for primary and secondary objectives. For the primary objectives, superiority of serogroup C was assessed in terms of hSBA seroprotection rates (defined as titers ≥1:8) and GMTs for MenACYW-TT compared to MCV4-TT, and rSBA GMTs compared to MenC-TT. The safety of all vaccines within 30 days post-vaccination was described. When administered as a single dose to meningococcal vaccine-naïve healthy toddlers the superiority of the MenACYW-TT serogroup C immune response versus MCV4-TT was demonstrated for hSBA GMTs (ratio 16.3 [12.7–21.0]) and seroprotection (difference 10.43% [5.68–16.20]); and versus MenC-TT in terms of rSBA GMTs (ratio 1.32 [1.06–1.64]). The safety profiles of a single dose of MenACYW-TT, MCV4-TT and MenC-TT were similar. In meningococcal vaccine-naïve toddlers, MenACYW-TT induced superior immune responses to serogroup C versus MCV4-TT in terms of hSBA seroprotection and GMTs and versus MenC-TT in terms of rSBA GMTs.

Introduction: Hepatitis A, caused by hepatitis A virus (HAV), is primarily transmitted via the fecal/oral route either through ingestion of contaminated food and water or through direct contact with an infectious person. Prevalence of hepatitis A is strongly correlated with socioeconomic factors, decreasing with increased socioeconomic development, access to clean water and sanitation. Vaccination against HAV should be part of a comprehensive plan for the prevention and control of viral hepatitis, either as part of regular childhood immunization programs or with other recommended vaccines for travelers. Areas covered: We present here evidence for the immunogenicity and safety of an inactivated HAV pediatric vaccine (Avaxim® 80U Pediatric, Sanofi Pasteur), indicated for use in children aged 12 months to 15 years. Data evaluated are from trials undertaken during the clinical development of this vaccine, a systematic literature review and post-market pharmacovigilance. Expert opinion: The pediatric HAV vaccine is highly immunogenic and generates long-lasting protection against hepatitis A disease in children. The safety and immunogenicity data presented in this review suggest that the pediatric HAV vaccine is a valuable option in the prevention of HAV infection in children in many areas of the world where the disease remains a healthcare issue.

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