Immunogenicity and Safety of an MF59-adjuvanted Quadrivalent Seasonal Influenza Vaccine in Young Children at High Risk of Influenza-associated Complications: A Phase III, Randomized, Observer-blind, Multicenter Clinical Trial.

BACKGROUND: Vaccination against seasonal influenza is recommended for all children with a history of medical conditions placing them at increased risk of influenza-associated complications. The immunogenicity and efficacy of conventional influenza vaccines among young children are suboptimal; one strategy to enhance these is adjuvantation. We present immunogenicity and safety data for an MF59-adjuvanted quadrivalent influenza vaccine (aIIV4) in healthy children and those at a high risk of influenza-associated complications, based on the results of a recently completed phase III study. METHODS: Children 6 months to 5 years of age (N = 10,644) were enrolled. The study was conducted across northern hemisphere seasons 2013-2014 and 2014-2015. Subjects received either aIIV4 or a nonadjuvanted comparator influenza vaccine. Antibody responses were assessed by hemagglutination inhibition assay against vaccine and heterologous strains. Long-term antibody persistence was assessed (ClinicalTrials.gov: NCT01964989). RESULTS: aIIV4 induced significantly higher antibody titers than nonadjuvanted vaccine in high-risk subjects. aIIV4 antibody responses were of similar magnitude in high-risk and healthy subjects. Incidence of solicited local and systemic adverse events (AEs) was slightly higher in aIIV4 than nonadjuvanted vaccinees, in both the healthy and high-risk groups. Incidence of unsolicited AEs, serious AEs and AEs of special interest were similar for adjuvanted and nonadjuvanted vaccinees in the healthy and high-risk groups. CONCLUSION: aIIV4 was more immunogenic than nonadjuvanted vaccine in both the healthy and high-risk study groups. The reactogenicity and safety profiles of aIIV4 and the nonadjuvanted vaccine were acceptable and similar in 6-month- to 5-year-old high-risk and healthy children.

Review: current knowledge on the role of HPV antibodies after natural infection and vaccination: implications for monitoring an HPV vaccination programme.

In 2006/2007, two vaccines were licensed against two of the most common HPV types that cause about 70% of cervical cancers. Clinical trials show that vaccinated individuals develop high levels of neutralizing antibodies. Although these data suggest that serum antibodies are the mode of action against HPV infection, it is uncertain whether immune responses generated by vaccination are similar to those induced by a natural infection. In this review, the current knowledge of humoral immune responses after natural infection and vaccination is described. Serosurveillance can be used as a monitoring tool to study vaccine uptake, the impact of HPV16/18 vaccination on other HPV types, dynamics of HPV infection and herd-immunity. In addition, factors that contribute to a higher seroresponse after a natural infection, which are summarized in this article (a persistent DNA infection, increased viral load, immunosuppression and high sexual risk behavior), can help to interpret these indirect effects better.