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Vaccines are increasingly based on new constructs, new technologies, and new compounds. Novel immunization programs are rapidly implemented globally. In this article, we highlight selected hot topics of this highly dynamic and broad field of scientific and public health development. The first section focuses on novel vaccines including malaria, dengue, serogroup B meningococcal, and respiratory syncytial virus vaccines and antibodies. The second section is addressing emerging strategies and programmatic challenges including maternal immunization, integrated mother-child safety monitoring, and finally coping strategies with vaccine shortages., (© 2018, The American College of Clinical Pharmacology.)

Replication-defective adenoviruses have been utilized as candidate HIV vaccine vectors. Few studies have described the international epidemiology of pre-existing immunity to adenoviruses. We enrolled 1904 participants in a cross-sectional serological survey at seven sites in Africa, Brazil, and Thailand to assess neutralizing antibodies (NA) for adenovirus types Ad5, Ad6, Ad26 and Ad36. Clinical trial samples were used to assess NA titers from the US and Europe. The proportions of participants that were negative were 14.8% (Ad5), 31.5% (Ad6); 41.2% (Ad26) and 53.6% (Ad36). Adenovirus NA titers varied by geographic location and were higher in non-US and non-European settings, especially Thailand. In multivariate logistic regression analysis, geographic setting (non-US and non-European settings) was statistically significantly associated with having higher Ad5 titers; participants from Thailand had the highest odds of having high Ad5 titers (adjusted OR=3.53, 95% CI: 2.24, 5.57). Regardless of location, titers of Ad5NA were the highest and Ad36 NA were the lowest. Coincident Ad5/6 titers were lower than either Ad5 or Ad6 titers alone. Understanding pre-existing immunity to candidate vaccine vectors may contribute to the evaluation of vaccines in international populations.

Background: Although the peak incidence of human papillomavirus (HPV) infection occurs in most populations within 5-10 years of first sexual experience, all women remain at risk for acquisition of HPV infections. We tested the safety, immunogenicity, and efficacy of the quadrivalent HPV (types 6, 11, 16, 18) L1 virus-like-particle vaccine in women aged 24-45 years., Methods: Women aged 24-45 years with no history of genital warts or cervical disease were enrolled from community health centres, academic health centres, and primary health-care providers into an ongoing multicentre, parallel, randomised, placebo-controlled, double-blind study. Participants were allocated by computer-generated schedule to receive quadrivalent HPV vaccine (n=1911) or placebo (n=1908) at day 1, and months 2 and 6. All study site investigators and personnel, study participants, monitors, and central laboratory personnel were blinded to treatment allocation. Coprimary efficacy endpoints were 6 months' or more duration of infection and cervical and external genital disease due to HPV 6, 11, 16, 18; and due to HPV 16 and 18 alone. Primary efficacy analyses were done in a per-protocol population, but intention-to-treat analyses were also undertaken. This study is registered with ClinicalTrials.gov, number NCT00090220., Findings: 1910 women received at least one dose of vaccine and 1907 at least one dose of placebo. In the per-protocol population, efficacy against the first coprimary endpoint (disease or infection related to HPV 6, 11, 16, and 18) was 90.5% (95% CI 73.7-97.5, four of 1615 cases in the vaccine group vs 41/1607 in the placebo group) and 83.1% (50.6-95.8, four of 1601 cases vs 23/1579 cases) against the second coprimary endpoint (disease or infection related to HPV 16 and 18 alone). In the intention-to-treat population, efficacy against the first coprimary endpoint was 30.9% (95% CI 11.1-46.5, 108/1886 cases vs 154/1883 cases) and against the second coprimary endpoint was 22.6% (-2.9 to 41.9, 90/1886 cases vs 115/1883 cases), since infection and disease were present at baseline. We recorded no vaccine-related serious adverse events., Interpretation: The quadrivalent HPV vaccine is efficacious in women aged 24-45 years not infected with the relevant HPV types at enrolment., Funding: Merck (USA).