Mathematical Modeling for Removing Border Entry and Quarantine Requirements for COVID-19, Vanuatu.

The Pacific Island country of Vanuatu is considering strategies to remove border restrictions implemented during 2020 to prevent imported coronavirus disease. We performed mathematical modeling to estimate the number of infectious travelers who had different entry scenarios and testing strategies. Travel bubbles and testing on entry have the greatest importation risk reduction.

Safety and immunogenicity of an investigational quadrivalent meningococcal tetanus toxoid conjugate vaccine (MenACYW-TT) co-administered with routine pediatric vaccines in infants and toddlers: A Phase II study.

BACKGROUND: The MenACYW-TT conjugate vaccine is approved for prevention of invasive meningococcal disease (IMD) as a single dose in individuals ≥2 years of age in the United States and ≥12 months in EU and some other countries. This Phase II study evaluated the safety and immunogenicity of this vaccine and of concomitant pediatric vaccines in infants/toddlers (6 weeks-15 months of age). METHODS: Five schedules of the MenACYW-TT conjugate vaccine were evaluated in the United States: 2, 4, 6, and 12 months; 2, 4, 6, and 15 months; 2, 4, and 12 months; 6 and 12 months; and 12 months alone. Routine pediatric vaccines (DTaP-IPV/Hib, PCV7/PCV13, MMR, and varicella) were administered per approved schedules. Proportions of participants with serum bactericidal antibodyassay with human complement (hSBA) titers ≥1:4 and ≥1:8, SBA with baby rabbit complement (rSBA) titers ≥1:8 and ≥1:128, and immune responses against concomitant vaccines were determined. RESULTS: Tenderness and irritability were the most frequent solicited injection site and systemic reactions. Similar proportions of participants achieved an hSBA titer ≥1:8 for all four serogroups regardless of whether 2 or 3 doses were administered in the first year of life. Following a second-year dose, 91-100% of participants achieved the threshold for all 4 serogroups in all schedules regardless of the number of doses in the first year of life. Similar responses were seen with rSBA. Immunogenicity and safety profile of concomitant vaccines was similar whether the MenACYW-TT conjugate vaccine was administered or not. CONCLUSION: MenACYW-TT conjugate vaccine administered with pediatric vaccines is safe and immunogenic regardless of the schedule and does not affect the immunogenicity or safety of the concomitant vaccines. CLINICAL TRIAL REGISTRY: NCT01049035.

Influenza A (H1N1) 2009 two-dose immunization of US children: an observer-blinded, randomized, placebo-controlled trial.

The goal of this pediatric clinical trial was to assess the safety and immunogenicity of two different doses of a monovalent inactivated pandemic (H1N1) 2009 vaccine in US children aged 6 months to 9 years of age. Randomized, observer-blinded, US multicenter phase 2 study assessing 2 doses of vaccine given 21 days apart in 474 children aged 6-35 months or 3-9 years. Children in each age group were randomly assigned to receive either a pandemic (H1N1) 2009 vaccine containing 7.5 or 15 µg of hemagglutinin (HA) or placebo in a 4:4:1 ratio. Primary outcome was hemagglutination inhibition (HI) antibody responses 21 days following each vaccination. Safety was monitored throughout the study. The first dose of either A H1N1 vaccine formulation was more immunogenic in children older than 3 years than in younger children. 45-50% of children aged 6-35 months and 69-75% of children aged 3-9 year-old attained HI titers of ≥ 1:40. A second dose of A H1N1 vaccine further increased HI antibody responses with seroprotection and seroconversion rates reaching 90-99% in both age groups. Interestingly, the pandemic (H1N1) 2009 vaccine formulations elicited similar rates of solicited and unsolicited injection site and systemic reactions as the placebo. The data therefore demonstrate the high level immunogenicity in infants and children of an (H1N1) 2009 influenza vaccine displaying a safety and reactogenicity profile similar to placebo.