Vaccine
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Influenza-pseudotyped Gag virus-like particles (VLPs) were produced via the expression of influenza hemagglutinin (HA), neuraminidase (NA) and the murine leukemia virus Gag product in the baculovirus-insect cell expression system. Hemagglutination specific activities of sucrose gradient-purified VLPs were similar to those of egg-grown influenza viruses but particle morphologies were gamma retrovirus-like in the form of consistent 100nm spheres. Immunization of mice and ferrets demonstrated robust immunogenicity and protection from challenge with no measurable morbidity. ⋯ H1N1 VLP immunization of ferrets resulted in partial protection against H5N1 challenge with markedly accelerated virus clearance from the upper respiratory tract relative to controls. The immunogenicity of influenza-pseudotyped VLPs was not dependent on the adjuvant properties of replication competent contaminating baculovirus. These data demonstrate robust vaccine protection of Gag-based, influenza-pseudotyped VLPs carrying a variety of influenza antigens and suggest applicability toward a number of additional respiratory viruses.
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Randomized Controlled Trial Comparative Study
Safety and efficacy of a novel microneedle device for dose sparing intradermal influenza vaccination in healthy adults.
Intradermal vaccine delivery has been shown to induce good immune responses with low vaccine doses. Technologies for drug-delivery which specifically target the skin may render intradermal vaccination more accessible. ⋯ Low-dose influenza vaccines delivered intradermally using microneedles elicited immunogenic responses similar to those elicited by the full-dose intramuscular vaccination. The microneedle injection device used in this study was found to be effective, safe, and reliable.
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Randomized Controlled Trial Comparative Study
Immunogenicity and safety of measles-mumps-rubella-varicella (MMRV) vaccine followed by one dose of varicella vaccine in children aged 15 months-2 years or 2-6 years primed with measles-mumps-rubella (MMR) vaccine.
In this open, randomized, comparative study (105908/NCT00353288), 458 age-stratified children (15 months-2 years and 2-6 years) previously primed with MMR received one dose of either a combined MMRV vaccine (Priorix-Tetra, MMRV group) or concomitant MMR and varicella vaccines (Priorix and Varilrix, MMR+V group), followed 42-56 days later by another dose of varicella vaccine (Varilrix) in both groups. Post-vaccination measles, mumps and rubella seropositivity rates and antibody geometric mean titers (GMTs) were high (99.5% for anti-measles and 100% for anti-mumps and anti-rubella) in both vaccine groups. In the two age strata, varicella seroconversion rates were, post-dose 1: > or =97.6% (MMRV), > or =96.6% (MMR+V) and, post-dose 2: 100% in both groups. ⋯ Post-dose 1, the incidence of any solicited local symptom during the 4-days follow-up was < or =28.2% (MMRV) and < or =19.8% (MMR+V) and the incidence of fever >39.5 degrees C (rectal temperature) within 15 days was < or =2.8% (MMRV) and < or =2.6% (MMR+V). This MMRV vaccine appears an immunogenic and safe substitute for a second dose of MMR vaccine in young children. The increase in anti-varicella antibodies observed after a second dose of varicella vaccine supports a two-dose schedule for varicella-containing vaccine.