IntroductionLive attenuated influenza vaccines (LAIVs) are being developed to protect humans against future epidemics and pandemics. This study describes the results of a double–blinded randomized placebo–controlled phase I clinical trial of cold–adapted and temperature sensitive H7N3 live attenuated influenza vaccine candidate in healthy seronegative adults.ObjectiveThe goal of the study was to evaluate the safety, tolerability, immunogenicity and potential shedding and transmission of H7N3 LAIV against H7 avian influenza virus of pandemic potential.Methods and FindingsTwo doses of H7N3 LAIV or placebo were administered to 40 randomly divided subjects (30 received vaccine and 10 placebo). The presence of influenza A virus RNA in nasal swabs was detected in 60.0% and 51.7% of subjects after the first and second vaccination, respectively. In addition, vaccine virus was not detected among placebo recipients demonstrating the absence of person–to–person transmission. The H7N3 live attenuated influenza vaccine demonstrated a good safety profile and was well tolerated. The two–dose immunization resulted in measurable serum and local antibody production and in generation of antigen–specific CD4+ and CD8+ memory T cells. Composite analysis of the immune response which included hemagglutinin inhibition assay, microneutralization tests, and measures of IgG and IgA and virus–specific T cells showed that the majority (86.2%) of vaccine recipients developed serum and/or local antibodies responses and generated CD4+ and CD8+ memory T cells.ConclusionsThe H7N3 LAIV was safe and well tolerated, immunogenic in healthy seronegative adults and elicited production of antibodies broadly reactive against the newly emerged H7N9 avian influenza virus.Trial registrationClinicalTrials.gov NCT01511419
A dramatic increase of influenza activity in Russia since week 3 of 2016 significantly differs from previous seasons in terms of the incidence of influenza and acute respiratory infection (ARI) and in number of lethal cases. We performed antigenic analysis of 108 and whole‐genome sequencing of 77 influenza A(H1N1)pdm09 viruses from Moscow and Saint Petersburg. Most of the viruses were antigenically related to the vaccine strain. Whole‐genome analysis revealed a composition of specific mutations in the internal genes (D2E and M83I in NEP, E125D in NS1, M105T in NP, Q208K in M1, and N204S in PA‐X) that probably emerged before the beginning of 2015/2016 epidemic season.
A recombinant vector vaccine TB/FLU-04L for the prevention of
tuberculosis was developed in RIBSP CS MES RK and SRII. The vaccine is based on
the attenuated influenza strain Flu NS106/ESAT-6_Ag85A
expressing mycobacterial antigens Esat-6 and Ag85A. This research aimed to
conduct pre-clinical safety studies of the vaccine as one of the basic and
mandatory stages in the development and introduction of immunobiological
preparations. The studies were performed at the research centers of the Republic
of Kazakhstan and the Russian Federation.The experiment was conducted on ferrets, monkeys, and rabbits. The
TB/FLU-04L vaccine was administered intranasally (7.5 lg
TCID50/animal). The clinical signs, body weight,
temperature, hematological parameters, and local irritant effects were monitored
throughout the study. The results of the study demonstrated the safety of the
TB/FLU-04L intranasal vector vaccine against tuberculosis since its
administration in laboratory animals led to no adverse effects in any of the
monitored parameters. No influenza A virus particles were isolated from samples
of nasal washes.
The producers of influenza vaccines are not capable today to meet the global demand for an influenza vaccine in case of pandemic, so the World Health Organization recommends to develop the own influenza vaccine production in each country. A domestic preservative- and adjuvant-free trivalent split vaccine against seasonal influenza was developed at the Research Institute for Biological Safety Problems. The paper presents the results of assessing safety and immunogenicity of the influenza split vaccine after single immunization of healthy volunteers aged 18-50 years in the course of Phase I Clinical Trials. This study was randomized, blind, and placebo-controlled. The volunteers were intramuscularly vaccinated with a dose of split vaccine or placebo. The study has shown that all local and systemic reactions had low degree of manifestation and short-term character, so there was no need in medication. Serious side effects were not observed. On day 21 post vaccination the portion of vaccinated persons with fourfold seroconversions to influenza А/H1N1pdm09 virus was 100.0%, to influenza А/H3N2 virus-95.5%, to influenza B virus-81.8%, and in placebo group this index was 0%. Seroprotection rates against influenza А/H1N1pdm09, А/H3N2 and B viruses were 95.5, 86.3, and 72.7%, respectively. Geometric mean titers (GMT) of antibodies by day 21 post vaccination reached 175.7 for influenza А/H1N1pdm09 virus, 64.2 for influenza А/H3N2 virus, and 37.6 for influenza B virus; in placebo group GMT growth was not observed. So, the seasonal influenza split vaccine is well tolerated and fits all immunogenicity criteria for human influenza vaccines.
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