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BackgroundWe report results of immunogenicity, safety and reactogenicity of SOBERANA 02 in a two-dose or three-dose heterologous scheme in adults in a phase IIb clinical trial. MethodThis phase IIb trial was designed as parallel, multicentre, adaptive, double blind, randomized and placebo-controlled. Subjects (N=810) aged 19-80 years were randomized to receive two doses of the recombinant SARS CoV-2 receptor binding domain (RBD) conjugated to tetanus toxoid (SOBERANA 02) and a third dose of dimeric RBD (SOBERANA Plus) 28 days apart; two production batches of active ingredient of SOBERANA 02 were evaluated. Primary outcome was the percentage of seroconverted subjects with [≥]4-fold the anti-RBD IgG concentration. Secondary outcomes were safety, reactogenicity and neutralizing antibodies. ResultsSeroconversion rate in vaccinees was respectively 76.3 and 96.8% after two or three doses, compared with 7.3% in placebo group. Anti-RBD IgG increased significantly after first and second dose of SOBERANA 02 respect to placebo group; and the third dose with SOBERANA Plus boosts the response compared to the second dose. Neutralizing IgG antibodies were detected against D614G and VOCs , {beta} and {delta}. Specific and functional antibodies were detected at least until 7-8 months after the third dose. The frequency of serious adverse events (AEs) associated with vaccination was very low (0.1%); with only one serious AE consistent with vaccination. Local pain was the most frequent AE. ConclusionsTwo doses of SOBERANA 02 were well tolerated, safe an immunogenic in adults aged 19-80 years old. The heterologous combination with a third dose of SOBERANA Plus increased neutralizing antibodies, detectable 7-8 months after finishing the vaccination schedule. Trial registryhttps://rpcec.sld.cu/trials/RPCEC00000347
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AimTo evaluate the safety and immunogenicity of a SARS-CoV-2 recombinant spike protein vaccine (Abdala), administered intramuscularly in different strengths and vaccination schedules. MethodA phase 1-2, randomized, double-blind, placebo-controlled trial was done. Subjects were randomly distributed in 3 groups: placebo, 25 and 50{micro}g RBD. The product was applied intramuscularly, 0.5 mL in the deltoid region. During the first phase, two immunization schedules were studied: short (0-14-28 days) and long (0-28-56 days). In phase 2, only the short scheme was evaluated. The main endpoints were: safety and proportion of subjects with seroconversion of anti-RBD IgG antibodies to SARS-CoV-2. Blood samples were collected in several points according to the corresponding vaccination schedule to determine the level of RBD-specific IgG antibodies (seroconversion rates and geometric mean of the titers), the percentage of inhibition of RBD-ACE-2 binding and levels of neutralizing antibodies. ResultsThe product was well tolerated. Severe adverse events were not reported. Adverse reactions were minimal, mostly mild and local (from the injection site), resolved in the first 24-48 hours without medication. In phase 1, at day 56 (28 days after the third dose of the short vaccination schedule, 0-14-28 days) seroconversion of anti-RBD IgG was seen in 95.2 % of the participants (20/21) for the 50g group and 81 % of the participants (17/21) for the 25g group, and none in the placebo group (0/22); whereas neutralizing antibodies to SARS-CoV-2 were seen in 80 % of the participants (8/10) for the 50g group and 94.7% of the participants (18/19) for the 25g group. For the long schedule, at day 70 (14 days after the third dose) seroconversion of anti-RBD IgG was seen in 100% of the participants (21/21) for the 50g group and 94.7% of the participants (18/19) for the 25g group, and none in the placebo group (0/22); whereas neutralizing antibodies to SARS-CoV-2 were seen in 95 % of the participants (19/20) for the 50g group and 93.8% of the participants (15/16) for the 25g group In phase 2, at day 56 seroconversion of anti-RBD IgG was seen in 89.2% of the participants (214/240) for the 50g group, 77.7% of the participants (185/238) for the 25g group, and 4.6% in the placebo group (11/239); whereas neutralizing antibodies to SARS-CoV-2 were seen in 97.3% of the participants (146/150) for the 50g group and 95.1% of the participants (58/61) for the 25g group. ConclusionAbdala vaccine against SARS-CoV-2 was safe, well tolerated and induced humoral immune responses against SARS-CoV-2 among adults from 19 to 80 years of age. Trial registration / Review protocolRPCEC00000346. Cuban Public Clinical Trial Registry (WHO accepted Primary Registry). Available from: https://rpcec.sld.cu/en/trials/RPCEC00000346-En Information about the ethical aspects and IRB approvalThe protocol was approved by the Ethic Committee of the participating hospital and by the Cuban Regulatory Authority (Center for State Control of Drugs, Medical Devices and Equipment). Summary boxCOVID-19 is a serious global health problem. Vaccines are urgently needed to protect humanity. Multiple vaccine candidates are currently being evaluated. The article shows promising safety and immunogenicity results for a vaccine candidate, based on the recombinant RBD subunit of the spike protein.
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SARS-CoV-2, a recently emerged coronavirus, is causing high morbidity and mortality worldwide since December 2019, posing an enormous health, social and economic problem. Obtaining effective treatments that can diminish deaths and sequelae and vaccines to slow or prevent viral transmission, and reduce disease severity and/or death are of utmost importance. Abdala is a Cuban vaccine based on the recombinant RBD subunit of the spike protein expressed in Pichia pastoris yeast. It demonstrated high efficacy (92.28 %) in phase III clinical trials for reducing transmission, and more than 90% effectiveness in reducing disease severity and mortality. Antibody titers were evaluated in 42 Abdala vaccinees using the Elecsys(R) Anti-SARS-CoV-2 S test. Fifteen days after immunization, sera from vaccinees showed high antibody titers (median of 1595 U/mL). The results obtained in this study also demonstrate correlation between the Cuban test UMELISA SARS-CoV-2 ANTI RBD used during the clinical trials and Elecsys(R) test results. HighlightsO_LIFifteen days after immunization with the Cuban Abdala vaccine, sera from vaccinees showed high antibody titers (median of 1595 U/mL). C_LIO_LIThere was high correlation between the Cuban test UMELISA SARS-CoV-2 ANTI RBD used during the vaccine clinical trials and Roches Elecsys(R) test results. C_LIO_LIAbdala vaccinees reached antibody titers by the Elecsys(R) Anti-SARS-CoV-2 S test comparable to those of Pfizer/BionTech vaccine using the same test. C_LI
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We evaluated response to a single dose of the FINLAY-FR-1A recombinant dimeric-RBD base vaccine during a phase I clinical trial with 30 COVID-19 convalescents, to test its capacity for boosting natural immunity. This short report shows: a) an excellent safety profile one month after vaccination for all participants, similar to that previously found during vaccination of naive individuals; b) a single dose of vaccine induces a >20 fold increase in antibody response one week after vaccination and remarkably 4-fold higher virus neutralization compared to the median obtained for Cuban convalescent serum panel. These preliminary results prompt initiation of a phase II trial in order to establish a general vaccination protocol for convalescents.
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Controlling the global COVID-19 pandemic depends, among other measures, on developing preventive vaccines at an unprecedented pace. Vaccines approved for use and those in development intend to use neutralizing antibodies to block viral sites binding to the hosts cellular receptors. Virus infection is mediated by the spike glycoprotein trimer on the virion surface via its receptor binding domain (RBD). Antibody response to this domain is an important outcome of the immunization and correlates well with viral neutralization. Here we show that macromolecular constructs with recombinant RBD conjugated to tetanus toxoid induce a potent immune response in laboratory animals. Some advantages of the immunization with the viral antigen coupled to tetanus toxoid have become evident such as predominant IgG immune response due to affinity maturation and long-term specific B-memory cells. This paper demonstrates that subunit conjugate vaccines can be an alternative for COVID-19, paving the way for other viral conjugate vaccines based on the use of small viral proteins involved in the infection process.