Safety, tolerability, and immunogenicity of a new SARS-CoV-2 recombinant Gamma variant RBD-based protein adjuvanted vaccine, used as heterologous booster in healthy adults: a Phase 1 interim report

Abstract

Background In view of the emergence of SARS-CoV-2 immune escape variants and evidence of waning immunity, new immunisation strategies and variant-adapted vaccines are needed. Based on preclinical proof of concept studies and requirement of variant-adapted and booster vaccines, the Gamma Variant RBD-based ARVAC-CG vaccine was selected for a first clinical trial in humans. Methods Eighty participants (healthy adults, 18-55 years-old) were sequentially assigned to receive two (28 days apart) intramuscular doses of 25-lower case Greek mug (n=60) or 50-lower case Greek mug (n=20) of a Gamma RBD-based subunit vaccine adjuvanted with aluminium hydroxide. The primary endpoint was safety. The secondary objective was to describe the neutralising antibody response against the SARS-CoV-2 Ancestral strain and several variants of concern (Gamma, Delta, Omicron BA.1 and Omicron BA.5) measured by a live virus-based neutralisation assay. Cellular immune responses were studied as an exploratory objective by an enzyme-linked immunospot (ELISpot) assay. This trial is registered in ClinicalTrials.gov (NCT05656508). Findings The interim results from the ongoing phase 1 study are described. ARVAC-CG exhibited a satisfactory safety profile, a robust and broad booster response of neutralising antibodies against the Ancestral strain of SARS-CoV-2, the Gamma variant, and other VOCs (Delta, Omicron BA.1 and Omicron BA.5) and a booster effect on T cell immunity. Interpretation ARVAC-CG is safe and highly immunogenic when used as booster in individuals previously immunised with different COVID-19 vaccine platforms. These results warrant further clinical evaluation of this vaccine candidate for boosting other COVID-19 vaccines.

Policy options and practical recommendations for determining priorities in public health research agendas in peripheral countries: insights from a collaborative work initiative in Argentina during the COVID-19 pandemic

“…Also in India, Bharat Biotech has developed COVAXIN ® , in collaboration with the Indian Council of Medical Research (ICMR)—National Institute of Virology (see text footnote 2). Recently, Argentina joined the group of the 10 countries in the world that locally produced a COVID-19 vaccine devised by the public sector and then finally developed through a public-private consortium ( 4 ). 15 These successful initiatives make us wonder about the possibilities that other peripheral countries may have to promote their own research and developments.…”

“…The majority of them were developed in central countries and resulted in several approaches that were distributed worldwide. However, peripheral countries, like Argentina, Brazil, Cuba, and India, have also made their own developments providing resources to local production necessary to fight against this respiratory disease ( 4 , 5 ). 1 , 2 One of these initiatives was the Argentinean AntiCovid Consortium, where we partnered with nearly 30 researchers (PIs, young researchers, postdocs and PhD students) from different scientific backgrounds, combining our knowledge and expertise to carry out a multidisciplinary strategy.…”