Introduction
DISEASE, VIRUS, CORONAVIRUS DISEASE 2019
The severe acute respiratory virus 2 (SARS-CoV-2) was first identified in November 2019 and soon thereafter, emerging new viral variants dramatically impacted the dynamics of Coronavirus disease 2019 (COVID-19) spread, globally. These virus variants are, in general, more contagious than previous strains. Moreover, some variants are capable of immunological and/or therapeutic escapeNumerous vaccines have been developed and proved effective to protect against severe disease, hospitalization, and fatal outcomesThe pandemic has disproportionately affected low- and middle-income countries (LMICs), which make up about 85% of the world population. Therefore, pandemic remains a threat unless most people get vaccinated. In response to the constraints imposed by the COVID-19 pandemic, and the limited access of many Latin American countries to costly vaccines, Laboratorio Pablo Cassará S.R.L., an Argentinian pharmaceutical company, launched a vaccine development program against SARS-CoV-2. ARVAC CG is a receptor binding domain (RBD)-based protein aluminum hydroxide-adjuvanted vaccine candidate that was designed and produced entirely in Argentina to be used as booster or primary vaccine against SARS-CoV-2. The vaccine is a variant-adapted vaccine based on the highly immune evasive Gamma SARS-CoV-2 variant of concern (VOC). Non-clinical studies of this vaccine prototype in mice indicated that the Gamma-variant vaccine-candidate is more immunogenic and induces a broader nAb response than the Ancestral vaccine-candidateIn this interim report safety and immunogenicity data after a booster dose of ARVAC CG vaccine from an ongoing first in human phase 1 study are presented. ARVAC CG exhibits a satisfactory safety profile, a robust and broad booster response of neutralizing 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 when used as booster in individuals previously immunized with different COVID-19 vaccine platforms.