mRNA-1283.222

mRNA-1283.222 is a next-generation, investigational bivalent COVID-19 vaccine developed by Moderna. It is designed to provide protection against SARS-CoV-2, including the Omicron BA.4/BA.5 variants and the original wild-type virus[4][6]. The vaccine uses messenger RNA (mRNA) technology to encode for antigens from these viral strains, prompting an immune response that generates neutralizing antibodies against the virus[2][5]. In Phase III clinical trials (NextCOVE), mRNA-1283.222 demonstrated a higher immune response compared to Moderna’s earlier bivalent vaccine (mRNA-1273.222), particularly in individuals over 65 years old—a group at higher risk for severe COVID-19 outcomes[3][6]. The safety profile of mRNA-1283 was similar to existing approved vaccines, with common adverse events including injection site pain, fatigue, headache, myalgia, and chills[2][5]. The improved storage and handling characteristics of this formulation may also facilitate broader public health access[3].