Safety and immunogenicity of DNA omicron booster Alveavax-v1.2 in Ad26.COV2.S-vaccinated adults

A phase I study assessed the safety and immunogenicity of the naked DNA Omicron BA.2 booster vaccine, Alveavax-v1.2, in 130 South African adults previously vaccinated with Janssen Ad26.COV2.S. Participants received varying doses intradermally or subcutaneously, or a Janssen booster as a control. The vaccine was well tolerated, with mild to moderate adverse events across all groups and no serious events linked to vaccination. However, the antibody response was modest, with no significant increases in Omicron BA.2 titers observed in any group. The vaccine remained shelf stable for over six months at room temperature.