The majority of current SARS-CoV-2 vaccine efforts focus on presenting the viral protein Spike (S) to the immune system, either in purified or small-particle form. However, coronaviruses have additional viral surface proteins, and previous vaccine trials for other coronaviruses using the S protein have yielded insufficient protection and even deleterious antibody responses that enhance disease. Other traditional viral inactivation methods for coronavirus vaccine development, including formalin or other cross-linkers, have also been tried unsuccessfully. These methods allowed presentation of multiple viral proteins to the immune system but disturbed the native structures of the viral proteins, which are critical for ideal presentation to the immune system and neutralizing antibody production. However, our laboratory recently developed a novel, rapid, and safe method to fully inactivate enveloped viruses while maintaining the native structures of multiple viral antigens, as a result generating neutralizing antibodies that increased protection upon vaccination. This new method may lead to an effective SARS-CoV-2 vaccine.

We recently discovered the antiviral XM-01 which has three effects on enveloped viruses. Such effects dramatically increase the production of neutralizing antibodies in animals and the efficacy of protection against influenza virus challenge (another enveloped virus; manuscript in preparation). These three effects include the following: 1) XM-01 inhibits infection of all enveloped viruses tested (10 so far); 2) XM-01 leaves the viral proteins in their native structures, crucial for enhancing neutralizing antibody responses; and 3) XM-01 forms membrane lipids that boost the innate immune response in host cells (adjuvant effect). We will use XM-01 to produce a novel SARS-CoV-2 vaccine.