On Mar. 17, 2022, Soligenix announced the results of a booster vaccination study using CiVax™ (heat stable COVID-19 subunit vaccine program) in non-human primates (NHPs) demonstrating rapid enhancement of neutralizing antibody responses to SARS-CoV-2, including against Delta and Omicron variants.

The NHPs had been double vaccinated with an adenovirus vaccine for COVID-19 seven months previously. Prior to administration of the booster vaccine, neutralizing antibody levels against the original and Delta strains of SARS-CoV-2 were low, but detectable, and were undetectable for the Omicron strain. Within one week of receiving booster, neutralizing antibody levels increased as much as 27-fold against the original and Delta strains.

By three weeks this increased up to 243-fold. Protective neutralizing antibody levels were also rapidly raised against Omicron by one-week post-vaccination. These results are consistent with the broad-spectrum activity observed to date with CiVax™ on primary vaccination, as described in an article published by ACS Infectious Diseases.