The design strategy of the current vaccines is to inject antibodies to fully envelop (surround) a Covid spike protein at its receptor binding domain, thereby fully neutralizing the virus and preventing (or treating) a Covid-19 infection. The overriding problem today is that the existing Covid Vaccines were developed as against the original, wild type Covid-19 and are incapable of fully neutralizing the Omicron variant of Covid-19.
This is because of Omicron’s numerous genetic mutations, fifteen of which are on the receptor binding domain (RBD) of the virus.
See this image showing genetic differences from Delta to Omicron; see this image showing an antigenic map of all Covid variants.
The vaccines’ antibody failure to fully surround Omicron’s spike protein virus, and resulting failure to fully neutralize the Omicron virus, cause immediate concerns about the efficacy of existing vaccines and the potential of reinfection, since by any measure, the vaccines no longer function in the human body (for Omicron Covid) the way originally intended or designed (for wild type Covid).