CP and infection: However, no evidence indicates that recovered people with existing SARS-CoV-2 antibodies are protected against a second infection of COVID-19,6 and a growing number of studies report COVID-19 reinfections.7, 8, 9 This comprehensive review provides a broad overview of the challenges associated with COVID-19 vaccines and treatment options, including the potential of CP therapy, herd immunity, and the probability of reinfection.