Sorry! You must be logged in to read this post. Please sign up for your FREE MY-DSC account here. Login Tags:adenovirus-vectoredbooster vaccinationbreakthrough infectionsCoronavirusCOVIDCovid-19covid-19 vaccineefficacyhigh riskimmune responseimmunityimmunizationJohnson & JohnsonModernamRNAOxford-AstraZenecapandemicPfizer-BioNTechsars-cov-2side effectsT21RSvaccinationvaccinevaccine efficacyvaccine safetyvirusWHOWorld Health Organization