A single vaccination with non-replicating MVA at birth induces both immediate and long-term protective immune responses

Abstract Newborns are considered difficult to protect against infections shortly after birth, due to their ineffective immune system that shows quantitative and qualitative differences compared to adults. However, here we show that a single vaccination of mice at birth with a replication-deficient live vaccine Modified Vaccinia Ankara[MVA] efficiently induces antigen-specific B- and T-cells that fully protect against a lethal Ectromelia viruschallenge. Protection was induced within 2 weeks and using genetically modified mice we show that this protection was mainly T-cell dependent. Persisting immunological T-cell memory and neutralizing antibodies were obtained with the single vaccination. Thus, MVA administered as early as at birth induced immediate and long-term protection against an otherwise fatal disease and appears attractive as a new generation smallpox vaccinethat is effective also in children. Moreover, it may have the potential to serve as platform for childhood vaccines as indicated by measlesspecific T- and B-cell responses induced in newborn mice vaccinated with recombinant MVA expressing measlesantigens.