In animals, effective immune responses against malignancies and against several infectious pathogens, including malaria, are mediated by T cells. Here we show that a heterologous prime-boost vaccination regime of DNA either intramuscularly or epidermally, followed by intradermal recombinant modified vaccinia virus Ankara (MVA), induces high frequencies of interferon (IFN)-gamma-secreting, antigen-specific T-cell responses in humans to a pre-erythrocytic malaria antigen, thrombospondin-related adhesion protein (TRAP). These responses are five- to tenfold higher than the T-cell responses induced by the DNA vaccine or recombinant MVA vaccine alone, and produce partial protection manifest as delayed parasitemia after sporozoite challenge with a different strain of Plasmodium falciparum. Such heterologous prime-boost immunization approaches may provide a basis for preventative and therapeutic vaccination in humans.

Hepatitis C virus (HCV) infection is a major global health problem that continues to grow with an estimated 170 million people infected. The consequences of chronic infection can include cirrhosis, end-stage liver disease and hepatocellular carcinoma. Due to shared routes of transmission, coinfection with HIV is a significant problem and individuals infected with both viruses have poorer outcomes. There is no effective vaccine though HCVis a potentially curable persistent viral infection. For many years, the standard of care has been subcutaneous interferon-alpha and oral ribavirin for between 24 and 72 weeks of treatment. This treatment results in a sustained virological response in only about 50% of individuals and is complicated by significant adverse events. In recent years, advances in HCV cell culture has allowed a greater understanding of HCV virology and this has paved the way for the development of many new directly acting antiviral drugs that target key components of virus replication such as protease and polymerase inhibitors. We are now at a point of improved and simplified treatments for HCV that may be administered as oral regimens of short duration and with far greater tolerability than regimens of old. The remaining hurdles may be access to appropriate care and cost of treatment as the epidemic continues to grow.

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