Zika, Ebola, Covid-19… Viruses from their nanoworld are at the origin of major health challenges and may cause pandemic threats. In the crusade for virus fight, being "small" may be an asset, for being active at the right scale. Nanosystems have recurrently been used to enhance the immune response of the body, by themselves or in combination with active agents (e.g. antigens) as well as for virus detection and isolation. This article is not an exhaustive review, but it envisions giving a general overview of the rationale behind the use of nanotechnology in virus fight, as illustrated by several significant examples including recent findings. Nanosystems, and in particular inorganic nanoparticles, offer a large variety of declinations that may be tailored in terms of physical and chemical characteristics to address the needs of virology. Among them, noble metals, metal oxides, mesoporous silica and calcium phosphates showed special promise. In particular, the bio-inspired character and modularity of calcium phosphates is appealing and allows envisioning further original developments in the fight against infections.