Systematically updated commercial collection of illustrations
Above several virus fighting visualisations @Dreamstime
with vaccination or specimen syringe
Virus graphics @ Shutterstock
Scanning Electron Microscopy stylized images
First version @BigStock
This is an universal and wide subject to cover, so there are plenty of ideas and concepts possible.
High resolution creative raster images available at Shutterstock, Dreamstime, Fotolia, 123RF, BigStock and others – see full portfolio
Viral images collection of images on IStockPhoto – different artists.