The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Dr Deb The Travel Doctor:
Record details of your vaccines, and have those details to hand when needed, either by referring to the app, or emailing a summary. Losing your vaccination records will cost you time, money, and pain in the arm when you have vaccines repeated.Vaccine Record also allows users to set reminder alerts, so their technology will remind them when vaccines need to be updated. You can even store a photograph of the yellow fever certificate in your device.There is currently a paper-based International Vaccine Record that is carried by travellers world wide. This app is the digital version. This app does not replace the paper version but is a handy tool so the vaccine information is easily at handThis app was developed by Dr Deb Mills, a Travel Medicine specialist for over 20 years.