Viruses are another example of unstable products, specifically in the face of higher temperatures. In the study below, attenuated herpes simplex virus and inactivated influenza A virus were stored in PT120 and also in solution at -80°C and +40°C for 12 weeks. They were then used to inoculate mice and these mice were subsequently challenged with the live virus. The results show clearly that protection by PT120 at 40°C, was as effective as freezing the vaccine at -80°C. The vaccine stored in solution at 40°C was also completely ineffective at protecting the mice.