The Hale Vaccine was a cure for the Chimeran virus created by Dr. Fyodor Malikov that was based on Pure Chimeran blood extracted from the body of Nathan Hale. Malikov discovered a unique protein within Hale's blood which he isolated and successfully cultivated into a vaccine for the Chimeran virus. Apparently, the Hale Vaccine was produced on a large enough scale for distribution to the surviving human population.
The vaccine was also compatible with Sentinels, allowing them to revert back to the pure human state. They would then live on without any trace of the virus or almost all of it's effects, thus removing the need for inhibitor treatments. However, this meant that the downside of doing so, would be the loss of their enhancements due to the virus, such as superhuman strength and regenerative abilities. The only known effect of the virus retained by humans who were formerly Sentinels are their gold-colored eyes.
Infected subjects injected with the vaccine are known to feel weak temporarily, due to their Chimeran cells being attacked.
- The Hale Vaccine is may be the explanation why human survivors have begun to use Chimeran Sym-Bac fluid as medication, reducing the number of human casualties as seen in throughout Resistance 3, and can be observed in by human settlements in Haven and Mount Pleasant.