Dr. Painokovic's Vaccine

For months everything seems lost, after the zombie holocaust desperation and desolation ravage the world. The virus spreads rapidly and the survivors are getting scarce. Various testimonies lead you to the apartment of Dr. Painokovic, who years ago was considered mad due to his obsession with what has happened...before it happened. Painokovic was a research master in medicine in his native country, where he spent years studying the development of certain viruses that his government wanted to use for war purposes. Given the danger of the project, and after warning of the terrible consequences of continuing to cultivate this strain, the doctor was expelled from the project and fled his country for his own safety, dedicating the rest of his life to creating a cure for the virus he created years ago. Finally, the doctor's warnings came true, and the world succumbed to the greatest known epidemic to date. Perhaps you can find the cure in the missing doctor's study, it is the last chance for humanity...and you are running out of minutes.