Protective Properties of Vaccinia Virus-Based Vaccines: Skin Scarification Promotes a Nonspecific Immune Response That Protects against Orthopoxvirus Disease

Abstract

The process of vaccination introduced by Jenner generated immunity against smallpox and ultimately led to the eradication of the disease. Procedurally, in modern times, the virus is introduced into patients via a process called scarification, performed with a bifurcated needle containing a small amount of virus. What was unappreciated was the role that scarification itself plays in generating protective immunity. In rabbits, protection from lethal disease is induced by intradermal injection of vaccinia virus, whereas a protective response occurs within the first 2 min after scarification with or without virus, suggesting that the scarification process itself is a major contributor to immunoprotection. IMPORTANCE These results show the importance of local nonspecific immunity in controlling poxvirus infections and indicate that the process of scarification should be critically considered during the development of vaccination protocols for other infectious agents.