SIU School of Medicine Foundation Springfield Office

William Halford - Medical Microbiology, Immunology and Cell Biology Faculty - SIU School of Medicine


Our Faculty

Andrea Braundmeier-Fleming

William Halford
Associate Professor

Research Interests

There are 126 known herpesviruses that infect animals and eight herpesviruses that infect humans.  Work in the Halford Lab focuses on two of these viruses: 

  • herpes simplex virus 1 (HSV-1), which causes recurrent cold sores (oral herpes)
  • herpes simplex virus 2 (HSV-2), which causes recurrent genital herpes.

Despite the tendency of these two viruses to infect different sites in the body, HSV-1 and HSV-2 are 99% genetically identical.  About 175 million Americans are latently infected with HSV-1, and ~55 million are latently infected with HSV-2.  Although only 5% of infected people experience frequent, recurrent outbreaks, this translates into roughly 10 million Americans who get recurrent cold sores and 3 million who experience 1 to 4 outbreaks of genital herpes each year.

Research Goals:

From a basic science viewpoint, Dr. Halford's research focuses on elucidating how key factors such as HSV's ICP0 protein and the host interferon response contribute to HSV's ability to "choose" between productive replication and non-productive infection each time the virus enters a new cell in vivo.  For more information on this topic, see Chapter 5 of Viruses and Interferon: Current Research, 2011.

From the clinical viewpoint, the basic science described above suggests a simple and rational path that would yield a new class of HSV-2 vaccine.  Specifically, interferon-sensitive HSV-2 ICP0- mutant viruses should be unable to cause disease in experimental animals or humans, but effectively prime the adaptive immune system such that the vaccine recipient is resistant to later exposures to wild-type HSV-2.  Published work and ongoing experiments in the lab indicate that, in fact, live HSV-2 ICP0- mutant viruses are a viable strategy to obtain a safe and effective HSV-2 vaccine that renders vaccinated animals completely resistant to HSV-2 genital herpes.  Work in the laboratory is currently focused on determining how effective these live HSV-2 vaccine strains are relative to three HSV-2 vaccine candidates that have previously advanced to human clinical trials; namely, 1. protein subunit vaccines such as Glaxo Smith Kline's Herpevac vaccine, 2. replication-defective HSV-2 viruses such as Sanofi Pasteur's ACAM-529 vaccine, and 3. live-attenuated HSV-2 viruses bearing mutations in 4 or more viral genes (Biovex's ImmunovexHSV-2 vaccine).

Updates on the status of research and development of Dr. Halford's live HSV-2 vaccine candidates may be found at


Professional Experience






Selected Publications

Pub Med

The mission of the Southern Illinois University School of Medicine is to assist the people of central and southern Illinois in meeting their health care needs through education, patient care, research, and service to the community.


Connect on FacebookMore About SIU SOM on YouTubeSIU Blogtwitter