June 15, 2013 |
WHO AM I?
My name is Bill Halford and I am an Associate Professor of Microbiology and Immunology at Southern Illinois University School of Medicine in Springfield, Illinois. I have studied herpes simplex virus (HSV) biology since 1991, and I became interested in trying to develop a safe and effective HSV-2 vaccine in 2006. There are at least 100 individuals in the world who are actively pursuing a HSV-2 vaccine, and I am one of these many researchers. In this blog, I will try to cut through the nomenclature and statistics and explain in relatively straightforward terms what we know about HSV-2 vaccines and what we need to do next to advance a safe and effective HSV-2 vaccine to human clinical trials. If you wish to contact me, you can do so via this blog or e-mail me at “email@example.com.”
The author of this website, Bill Halford, is an employee of the Southern Illinois University School of Medicine in Springfield, Illinois. The viewpoints expressed on this website are solely that of the author, and should not be construed as an official statement of the policies, procedures, or opinions of Southern Illinois University, the School of Medicine, or any of the academic departments contained therein.
BACKGROUND ON HSV-2 INFECTIONS AND GENITAL HERPES
Genital herpes caused by herpes simplex virus type 2 (HSV-2) remains a huge medical and public health problem. About 1 billion people (out of ~7 billion total) are life-long carriers of the HSV-2 virus. About 40 million of those HSV-2 infected persons live with genital herpes outbreaks that recur once every 2 to 12 months over the duration of their lives. Each outbreak can last from 2 to 20 days in duration, and is physically uncomfortable and emotionally distressing. Antiviral drugs such as acyclovir or valacyclovir (valtrex) reduce, but do not prevent. the symptoms of recurrent genital herpes. Likewise, antiviral drugs have not slowed the spread of HSV-2 infection at all; ~20 million per year continue to acquire new HSV-2 infections from the 1 billion people who already carry the HSV-2 virus.
HSV-2 genital herpes has been described as a silent epidemic. This term is apt, as HSV-2 exists all around us and is carried by friends and family members, but people are reluctant to disclose that they are infected with HSV-2 as there remains a historical stigma associated with this infection. Many people who have the HSV-2 virus have not had many sexual partners, and many teenagers who acquire HSV-2 have the misfortune of acquiring HSV-2 with their first sexual partner. Nonetheless, the social stigma that people with HSV-2 wish to avoid is the perception that they have slept with dozens of people. For this and a variety of other reasons, the ~200 million people who have experienced symptoms of HSV-2 genital herpes do not tend to share this information with many people. Thus, it is hard to estimate the magnitude of the problems caused by HSV-2 genital herpes. One number helps put the problem into perspective; each of our children has a 1-in-10 chance of contracting a HSV-2 infection before they are married.
Aside from the individual suffering caused by recurrent genital herpes, HSV-2 infections can cause more severe complications such as HSV-2 infections of newborns as they pass through the vagina / birth canal. The immune system of neonates is not yet developed, and thus HSV-2 infections in newborn babies can be devastating often resulting in death or severe mental / cognitive impairment, as HSV-2 infection can spread to the central nervous system of newborns.
THE POTENTIAL UTILITY OF A HSV-2 VACCINE
Effective vaccines have been responsible for the eradication and/or control of many viral diseases such as smallpox, yellow fever, red measles, mumps, German Measles, hepatitis B, chickenpox, and poliomyelitis. In principle, there is no reason that a safe and effective HSV-2 vaccine could not be deployed in the human population to prevent HSV-2 genital herpes.
The applications of a safe and effective genital herpes vaccine would be two-fold.
First, an effective HSV-2 vaccine could be given to adolescents or prospective sexual partners of those who already carry the HSV-2 virus. Exposure to an effective HSV-2 vaccine would bolster the immune system of such individuals such that their bodies were at least 100 times better prepared to repel the real (wild-type) HSV-2 pathogen if they were exposed later in life. Such a “preventative HSV-2 vaccine” could be used to prevent ~20 million per year from newly acquiring the HSV-2 virus.
Second, an effective HSV-2 vaccine could be given to those who suffer from frequent outbreaks of recurrent genital herpes. Such a “therapeutic HSV-2 vaccine” could be used to reduce the frequency and duration of genital herpes outbreaks in those ~40 million people worldwide who suffer from this chronic viral disease. This latter application of a HSV-2 vaccine (i.e., to reduce symptoms in those who already carry the HSV-2 virus) would be more experimental, and less of a sure thing than a preventative HSV-2 vaccine. Nonetheless, there are several publications dating back to the 1950s that claim such an effect has been obtained by treatment with a variety of vaccine formulations including inactivated-preparations of HSV virion particles. Therefore, once a safe and effective HSV-2 preventative vaccine is identified, it will be relevant to determine if it has potential to also serve as a therapeutic HSV-2 vaccine.
WHY DO WE STILL LACK AN EFFECTIVE HSV-2 VACCINE?
This is the million dollar question, and will be precisely the focus of the Herpes Vaccine Blog.
I envision posts on the Herpes Vaccine Blog serving one of three general purposes, and these will be discussions of:
1. The science of HSV-2 vaccines
2. Moving a safe and effective HSV-2 vaccine into human trials
3. Answers to specific reader queries (which may be sent to firstname.lastname@example.org)
What I hope to make clear through the development of this blog is that a safe and effective HSV-2 vaccine lies within our grasp, but what we lack is a critical mass of support to advance such a HSV-2 vaccine to human clinical trials. The primary barriers to the advancement of an effective HSV-2 vaccine are (1) misinformation and (2) a pre-conceived notion that certain types of HSV-2 vaccines (e.g., live-attenuated) should not be investigated or considered for use as a human vaccine.
One of the central purposes of this blog will be to (try to) simply explain why past HSV-2 vaccines have not worked, and define what we need to do differently in the future if we intend to end the needless suffering caused by genital herpes. Make no mistake…..HSV-2 genital herpes is a vaccine-preventable disease. However, the field of HSV-2 vaccine research is long overdue for a “course correction.” I hope that this blog serves as a vehicle to increase the public’s understanding of what we need to be doing differently if we hope to make HSV-2 genital herpes a disease of the past.
– Bill Halford