Herpes simplex virus includes a broad spectrum of diseases. There are primarily two types of herpes simplex virus; HSV type 1 and type 2. HSV-1 is classified as oral Herpes because it causes cold sores around the mouth. It can also cause genital Herpes due to an increase in oral sex. It generally transmits through direct contact, which usually involves saliva. HSV-2 is an STD, and it usually causes sores around the genital of a person. It occurs after sexual contact below the waist.
There are severe complications between these two viruses. After the initial outbreak, these viruses become dormant in the human body, and they remain inactive in the nervous system. HSV-1 is generally related to oral-facial infections, but it is growing to cause genital and neonatal Herpes. Neonatal Herpes can pass on to an infant during birth, causing complications with an infant’s nervous system, leading to death. Moreover, HSV-1 can also cause infections to the eye (keratitis) and inflammation of the brain (encephalitis).
Similarly, HSV-2 mainly causes genital Herpes. Most people are not aware that they have the infection, which makes spreading the virus much easier. It is a major cause of neonatal Herpes as well as the transmission of HIV.
Cure and Vaccine Development of Herpes Simplex
There is no proper vaccine available for preventing and curing HSV currently. The research for the immunization of Herpes dates back to 1930. There have been many trials, but there were no favorable responses due to the virus’s complex nature. FDA has approved antiviral treatment for the Herpes virus. Antiviral drugs like acyclovir, famciclovir, and valacyclovir can prevent and reduce outbreaks. After the initial treatment, patients can use these drugs for suppressive or intermittent therapy. These drugs have helped to reduce the outbreaks as well as the symptoms.
There has been ongoing research regarding the vaccine of Herpes simplex. There was some development for therapeutic and preventive vaccines for Herpes Simplex. From 1940 to the 1960s, scientists were using eggs and cell cultures to grow the vaccine. There were several inactivate vaccine trials conducted, but they were not effective. The most widely used research for the vaccine has regarded glycoprotein and subunit vaccines. There are several vaccines currently in development. The largest trial conducted was HerpeVac by GSK. It involved 8300 young women who were uninfected. The purpose of the trial was to check the response of a vaccine for the prevention of Herpes. It showed favorable results for HSV-1, but not for HSV-2. Consequently, there was no further research for the vaccine.
Current State of HSV-1 Vaccine
One of the prominent vaccines in development is EXD-12 by Excell. It is an alive, weakened form of virus, and currently, scientists are testing it on laboratory animals, mainly guinea pigs. Scientists are expecting that the company will advance into clinical trials in early 2020. Moving on, researchers from the University of Pennsylvania announced that they developed a vaccine against Genital Herpes. The vaccine has experimented on mice and pigs; the results showed no infection traces in mice and pigs after infection. The university is seeking permission from the FDA to start human testing of its vaccine. Likewise, another Biotech company, X-Vax technology, has created a vaccine candidate called delta gD-2. It has this name because scientists are trying to genetically remove a glycoprotein (gD-2), and it has shown effectiveness against HSV-1.
Furthermore, the Sanofi company is developing another vaccine, HSV529, which prevents replicating the virus. It showed a favorable response in phase-1 trials, and researchers are moving to phase-2 trials. However, several companies like Vical abandoned its research for Herpes after it failed phase 2 trials. Likewise, Genocea Bioscience had positive trial-2 results from its GEN-003 vaccine trials, but it abandoned it in February 2018. However, in 2020, it has partnered with Shionogi Ltd to develop a vaccine using GEN-003 properties. Experts expect that Excell and X-Vax technology and other companies will make a breakthrough in developing a successful vaccine.