Are we getting closer to eliminating the herpes simplex virus once and for all? A new study suggests that this may very well be the case.
Leading Herpes Vaccine Candidate Shows a Lot of Promise
Clinical trials are already taking place to tackle the herpes simplex virus type 1 (HSV-1), the virus responsible for causing mouth and lip sores. A modification of this leading vaccine candidate, however, could enable the tackling of herpes simplex virus type 2 (HSV-2) – the one that causes genital herpes.
For the purpose, a genetically-modified form of HSV has been utilised by researchers at the University of Cincinnati and the University of Nebraska-Lincoln. Their findings were presented in Nature journal in November 2020.
To come up with the vaccine, researchers modified the virus in a way that kept it from concealing itself within the nervous system as to evade eradication by the immune cells.
The study is still in its early stages. Researchers used the genetically-modified vaccine candidate on guinea pigs. The results were very exciting – the vaccinated guinea pigs quickly started producing the antibodies required to fight off HSV.
Next, researchers tested the vaccine on animals that were later on exposed to the highly virulent HSV-2. As a result of the vaccination, very few of the animals experienced the genital lesions that are a typical consequence of getting herpes. Virus replication was also slowed down and the ability of the guinea pigs to spread the infection to others was minimised.
According to researchers, the most important quality of the vaccine for the prevention of genital herpes is its ability to prevent viral shedding.
Viral shedding is a term that refers to the expulsion and release of a virus via many kinds of particles. Depending on the nature of a virus, it can be released in mouth or nose droplets, as well as in other bodily fluids.
Genital herpes can be passed on, even when a person doesn’t have lesions or other symptoms of the infection. If a vaccine can minimise or eliminate viral shedding completely, it would curb the rapid spread of virulent infections.
How Genital Herpes Work
HSV-1 and HSV-2 work in similar ways.
After the virus gets inside the body, it starts affecting the mucosal tissues of the mouth or the genitals. It finds itself inside the nerve endings. This is a very important step because it ensures quick entry into the nucleus of a sensory neuron.
While this is happening, the viral infection affecting mucosal tissues is cleared by the immune system. This isn’t the end of the story, however. HSV remains hidden inside nerve cells and in this part of the body, the virus will be left undisturbed for prolonged periods of time.
Eventually, HSV will become reactivated and a person will experience a flare-up of the symptoms.
This sneaky infection method is the one that made the infection impossible to tackle for more than four decades. The manner in which HSV evades the immune system is highly sophisticated, which prevents traditional vaccine developments from being effective.
The researchers that came up with the genetically-modified version of the virus spent years examining numerous tactics aimed at preventing the entry of HSV into the nervous system. Eventually, computer analysis and a focus on a specific protein enabled the team to identify the exact mechanism that HSV employs to infiltrate the nerves.
Using this information, the academics replaced part of the viral DNA to impede the effortless entry into the one bodily system that couldn’t been tackled by immune cells. The first animal-based studies showed that the modification was a highly successful one.
The Next Step
What the academic teams at the two universities accomplished is exceptional.
Genetic modifications have to be carried out carefully.
If the modified version of the virus is way too impotent, lasting immunity would not be established. This is why the researchers needed to “weaken” HSV without destroying it completely. Luckily, the modification of HSV-1 was just right and it has opened the doors to new opportunities in the future.
The next step in the clinical trials is going to be a very important one. Researchers will focus exclusively on HSV-2 and developing a highly specific vaccine against genital herpes.
According to the World Health Organization, more than 500 million people across the world live with a genital herpes infection. Once acquired, the viral disease persists a lifetime and can only be controlled. Whenever a person experiences a stressful episode or another kind of trigger, an infection flare-up would occur.
A herpes infection isn’t just characterised by unpleasant symptoms. Having genital herpes also increases the risk of contracting other sexually transmitted infections (STDs) like HIV. Some new research also suggests that a herpes infection could be linked to a higher risk of developing a neurodegenerative disorder like Alzheimer’s disease.
Until a vaccine is developed, you will have to be on the safe side by protecting yourself and undergoing regular STI screening.
At Shim Clinic, we do regular STD testing for an array of common infections, including genital herpes. Herpes testing is highly reliable and specific, giving you results within one to two days. Come and visit us during working hours every day of the week to find out more about testing and learn about the herpes infection management opportunities.
- Bernstein, D. I., Cardin, R. D., Smith, G. A., Pickard, G. E., Sollars, P. J., Dixon, D. A., Pasula, R., & Bravo, F. J. (2020, November 6). The R2 non-neuroinvasive HSV-1 vaccine affords protection from genital HSV-2 infections in a guinea pig model. Nature Journal. https://www.nature.com/articles/s41541-020-00254-8?error=cookies_not_supported&code=39e109f4-4ba3-4e2a-bc77-e17ab9b2e112