Herpes simplex viruses (HSV) belong to the group of herpesviruses. They are quite common — about 90% of adults worldwide have them. And they can result in painful sores in or around the mouth or genitals. There is no cure for HSV infections, and people who have the virus must manage their outbreaks using drugs. A number of HSV vaccines have been evaluated. But none have yet been brought to market.
But companies are still grappling with how to block these infections with vaccination — and with good reason. Modeling has indicated that a vaccine for HSV — the main cause of genital herpes — could prevent up to 350,000 new infections each year.
There are several HSV vaccine candidates under development. The idea is that they’ll have potential where earlier prospects failed. Here we discuss new and ongoing research in the area, and whether we can expect a vaccine soon.
What is the Herpes Simplex Virus (HSV)?
HSV is a virus that can lead to painful ulcers in your mouth (cold sores) or on your genitals. There are two major herpes simplex viruses — HSV-1 and HSV-2. HSV-1 infections most commonly affect your mouth, but they may also result in sores on your genitals. HSV-2, on the other hand, heavily affects your genitals.
Once you’ve been infected with HSV, the virus stays in your body long term. This can cause sores or blisters to appear periodically (called an outbreak). In rare cases, it can cause life-threatening infections like meningitis and encephalitis.
When you think of herpesviruses, HSV is likely what comes to mind. But both types of HSV are actually part of a larger family of herpesviruses, including:
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Varicella-zoster virus (causes chickenpox and shingles)
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Epstein-Barr virus (causes mononucleosis)
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Cytomegalovirus
Is There a Cure for Herpes?
It’s a pity there is no cure for herpes till now. But gene therapy is also offering up hope that a cure for herpes might be on the horizon. Animal studies have shown promising results so far.
Until then, herpes infections are treated with antiviral drugs such as Valtrex (valacyclovir) or Zovirax (acyclovir). These medications may help blisters go away when they do develop. And some people take them daily to keep outbreaks from ever happening.
Yet some people will have trouble finding a medication that works for them. And condoms might not cover all sites where genital blisters occur in order to prevent passing your infection to your partner. This has led to the investigation of a potential vaccine for the viruses.
Why is Creating an HSV Vaccine so Difficult?
Jennifer, Herpesviruses are long-lived in the body before being recognized. That’s because your immune system doesn’t respond to them immediately. The longer the virus is allowed to circulate unchecked, the harder it will be to develop an effective vaccine. While we have vaccines for other diseases caused by herpesviruses — chickenpox and shingles, for example — HSV is better than most at dodging the immune system.
When scientists create vaccines, their goal is to train some part of the immune system to recognize an invader, such as a virus or bacteria, in your body. The vaccine goes on to show your body how to kill the invader before it can make you sick. A vaccine can’t teach your immune system to protect you if it never responds to HSV in the first place.
Animal models. The results of HSV vaccine studies in animals have been encouraging. When these vaccines were tested in humans, however, they didn’t perform as well. And that is when pharmaceutical companies had to reboot their efforts on research.
Has an HSV Vaccine Ever Been Tested on Humans?
Yes. Human studies of several vaccines have taken place in the last few years. People who took part in the vaccine trials didn’t have many side effects.
But they did not see much benefit either. Even though earlier studies did not work out, several vaccines are still being tested.
The Bottom Line
Efforts are in progress to identify vaccines that can treat or prevent herpes simplex virus (HSV) infections. HSV vaccines are over here helping millions of people. To ensure that vaccines are safe and effective, they must navigate through a series of steps before they are approved.
Although previous vaccines didn’t succeed in humans, researchers are still trying to hit on a new approach in hopes of finding something that does.
Vaccine may become possible in the future As we get to know more about the HSV infections as well as how they function, a vaccine may potentially become possible.
