The search for a vaccine to protect against oral and genital herpes has been a long one. Researchers have been experimenting with possible vaccines since at least the early 1930s. To date, they've seen little success. While herpes vaccines have been successful in mice, they've been largely unsuccessful in human trials. Show
This article explains the steps that have been taken thus far to develop vaccines for oral and genital herpes, the reasons why these vaccines are important, and the roadblocks keeping researchers from better preventing or controlling herpes infections. Where Herpes Vaccine Research StandsAlthough some vaccines for these herpes types have initially appeared to have promise, stringent testing has shown them to be no better than a sham vaccine, or placebo. With that said, newer approaches to vaccine development—including genetic editing—have begun to show promise in early-stage animal research, offering a glimpse of hope of a possible breakthrough. Existing Herpes VaccinesTechnically speaking, there are already herpes vaccines on the market. They just don't protect you from herpes simplex virus (HSV) type 1 (the type most commonly associated with oral herpes) or HSV type 2 (the type most commonly associated with genital herpes). Rather, the two vaccines currently available protect against a type of herpes virus known as varicella-zoster virus (VZV), more commonly called the chickenpox virus. Once a chickenpox infection resolves, the virus remains in a dormant (latent) state. It does so in a cluster of nerve cells called the dorsal root ganglion, where it could reactivate later in life. If it does, it causes shingles (herpes zoster). The shingles vaccine and chickenpox vaccine both guard against the virus, but in different ways:
These are similar to the two types of vaccines that have been proposed to protect against oral and genital herpes. One type aims to prevent the virus from infecting people who've never had it, while the other aims to protect against outbreaks in people who already have herpes. Protecting people who have had herpes from future outbreaks is important because once you're infected with a herpes virus, it stays in your body forever. It goes dormant, but can suddenly reactivate at any point, bringing on symptoms again. An adult in their 60s, for example, might develop shingles due to a reactivation of VZV that they acquired when they had chickenpox as a child. Oral and genital herpes outbreaks can recur in the same way. RecapThe chickenpox vaccine protects you from a type of herpes. The shingles vaccine protects you from reactivation of that same virus. However, this is not the type of herpes associated with oral or genital cases. Herpes Vaccine PrioritiesTheoretically, it makes sense that a vaccine could work to prevent oral and genital herpes outbreaks. After all, in many people, the immune system controls herpes infections so that they never have symptoms. This makes herpes a good target for a therapeutic vaccine—that is, one that treats rather than prevents disease. However, the herpes simplex viruses have proven to be difficult to control with vaccines. In 2017, the World Health Organization (WHO) defined a series of priorities for developing a herpes vaccine:
The WHO suggests that two types of vaccines could be useful for herpes simplex infections:
RecapDeveloping vaccines that can prevent oral or genital herpes infection and reactivation are worldwide goals. This is not just because of a desire to reduce complications of HSV itself, but to address the increased risk of HIV infection that comes with genital herpes. Barriers and SuccessesSome promising trials of herpes vaccines have been performed. However, to date, no human trials have shown high enough efficacy to bring a herpes vaccine to market. ChallengesScientists have several hurdles to face when developing a vaccine to protect against oral or genital herpes. No animal model perfectly replicates HSV infection in humans. Several vaccine candidates have shown promise in animal studies but have, thus far, not been effective in clinical trials in humans. Aside from mice, rabbits and guinea pigs are also being used to develop therapeutic herpes vaccines (for eye and genital herpes, respectively). Early results have been promising, but current animal models still don't do a great job of showing how the disease progresses in humans. Herpes vaccines are also difficult to study for several other practical reasons:
Addressing any of these factors can make vaccine trials slow-going, burdensome, impractical, and expensive. AdvancesA 2020 study from researchers from the University of Cincinnati, Northwestern University, and the University of Nebraska-Lincolnoffers hope of a possible breakthrough. According to the research, a genetically modified form of herpes simplex virus type 1 was able to prevent symptoms of herpes simplex virus type 2 in guinea pigs. The response was far more robust than seen with any herpes vaccine study to date. It significantly slowed the virus's replication and showed less viral shedding. Another research team at the University of California, Irvine, School of Medicine proposed the use of lasers as part of the vaccination procedure. Their goal was to stimulate the development of immune cells in the layers of the skin where herpes reactivation occurs. The procedure involved mice. It, too, showed promise in preventing genital herpes, improving the effect of an experimental vaccine. Although it's far too soon to tell whether the studies will lead to a successful vaccine, these advances are considered significant. RecapThe lack of a vaccine for oral or genital herpes is not for a lack of effort. Several issues, including the poor translation of results in animals to results in humans, have made development challenging. Summary Putting
an end to oral and genital herpes would have a far-reaching impact on the health of people around the world. The virus increases the risk of HIV, affects fertility, and places significant psychological and physical stress on those infected. Unfortunately, there are a number of barriers to developing a vaccine. First, it’s hard to find people who are able to participate in the studies needed to test possible vaccines. Also, people who are infected may
not have symptoms, which makes it more complicated to tell whether a vaccine is effective. A Word From VerywellFortunately, you have other options for reducing the risk of transmission as research on herpes vaccines continues. Both suppressive therapy and reliably practicing safe sex can help protect the sexual partners of people with HSV infections. Frequently Asked Questions
Can you get shingles if you have herpes?Is it possible to have both shingles and herpes? Shingles and herpes are caused by two different viruses and are acquired in different ways. It's possible for you to have symptoms of shingles and a herpes flare-up at the same time.
Can you get the shingles vaccine if you have herpes zoster?There are no recognized safety concerns in giving the vaccine to people with prior history of herpes zoster. The general guideline for any vaccine is to wait until the acute stage of the illness is over and symptoms abate.
Who Cannot receive shingles vaccine?Someone with a minor acute illness, such as a cold, may be vaccinated. But anyone with a moderate or severe acute illness should usually wait until they recover before getting the vaccine. This includes anyone with a temperature of 101.3°F or higher.
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