Herpes Vaccine Development: Priorities and Progress

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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. They have had little success to date. Herpes vaccines have been successful in mice, but have largely failed in human trials .

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While some herpes vaccines initially seemed to have promising results, rigorous trials have shown that they are no better than a dummy vaccine or a placebo .

That said, new approaches to vaccine development (including gene editing) have started to show promising results in the early stages of animal research, offering a ray of hope for possible breakthrough.

Existing herpes vaccines

Technically, there are already herpes vaccines on the market. They just don't protect you from the herpes simplex virus type 1 (the type most commonly associated with oral herpes). or herpes simplex virus type 2 (the type most commonly associated with genital herpes).

Rather, the two currently available vaccines protect against a type of herpes virus known as varicella-zoster virus (VZV), more commonly known as varicella- zoster virus .

Once the chickenpox infection clears, the virus remains inactive (inactive) in a group of nerve cells called the dorsal root ganglion, where it can reactivate later in life, causing shingles .

The shingles vaccine and chickenpox vaccine protect against the herpes viruses, but in different ways:

  • The chickenpox vaccine is usually given in early childhood to protect you from getting VZV.
  • The shingles vaccine is given at age 50 to prevent VZV from reactivated.

They are similar to the two types of vaccines that have been proposed to protect against oral and genital herpes. One type aims to prevent people who have never had it from contracting the virus, and the other aims to protect against outbreaks among people who already have herpes .

The latter is especially important because once you become infected with the herpes virus, it remains in your body forever. The virus is not cleared, but remains in a dormant state where it can suddenly and sometimes inexplicably reactivate.

This is why the virus that causes chickenpox can suddenly reactivate in adulthood, causing shingles or why outbreaks of oral or genital herpes can reappear.

Herpes Vaccine Priorities

In theory, it makes sense that a vaccine can help prevent herpes outbreaks . After all, in many people, the immune system controls herpes infections so that they never have symptoms.

This makes the virus a good target for a therapeutic vaccine , that is, a vaccine that treats rather than prevents disease. However, herpes simplex viruses have proven difficult to combat with vaccines.

In 2017, the World Health Organization (WHO) identified a number of priorities for the development of a herpes vaccine:

  • Reduce the number of people infected with the human immunodeficiency virus (HIV) due to genital herpes infection. ( Genital ulcers increase the risk of HIV transmission.)
  • Reduce the number of people with HSV by reducing physical and psychological symptoms and serious consequences such as neonatal herpes.
  • Reduce the impact of herpes infection on reproductive health.

The WHO has suggested that two types of vaccines may be helpful for herpes simplex infections:

  1. Preventive vaccines, such as the chickenpox vaccine, can help prevent people from getting herpes.
  2. Therapeutic vaccines, such as the shingles vaccine, would reduce the number of outbreaks.

Herpes Vaccine Research

There have been promising trials of herpes vaccines. However, to date, no human trials have shown high enough efficacy to bring a herpes vaccine to market .

Challenges

There are several obstacles to developing a vaccine to protect against oral or genital herpes.

One problem is that no animal model exactly replicates HSV infection in humans. Several candidate vaccines have shown promise in animal studies, but have not yet shown efficacy in human clinical trials.

In addition to mice, rabbits and guinea pigs are also being used to develop therapeutic herpes vaccines (for ocular and genital herpes, respectively). Although the first results were promising, current animal models still fail to mimic disease processes and progression in humans.

Herpes vaccines are also difficult to study for other practical reasons:

  • Limited study population: Researchers must test multiple people to make sure the vaccine works. These people can be difficult to find.
  • Asymptomatic infection: Since many infected people never have symptoms of herpes, evaluating the effectiveness of a preventive vaccine means that active testing is required to see if they have been infected with the virus since vaccination.
  • Virus isolation: Scientists must test how the vaccine affected the amount of virus shed to determine the effectiveness of a therapeutic candidate vaccine. (Low viral shedding reduces the risk of infection).

Eliminating any of these factors can make vaccine trials time-consuming, cumbersome, impractical, and expensive.

Achievements

A 2020 study conducted by scientists from the University of Cincinnati, Northwestern University, and the University of Nebraska-Lincoln. he hoped for a possible breakthrough.

According to one study, 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 much stronger than has been seen in any herpes vaccine study to date, with significantly impaired viral replication and less shedding of the virus.

Another group of researchers at the University of California Irvine School of Medicine proposed the use of lasers as part of the vaccination procedure. Its objective was to stimulate the development of immune cells in those layers of the skin where the reactivation of herpes occurs. The mouse procedure again showed promise in preventing genital herpes by amplifying the effects of the experimental vaccine.

While it is too early to predict whether any of these studies will lead to a viable vaccine candidate, these advances are considered significant.

Get the word of drug information

Around the world, doctors and scientists are realizing the priority of fighting herpes. Although many people infected with the virus do not have any symptoms, herpes can have a significant impact on people's lives. This is especially true for those who become infected during pregnancy or live in areas with a high incidence of HIV.

Fortunately, you have other options to reduce the risk of transmission as research on herpes vaccines continues. Both suppressive therapy and safe sexual practices can help protect sexual partners from people with HSV infections.

Frequently asked questions

  • No. The shingles vaccine protects you against shingles (shingles), a viral infection that is a reactivation of the varicella-zoster virus. There is currently no vaccine to protect against genital or oral herpes.

  • There is no cure for oral or genital herpes. However, antiviral medications can prevent or reduce the severity of an outbreak.

  • There is some evidence that certain types of oils can alleviate a cold sore outbreak. For example, oregano oil has been shown to have antiviral properties that act on HSV, and other vegetable oils have shown promise as well. But more research is needed to see if they will reduce the outbreak.

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