Herpes Vaccine Candidates
The development of protective herpes simplex virus (HSV) vaccines has been an ongoing challenge for decades. The herpes simplex virus exists as 2 biologically distinct serotypes, HSV-1 and HSV-2, which differ mainly by their mode of transmission, says the U.S. CDC.
The spread of HSV- 1 generally occurs by direct contact, usually involving saliva, and most commonly appears as cold sores in or around the mouth, according to the CDC.
And HSV-2 infections usually occur after sexual contact, leading to recurring, often painful, genital sores in up to a third of people infected.
"A vaccine against HSV infection would not only help to promote and protect the health and wellbeing of millions of people, particularly women, worldwide, it could also potentially have an impact on slowing the spread of HIV," Dr. Meg Doherty, director of the WHO's global HIV, hepatitis and sexually transmitted infections programs, commented in a WHO statement published on May 1, 2020.
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Herpes Vaccine Candidates In Development
Clinical researchers have been working on developing herpes vaccines in clinical trials aimed at testing both therapeutic (intended to reduce viral shedding in people who are already infected with HSV) and preventive (designed to prevent infection) vaccine candidates.
- HSV529 (HSV15) is a vaccine candidate that is classified as a replication-defective virus, where the virus possesses all the components of the wild-type HSV virus with the exception of two proteins UL5 and UL29 that are involved in viral DNA replication. This phase 1/2 study was last updated on June 4, 2020, by Sanofi Pasteur.
- EXD-12 vaccine candidate is currently in preclinical testing for safety and efficacy as both a prophylactic and therapeutic vaccine for both Herpes Simplex Virus-1, HSV-1, and Herpes Simplex Virus-2, HSV-2.
- Delta gD-2 is a vaccine candidate based on an HSV-2 virus genetically deleted for glycoprotein D (gD-2).
- NanoVax is an adjuvant platform used in the development of a vaccine candidate that will provide protection against the two viruses that can cause genital herpes.
- GSK’s HSV vaccine SB208141 is in a double-blind, randomized, controlled phase 3 clinical study to assess the prophylactic efficacy and safety of gD-Alum/MPL vaccine in the prevention of genital herpes disease in young women who are herpes simplex virus (HSV)-1 and -2 seronegative.
Herpes Vaccine Development News
- July 27, 2020 - In a mice study, these researchers compared protection by the HSV-2 mRNA vaccine against genital HSV-1 and HSV-2 infection. Mice infected with either virus were totally protected from genital disease. Importantly, in two experiments, the mRNA vaccine prevented HSV invasion of the dorsal root ganglia, the site of virus latency, in 39/40 (97.5%) mice infected with either HSV-1 or HSV-2. They conclude that the HSV-2 trivalent mRNA vaccine provides potent protection against both HSV-1 and HSV-2 genital infection and is a promising vaccine candidate for human trials.
- July 17, 2020 - This article sheds light on the molecular and structural interactions between HHV-6B tetramer and its host receptor along with their neutralizing antibodies, and their affinities, competition, and binding modes based on the HHV-6B tetramer structure are described. Our findings provide molecular and structural bases for a comprehensive understanding of these interactions and relationships.
- July 16, 2020 - Herpes simplex virus type 1 in Europe: a systematic review, meta-analyses, and meta-regressions.
- March 3, 2020 - Tissue-resident T cell-derived cytokines eliminate herpes simplex virus-2–infected cells.
- May 19, 2020 - Genocea Biosciences, Inc. announced it has entered into a material transfer agreement and exclusive license option with Shionogi & Co., Ltd. to develop a novel HSV-2 vaccine using Genocea’s proprietary HSV-2 antigens from the GEN-003 program.
- May 7, 2020 - This model recapitulates clinical responses to natural infection and the rgD-2 vaccine trial outcomes and suggests that ΔgD-2 may prove protective in HSV-1-seropositive hosts.
- May 6, 2020 - Newly published research is the first to show in a lab model that the herpes simplex virus HSV-1 might cause Alzheimer's. In the study, scientists found that mini 3D models of the human brain, when infected with the virus that causes cold sores, went on to develop hallmarks of Alzheimer's, including amyloid plaque-like formations and neuroinflammation.
- May 1, 2020 - The WHO issued a statement saying 'About half a billion people worldwide are living with genital herpes, and several billion have an oral herpes infection, new estimates show, highlighting the need to improve awareness and scale-up services to prevent and treat herpes.'
- March 2, 2020 - WSU researchers recently published a study in the American Society for Microbiology’s journal mSphere that is the first to identify how one of the virus’ proteins acts as a critical signaler for the virus to succeed in infecting a cell.
- April 27, 2020 - Study: Based on our revised annotation of 201 viral transcripts and 284 ORFs, we extended the existing nomenclature to include these all our novel viral gene products. This did not involve any renaming of previously described viral gene products. Our nomenclature thereby explains gene expression of the majority of viral ORFs in the context of different transcript isoforms, uORF and uoORFs. This will facilitate functional studies on the viral gene products as well as their transcriptional and translational regulation.
- January 10, 2020 - Sanofi announced Phase 1 and 2 studies were posted. The primary objectives of the studies are: To describe the safety profile of different investigational vaccine regimens against herpes simplex virus type 2 (HSV-2).To evaluate the efficacy of the investigational vaccine regimens with respect to the frequency of herpes simplex virus (HSV) deoxyribonucleic acid (DNA) detection in the genital area (shedding rate) following a 2 dose vaccine schedule; the proportion of participants free of HSV genital recurrence at 6 months after the 2-dose vaccine schedule.
- January 8, 2020 - Candel Therapeutics announced the acquisition consolidates a next-generation herpes drug development platform and manufacturing expertise that can be tailored to multiple tumor types and indications.
- December 10, 2019 - A recent study provides new insights into the early stages of a Herpes Simplex Virus 1 (HSV-1) infection and serves as a general blueprint for the investigation of heterogeneous cell states in virus infection.
- December 5, 2019 - A recent study said ‘a large burden of Human Immunodeficiency Virus (HIV) is likely attributable to a Herpes Simplex Virus type 2 (HSV-2) infection.
- November 21, 2019 - Cornell University researchers hoping to learn ‘what’ switches this life-long virus between latent and lytic stages, may have found the ‘hidden’ answer to this question.
- September 20, 2019 - A new herpes simplex 2 virus vaccine study in animals reported an experimental vaccine developed at the University of Pennsylvania has prevented genital lesions in 98 percent of mice and guinea pigs tested. Friedman and colleagues just published a paper in Science Immunology in which they describe the trivalent herpes vaccine that they developed and its efficacy in animal models. This trivalent vaccine protected mice and guinea pigs from developing genital lesions and reduced viral shedding. Neutralizing antibody and CD4+ T cell responses were detected in immunized mice.
- July 23, 2019 – A patent was issued on February 19, 2019, protects the use of BlueWillow Biologics’ unique NanoVax adjuvant platform in the development of a vaccine that provides protection against HSV-1 and HSV-2.
- June 15, 2019 – A new study published in Nature on June 12, 2019, by Yale researchers offered insights that could lead to a better genital herpes therapeutic vaccine.
- April 17, 2019 - Therapeutic Mucosal Vaccination of Herpes Simplex Virus 2-Infected Guinea Pigs with Ribonucleotide Reductase 2 (RR2) Protein Boosts Antiviral Neutralizing Antibodies and Local Tissue-Resident CD4+ and CD8+ TRM Cells Associated with Protection against Recurrent Genital Herpes.
- August 11, 2028 - Herpes simplex virus‐2 dynamics as a probe to measure the extremely rapid and spatially localized tissue‐resident T‐cell response.
Herpes Vaccine Overview
There is no cure for herpes. Antiviral medications, such as acyclovir, famciclovir, and valacyclovir, can help to reduce the severity and frequency of symptoms but cannot cure the infection.
About 500 million people worldwide are living with genital herpes, and several billion have an oral herpes infection, said the WHO on May 1, 2020.
About 13% of the world’s population aged 15 to 49 years were living with herpes simplex virus type 2 infection in 2016, the latest year for which data is available. In 2016, two-thirds of the world's population under 50 — about 3.7 billion people — had herpes simplex virus type 1, which most commonly appears as cold sores in or around the mouth.
Genital herpes infections play a significant role in the spread of HIV globally, WHO researchers said.
If a vaccine program for HSV were implemented today and the vaccine was 100% efficacious and utilized by 100% of the target population, the annualized present value of the QALYs gained would be 28,000, says the NIH.
Using committee assumptions of less-than-ideal efficacy and utilization and including time and monetary costs until a vaccine program is implemented, the annualized present value of the QALYs gained would be 7,500.
Most of the disease burden is associated with genital and CNS infections due to the large number of genital infections and the serious, chronic sequelae associated with the relatively fewer cases of CNS HSV disease.
The NIH estimates that there are 500,000 new oral infections with HSV each year in the United States. These infections occur in people between 1 and 44 years of age. There are approximately 20,000 new ocular infections with HSV each year. These occur in people between 1 and 84 years of age.
There are approximately 1,500 cases of central nervous system infection with HSV each year. The incidence was assumed to be highest in children between 5 and 14 years of age. It was also assumed that there are 300,000 new cases of genital HSV infections occurring primarily in people between 15 and 34 years of age.
There are also 1,500 new cases of neonatal HSV infections each year, says the CDC.
Certain antiviral drugs, including acyclovir and valaciclovir, can control outbreaks but they don’t cure a herpes infection, says the CDC.
Herpes and HIV
People with HSV-2 infection are at least three times more likely to become infected with HIV if exposed. Thus, HSV-2 likely plays a substantial role in the spread of HIV globally. Women are more susceptible to both HSV-2 and HIV.
Women living in the WHO Africa Region have the highest HSV-2 prevalence and exposure to HIV – putting them at the greatest risk of HIV infection.
Herpes Antiviral Treatments
Most herpes simplex virus infections are self-limited and treatment is not always indicated or necessary. However, antiviral therapy shortens the course of the symptoms and may prevent dissemination and transmission.
Treatment of herpes labialis and herpes genitalis generally consists of episodic courses of oral acyclovir, valacyclovir, and ganciclovir. Complicated HSV infections, cutaneous and/or visceral dissemination, neonatal HSV infection, and severe infections in those who are immunocompromised should be treated promptly with intravenous acyclovir, says the CDC.
In patients who are immunocompromised and have recurrent HSV infections, acyclovir-resistant HSV strains have been identified, and treatment with intravenous foscarnet or cidofovir may be used.
Content sources: The WHO, US CDC, WHO, NIH, research papers, ClinicalTrials.gov, and the Precision Vaccinations news network. Content is fact-checked by healthcare providers, such as Dr, Robert Carlson.