Study validates pre-clinical safety of novel live-attenuated HSV-2 vaccine candidates

CAMBRIDGE, Mass., March 30, 2021 /PRNewswire/ -- Two novel vaccine candidates for the prevention and treatment of genital herpes have shown to be safe in pre-clinical animal studies according to a study published in the journal Vaccines.

Preclinical animal studies show two novel vaccine candidates for the prevention and treatment of genital herpes safe.

HSV-2 is the leading cause of genital herpes, a sexually transmitted disease that is associated with 60 percent of all genital ulcers. According to the World Health Organization, nearly 500 million people between the ages of 15 and 49 are infected with HSV-2 worldwide.

There have been treatments to alleviate the symptoms and partially suppress recurring outbreaks, or reactivation, of the virus for decades, but according to the study's authors, there has never been a safe or effective preventive or therapeutic vaccine developed.

"These results are encouraging and validate the need for continued development and testing of these live-attenuated vaccine candidates, which are historically underdeveloped vaccine types for the treatment or prevention of genital herpes," said Jonathan Joyce, the lead author of the study and Ph. D. candidate in Dr. Andrea Bertke's group at the Department of Population Health Sciences, Virginia Tech.

The study tested two different vaccine candidates from Rational Vaccines, RVx201 and RVx202, which were administered to guinea pigs either vaginally or intradermally. After 28 days of observation, neither vaccine candidate established latency in the guinea pigs and all survived to the end of the study without developing HSV-2-associated disease or serious adverse reactions.

Rational Vaccines Dr. Edward Gershburg, a co-author of the study, said he's highly encouraged by the study's finding that the vaccine candidates are safe and can be brought forward as a preventative or therapeutic vaccine for herpes.

"Several vaccine candidates using various platforms have been tested in clinical trials in humans but have failed to prevent HSV-2 infection in any meaningful way," said Gershburg. "Most vaccine candidates studied have been subunit vaccines or replication deficient viruses, which do not present the full range of viral antigens and are therefore unable to elicit a truly robust protective immune response. This study demonstrates that a live-attenuated HSV-2 vaccine is an attractive alternative to previous vaccine candidates."

The study concluded that these novel vaccine candidates are safe in guinea pigs and should be tested for efficacy as a preventive and/or therapeutic vaccine against genital herpes. Full text and results can be found in the current issue of Vaccines, Volume 9, Issue 3 (March 2021) or by clicking the following link Vaccines | Free Full-Text | Assessment of Two Novel Live-Attenuated Vaccine Candidates for Herpes Simplex Virus 2 (HSV-2) in Guinea Pigs (

About Rational Vaccines

Rational Vaccines develops rationally engineered, live attenuated viral immunotherapeutic and prophylactic vaccine candidates, particularly focused on combating all diseases resulting from herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2) infections. Led by our team of world-renowned scientists and closely following all regulatory guidelines, the company currently has seven vaccine candidates in the pipeline. We are confident our team and technology will revolutionize the treatment, prevention, and diagnosis of herpes and herpes-related diseases so we can bring hope and healing to a world suffering from these recurring infections. Based in Cambridge, MA, Rational Vaccines is also joining the battle against COVID-19 with a serological assay currently in development, and a future COVID-19 vaccine planned.

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