A genital herpes vaccine still far off

Research into testing and vaccination for both the oral and genital forms of the herpes simplex virus (HSV) continues, but the prevalence and evolution of the virus add to the challenge of this task.

Thomas Quinn, MD, a professor of medicine at Johns Hopkins University School of Medicine who is also an international researcher with the NIH’s National Institute of Allergy and Infectious Diseases, has been working to analyze the genetic diversity of HSV-2 (genital herpes) strains from around the world.

Dr Quinn has been conducting research in East Africa for 30 years and is a senior author of 2 studies on sequencing the HSV genome that appeared in the August issue of the Journal of Virology.

Thomas Quinn, MD

HSV was first genetically sequenced using only European patient strains, and the resulting diagnostic test was developed to identify sequences common to those strains, according to a press release from Johns Hopkins. Scientists have long suspected that the glycoproteins present in African patients who are HSV-positive might differ from those in patients in the United States and Europe. 

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The researchers note that HSV-2 is a causative agent of genital and neonatal herpes. Therefore, knowledge of its DNA genome and genetic variability is central to prevention and treatment of genital herpes. However, until now, only 2 full-length HSV-2 genomes had been reported. The researchers’ new analysis of additional genomes will facilitate research aimed at vaccine development, diagnosis, and the evaluation of clinical manifestations and transmission of HSV-2. This information will also contribute to the understanding of HSV evolution, they claim.

Read: Potential vaccine tested on mice

“We really can’t predict when we will have a safe and effective vaccine against HSV-2,” Dr Quinn told Contemporary OB/GYN in an email. “Several vaccines have been made and evaluated but did not demonstrate high efficacy in the volunteers. Another large trial is currently under way and we will have to see how effective that will be.

“Developing an effective vaccine is tough due to the high frequency of HSV-1 infections in many people that seem to interfere with the overall immunogenicity of the vaccine,” he explained. “But we keep on trying with new vaccines that are developed thanks to the new molecular information on herpes.”

Newman RM, Lamers SL, Weiner B, et al. Genome sequencing and analysis of geographically diverse clinical isolates of herpes simplex virus 2. J Virol. 2015;89:8219–8232.