Doha, Qatar: Researchers at Weill Cornell Medicine-Qatar (WCM-Q) and Qatar University (QU) have projected that a future herpes simplex virus type 1 (HSV-1) vaccine could substantially reduce oral and genital HSV-1 infections and avert tens of millions of infections over coming decades.
The study, titled "Projected Public Health Benefits of a Hypothetical HSV-1 Vaccine in the United States: A Mathematical Modeling Analysis," was published in the prestigious journal Science Advances and provides the first quantitative assessment of the population-level impact of an HSV-1 vaccine in any population.
HSV-1 is one of the world’s most common viral infections. Traditionally associated with oral herpes, the virus is increasingly becoming a major cause of genital herpes in high-income countries, including the United States.
HSV-1 infection can also lead to severe disease manifestations, including neonatal herpes, encephalitis, corneal blindness, and recurrent painful oral and genital lesions.
Declining childhood exposure has left more adolescents and young adults susceptible to sexual acquisition of the virus, contributing to a growing burden of genital HSV-1 herpes.
Using a sophisticated age-structured mathematical model calibrated to four decades of nationally representative U.S. data from the National Health and Nutrition Examination Surveys (NHANES), the researchers evaluated multiple vaccination strategies beginning in 2030, including infant vaccination, adolescent catch-up vaccination, and booster programs, under a range of plausible vaccine characteristics reflecting the current progress and momentum in HSV vaccine development.
The findings indicate that even a moderately effective vaccine could deliver major public health benefits in the United States. Under one modeled scenario assuming 70 percent vaccine efficacy and lifelong protection, infant vaccination alone reduced oral HSV-1 incidence by nearly 50 percent and genital HSV-1 incidence by nearly 60 percent by 2075, while averting approximately 28.5 million infections cumulatively. Adding adolescent catch-up vaccination further amplified the projected impact, averting approximately 41.8 million infections by 2075.
A key finding of the study was that the duration of vaccine-induced protection strongly shaped the long-term public health impact. Vaccines providing lifelong protection produced approximately three times greater impact than vaccines with protection lasting an average of 15 years.
The study also showed that adolescent catch-up vaccination could accelerate population-level benefits, especially for preventing genital HSV-1 herpes among adolescents and young adults.
Dr. Bechir Naffeti, first author of the study and postdoctoral researcher in the Mathematics Program, Department of Mathematics and Statistics, College of Arts and Sciences at QU, said: "This study shows that HSV-1 vaccination could become a powerful prevention tool, not only by reducing oral infection but also by curbing the growing burden of genital HSV-1 herpes among adolescents and young adults. The projected benefits underscore the importance of advancing vaccine candidates that can provide durable protection."
Dr. Houssein Ayoub, co-lead author of the study and associate professor in the Department of Mathematics and Statistics, College of Arts and Sciences at QU, said: "This study highlights the value of sophisticated quantitative assessments of vaccination impact in guiding vaccine development and public health planning. Our results indicate that durable protection, adolescent catch-up vaccination, and timely implementation are critical to maximizing the benefits of a future HSV-1 vaccine."
Dr. Laith Abu-Raddad, co-lead author of the study and professor of population health sciences at WCM-Q, said: "HSV infections remain a major public health challenge, yet prevention options are still very limited. This study presents a compelling case for accelerating HSV vaccine development to reduce the burden of multiple diseases caused by HSV infection."
The researchers noted that momentum for HSV vaccine development has accelerated in recent years, with several vaccine candidates currently under development internationally.
The study argues that the growing burden of genital HSV-1 herpes, combined with advances in vaccine science, strengthens the case for prioritizing HSV vaccine research and development.
