Researchers at Weill Cornell Medicine-Qatar (WCM-Q) found that transmission patterns of herpes simplex virus type 1 (HSV-1) are changing in Asia in a striking way, emerging as a key to sexually transmitted infection.

According to findings published in the prestigious Journal of Clinical Infectious Diseases, 20% of genital herpes cases and 6% of genital ulcer cases are caused by HSV-1.


HSV-1 is one of the most widespread infections globally. It is normally transmitted orally, leading to blisters and lesions around the mouth known as oral herpes. Recent data from the United States and Western Europe, however, showed that HSV-1 can also be transmitted sexually, leading to genital herpes and genital ulcer disease. The data also indicated that the rate of genital infection is increasing in Western countries. Nonetheless, it was unknown whether this newly emerging trend is happening in other parts of the world.

However, the study, conducted by the Infectious Disease Epidemiology Group (IDEG) at WCM-Q, demonstrated that this is also the case in Asia. The study found that although HSV-1 remains mostly orally transmitted, the virus is increasingly being transmitted sexually. The study, which provided a comprehensive characterisation of HSV-1 infection patterns in Asian countries, also estimated that about 50% of children are infected with the virus orally, and that 75% of adults are infected with the virus, through both the oral and genital routes.

The shift in HSV-1 transmission patterns, from oral to genital infection in Asia, was a ‘striking’ discovery, said Manale Harfouche, a Senior Research Specialist at WCM-Q and a joint first author of the study. Lara Khadr, another joint first author and a Research Intern at WCM-Q added that this is an intriguing transition for an infection known historically only as an oral infection. She said it remains to be seen whether the transition is also happening in other parts of the world.

Laith Abu-Raddad, Principal Investigator of the Study and Professor of Healthcare Policy and Research at WCM-Q, said that the findings demonstrate how critical the development of HSV-1 vaccine to control transmission and to prevent the medical and psycho-social burden emerging from the infection.

The study, entitled ‘The Epidemiology of Herpes Simplex Virus Type 1 in Asia: Systematic Review, Meta-Analyses, and Meta-Regressions’, was conducted with funding from Qatar National Research Fund through the National Priorities Research Programme (NPRP 9-040-3-008).

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