Herpes infections surge globally, new study reveals huge disease burden

Uncovering a global crisis: Groundbreaking research highlights the enormous health impact of HSV infection and prompts a shift toward vaccine innovation and prevention.

study: Estimating global and regional incidence and prevalence of herpes simplex virus infection and genital ulcer disease in 2020: a mathematical modeling analysis. Image credit: sokolova_sv / Shutterstock

In a recent study published in the journal sexually transmitted diseasesA group of researchers estimated the global and regional incidence and prevalence of genital herpes simplex virus (HSV) infection and associated genital ulcer disease (GUD) in 2020 by region, gender, and region of the World Health Organization (WHO). , and estimated by aggregation by type of HSV.

background

HSV types 1 and 2 cause lifelong infections and are highly prevalent worldwide, resulting in significant morbidity and economic burden. Both types involve frequent subclinical withdrawal and reactivation of symptoms, with negative effects on quality of life, sexual health, and mental health, including depression and anxiety.

HSV-2 increases the risk of HIV infection and transmission by threefold, indicating a synergistic relationship between the two infections. HSV-2 is primarily transmitted through sexual contact and is the main cause of recurrent GUD. Neonatal herpes is transmitted by oral contact at or after birth, has a high mortality rate, and poses a significant public health problem.

HSV-1, which is usually transmitted orally during childhood, can cause serious complications, including neurological, corneal, and mucocutaneous diseases, and has emerged as a leading cause of genital herpes in high-income countries. Masu. Further research is essential to develop effective prevention and treatment strategies, including vaccines.

About research

This study utilized data from systematic reviews and meta-analyses to provide updated model inputs as of March 30, 2022 to ensure completeness for all WHO regions. Only data collected up to 2020 is included, with country-level data reorganized into WHO regional groups.

The study also incorporates methodological enhancements, such as sophisticated calibration techniques and updated prevalence data, to improve the accuracy of the estimates. The efficacy of HSV diagnostic assays was evaluated to address limitations such as sensitivity, specificity, and cross-reactivity between HSV-1 and HSV-2 antibodies.

Studies using unreliable laboratory methods were excluded. To ensure accuracy, the assay needed to detect type-specific antibodies such as: glycoprotein G-2 for HSV-2.

A meta-analysis was performed using a DerSimonian-Laird random-effects model, with pooled prevalence estimates stratified by sex and age. These estimates were used to calibrate a mathematical model based on the WHO HSV estimation framework. Calibrations incorporated prevalence data using a constant incidence model to adjust for demographic changes and sparse data in specific regions.

This study provides estimates of the incidence and prevalence of genital HSV-1 and HSV-2 infections in individuals aged 15 to 49 years, and the incidence and prevalence of oral HSV-1 infections in individuals aged 0 to 49 years. Prevalence estimates were generated. GUD estimates were derived by applying natural history parameters to infection estimates. Uncertainty intervals were calculated using Monte Carlo simulation.

Research results

HSV-2 remains the main cause of genital infections and recurrent GUD. In 2020, the number of new HSV-2 infections among individuals aged 15 to 49 years worldwide was estimated at 25.6 million (95% uncertainty interval). [UI]: 23.1 million to 29.4 million), women accounted for 15.6 million and men accounted for 10 million.

The African region has the highest incidence, accounting for 38.3% of all infections. Incidence was significantly higher among young adults, particularly in Africa and the Americas. This reflects both demographic trends and different regional patterns of sexual behavior.

The estimated global prevalence of HSV-2 in the same age group was 519.5 million people (95% UI: 464.3 million to 611.3 million), with a higher prevalence in women compared to men ( 17.0%, 95% UI: 14.9-20.1%). (9.7%, 95% UI: 8.0-13.0%).

Regarding genital HSV-1 infections, the number of new infections among people aged 15 to 49 years worldwide in 2020 was 16.8 million (95% UI: 10.6 to 22.4 million), evenly distributed between men and women. The highest incidence was recorded in the Western Pacific region.

The global prevalence of genital HSV-1 infection in the same demographics is estimated to be 376.2 million people (95% UI: 235.6-483.5 million), with a lower prevalence in women (10.5%, 95%). % UI: 6.4 to 13.8%) was slightly higher. Male (9.9%, 95% UI: 5.9-13.4%).

Overall, the global incidence of genital HSV infections (HSV-1 and HSV-2) in individuals aged 15 to 49 years is 42.4 million (95% UI: 33.7 to 51.8 million), with a prevalence of was 846.1 million (95% UI). : 661.1 million to 1.0342 billion). The prevalence of GUD due to HSV-2 in this age group is 4.8% (95% UI: 3.0-7.5%), affecting an estimated 187.9 million people, with a higher prevalence in women (6.2%, 95% UI: 3.8-9.6%). ) than men (3.5%, 95% UI: 2.2-5.8%).

For HSV-1, the GUD prevalence is 0.5% (95% UI: 0.3-0.7%), affecting 16.7 million people worldwide. This results in a total GUD burden of 204.6 million people, with significant psychosocial and economic impacts. The total HSV-related GUD effort was estimated at 8.8 billion (95% UI: 5.8-15.4 billion).

Regarding oral HSV-1 infection, the global infection rate among people aged 0–49 years in 2020 was 58.6% (95% UI: 53.5–62.1%), which corresponds to approximately 3.4 billion people. The African region had the highest oral HSV-1 infection rate, and the Western Pacific region had the highest number of infections.

conclusion

In summary, in 2020, 26 million people aged 15 to 49 will acquire new HSV-2 infections, of which 520 million will live with HSV-2 and 188 million will have HSV-2. This means that you have experienced related GUD. Similarly, 17 million people developed new genital HSV-1 infections, 376 million people lived with genital HSV-1, and 17 million people experienced HSV-1-associated GUD.

Despite therapeutic advances, prevention efforts remain inadequate, highlighting the critical need for HSV vaccines to control transmission and reduce disease burden. HSV-2 is primarily transmitted sexually, whereas HSV-1 is primarily transmitted orally during childhood, although genital infections are on the rise. Genital HSV-1 infections are less likely to recur than HSV-2.