Viral DNA Load and Recurrence Frequency in Herpes Simplex Infection: A Three-Group Comparative Study

Abstract

Background Recurrent herpes simplex infection markedly reduces patients' quality of life. How closely viral replicative activity tracks the severity of the course has not been sufficiently measured. We set out to compare viral DNA load in patients with differing recurrence frequency and to describe it alongside clinical, immunological, and epidemiological indicators.

Materials and Methods 240 participants aged 18 to 68 years were allocated to three groups: a main group (n = 140, frequently recurring course), a comparison group (n = 60, infrequently recurring course), and a control group (n = 40, apparently healthy individuals). Viral DNA load was measured by real-time PCR, serum IFN-γ, IL-4, and total IgE by enzyme-linked immunosorbent assay, and the CD4/CD8 ratio by flow cytometry. Epidemiological data were collected by questionnaire and review of medical records.

Results Viral DNA load rose stepwise across the groups: undetectable in the control group, 2.4 ± 0.2 in the comparison group, and 4.1 ± 0.3 log₁₀ copies/mL in the main group (p < 0.001). In parallel, the annual number of recurrences in the main group was 2.7-fold higher than in the comparison group (5.8 ± 0.3 vs 2.1 ± 0.2) and remission was 2.9-fold shorter (2.3 ± 0.2 vs 6.7 ± 0.5 months; p < 0.001). Immunological indicators in the main group differed from control: IFN-γ and the CD4/CD8 ratio were lower, IL-4 and total IgE higher (p < 0.001). Hypothermia (62.1%) and stress (55.7%) were the triggers most often reported, and 65.7% of recurrences occurred in autumn and winter.

Conclusion A recurring course was associated with disturbed immunological balance, higher viral DNA load, and a set of epidemiological factors. A stepwise relationship was found between viral DNA load and recurrence frequency. Establishing the prognostic value of this indicator will require a prospective study with baseline measurement followed by observation.

Keywords:

Herpes simplex, interferon-gamma, polymerase chain reaction

References

World Health Organization. Herpes simplex virus. Fact sheet. Geneva: WHO; 30 May 2025. Available at: https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus

Harfouche M, AlMukdad S, Alareeki A, Osman AMM, Gottlieb S, Rowley J, Abu-Raddad LJ, Looker KJ. Estimated global and regional incidence and prevalence of herpes simplex virus infections and genital ulcer disease in 2020: mathematical modelling analyses. Sex Transm Infect 2025;101(04):214–223. doi:10.1136/sextrans-2024-056307

Ageeb RA, Harfouche M, Chemaitelly H, Abu-Raddad LJ. Epidemiology of herpes simplex virus type 1 in the United States: systematic review, meta-analyses, and meta-regressions. iScience 2024;27(09):110652. doi:10.1016/j.isci.2024.110652

Mehrmal S, Mojica R, Guo AM, Missall TA. Diagnostic methods and management strategies of herpes simplex and herpes zoster infections. Clin Geriatr Med 2024;40(01):147–175. doi:10.1016/j.cger.2023.09.003

Smith JB, Herbert JJ, Truong NR, Cunningham AL. Cytokines and chemokines: the vital role they play in herpes simplex virus mucosal immunology. Front Immunol 2022;13:936235. doi:10.3389/fimmu.2022.936235

Boboev SA, Agzamova SS, Palvanov KhA, Odilova GR. Interferons and IFNL3/IFNL4 gene variability in herpetic keratitis: from epithelial immunity to personalized therapy. Problems of Biology and Medicine 2025;(06/166):374–380 (in Russian)

Rizaev JA, Imamov OS, Abduvakhitova IN. Vitamin D in the prevention of recurrences of herpes-associated erythema multiforme. Problems of Biology and Medicine 2024;(04/155):420–423 (in Russian)

Herpesvirus infection: protocol for diagnosis and treatment. Clinical protocols of the Republic of Uzbekistan. Tashkent; 2024

Kamilov KhP, Kamalova MK. Modern approaches to the treatment of chronic recurrent herpetic stomatitis in children. Dostizheniya Nauki i Obrazovaniya 2018;(03/25):46–48 (in Russian)

von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Lancet 2007;370(9596):1453–1457

Steyerberg EW, Vickers AJ, Cook NR, et al. Assessing the performance of prediction models: a framework for traditional and novel measures. Epidemiology 2010;21(01):128–138

Corey L, Wald A, Patel R, et al. Once-daily valacyclovir to reduce the risk of transmission of genital herpes. N Engl J Med 2004;350(01):11–20

Workowski KA, Bachmann LH, Chan PA, et al. Sexually transmitted infections treatment guidelines, 2021. MMWR Recomm Rep 2021;70(04):1–187

Aurelian L. Herpes simplex virus type 2 vaccines: new ground for optimism? Clin Vaccine Immunol 2004;11(03):437–445

Johnston C, Corey L. Current concepts for genital herpes simplex virus infection: diagnostics and pathogenesis of genital tract shedding. Clin Microbiol Rev 2016;29(01):149–161

Zhu S, Viejo-Borbolla A. Pathogenesis and virulence of herpes simplex virus. Virulence 2021;12(01):2670–2702

Whitley R, Baines J. Clinical management of herpes simplex virus infections: past, present, and future. F1000Res 2018;7:F1000 Faculty Rev-1726

James C, Harfouche M, Welton NJ, et al. Herpes simplex virus: global infection prevalence and incidence estimates, 2016. Bull World Health Organ 2020;98(05):315–329

Looker KJ, Magaret AS, May MT, et al. Global and regional estimates of prevalent and incident herpes simplex virus type 1 infections in 2012. PLoS One 2015;10(10):e0140765

Wald A, Zeh J, Selke S, et al. Reactivation of genital herpes simplex virus type 2 infection in asymptomatic seropositive persons. N Engl J Med 2000;342(12):844–850

Tronstein E, Johnston C, Huang ML, et al. Genital shedding of herpes simplex virus among symptomatic and asymptomatic persons with HSV-2 infection. JAMA 2011;305(14):1441–1449