Influence of viral genome variations on HSV-2 shedding rate and infection severity

Below is a summary of “Viral genomic variation and severity of genital HSV-2 infection quantified by shedding rate: a viral genome-wide association study,” published in the May 2024 issue of Infectious disease by Casto et al.

Genital herpes caused by HSV-2 varies in severity. Some people have frequent genital lesions, while others show no symptoms. The rate of viral shedding is a key indicator of this clinical severity.

Researchers conducted a retrospective study to investigate whether variations in the herpes simplex virus type 2 (HSV-2) genome are associated with differences in shedding rates.

The study included 145 people in whom the severity of genital herpes was assessed by measuring the rate of genital HSV shedding. An HSV-2 sample was collected from each participant to identify biallelic variants within the genome.

The result showed no correlation between the shedding rate and the genome-wide variation of HSV-2. However, the minor alleles of three different, unlinked variants were significantly associated with a higher shedding rate (P<8.4×10-5) by a viral genome-wide association study (vGWAS), A74534G was a synonymous variant in UL36 (large tegument protein), T119283C was an intergenic variant, and C44973T (A512T) is a non-synonymous variant in UL22 (glycoprotein H). In addition, a relationship was observed between the total number of minor alleles for the significant variants and the shedding rate (P=6.6×10-7).

The researchers concluded that the results support the growing evidence that viral genetic variation in HSV is associated with clinically significant infection phenomena.