HSV-1 IgG Positive: Interpretation and Management
A positive HSV-1 IgG test indicates past exposure and ongoing latent infection with herpes simplex virus type 1, with antibodies persisting indefinitely after infection—no treatment is necessary unless symptomatic lesions develop. 1, 2
What This Result Means
HSV-1 IgG positivity confirms lifelong latent infection that was acquired at some point in the past, though the test cannot distinguish between recent and long-standing infections. 1, 2
The virus remains dormant in cervical ganglia and can reactivate periodically, causing recurrent oral lesions (cold sores) or, less commonly, genital lesions if transmitted through oral-genital contact. 3, 2
Up to 70% of adults worldwide have HSV-1 antibodies, making this an extremely common finding that typically reflects childhood acquisition through non-sexual contact. 2
The presence of HSV-specific IgG alone (without IgM) indicates established infection rather than acute or recent acquisition. 3
Clinical Implications Based on Symptoms
If You Are Asymptomatic
No treatment is indicated for asymptomatic HSV-1 seropositivity. 2
The positive result simply documents immune status and does not require intervention in the absence of clinical disease. 2
If You Have Oral Lesions (Cold Sores)
Episodic antiviral therapy can be considered for symptomatic outbreaks, using acyclovir 400mg orally five times daily for 5 days or valacyclovir 2g orally twice daily for 1 day. 4, 5
Suppressive therapy may be appropriate if recurrences are frequent (≥6 per year), using acyclovir 400mg orally twice daily or valacyclovir 500mg-1g orally once daily. 4, 5
If You Have Genital Lesions
HSV-1 can cause genital herpes through oral-genital transmission, though it causes fewer recurrences and less subclinical shedding than HSV-2 genital infections. 3, 2
The same antiviral dosing regimens apply to both HSV-1 and HSV-2 genital infections, despite less comprehensive study data for HSV-1. 1
For active genital lesions, nucleic acid amplification testing (NAAT/PCR) from the lesion should be performed to confirm HSV-1 as the causative agent, as serology alone cannot determine the etiology of a presenting lesion. 3, 6
Important Caveats
Serology cannot inform the cause of any current genital lesion with certainty—direct testing of lesions via NAAT/PCR is required for definitive diagnosis of active infection. 3, 6
If concerned about recent HSV-2 exposure (which your test does not show), retesting should not occur until at least 12 weeks after exposure to avoid false-negatives during the antibody "window period." 1, 6
The detection of HSV-specific IgM is a poor indicator of recent infection, as approximately one-third of patients with recurrent herpes have IgM responses. 3
Counseling Points
Type determination is important for prognosis: HSV-1 genital infections have significantly fewer recurrences than HSV-2 genital infections. 3, 1
Transmission risk exists during both symptomatic outbreaks and asymptomatic viral shedding, though shedding is less frequent with HSV-1 than HSV-2. 1
Your negative HSV-2 result (if tested) suggests lower risk for transmitting genital herpes to partners compared to those with HSV-2 infection. 2