How can Herpes Simplex Virus (HSV) 1 and 2 be prevented from spreading?

How to Prevent Spreading HSV-1 and HSV-2

To prevent HSV transmission, infected individuals must abstain from sexual contact when lesions or prodromal symptoms are present, consistently use condoms during all sexual exposures with uninfected partners, inform partners of their HSV status, and consider daily suppressive antiviral therapy which reduces transmission risk by approximately 50%. 1, 2

Behavioral Prevention Strategies

Sexual Activity Modifications

• Abstain completely from sexual activity when lesions or prodromal symptoms (tingling, itching, burning) are present, as this is when viral shedding and transmission risk are highest 1, 2, 3
• Use condoms during all sexual exposures with new or uninfected partners, even when asymptomatic 1, 2, 4
• Inform all sex partners about having genital herpes before sexual contact 1, 2, 4

Understanding Asymptomatic Transmission Risk

• Asymptomatic viral shedding occurs frequently and can lead to transmission even without visible lesions or symptoms 1, 2
• HSV-2 causes more frequent asymptomatic shedding than HSV-1, particularly in the first 12 months after infection 2
• Even with suppressive therapy, short bursts of subclinical viral reactivation occur and account for continued transmission 5

Pharmacologic Prevention: Suppressive Antiviral Therapy

Transmission Reduction Evidence

• Daily valacyclovir 500 mg once daily reduces symptomatic HSV-2 transmission by 75% and overall HSV-2 acquisition by 48% in discordant couples 3, 6
• Suppressive therapy reduces HSV-2 genital shedding from 10.8% of days to 2.9% of days 6
• Acyclovir 400 mg twice daily reduces subclinical shedding by 94% 7

Recommended Suppressive Regimens for Transmission Prevention

• Valacyclovir 500 mg once daily (most studied for transmission reduction) 4, 3, 6
• Alternative: Acyclovir 400 mg twice daily 4, 7
• Alternative: Famciclovir 250 mg twice daily 1, 2

Important Caveats About Suppressive Therapy

• Suppressive therapy does not eliminate transmission risk entirely—it reduces but does not prevent all viral shedding 5, 6
• Must be combined with safer sex practices (condoms, abstinence during outbreaks) for maximum protection 3, 6
• Safety documented for acyclovir up to 6 years and valacyclovir/famciclovir for 1 year 1, 2

Type-Specific Considerations

HSV-1 vs HSV-2 Differences

• HSV-1 now causes 5-30% of first-episode genital herpes cases but has much less frequent clinical recurrences than HSV-2 2, 8
• HSV-1 is more common than HSV-2 as a cause of both oral and genital infections in young women 8
• Type-specific serologic testing of partners can determine if HSV-2 acquisition risk exists 3

Oral Herpes (HSV-1) Prevention

• Apply sunscreen (SPF 15 or above) to prevent UV-triggered reactivation 9
• Avoid direct contact with cold sores (kissing, sharing utensils, oral-genital contact) when lesions present 9
• Suppressive therapy (acyclovir 400 mg 2-3 times daily or valacyclovir 500-2000 mg twice daily) can prevent recurrent herpes labialis 9

Partner Counseling and Testing

Essential Partner Communication

• Partners should be advised they might be infected even if asymptomatic 3
• Type-specific serologic testing of asymptomatic partners determines whether HSV-2 acquisition risk exists 3
• Valacyclovir has not been shown to reduce transmission of sexually transmitted infections other than HSV-2 3

Common Pitfalls to Avoid

• Do not rely on condoms alone—they reduce but do not eliminate transmission risk, as HSV can be shed from areas not covered by condoms 1, 2
• Do not assume absence of symptoms means no transmission risk—most HSV transmission occurs during asymptomatic shedding 1, 2, 8
• Do not use topical acyclovir—it is substantially less effective than oral therapy for both treatment and prevention 1, 2
• Do not initiate sexual activity immediately after lesions heal—viral shedding may continue briefly after visible healing 1

Special Population: Pregnancy

• Pregnant women with genital herpes should inform healthcare providers about HSV infection 2, 4
• Suppressive therapy starting at 36 weeks gestation may reduce HSV shedding at delivery and decrease need for cesarean delivery 4
• Cesarean delivery is recommended for women with visible lesions or prodromal symptoms at labor onset 4