What is the duration of contagiousness from herpes zoster (shingles)?

From the Guidelines

Shingles is contagious from the time blisters appear until they crust over completely, typically until all lesions dry and crust. According to the Advisory Committee on Immunization Practices (ACIP) recommendations 1, individuals with localized herpes zoster in immunocompetent persons should cover lesions and restrict from care of high-risk patients until all lesions dry and crust. The varicella-zoster virus can be transmitted to people who haven't had chickenpox or the chickenpox vaccine through direct contact with fluid from shingles blisters, potentially causing chickenpox in them, not shingles.

• Key considerations for preventing transmission include:
  • Covering the rash with clean, non-stick bandages
  • Washing hands frequently
  • Avoiding touching the blisters
  • Staying away from pregnant women, newborns, and people with weakened immune systems
• Antiviral medications like acyclovir, valacyclovir, or famciclovir, started within 72 hours of rash appearance, can reduce the contagious period and severity of symptoms, as supported by general medical knowledge.
• It is essential to note that the virus remains dormant in the body after recovery but cannot be transmitted unless shingles reactivates with a new rash.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Contagious Period of Shingles

• The contagious period of shingles is not explicitly stated in the provided studies, but it can be inferred that the risk of transmission is present as long as the rash is active and has not crusted over.
• According to general knowledge, people with shingles can spread the virus to others who have not had chickenpox, but this is more likely to occur through direct contact with the rash rather than through the air 2, 3.
• It is essential to note that the provided studies focus on the treatment and management of shingles rather than its contagious period.

Treatment and Management of Shingles

• Antiviral medications such as aciclovir, famciclovir, and valaciclovir can help shorten the duration of the illness and reduce the risk of complications 2, 3, 4.
• These medications are most effective when started within 72 hours of the onset of symptoms 3.
• Valaciclovir has been shown to be more effective than famciclovir in reducing pain and accelerating the resolution of zoster-associated pain 4.

Duration of Shingles

• The cutaneous manifestations of shingles usually resolve in approximately 4 weeks, but the pain can persist for several months or even years in some cases 2.
• Antiviral therapy can help shorten the duration of post-herpetic neuralgia (PHN), a common complication of shingles 2, 3.