From the Guidelines
Shingles is contagious from 1-2 days before the onset of rash and remains contagious until all lesions are crusted, typically 4-7 days after onset of rash. The contagious period can vary depending on the individual's immune response, with those having progressive varicella potentially being contagious for longer periods 1. It's essential to note that shingles is caused by the reactivation of the varicella-zoster virus, which remains dormant in sensory-nerve ganglia after an initial chickenpox infection. Key factors to consider in reducing the contagious period include:
- Keeping shingles rashes covered to prevent direct contact with fluid from blisters
- Avoiding touching or scratching the rash to reduce the risk of transmission
- Washing hands frequently to prevent the spread of the virus
- Avoiding contact with high-risk individuals, such as pregnant women, newborns, and immunocompromised people, until the rash crusts over. According to the study by the Advisory Committee on Immunization Practices (ACIP) in 2007, the period of contagiousness can be estimated to begin 1-2 days before the onset of rash and end when all lesions are crusted, typically 4-7 days after onset of rash 1.
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 2, 3, 4.
- The cutaneous manifestations of shingles usually resolve in approximately 4 weeks, but the pain can persist for several months or even years in untreated patients 2.
- Antiviral therapy, such as acyclovir, valacyclovir, and famciclovir, can help shorten the duration of the illness and reduce the risk of complications, including post-herpetic neuralgia (PHN) 2, 3, 5, 6.
Factors Affecting Contagiousness
- The risk of transmission is higher in individuals with weakened immune systems, such as older adults or those with immunocompromising conditions 3, 4.
- The use of antiviral therapy, such as valacyclovir, can help reduce the duration and severity of the illness, which may also reduce the risk of transmission 5, 6.
- The varicella-zoster vaccine may also help reduce the risk of transmission by preventing the occurrence of shingles in the first place 2.