Is there a risk of infection if the scabs from chickenpox have not yet fallen off?

In general, chickenpox is typically not contagious once the blisters have formed scabs, although specific circumstances may still pose a risk of transmission.

Chickenpox is an acute infectious disease caused by the initial infection of varicella-zoster virus (VZV), and patients are the sole source of infection. After the blisters have scabbed over, the blister fluid is absorbed by the body. Without blister fluid serving as a culture medium, the VZV cannot survive within the scabs. Therefore, even if the scabs have not yet fallen off, chickenpox is generally not contagious. This is also why the isolation period for chickenpox is defined either by the formation of scabs on the blisters or by seven days after the rash appears.

If scabs fall off prematurely or become damaged due to scratching, the virus may be released from the damaged areas and remain contagious. If there are still exudates present at the site after the blisters have scabbed, these exudates may contain the virus. Transmission can occur through close contact with such exudates. For individuals with weakened immune systems, including children, elderly people, pregnant women, or those suffering from immunodeficiency diseases, the risk of infection upon contact with a chickenpox patient who still has incompletely detached scabs and remains contagious is relatively high.

To prevent the spread of chickenpox, it is recommended that patients resume normal social activities only after all skin lesions have completely scabbed over and fallen off naturally. Attention should also be paid to personal hygiene, and close contact with susceptible individuals should be avoided, especially in group settings such as schools and daycare centers. For children and adults who have not previously received the varicella vaccine or contracted chickenpox, vaccination against varicella should be considered to prevent the occurrence of the disease.