Most normal people can achieve lifelong immunity after receiving the chickenpox vaccine. Patients who have had chickenpox will also develop antibodies and will no longer transmit chickenpox, but the virus can be latent in the body and can later be activated to cause shingles. People who are susceptible to chickenpox are those who are immunocompromised, such as those with AIDS or long-term immunosuppression, and the elderly who are extremely immunocompromised. The rash appears from the trunk and gradually spreads to the head, face and extremities, with more rashes on the trunk and fewer on the extremities, often with a centripetal distribution, the rash can be spotted, papular, herpetic and crusted. The rash can be spotted, papular, herpetic and crusted. The rash is also contagious, but after the rash has crusted over, it is usually no longer contagious.