San Quentin State Prison is under a medical lockdown after a case of chickenpox was discovered among the inmates.
Volunteer programs and visitations will be suspended until the prison medical staff determines it is safe for them to resume. Prison staff said they are trying to limit the exposure and spread of the chickenpox virus among inmates, prison staff and outsiders.
The medical staff is currently trying to determine which inmates and staff are immune to the virus and to isolate those who currently have chicken pox.
While chickenpox is generally thought of as a relatively harmless childhood disease, it can be more dangerous for infants, adolescents, adults, pregnant women and people with weakened immune systems.
Those who suffer severe complications might need to be hospitalized. Chickenpox can even be fatal for some people, according to the Center for Disease Control.