Four cases of chickenpox, or varicella, have been confirmed in young adults at an unspecified residential college in Penobscot County. The Maine Center for Disease Control and Prevention said it is unknown whether the affected individuals were up to date on their varicella vaccines.
Chickenpox is a highly infectious viral disease characterized by an itchy red skin rash with small, fluid-filled blisters. Other symptoms include a fever, cough, headache, abdominal distress and general discomfort.
Chickenpox is most common in children, but its symptoms often are more severe in older people. It is of particular concern for pregnant women and people with weakened immune systems.
Chickenpox is spread person to person, primarily through direct contact with another infected person. Airborne droplets from coughing or sneezing also can spread the virus. The incubation period is generally 14 to 16 days, and varicella is infectious two days before the rash appears and up to five days after it disappears.
Mandatory varicella vaccination for Maine schoolchildren was implemented in 2003. Effectiveness of the vaccine is more than 90 percent, though breakthrough infection has been reported in some vaccinated individuals.
For most people, a case of chickenpox protects for life against a second infection, but the varicella virus can re-emerge years later in the form of a painful rash known as shingles.
Public health recommendations include a first vaccine between 12 and 15 months of age, and a second dose at 4 to 6 years. Immunity may weaken with age, and it is recommended that adults receive a vaccine if they live or work in high-risk settings. At-risk groups include teachers, day care workers, residents and staff in institutional settings, and college students living in dormitories.