Early warning signs of chickenpox in adults and children alike include fever, fatigue and loss of appetite, states Mayo Clinic. Symptoms that develop as the disease progresses include red, itchy spots followed by blistering and scabbing, notes The Huffington Post. Chickenpox is generally more severe in adults than in children.
Vaccination is the most effective method for preventing chickenpox, according to WebMD. Adults who receive the chickenpox vaccine within three days of exposure have a 90 percent chance of preventing the sickness altogether. Adults who experienced chickenpox as a child are immune to developing the disease a second time, so they do not need the vaccine.