One virus causes 2 infections decades apart.
As viruses go, varicella zoster virus (VZV) is particularly resilient. It is one of more than 130 identified herpes viruses that cause infections and diseases in mammals. In humans, VZV is responsible for 2 separate and distinct infections that typically occur decades apart: chickenpox and shingles.
VZV first infects the body as chickenpox (varicella), a highly contagious but relatively minor infection that primarily affects young children, although it can be far more serious if contracted by adults.
The first symptoms of chickenpox are sudden-onset fever, fatigue, headache, body aches, and loss of appetite. A blistering, itchy rash emerges a couple of days later, usually beginning on the face, back, or chest and spreading quickly to the rest of the body.
The virus is most likely to spread during this active phase of the infection, either through direct contact with the lesions or through breathing in viral particles from the lesions. The contagious period for chickenpox runs from 1 to 2 days before the rash erupts until all the blisters have scabbed over.
The chickenpox patient recovers, but VZV remains in the body. It lies dormant in the nervous system for decades until it reactivates to cause shingles (herpes zoster).
The first symptoms of shingles are a tingling, itching, or stabbing pain on the skin. Within a few days, the rash appears, starting as a band of raised lesions on one side of the face, torso, or other areas of the body. The lesions soon develop into red, fluid-filled blisters that eventually break open, dry up, and crust over.
Symptoms during the rash can vary from mild itching to intense pain which typically subsides after 3 to 5 weeks. Early treatment with antivirals can help to shorten the course of the infection and reduce complications.
Unlike chickenpox, shingles is not contagious. However, if a person who has never had chickenpox or been vaccinated against it comes in contact with fluid from the shingles blisters, they are likely to contract chickenpox. Once VZV is in their body, they are also at risk of developing shingles at a later date.
Fortunately for individuals at both ends of the age spectrum, chickenpox and shingles are preventable through vaccination.
The 2 options for vaccination against chickenpox are 2 doses of the varicella vaccine or the combination MMRV vaccine that guards against measles, mumps, rubella, and varicella.
The CDC recommends 2 doses of chickenpox vaccine for children, adolescents, and adults who have never had chickenpox and were never vaccinated. The first dose is administered to children between the ages of 12 and 15 months, and the second dose follows when they are 4 to 6 years old. Two doses are more than 90% effective at preventing chickenpox.
To prevent shingles, the CDC recommends that healthy adults aged 50 and older receive Shingrix, the only herpes zoster vaccine available in the United States. The vaccine is given in 2 doses administered 2 to 6 months apart. Individuals who have previously had shingles or received the earlier shingles vaccine Zostavax can also receive Shingrix.