Chickenpox: Symptoms, How It Spreads, and Why the Vaccine Matters

Chickenpox is a highly contagious disease caused by the varicella-zoster virus (VZV). It spreads mainly through close contact with someone who has it, and the best protection is the chickenpox vaccine.

Symptoms

The hallmark is an itchy rash that turns into fluid-filled blisters and then scabs. It often starts on the chest, back and face before spreading over the body, and a person can have as many as 500 blisters. It usually takes about a week for all of them to scab over. The illness usually lasts about 4 to 7 days, and children typically miss 5 to 6 days of school or childcare.

For most people, having chickenpox once gives lifelong immunity; getting it twice is possible but uncommon. Some vaccinated people still catch chickenpox, but they usually have milder symptoms.

Who is at risk

Anyone who has never had chickenpox or the vaccine can get it. It can be serious — even life-threatening — especially for:

• pregnant people;
• babies;
• adolescents and adults;
• people with weakened immune systems, who are less able to fight off germs and illness.

How it spreads

Chickenpox spreads mainly from unvaccinated people who have it to others who have never had the virus. Up to 90% of people who aren't immune and are close to someone with chickenpox will become infected.

• A person is contagious from 1 to 2 days before the rash appears until all the blisters have crusted over.
• Vaccinated people who get chickenpox can still spread it. Their spots may not crust, so they are contagious until no new spots have appeared for 24 hours.

From shingles, too

The same virus causes shingles. After someone recovers from chickenpox, VZV stays dormant in the body and can reactivate later in life as shingles. A person who has never had chickenpox or the vaccine can catch VZV from someone with shingles — by touching fluid from the shingles blisters or breathing in virus particles from them — and will develop chickenpox, not shingles.

Chickenpox appears about 2 weeks (10 to 21 days) after exposure to someone with chickenpox or shingles.

Prevention

Vaccination is the best way to prevent chickenpox. Children, adolescents and adults who have never had chickenpox or the vaccine should all get two doses. Most vaccinated people will never get chickenpox, and the vaccine prevents almost all cases of severe illness. Since the U.S. chickenpox vaccination program began, cases have fallen by more than 97%, and hospitalizations and deaths have become rare.

Treatment

Home care can ease symptoms and help prevent skin infections, and a health care provider can advise on options. Antiviral medicine is recommended for people with chickenpox who are more likely to become seriously ill.

Skip the "chickenpox party"

Some parents once held "chickenpox parties," deliberately exposing unvaccinated children to a child with chickenpox so they would catch it. CDC strongly recommends against them. Chickenpox can cause severe complications and even death in healthy children, and there is no way to know in advance how sick a child will get. Vaccination is the best way to protect infants and children.

Sources

• Centers for Disease Control and Prevention: "About Chickenpox"; a work of the United States government in the public domain. The page's photographs and infographic are not reproduced.