How Is Chickenpox Transmitted?

Chickenpox spreads from person to person very easily. The varicella-zoster virus causes it, and it travels through the air when an infected person coughs, sneezes, or talks. You can also catch it by touching the fluid from chickenpox blisters. The virus is highly contagious, and exposure alone is often enough to cause infection in someone who has not had the disease or the vaccine.

How Is Chickenpox Transmitted?

Chickenpox is transmitted through respiratory droplets and direct contact with blister fluid. When an infected person breathes out, the virus rides on tiny droplets of moisture. If you breathe those droplets in, the virus can enter your respiratory tract and start an infection.

Direct contact is the second major route. The fluid inside chickenpox blisters is packed with live virus. Touching the blisters and then touching your mouth, nose, or eyes can transfer the virus into your body. This is why scratching the blisters and then touching your face is a common way the infection spreads.

In rare cases, the virus can also spread through the air from blister fluid that has dried into particles. This is less common than droplet spread but still possible, especially in closed indoor spaces.

How Long Is Chickenpox Contagious?

A person with chickenpox can spread the virus for a long window of time. The contagious period starts about 1 to 2 days before the rash appears. At that point, the person may feel tired, have a mild fever, or show no symptoms at all — but they can still infect others.

The contagious period lasts until all blisters have crusted over. This usually takes about 5 to 7 days after the rash first appears. Once every single blister has formed a dry scab, the person is no longer considered contagious. Until then, they should stay home and avoid contact with others, especially people who are pregnant, unvaccinated, or have weakened immune systems.

This long contagious window is why chickenpox spreads so quickly through households and classrooms. One infected child can expose dozens of people before anyone even knows they are sick.

Can You Get Chickenpox From Shingles?

Yes, but with an important distinction. Shingles is caused by the same virus — varicella-zoster — that causes chickenpox. After a chickenpox infection, the virus stays dormant in nerve tissue. Years or decades later, it can reactivate and cause shingles, a painful blistering rash.

If someone with shingles has open blisters, the fluid contains live virus. A person who has never had chickenpox and has not been vaccinated can catch chickenpox from that fluid. They will not get shingles — they will get chickenpox first. Shingles itself only develops in someone who already had chickenpox.

Shingles is not transmitted through coughing or sneezing. The virus spreads only through direct contact with the shingles rash. Covering the rash with a bandage or clothing greatly reduces the risk of spreading the virus.

Who Is Most at Risk of Catching Chickenpox?

Anyone who has not had chickenpox and has not been vaccinated is at risk. In the United States, routine childhood vaccination has made chickenpox far less common than it was decades ago. But the virus still circulates, and unvaccinated people remain vulnerable.

Certain groups face higher risk of severe illness if they catch chickenpox:

• Newborns and infants too young for the vaccine
• Pregnant women who have not had chickenpox
• People with weakened immune systems, including those on chemotherapy or immunosuppressive medications
• Unvaccinated adults — chickenpox is often more severe in adults than in children

For these groups, exposure to chickenpox is a medical concern. If exposure happens, a doctor should be contacted promptly. In some cases, preventive treatment with varicella-zoster immune globulin may be recommended, especially for pregnant women and immunocompromised people.

How Do You Prevent Chickenpox Transmission?

The varicella vaccine is the most effective way to prevent chickenpox. It is a live attenuated vaccine, meaning it contains a weakened form of the virus that does not cause disease in healthy people but triggers the immune system to produce protective antibodies. Two doses of the vaccine provide strong protection, and most vaccinated people who do get chickenpox have a much milder case.

The vaccine is routinely given to children in two doses: the first around 12 to 15 months of age and the second around 4 to 6 years of age. Adults who have never had chickenpox or the vaccine should also receive two doses, given 4 to 8 weeks apart.

If someone already has chickenpox, the best way to prevent spread is isolation. The infected person should stay home until all blisters have crusted over. They should avoid contact with pregnant women, newborns, and people with weakened immune systems. Covering the rash, washing hands frequently, and not sharing personal items like towels or bedding also reduce the risk of transmission.

What Should You Do If You Have Been Exposed?

If you have been exposed to chickenpox and you are vaccinated or have had the disease before, your risk is low. The vaccine is very effective, and prior infection provides long-lasting immunity. You may not need to do anything other than watch for symptoms.

If you are unvaccinated and have never had chickenpox, the situation is different. The varicella vaccine can still prevent the disease if given within 3 to 5 days of exposure. This is called post-exposure prophylaxis. It does not always prevent infection, but it significantly reduces the chance of severe illness.

For high-risk individuals — pregnant women, newborns, and immunocompromised people — a doctor should be contacted immediately after exposure. They may be candidates for varicella-zoster immune globulin, a treatment that provides temporary passive immunity. This is most effective when given within 96 hours of exposure.

Do not wait for symptoms to appear before seeking medical advice. By the time the rash shows, the opportunity for preventive treatment has passed.

Is Chickenpox Still Common in the United States?

No. Before the varicella vaccine was introduced in 1995, chickenpox was extremely common — nearly everyone in the United States got it by adulthood. Each year, there were roughly 4 million cases, over 10,000 hospitalizations, and about 100 to 150 deaths.

Since routine vaccination began, cases have dropped by more than 90%. Hospitalizations and deaths have fallen even more dramatically. Outbreaks still occur, but they are mostly in communities with low vaccination rates or among people who are unvaccinated.

This does not mean chickenpox has disappeared. The virus still circulates, and unvaccinated people can and do get infected. But for most people in the United States today, chickenpox is a preventable disease rather than an inevitable childhood illness.

Can You Get Chickenpox Twice?

It is rare but possible. Most people who have had chickenpox develop lifelong immunity. The immune system produces antibodies that recognize the virus and prevent reinfection.

However, people with severely weakened immune systems — such as those undergoing chemotherapy, organ transplant recipients, or people with advanced HIV — can sometimes get chickenpox a second time. This is uncommon, and when it happens, the second case is usually milder.

More commonly, a person who had chickenpox can develop shingles later in life. This is not a second case of chickenpox. It is a reactivation of the dormant virus, and it produces a different illness with a different rash pattern.