How long is chickenpox contagious and how does it spread?

Chickenpox is already contagious one or two days before the typical rash appears. People usually already have a headache and body pain at that point. Chickenpox remains contagious until the last blisters have dried up and the scabs have all fallen off.

Chickenpox is spread by tiny droplets of saliva (spit) released into the air when someone who is contagious breathes, coughs, sneezes or speaks. The viruses may also spread through direct contact or by touching objects or clothing.

One thing many people don't know is that you can also get chickenpox from contact with people who have shingles. They can spread the varicella-zoster virus through direct contact, but not through droplets in the air. Shingles is a possible long-term consequence of chickenpox. It can develop years or even decades later.

Who is the chickenpox vaccination recommended for?

As of August 2004, STIKO recommends that all children have a chickenpox vaccination (varicella vaccination): the first dose between the ages of 11 and 15 months, and a second one between the ages of 15 and 23 months. Depending on the specific vaccine that is used, the two vaccines should be given at least four to six weeks apart. The vaccine is injected. It can be given at the same time as a combination vaccine known as the MMR vaccine, which vaccinates against measles, mumps and rubella (also called German measles). A combination vaccine against measles, mumps, rubella and varicella (MMRV vaccine) is also available.

Other groups of people are also advised to get vaccinated if they haven't yet had chickenpox. These include teenagers, women who are hoping to get pregnant, and people who have certain other conditions, such as severe eczema. You can find more information about the varicella vaccination and STIKO’s recommendations on the Robert Koch Institute website.

A chickenpox vaccination may cause side effects similar to those of other vaccinations, such as redness around the injection site and mild fever, but these go away after a few days.

People who have been vaccinated can still get chickenpox. That is rare, though, and the symptoms are usually milder then. The risk of complications is lower, too.

What if you're not immune and come into contact with someone who has chickenpox?

If you’ve never had chickenpox and aren’t vaccinated, you can get vaccinated within five days of coming into contact with someone who is infected. Studies involving a total of 110 healthy children whose siblings had chickenpox showed the following:

• Without the vaccination: About 78 out of 100 healthy siblings who weren’t vaccinated after contact developed chickenpox.
• With the vaccination: About 23 out of 100 healthy siblings who were vaccinated after contact developed chickenpox.

The vaccinated children who still got chickenpox generally had a milder case than children who were not vaccinated.

Chickenpox vaccinations should not be given during pregnancy. If a pregnant woman who has not been vaccinated and isn't immune comes into contact with someone who has chickenpox, she should see a doctor quickly. Within four days of contact, she can have treatment with special antibodies to fight the virus. This is called “passive immunization.” It can stop chickenpox from developing fully, or at least lessen the symptoms. Passive immunization is also an option for newborns if their mother develops chickenpox a few days before or after giving birth. The aim is to protect the baby from severe symptoms.

How can you avoid infection in everyday life?

If someone in your family has chickenpox, the following precautions may help to lower the risk of infection:

• Call the doctor first to let them know you will be coming in with a suspected case of chickenpox, and ask what you should do when you get there. People who are thought to have chickenpox are usually taken to a separate waiting room so they don't infect others. The doctor might be able to make a home visit instead.
• Wherever possible, the person who has chickenpox should avoid contact with anyone who has never had it. That also means not spending much time in a room with other people because chickenpox can also be spread through the air.
• Children with chickenpox aren’t allowed to go to school or daycare. They should also not play with other children until they are no longer contagious.
• Try to avoid scratching blisters because they may break and the fluid inside is contagious. It may help to keep children’s fingernails trimmed, and put cotton mittens on babies’ and toddlers' hands.

The person is no longer contagious once all of the blisters have scabbed over (usually five to seven days after the rash appears).

Sources

• Macartney K, Heywood A, McIntyre P. Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults. Cochrane Database Syst Rev 2014; (6): CD001833. [PMC free article: PMC7061782] [PubMed: 24954057]
• Robert Koch-Institut (RKI). Empfehlungen der Ständigen Impfkommission (STIKO) am Robert Koch-Institut (Epidemiologisches Bulletin 4/2022). 2022.
• Robert Koch-Institut (RKI). RKI-Ratgeber: Varizellen (Windpocken), Herpes zoster (Gürtelrose). 2017.

• IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

  Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

  Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.