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Varicella (Chickenpox)

An acute contagious disease that usually occurs in children and is caused by the varicella-zoster virus.

PubMed Health Glossary
(Source: NIH - National Institute of Neurological Disorders and Stroke)

About Chickenpox

Chickenpox is a highly contagious viral infection which mainly affects children. A very itchy skin rash with red blisters and mild fever are typical signs. Because most children are now vaccinated, chickenpox (also referred to as varicella) is much less common than it was in the past.

If someone comes down with chickenpox, they are contagious after just one or two days, which is before they have any visible rash. But taking precautions and improving hygiene can help to avoid infecting others. Although chickenpox is very unpleasant, it rarely has any serious effects in children who are otherwise healthy. But it may become more severe in newborns and adults, as well as people who have a weakened immune system.

Symptoms

If you get chickenpox you will feel generally ill at first. It causes pain in the joints and headaches, and body temperature rises. The itchy rash typical of chickenpox develops next, usually on your face and torso first, and then spreading to the scalp, and arms and legs... Read more about Varicella

What works? Research summarized

Evidence reviews

Post‐exposure prophylaxis vaccine to prevent varicella (chickenpox)

This review assessed how useful the varicella (also known as chickenpox) vaccine is in preventing chickenpox when given to children or adults who have never been immunised or previously had chickenpox, but who receive the vaccine within a short time following exposure to a person infectious with chickenpox. Varicella is a highly contagious viral infection characterised by a widespread pustular rash, fever and generally feeling unwell. We identified three trials involving 110 healthy children who were siblings of household contacts.

Acyclovir can reduce the number of days with fever in otherwise healthy children with chickenpox, but its effect on sores and itching is not yet certain

Chickenpox (varicella) is caused by a virus. It begins with a fever, followed by a rash of red pimples which become itchy sores that form scabs. Chickenpox usually affects children from one to 14 years. In young babies, adults or people with impaired immune system, chickenpox is more severe. Treatments include lotions to relieve itchiness, paracetamol (acetaminophen) for fever and the antiviral drug acyclovir. The review of trials found that acyclovir reduces the number of days of fever from chickenpox in otherwise healthy children, usually without adverse effects. It is not clear whether it improves sores and itching.

Varicella and influenza vaccines may reduce morbidity in patients with blood cancers

Viral infections cause significant disease and even death in patients with blood cancers. In the current systematic review of randomized controlled trials (RCTs) we aimed to evaluate the efficacy and safety of viral vaccines in these patients. The pre‐defined primary outcome was incidence of the infection concerned. Secondary outcomes were mortality due to the viral infection, all‐cause mortality, incidence of complications, incidence of severe viral infection, hospitalization rate, in vitro immune response and frequency of adverse effects. Eight RCTs were included. They evaluated heat‐inactivated varicella zoster virus (VZV) vaccine (two trials), influenza vaccines (five trials) and inactivated poliovirus vaccine (one trial). There were no RCTs on other viral vaccines (hepatitis A, hepatitis B, measles, mumps, rubella). Only the two trials on VZV vaccine reported our pre‐defined primary outcome. All trials reported some of the pre‐defined secondary outcomes. We found that inactivated VZV vaccine might reduce the severity of herpes zoster when given before and after stem cell transplant in adults with lymphoma or leukemia. Inactivated influenza vaccine might reduce upper and lower respiratory infections and hospitalization in adults with multiple myeloma who are undergoing chemotherapy, or children with leukemia or lymphoma within two years post‐chemotherapy. However, the quality of evidence is not high. Local adverse effects occur frequently with the vaccines, although serious adverse effects appear uncommon. Further high‐quality RCTs are needed to clarify the benefits and optimal regimens of viral vaccines for patients with blood cancers.

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Summaries for consumers

Post‐exposure prophylaxis vaccine to prevent varicella (chickenpox)

This review assessed how useful the varicella (also known as chickenpox) vaccine is in preventing chickenpox when given to children or adults who have never been immunised or previously had chickenpox, but who receive the vaccine within a short time following exposure to a person infectious with chickenpox. Varicella is a highly contagious viral infection characterised by a widespread pustular rash, fever and generally feeling unwell. We identified three trials involving 110 healthy children who were siblings of household contacts.

How can you avoid getting chickenpox?

Chickenpox is highly contagious. If you are not immunized and have never had chicken pox, contact with someone who has it will almost always leave you infected. Early vaccination and being careful around those who already have chickenpox are the most important precautions you can take.Chickenpox is caused by the varicella-zoster virus, one of the herpes viruses. The German Standing Committee on Vaccination (STIKO) at the Robert Koch Institute recommends being vaccinated to lower your chances of infection. If you or someone in your family gets chickenpox there are several things you can do to avoid getting it yourself.Most importantly, people who have chickenpox should avoid contact with anyone who has not had it and who also may be more likely to develop more severe symptoms. This especially includes people with a weakened immune system, newborn babies, and non-vaccinated adults. The virus can harm the unborn child during pregnancy, and can be life-threatening for newborns. But although chickenpox is very unpleasant, it only rarely has serious consequences for otherwise healthy children.

Acyclovir can reduce the number of days with fever in otherwise healthy children with chickenpox, but its effect on sores and itching is not yet certain

Chickenpox (varicella) is caused by a virus. It begins with a fever, followed by a rash of red pimples which become itchy sores that form scabs. Chickenpox usually affects children from one to 14 years. In young babies, adults or people with impaired immune system, chickenpox is more severe. Treatments include lotions to relieve itchiness, paracetamol (acetaminophen) for fever and the antiviral drug acyclovir. The review of trials found that acyclovir reduces the number of days of fever from chickenpox in otherwise healthy children, usually without adverse effects. It is not clear whether it improves sores and itching.

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Terms to know

Fever
An increase in body temperature above normal (98.6 degrees F), usually caused by disease.
Herpes Zoster (Shingles)
A painful skin rash with blisters in a limited area on one side of the body (left or right), often in a stripe.
Postherpetic Neuralgia
A condition characterized by pain that persists more than 3 months after healing of a shingles rash. Caused by damage to the nervous system.
Varicella Zoster Virus (VZV)
Varicella zoster virus (VZV) is one of eight herpesviruses known to infect humans and vertebrates. VZV only affects humans, and commonly causes chickenpox in children, teens and young adults and herpes zoster (shingles) in adults and rarely in children.

More about Varicella

Photo of a child

Also called: Chicken pox, Varicella infection

Other terms to know: See all 4
Fever, Herpes Zoster (Shingles), Postherpetic Neuralgia

Related articles:
How Can You Avoid Getting Chickenpox?

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