Chickenpox, medically known as varicella, is a highly contagious viral infection that can affect both children and adults.
It is caused by the varicella-zoster virus (VZV).
Chickenpox is often mild in otherwise healthy children, but it should not be dismissed as harmless. Serious complications can occur, particularly in babies, adolescents, adults, pregnant women and people with weakened immune systems.
Vaccination can prevent chickenpox and substantially reduce the risk of severe disease.
What Causes Chickenpox?
Chickenpox is caused by the varicella-zoster virus, a member of the herpesvirus family.
The first infection with VZV causes chickenpox.
After someone recovers, the virus does not necessarily disappear completely from the body. Instead, it can remain inactive in nerve tissue for many years.
Later in life, the virus may reactivate and cause shingles (herpes zoster).
Therefore:
Chickenpox and shingles are caused by the same virus, but they are different clinical conditions.
Is Chickenpox Contagious?
Yes.
Chickenpox is highly contagious.
Among people without immunity, close contact with someone who has chickenpox can result in a very high likelihood of infection.
CDC estimates that up to 90% of susceptible people who have close contact with someone with chickenpox may become infected.
This is why chickenpox can spread rapidly through households, schools and other settings where people have close contact.
How Does Chickenpox Spread?
Varicella-zoster virus can spread from one person to another through:
- airborne respiratory particles,
- respiratory secretions,
- direct contact with fluid from chickenpox blisters,
- and exposure to someone with active shingles in certain circumstances.
A susceptible person exposed to VZV from shingles can develop chickenpox, not shingles as their first infection.
Can You Catch Chickenpox From Someone With Shingles?
Yes, if you are susceptible to varicella-zoster virus.
A person with shingles can transmit VZV through contact with fluid from the shingles rash and, in some circumstances, through airborne particles.
A susceptible person exposed to the virus may develop chickenpox.
They do not directly “catch shingles” from another person.
Shingles results from reactivation of VZV already present in someone's body following an earlier chickenpox infection or, less commonly, vaccination.
When Is Chickenpox Contagious?
A person with chickenpox is generally contagious from approximately 1–2 days before the rash appears until all the blisters have crusted over.
This means the virus can spread before someone realizes that the characteristic rash has developed.
It usually takes approximately a week for all blisters to become scabs.
Vaccinated people who develop a mild form without typical crusting blisters may require different criteria for determining when they are no longer contagious.
Follow advice from an appropriate healthcare or public-health professional.
How Long After Exposure Does Chickenpox Develop?
Chickenpox does not normally appear immediately after exposure.
The incubation period is usually approximately 14–16 days, although symptoms can develop anywhere from about 10–21 days after exposure.
Someone may therefore appear completely well for days after being infected.
What Are the First Symptoms of Chickenpox?
Symptoms can begin before the rash, particularly in adolescents and adults.
Early symptoms may include:
- fever,
- tiredness or generally feeling unwell,
- reduced appetite,
- and headache.
In children, the rash may sometimes be the first obvious sign.
What Does a Chickenpox Rash Look Like?
The characteristic chickenpox rash is itchy and develops in stages.
It generally progresses from:
flat or raised red spots → fluid-filled blisters → crusted scabs.
New spots may continue appearing while older spots are already blistering or crusting.
As a result, someone with chickenpox may have lesions at several different stages at the same time.
This is a useful feature when distinguishing chickenpox from some other rashes.
Where Does the Rash Usually Start?
The rash often first appears on the:
- chest,
- back,
- and face.
It can then spread across much of the body.
Lesions may also occur in uncomfortable areas such as:
- inside the mouth,
- eyelids,
- scalp,
- and genital region.
The number of spots varies considerably between individuals.
How Long Does Chickenpox Last?
In many otherwise healthy people, symptoms last approximately 4–7 days.
It commonly takes around one week for all the blisters to crust.
Recovery time can vary depending on:
- age,
- severity,
- vaccination status,
- immune function,
- and whether complications develop.
What Is Breakthrough Chickenpox?
People who have been vaccinated can occasionally still develop chickenpox.
This is known as breakthrough varicella.
It is usually milder than chickenpox in an unvaccinated person.
Vaccinated people may have:
- fewer skin lesions,
- little or no fever,
- fewer blisters,
- and a shorter illness.
Because the rash can look different, breakthrough chickenpox can sometimes be difficult to recognize.
Is Chickenpox Always Mild?
No.
Chickenpox is mild in many healthy children, but serious illness can occur.
People at greater risk of complications include:
- babies,
- adolescents,
- adults,
- pregnant women,
- and people with weakened immune systems.
Some people may require hospital treatment.
Rarely, chickenpox can be fatal.
What Complications Can Chickenpox Cause?
Possible complications include:
- bacterial infection of the skin,
- pneumonia,
- dehydration,
- encephalitis or other neurological complications,
- bloodstream infection or sepsis,
- bleeding complications,
- and other serious illness.
Bacterial skin and soft-tissue infection is an important complication among children.
Pneumonia is a particularly important complication among adults.
Skin Infection
Chickenpox blisters can become infected with bacteria.
Warning signs may include skin that becomes increasingly:
- red,
- swollen,
- warm,
- painful,
- or begins draining pus.
A fever that persists or returns as skin lesions worsen can also be concerning.
Medical assessment may be required.
Chickenpox and Pneumonia
Varicella pneumonia is a potentially serious complication.
Adults and pregnant women can be at greater risk than healthy young children.
Seek urgent medical assessment if someone with chickenpox develops:
- difficulty breathing,
- persistent severe coughing,
- chest pain,
- bluish or unusually pale skin,
- or rapidly worsening breathing symptoms.
Difficulty breathing should not be treated as an ordinary chickenpox symptom.
Chickenpox and the Brain
Chickenpox can rarely cause serious neurological complications such as encephalitis, which is inflammation of the brain.
Warning symptoms can include:
- confusion,
- extreme drowsiness,
- difficulty waking,
- seizures,
- severe loss of coordination,
- or unusual behaviour.
These require urgent medical attention.
Why Scratching Can Be a Problem
Chickenpox can be extremely itchy.
Scratching may damage the skin and increase the risk of:
- bacterial infection,
- bleeding,
- and scarring.
Keeping fingernails short and clean may help reduce skin damage, especially in children.
Young children may need additional measures to discourage scratching during sleep.
How Can Chickenpox Itching Be Relieved?
Comfort measures can help manage itching.
Depending on age and individual circumstances, these may include:
- cool or lukewarm baths,
- loose comfortable clothing,
- keeping the skin cool,
- calamine lotion,
- and appropriate antihistamines when recommended by a healthcare professional.
Calamine lotion may help soothe itching, but it is important to understand:
Calamine does not prevent chickenpox and does not kill the varicella-zoster virus.
It is a symptom-relief measure.
Should Aspirin Be Used for Chickenpox?
Children and teenagers with chickenpox should not be given aspirin or aspirin-containing medicines unless specifically directed by an appropriate specialist for an exceptional medical reason.
Aspirin use during certain viral illnesses, including chickenpox, has been associated with Reye syndrome, a rare but serious condition affecting the brain and liver.
Check medicine labels carefully.
If you are uncertain which fever or pain medicine is appropriate, ask a healthcare professional or pharmacist.
What About Ibuprofen?
There have been concerns about using ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDs) during chickenpox because of an association with serious skin and soft-tissue complications.
Guidance can vary between countries.
Do not automatically give ibuprofen to someone with chickenpox without checking current advice from an appropriate healthcare professional or pharmacist.
Can Paracetamol/Acetaminophen Be Used?
Paracetamol, also called acetaminophen, is commonly used in many countries for fever or discomfort when appropriate.
However, dosing must be based on:
- age,
- weight,
- product strength,
- medical conditions,
- and local recommendations.
Never exceed the recommended dose.
Check with a healthcare professional or pharmacist if you are uncertain, especially when treating a young child.
Is There a Cure for Chickenpox?
Most uncomplicated cases are managed with supportive care while the immune system controls the infection.
Treatment may involve:
- adequate fluids,
- rest,
- relief of itching,
- appropriate fever or pain management,
- and monitoring for complications.
However, antiviral treatment can be important for some people.
When Are Antiviral Medicines Used?
Antiviral medicines such as acyclovir or related medicines may be considered for people at increased risk of moderate or severe chickenpox.
These can include certain:
- adolescents and adults,
- pregnant women,
- people with chronic skin or lung disease,
- people receiving some steroid treatments,
- and people with weakened immune systems.
Antiviral treatment works best when started early, often preferably within the first 24 hours after the rash begins when oral therapy is indicated.
People with severe disease or major immune suppression may require intravenous antiviral treatment.
These medicines require appropriate clinical assessment.
Does Everyone With Chickenpox Need Antiviral Medicine?
No.
Otherwise healthy children with uncomplicated chickenpox generally do not routinely require antiviral treatment.
Treatment decisions depend on:
- age,
- severity,
- immune status,
- pregnancy,
- underlying conditions,
- and timing of symptoms.
A healthcare professional should determine whether antiviral treatment is appropriate.
Chickenpox During Pregnancy
Chickenpox deserves particular attention during pregnancy.
Pregnant women who are not immune and develop chickenpox have an increased risk of serious complications, particularly pneumonia.
Infection during certain stages of pregnancy can also affect the developing baby.
Chickenpox in early pregnancy carries a small risk of congenital varicella syndrome, which can cause abnormalities involving the skin, limbs, eyes and nervous system.
Chickenpox occurring very close to delivery can also put a newborn at risk of serious neonatal infection.
What Should a Pregnant Woman Do After Exposure?
If you are pregnant and believe you have been exposed to chickenpox or shingles, especially if you do not know whether you are immune:
contact an appropriate healthcare professional promptly.
Do not wait for a rash to develop before seeking advice.
Your immunity may need to be assessed, and post-exposure treatment may sometimes be appropriate.
Can Pregnant Women Receive the Chickenpox Vaccine?
The varicella vaccine is a live attenuated vaccine and is generally contraindicated during pregnancy.
Women who are not immune may be advised to receive vaccination before pregnancy or after pregnancy, depending on local recommendations and individual circumstances.
Always follow professional vaccination guidance.
Chickenpox in Newborn Babies
Chickenpox can be particularly serious in newborns.
A baby may be at increased risk when the mother develops chickenpox around the time of delivery.
Premature babies can also be at increased risk following certain exposures.
These situations require prompt specialist medical assessment.
Chickenpox in People With Weakened Immune Systems
People with weakened immune systems can develop severe or widespread varicella.
Higher-risk groups may include some people with:
- leukemia or lymphoma,
- immune deficiencies,
- organ transplants,
- chemotherapy treatment,
- or medicines that significantly suppress immune function.
Serious complications can involve organs such as the:
- lungs,
- liver,
- brain,
- and blood-clotting system.
Anyone with significant immune suppression who is exposed to chickenpox or shingles should seek medical advice promptly.
What Should You Do After Exposure?
If you have been exposed to chickenpox or shingles and you are unsure whether you are immune, contact a healthcare professional—particularly if you are:
- pregnant,
- immunocompromised,
- caring for a vulnerable newborn,
- or otherwise at high risk of severe disease.
Post-exposure measures may sometimes prevent disease or reduce its severity.
Timing matters.
Can Vaccination After Exposure Help?
For eligible people without immunity, chickenpox vaccination after exposure can sometimes prevent chickenpox or make the illness less severe.
Whether vaccination is appropriate depends on:
- age,
- vaccination history,
- medical conditions,
- pregnancy status,
- immune status,
- and time since exposure.
Follow local immunization guidance.
What Is Varicella-Zoster Immune Globulin?
Certain people at high risk of severe chickenpox who cannot receive the vaccine may be offered varicella-zoster immune globulin after significant exposure.
It provides antibodies against the virus and may prevent chickenpox or reduce its severity.
This is particularly relevant to selected high-risk people without immunity.
It should be administered according to professional guidance and within the recommended time after exposure.
How Can Chickenpox Be Prevented?
Vaccination is the most effective specific method of preventing chickenpox where varicella vaccination is recommended and available.
Other measures include:
- avoiding close contact with susceptible high-risk people while infectious,
- staying away from school, work or public settings according to local public-health guidance,
- covering lesions where appropriate,
- practising good hand hygiene,
- and avoiding direct contact with blister fluid.
How Effective Is the Chickenpox Vaccine?
Varicella vaccination provides strong protection.
CDC reports that two doses are more than 90% effective at preventing chickenpox.
Vaccinated people who nevertheless become infected generally experience milder illness.
Is Chickenpox Vaccination Recommended Everywhere?
Vaccination policy varies internationally.
Some countries routinely vaccinate children against chickenpox, while others use different strategies based on local disease patterns, healthcare priorities, vaccine coverage and cost-effectiveness.
WHO issued an updated varicella vaccine position paper in November 2025, providing current international guidance for national immunization programmes.
Follow the vaccination schedule recommended in the country where you live.
Is the Chickenpox Vaccine Safe?
Varicella vaccines have been extensively studied.
Common reactions are generally mild and may include:
- soreness at the injection site,
- redness,
- fever,
- or a mild rash.
Serious reactions are rare.
Because it is a live vaccine, there are circumstances in which varicella vaccination may not be appropriate, including pregnancy and certain severe immune deficiencies.
A healthcare professional can determine eligibility.
Can You Get Chickenpox Twice?
Most people who recover from chickenpox develop long-lasting immunity, and a second episode is uncommon in otherwise healthy people.
However, repeat chickenpox can occasionally occur, particularly in people with weakened immune systems.
More commonly, VZV later reactivates as shingles rather than causing another typical episode of chickenpox.
Chickenpox vs Shingles
Chickenpox and shingles are related but not identical.
Chickenpox: the initial illness caused by VZV infection.
Shingles: reactivation of VZV that has remained dormant in nerve tissue after the initial infection.
Shingles commonly causes a painful blistering rash affecting a limited area on one side of the body.
The risk of shingles generally increases with age and weakened immunity.
Chickenpox vs Measles
Chickenpox and measles are completely different infections.
Chickenpox is caused by varicella-zoster virus.
Measles is caused by the measles virus.
Both can cause fever and rash, but their rashes, transmission patterns, complications and vaccines differ.
A healthcare professional should assess an uncertain rash rather than relying solely on photographs or online descriptions.
When Should You Contact a Healthcare Professional?
Seek medical advice if chickenpox is suspected in someone who:
- is pregnant,
- is an infant,
- is an adolescent or adult with significant symptoms,
- has a weakened immune system,
- has chronic lung or skin disease,
- or develops concerning complications.
Also seek medical advice if symptoms are becoming worse instead of gradually improving.
When Is Urgent Medical Care Needed?
Seek urgent medical assessment if someone with chickenpox develops:
- difficulty breathing,
- severe or persistent coughing with breathing problems,
- confusion,
- extreme drowsiness or difficulty waking,
- seizures,
- severe weakness,
- difficulty walking or loss of coordination,
- severe dehydration,
- repeated vomiting,
- severe headache with neurological symptoms,
- a rapidly spreading painful or infected-looking skin rash,
- or a rapidly worsening overall condition.
Contact your local emergency medical service if symptoms appear life-threatening.
Should Someone With Chickenpox Stay Home?
Yes, while infectious.
People with chickenpox should generally avoid school, work and close contact with susceptible people until all lesions have crusted over, unless a healthcare or public-health authority gives different instructions.
Particular care should be taken to avoid exposing:
- pregnant women without immunity,
- newborn babies,
- and people with weakened immune systems.
Is Disinfecting the Entire House the Main Prevention Strategy?
No.
The original article emphasized regular disinfection of areas touched by the infected person.
Normal hygiene and cleaning are sensible, but chickenpox transmission cannot be controlled simply by disinfecting surfaces.
The virus spreads efficiently through close contact, respiratory particles and contact with blister fluid.
Vaccination, appropriate isolation and protecting susceptible high-risk people are more important preventive measures.
The Bottom Line
Chickenpox is a highly contagious infection caused by varicella-zoster virus.
The classic symptom is an itchy rash that develops from spots into fluid-filled blisters and then crusts.
A person can spread chickenpox from approximately 1–2 days before the rash begins until all lesions have crusted over.
Most healthy children recover without serious problems, but chickenpox can cause severe complications, particularly in:
- infants,
- adolescents,
- adults,
- pregnant women,
- and people with weakened immune systems.
Vaccination provides strong protection and is used routinely in many countries.
People at high risk who are exposed to chickenpox should seek medical advice promptly because vaccination, immune globulin or antiviral treatment may be appropriate depending on the circumstances.
And remember: calamine lotion can relieve itching, but it does not prevent chickenpox.
Medical Disclaimer
This article provides general health information for an international audience and is not a substitute for diagnosis, vaccination advice or treatment from a qualified healthcare professional. Chickenpox vaccination schedules and treatment recommendations vary between countries. Pregnant women, newborns, people with weakened immune systems and anyone with severe symptoms should seek appropriate professional medical advice promptly.
Sources and Further Reading
World Health Organization — Varicella
https://www.who.int/teams/immunization-vaccines-and-biologicals/diseases/varicella
World Health Organization — Varicella Vaccine Position Papers
https://www.who.int/teams/immunization-vaccines-and-biologicals/policies/position-papers/varicella
World Health Organization — Varicella Vaccine Position Paper, November 2025
https://www.who.int/publications/i/item/who-wer10047-567-590
Centers for Disease Control and Prevention — About Chickenpox
https://www.cdc.gov/chickenpox/about/index.html
Centers for Disease Control and Prevention — Chickenpox Symptoms and Complications
https://www.cdc.gov/chickenpox/signs-symptoms/index.html
Centers for Disease Control and Prevention — Treating Chickenpox
https://www.cdc.gov/chickenpox/treatment/index.html
Centers for Disease Control and Prevention — Chickenpox Vaccination
https://www.cdc.gov/chickenpox/vaccines/index.html
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