Chickenpox (varicella) is a highly infectious viral disease caused by the VZV virus (varicella-zoster virus). The same virus can reactivate after years and cause shingles.
How infection occurs: mainly by airborne droplets and by contact with secretions/fluid from skin lesions (less often) – also from a person with shingles.
Source of pathogen / reservoir: humans (sick people, infected people).
Incubation period: usually 14–16 days, range 10–21 days.
When is it infectious: from 1–2 days before the rash until all lesions have crusted over (scabs); in vaccinated people with mild lesions – until no new lesions appear for 24 hours.
Who is most at risk: people without immunity (who have not had the disease and are unvaccinated). The greatest risk of severe course/complications concerns, among others, adolescents and adults, pregnant women, and people with reduced immunity.
2. Symptoms of chickenpox
Most common symptoms:
itchy vesicular rash (appears in "crops", some lesions are fresh, some are already drying up),
fever, weakness, headache, muscle pain.
Course of the disease: usually milder in children, more often severe in adults. Infectious lesions usually dry up within a few days, but the whole ailment may last about 1–2 weeks (depending on the course and number of rash "crops").
Possible complications: including bacterial skin superinfections, pneumonia, neurological complications (e.g., encephalitis), thrombocytopenia; the risk of complications increases in adults and people with reduced immunity.
When to urgently see a doctor / ER:
shortness of breath, severe cough, chest pain (suspicion of pulmonary complications),
disturbances of consciousness, severe headache, convulsions, stiff neck,
very high persistent or increasing fever, signs of dehydration,
rapidly spreading, purulent skin lesions,
any suspicion of chickenpox in a pregnant woman or a person with significantly reduced immunity.
3. Where does chickenpox occur?
Chickenpox occurs all over the world and is very common. Globally, WHO estimates about 140 million cases annually (with millions of severe complications requiring hospitalization).
In Poland, the disease is still frequent – e.g., in 2023 approx. 190,825 cases were registered.
For travelers: the information is particularly important for people who have not had the disease and have not been vaccinated – because the risk of contact with the virus is real practically everywhere (including in hotels, planes, at family events, among children).
4. How to protect yourself against chickenpox?
A. General prevention
avoiding close contact with a sick person until all lesions have crusted over,
hand hygiene, ventilating rooms, limiting sharing of towels/bedding,
quick medical consultation if there is a pregnant person, newborn, or someone with reduced immunity in the house.
B. Vaccination (most important)
Type of vaccine: live, attenuated (weakened virus) – e.g., Varilrix/Varivax (preparation depends on availability).
For whom recommended: for people without immunity (who have not had the disease and are unvaccinated), especially in adolescents and adults due to the greater risk of severe course; in Poland, vaccination is also mandatory in selected risk groups (including some children in special clinical/epidemiological situations).
Vaccination schedule: total 2 doses.
Standard second dose after ≥6 weeks (not less than 4 weeks).
In practice, intervals depend on age and recommendations – e.g., in children a longer minimum interval is often assumed, and in older people shorter (according to recommendations).
Vaccination after contact (post-exposure): best up to 72 hours, possible up to 5 days after exposure – can prevent illness or alleviate the course.
Booster doses: routinely not standardly required; immunity after a full schedule is usually long-lasting.
Important contraindications/notes: due to the nature of the vaccine (live), it is not used in pregnancy and is usually not given with significant immunosuppression – medical qualification is key.
5. Summary
Chickenpox is a frequent and highly infectious disease, and in adolescents and adults, it can be severe and cause dangerous complications. Vaccination (2 doses) is the most effective method of protection – it is particularly worth considering if you have not had chickenpox and do not have confirmed vaccination, and also if you have particularly sensitive people in your environment (e.g., pregnancy, immunosuppression).
If you are planning a trip or an important family event, it is best to start vaccination in advance so as to manage to give 2 doses at the recommended interval (and after exposure act immediately – preferably within 72 h).