Chickenpox in a healthy child over a year old is usually a manageable two-week stretch of itching and calamine lotion. But there are three situations where chickenpox is genuinely serious and time-sensitive: a pregnant woman who's never had it, a newborn whose mother developed it around the time of delivery, and anyone who's immunocompromised.
Most parents worry about everyday childhood chickenpox more than they need to. A smaller group – pregnant women without immunity, parents of newborns exposed in the first month of life – need to act quickly, and this is the article for them.
Healthbooq (healthbooq.com) covers childhood illnesses and the specific situations where they become higher risk through the early years.
Chickenpox in the Healthy Child: What Is Normal
Chickenpox (varicella) is caused by the varicella-zoster virus. The classic picture: an itchy rash of fluid-filled blisters appearing in crops over three to seven days, with fever, malaise, and sometimes a headache in the day or two before the rash starts.
The incubation period is 10 to 21 days after exposure. The child is contagious from one to two days before the rash appears until every blister has crusted over – typically five to seven days after the rash starts.
Management for a healthy child over six months: paracetamol for fever and discomfort. Avoid ibuprofen – it's associated with serious secondary bacterial skin infection in chickenpox. Calamine lotion for spots, antihistamines for severe itch, fingernails kept short to limit scratching damage. Keep the child off nursery or school until every blister has crusted.
Get medical assessment if the rash is unusually severe, blisters look infected (spreading redness, warmth, pus), the child has breathing problems or a severe headache, or they're immunocompromised.
Chickenpox in Pregnancy
Around 3 in 1,000 pregnant women develop chickenpox. Roughly 90% of UK adults are immune from childhood infection, so the risk applies primarily to the 10% or so who aren't.
In the pregnant woman herself, chickenpox tends to be more severe than it would be in a child, with a real risk of varicella pneumonia – particularly in the third trimester. Antiviral treatment with aciclovir, started within 24 hours of the rash appearing, reduces severity and is recommended for pregnant women beyond 20 weeks' gestation.
Effects on the baby depend on timing of maternal infection. In the first 28 weeks – particularly between 13 and 20 weeks – there's a small risk of fetal varicella syndrome (skin scarring, limb hypoplasia, eye abnormalities, neurological problems). The risk is around 2% when maternal infection occurs between 13 and 20 weeks. Small in absolute terms, but real.
If you're pregnant, not immune (or unsure), and have been exposed to chickenpox, contact your midwife or GP immediately – ideally within 24 hours. Varicella zoster immunoglobulin (VZIG) given within 10 days of exposure reduces severity and risk to the baby. A blood test can confirm immune status quickly.
Neonatal Varicella
The most serious situation: the mother develops chickenpox within five days before or two days after delivery. In this window, the baby is exposed to the virus but doesn't have time to receive protective antibodies from the mother. Neonatal varicella here can be severe – affecting lungs, liver, and brain – and carries a mortality of around 25-30% without treatment.
These babies receive VZIG at birth as prophylaxis, and if they go on to develop chickenpox despite this, they're treated with intravenous aciclovir in hospital.
Any baby exposed to chickenpox in the first four weeks of life, from any household member, should be discussed with a GP or community midwife immediately. The baby's protection depends on maternal immune status, which can be checked promptly.
The Chickenpox Vaccine
The varicella vaccine is not currently part of the routine UK childhood immunisation schedule. It's used for specific at-risk groups – immunocompromised individuals who are susceptible, healthcare workers, household contacts of immunocompromised people.
In other countries, including the US, Germany, and Australia, universal childhood vaccination against chickenpox is standard. The Joint Committee on Vaccination and Immunisation (JCVI) has periodically reviewed the evidence for the UK and has so far stopped short of recommending universal vaccination, partly because of concerns that fewer chickenpox cases in children reduce the immune boosts that adults get from environmental exposure – which could increase shingles in older adults. The debate is ongoing and the position may change.
Parents who want their child vaccinated can pay privately. Two doses are typically given, separated by at least four to eight weeks.
Key Takeaways
Chickenpox in a healthy child is usually mild and self-limiting, but it presents serious risks in specific situations: in pregnant women who are not immune, in newborns exposed around the time of delivery, and in immunocompromised individuals. A pregnant woman who has not had chickenpox and is exposed should contact their midwife or GP immediately: varicella zoster immunoglobulin (VZIG) can reduce severity if given promptly. Neonatal varicella, occurring when a baby is born within five days of the mother developing chickenpox or within two days of delivery, can be severe and requires VZIG and antiviral treatment. Chickenpox is a vaccine-preventable disease; the UK does not currently include it in the standard childhood immunisation schedule but it is recommended for certain at-risk groups.
