Chickenpox in a healthy child over one year is usually an uncomplicated illness that parents can manage at home. But chickenpox in very specific circumstances, notably in a pregnant woman who has never had it, in a newborn whose mother developed chickenpox around delivery, or in any person who is immunocompromised, is a genuinely serious matter.
Most parents are more worried about routine childhood chickenpox than they need to be. A smaller group, including pregnant women without immunity and parents of newborns exposed to chickenpox, need to act quickly.
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. It typically causes an itchy rash of fluid-filled blisters appearing in crops over three to seven days, accompanied by fever, malaise, and occasionally a headache before the rash appears.
The incubation period is ten to twenty-one days after exposure. The child is contagious from one to two days before the rash appears until all the blisters have crusted over, typically five to seven days after the rash started.
Management in healthy children over six months: paracetamol for fever and discomfort (avoid ibuprofen, which has been associated with secondary bacterial skin infection in chickenpox). Calamine lotion, antihistamine (if the itch is severe), and cutting the child's fingernails to reduce scratching and secondary infection. Keep the child out of school or nursery until all blisters have crusted.
Seek medical assessment if the rash is very severe, if blisters become infected (increased redness, warmth, pus), if the child has difficulty breathing or a severe headache, or if they are immunocompromised.
Chickenpox in Pregnancy
About 3 in 1,000 pregnant women develop chickenpox. Around 90 per cent of adults in the UK are immune from childhood infection, so the risk applies primarily to the approximately 10 per cent who are not.
In the pregnant woman herself, chickenpox can be more severe than in a child, with a significant risk of 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.
Foetal effects depend on the timing of maternal infection. In the first 28 weeks of pregnancy, particularly between 13 and 20 weeks, there is a risk of foetal varicella syndrome: skin scarring, limb hypoplasia, eye abnormalities, and neurological problems. The risk is small (around 2 per cent when maternal infection occurs between 13 and 20 weeks) but real.
A pregnant woman who is not immune and is exposed to chickenpox should contact their midwife or GP immediately, ideally within 24 hours. Varicella zoster immunoglobulin (VZIG) given within 10 days of exposure can reduce the severity and risk to the foetus. Immune status can be confirmed quickly with a blood test.
Neonatal Varicella
The most serious risk is to the newborn when the mother develops chickenpox within five days before or two days after delivery. In this situation, the baby has been exposed to the virus but has not had time to receive protective maternal antibodies. Neonatal varicella in this group can be severe, affecting the lungs, liver, and brain, and carries a mortality rate of around 25 to 30 per cent without treatment.
These babies receive VZIG at birth as prophylaxis, and if they develop chickenpox despite this, they are treated with intravenous aciclovir in hospital.
A baby exposed in the first four weeks of life to chickenpox from any household member should have their GP or community midwife informed immediately, and the baby's immune status (via maternal immune status) should be checked promptly.
The Chickenpox Vaccine
The varicella vaccine is not currently part of the routine UK childhood immunisation schedule. It is used for specific at-risk groups: immunocompromised individuals who are susceptible, healthcare workers, household contacts of immunocompromised people, and some other groups.
In many other countries, including the USA, Germany, and Australia, universal childhood vaccination against chickenpox is standard practice. The Joint Committee on Vaccination and Immunisation (JCVI) has reviewed the evidence periodically and has so far not recommended universal vaccination in the UK, partly on the basis of concerns about increasing shingles in older adults (when fewer children are infectious, adults have fewer immune boosts from exposure). This debate continues.
Parents who want their children vaccinated can access the vaccine privately.
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.
