CHICKENPOX / VARICELLA
Information Leaflet
What is chickenpox or varicella?
Chickenpox or varicella is a viral illness that causes a generalised, pruritic, vesicular rash
typically consisting of 250 to 500 lesions in varying stages of development and resolution
(crusting), mild fever and other systemic symptoms.
How is varicella spread?
Varicella is spread via airborne and droplet routes, from person to person. It is highly contagious
to those who are non-immune. A case is infectious from 2 days before onset of rash until all
lesions are crusted and no new lesions are appearing (5-7 days after onset of rash). If possible
postpone hospital visits during this time. The incubation period (time from exposure to the
infection until development of rash) is 10-21 days (average 14 days between household cases). If
possible, postpone hospital visits during this time if a non-immune patient is exposed to varicella.
Varicella and pregnancy
Varicella <28/40 gestation is associated with a small risk of fetal varicella syndrome (0.4% risk
<13/40; 2% risk 13-20/40; negligible risk 20-28/40; no risk >28/40). Varicella is more likely to
cause complications in pregnant adults compared to children. The most common complication is
pneumonitis which is more common in the third trimester. Varicella occurring 5 days before to 2
days after delivery is associated with severe varicella in the neonate. Varicella within 3 weeks
before delivery is associated with mild to moderate varicella in the newborn.
Is there any treatment for varicella in pregnancy?
The antiviral acyclovir 800mg 5 times per day p.o. can be prescribed if <24-48 hours of rash
appearing. Acyclovir is not licensed in pregnancy although the ‘Registry of acyclovir in
pregnancy’ did not find any association with fetal anomalies. Recommend acyclovir if >20/40
and consider if <20/40 and at risk of complications. Recommend regular paracetamol to reduce
fever, bed rest and fluids. Do NOT use Varicella immunoglobulin (VZIG) if the patient has
varicella. Discuss any case with Microbiologist as required (Bleep 162 or via switch).
Is there any treatment for a non-immune pregnant woman exposed to varicella?
Non-immune pregnant women with a significant exposure to varicella can be offered VZIG
within 4 days of exposure. VZIG reduces the likelihood of developing varicella or if varicella
develops, it reduces the risk of complications. If 5 or more days have elapsed after exposure to
chickenpox, there is no benefit to VZIG. After receiving VZIG, the patient is potentially
infectious from 10-28 days after exposure. If possible postpone hospital visits during this time.
How can varicella be prevented?
Receive 2 doses of the live attenuated varicella vaccine (not in pregnancy).
How do I know if a patient is immune?
A person who has had varicella or zoster (shingles) or has had 2 doses of the varicella vaccine,
will be immune. If immunity testing is required, serum can be tested for varicella IgG (can be
ordered on stored antenatal bloods if booked).
 Varicella IgG negative: patient is susceptible. Offer VZIG if definite varicella exposure.
Discuss with Microbiologist as required (Bleep 162 or via switch).
 Varicella IgG positive: patient is immune. Reassure
Infection Control, October 2012