OGCO-C1.8 Chickenpox and shingles in pregnancy

Question 1

What is antenatal history screening for chickenpox and shingles?

Answer 1

• Women screened for history of chickenpox infection or immunization at the booking exit
• Immunity assumed and documented in the ARS record in patients volunteering a positive history of either infection or immunization

Question 2

What are the clinical features of chickenpox/shingles?
When may lab tests be used?

Answer 2

• Dx usually clinically with the appearance of the typical rash. However, may also be atypical in appearance (maculopapular with few or no lesions)

In uncertain cases, lab tests may be used
* Isolation of VZV from a clinical specimen
* Demonstration of >4 fold rise in antibody (Ab) titer
* Demonstration of viral antigen in vesicular fluid or scrapings using fluorescent antibody stianing
* PCR for VZV in clinical specimens

History of contact as:
* Continuous household contact, face to face contact
* Stay in the same room/cubicle for 15 mins or more
* Neonates whoe mothers have SS of varicella around the time of delivery (5 days before to 2 days after)

Question 3

What is Mx for women with non immunity to chickenpox?

Answer 3

• Patients advised to avoid contact with chickenpox and shingles during pregnancy and inform healthcare workers of potentia lexposure
• Advise postpartum varicella vaccination to all non immune mothers. Contraception advised for 3 months after the vaccination.
• A monovalent live attenuated varicella vaccine available in HK
• Varicella vaccination not recommended during pregnancy.
• Breastfeeding can be continued after the vaccination

Question 4

What is the treatment for confirmed chickenpox mother?

Answer 4

Question 5

At what gestational age is mothers at risk of fetal varicell syndrome?

Answer 5

• Before 28 weeks gestation.
• Referral to PDC for follow up at least 5 weeks after infection for further counselling

Induction of labor or elective delivery should be delayed for 7 days after onset of rash to facilitate passive immunity of the neonate.

Question 6

What is the Mx for post exposure prophylaxis in susceptible women with significant VZV contact?

Answer 6

• VZIG offered as soon as pssible or can be given within 10 days after exposure.
• Dosage of ZVIG is 1-2ml (25-50IU)/kg body weight IV. It should be infused IV at an initial rate of 0.1ml/kg/hour for 10 mins. If well tolerated with no AE, the rate of infusion may gradually be increased to a maximum of 1ml/kg//hour
• Ensure there is no fever or appearance of vesicles prior to administration of ZVIG. It has no therapeutic benefit once chickenpox has developed.
• AE include headache, nuasea, vomiting, renal and urinary disorers, arthralgia, mild back pain, low BP, anaphylactic reactions.
• ZVIG may prolong incubation up to 28 days. Patient should be advised not to contact other susceptible individuals (other pregnant women).
• For high risk cases with additional exposure to VZV more than 3 weeks after initial ZVIG admin –> another dose may be considered
• After delivery, varicella vaccine may be considered for breastfeeding mothers. After ZVIG therapy, the efficacy of VZV vacine may be impaired. An interval of 3 months should elapse before vaccination

Question 7

What is the Mx algorithm for women with suspected VZV contact?

Answer 7

Question 8

How is a dx of shingles in pregnancy done?

Answer 8

• Clinical dx mainly with a vesicular erythrematous skin rash in a dermatomal distribution (most frequently over thoracic dermatomes or the head).
• Rash may be proceeded by prodromal pain, pruritis or paresthesia for 48-72 hours before onset of rash. Vesicles can become confluent in 2-4 days and will resolve over 7-12 days
• Vesicular fluid for VZV PCR can be considered if in doubt

Question 9

What is the Mx of women presenting with possible exposure to herpes zoster (shingles)?

Answer 9

• Review antenatal history for status of VZV immunity
• Reassure women who are known to be immune to VZV
• For non immune women, the risk of acquiring infection from an immunocompetent individual with herpes zoster in non exposed sites (thoracolumbar) is remote but can occur
• Disseminated zoster or exposed zoster (ophthalmic) in any individual or localizef zoster in any immunosuppressed patient should be considered to be infectious as the viral shedding may be higher. Patients should be treated as per women who have been exposed to chickenpox and consider VZIG if necessary.

Question 10

What is the infection control for shingles?

Answer 10

• Small risk of transmission of VZV to others from exposed rash, usually via direct contact of vesicular fluid
• Standard precautions adopted until lesions are dry and crusted for immunocompetent women with shingles involving single dermatome in non exposed areas
• Airborne, contact and standard precautions if disseminated herpes zoster in any women, localized disease in immunocompromised women until dissemination is ruled out.

Question 11

What is the Tx of shingles and objective of

Answer 11