shingles (Zoster) and breastfeeding

Herpes simplex virus (HSV) is not transmitted through breast milk (1)

• rather, postnatal acquisition of HSV is due to direct contact with a person shedding the virus, usually via an orolabial or other cutaneous lesion

Varicella Zoster virus (VZV)/Shingles (Zoster):

• is a risk of chicken pox to the infant if they come in contact with the shingles sores
  • if sores are on the breast or close to the nipple, it may not be possible to feed from that breast, although this would need thorough assessment

Guidance suggests that (2):

• aciclovir is the preferred antiviral for treating herpes simplex and varicella zoster as there are only very small amounts present in breast milk
  • as a precaution, monitor infant for drowsiness, irritability, skin rashes, vomiting and diarrhoea
  • is limited published evidence of use in breastfeeding
  • only very small amounts pass through into breast milk from oral administration
  • intravenous administration will result in higher breast milk levels, however its poor oral bioavailability will limit the amount the infant can absorb from breast milk
  • side effects in the breastfed infant would not be expected
    • have been no side effects reported in infants exposed to aciclovir through breast milk
  • aciclovir is used in full-term neonates from birth; the doses used are far greater than the amounts reported in breast milk
    
    
• valaciclovir is also an acceptable alternative, since it is converted to aciclovir before passing into breast milk
  • can be used during breastfeeding, but infant monitoring is required - monitor for drowsiness, irritability, skin rashes, vomiting and diarrhoea
    
    
• ophthalmic preparations have limited systemic absorption in the mother, and pose negligible risk to a breastfed infant
  • topical or ophthalmic aciclovir can be used during breastfeeding.
  • if clinically appropriate, topical routes of administration are usually preferred due to lower systemic concentrations, leading to lower concentrations in breast milk.
  • no specific infant monitoring is usually required. If a side effect is suspected, contact a healthcare professional for further advice
    
    
• treatment choice should be primarily based on clinical indications, with suitability in breastfeeding as a secondary consideration

For more detailed information then see NHS Specialist Pharmacy Service (January 2024). Treating herpes virus infections during breastfeeding

Reference:

• James SH, Sheffield JS, Kimberlin DW. Mother-to-Child Transmission of Herpes Simplex Virus. J Pediatric Infect Dis Soc. 2014 Sep;3 Suppl 1(Suppl 1):S19-23.
• NHS Specialist Pharmacy Service (January 2024). Treating herpes virus infections during breastfeeding