Perinatal transmission of bloodborne infections

• Main risk is for HIV and HBV

Investigations

Unknown maternal serostatus

• If possible, send STAT maternal HIV serology, HBV, HCV, and syphilis; can consider viral load
• For infant:
  • At birth send HIV, HBV (sAg, sAb, cAb), HCV-Ab, and syphilis serologies, as well as an HIV PCR (not viral load)
  • Repeat HIV PCR at 1, 2, and 4-6 months

HIV

Diagnosis

• Up to 18 months of age, only use HIV PCR
  • In general, all infants with perinatal exposure should be checked at 14 to 21 days, 1 to 2 months, and 4 to 6 months
  • If high risk, can also check at birth and 2 to 4 weeks after stopping antiretrovirals
  • Confirm a positive result with repeat testing
• Serology can be tested starting at 18 to 24 months

Management

Antepartum management

• See HIV in pregnancy for management of an HIV-positive mother
• Note that integrase inhibitors are effective for achieving fast viral suppression

Peripartum management

• Immediate management depends on maternal viral load and treatment status
• In general, a mom with HIV should get IV zidovudine during labour
  • If it is unavailable or resistant, could use any pregnancy-safe medication

VL	Antenatal Rx	C-section	Neonatal Rx
>1000	Any	Yes	ART
40-999	None	Yes	ART
40-999	ART	Maybe	ART
<40	None	Maybe	ART
<40	ART	No	Zidovudine x4 weeks
Unknown	None	Maybe	ART
Unknown	ART	Maybe	Unclear

Selection of antiretrovirals

• Can either do a prophylactic regimen, or treat empirically
• Prophylaxis:
  • ZDV/NVP: zidovudine x6 weeks, plus nevirapine x3 in the first week of life
• Empiric treatment:
  • ZDV/3TC/NVP: zidovudine for 6 weeks, plus lamivudine and nevirapine for 2 to 6 weeks (preferred)
  • ZDV/3TC/RAL: zidovudine for 6 weeks, plus lamivudine and raltegravir for 2 to 6 weeks
  • Regarding duration, in the UK they typically treat for 2 weeks while in Canada it is typically 4 weeks

Follow-up

Age	Investigations	Management
Birth	CBC/diff, ALT, lactate, and HIV PCR	Start ART as described below
7 days	CBC/diff, nevirapine level	Dose-adjust nevirapine if needed
14 days	CBC/diff, nevirapine level, and HIV PCR	Dose-adjust nevirapine if needed
4 weeks	CBC/diff and ALT; ?HIV PCR?	Stop nevirapine if prior HIV PCR is negative, and continue other ART
6 weeks	?HIV PCR?	Stop zidovudine and lamivudine if HIV PCR has been negative
2 months		Review as needed
6 months	CBC/diff and ALT
18 months	HIV serology	Developmental assessment
3.5 years		Developmental assessment
5.5 years		Developmental assessment

Breastfeeding

• Generally recommend against breastfeeding for HIV-positive mothers in Canada, even if HIV is well-controlled
  • 10-20% risk if breastfeeding and uncontrolled; less than 1% if fully and reliably suppressed
• As well as risk of HIV transmission, it could theoretically expose child's HIV to low-level antivirals which could induce resistance

Hepatitis B virus

Background

• Pregnant women are screened with HBsAg for active infection, usually during the first trimester
• Transmission mostly occurs intrapartum, and is highest if they have acute infection in the third trimester

Management

Antepartum management

• Tenofovir is safe in pregnancy; lamivudine and telbivudine are alternatives
• Treatment is started if the viral load is greater than 200,000 copies/mL at 28-32 weeks gestation, and continued until delivery

Peripartum management

• Prophylaxis should be considered it mother has active hepatitis B (i.e. HBsAg positive), or her status is unknown
  • If status is unknown, try to get HBsAg done STAT (but often not possible)
• Prophylaxis is with hepatitis B immune globulin (HBIG) and hepatitis B vaccine given within 12 hours of life into different limbs
  • Vaccine prevents about 90% of infections, with HBIG adding a bit more
  • HBIG can be given up to 7 days of life but is most effective when given earlier
• Despite optimal treatment, there is still a 2% risk of vertical transmission

Postpartum management

• Complete a routine vaccination schedule for hepatitis B in the infant
  • If the birth weight is less than 2000 g, this birth dose should not count towards their vaccine series
• Check infant serology for HBsAb and HBsAg at 9 to 12 months
  • Maternal HBcAb may be detected up to 24 months post-partum and should not be tested
• Remember to screen other family members for hepatitis B
• Recommend breastfeeding, since hepatitis B is not a contraindication

Further Reading

• Prevention of Hepatitis B Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep. 2018;67(RR-1):1–31. doi: 10.15585/mmwr.rr6701a1

Hepatitis C virus

• About 5% risk of vertical transmission, though higher if coinfected with HIV
  • About half are transmitted antepartum and half intrapartum
• Not urgent, as it is a chronic illness that may not manifest for decades
• Serology to be done at 12-18 months for diagnosis
• If significant anxiety, can send HCV-PCR at 3 to 6 months
  • 25-30% will spontaneous clear it
  • Still need serology at 12-18 months, and repeat PCR around 18 months

Further Reading

• AIDSinfo. Recommendations for the Use of Antiretroviral Drugs in Pregnant Women with HIV Infection and Interventions to Reduce Perinatal HIV Transmission in the United States.
• Ontario HIV Treatment Network. Guidelines for the Prevention of Mother-to-Child HIV Transmission. 2017.