ImmunologyTier 2Medical Sciences concept

Live vaccine contraindications (pregnancy, immunosuppression, HIV CD4 threshold)

Core concept

Live attenuated vaccine = replicating organism -> in an immunocompromised host it can cause the disease it prevents

The live vaccines to know

MMR, MMRV, varicella, zoster (Zostavax - live), BCG, oral typhoid (Ty21a), yellow fever, rotavirus, live attenuated influenza (intranasal), oral polio (not used in Australia)
Shingrix (recombinant zoster) is NOT live and is the correct product in the immunocompromised - Zostavax is contraindicated

Absolute or near-absolute contraindications

Pregnancy - and avoid pregnancy for 28 days after MMR or varicella
- Inadvertent MMR/varicella in pregnancy has never been shown to cause congenital disease and is NOT an indication for termination
Significant immunosuppression
- Prednisolone >=20 mg/day (or >=2 mg/kg/day in children <20 kg) for >=14 days -> wait >=1 month after stopping
- Inhaled, topical, intra-articular and physiological replacement doses are NOT a contraindication
- Most biologic and conventional immunosuppressive DMARDs (anti-TNF, rituximab, abatacept, tocilizumab, JAK inhibitors); methotrexate >20 mg/wk, azathioprine >3 mg/kg/day, 6-MP >1.5 mg/kg/day
- Chemotherapy - wait >=3 months (>=6 months after rituximab or anti-B-cell therapy)
- HSCT - wait 24 months, off immunosuppression, no GVHD; solid organ transplant - live vaccines generally contraindicated lifelong, so give them before transplant
Combined immunodeficiency, SCID, complete DiGeorge - lifelong
Infants of mothers given a biologic in pregnancy: no live vaccines (especially rotavirus and BCG) in the first 6-12 months after third-trimester anti-TNF exposure

HIV

CD4	Live vaccines
>=200 cells/microL (adults) / >=15% in children	MMR and varicella can and should be given if non-immune
<200 (or <15%)	Contraindicated
Any	Yellow fever - only if CD4 >=200 and after specialist advice; BCG contraindicated (disseminated BCG)

Yellow fever

Contraindicated: age <6 months (relative 6-9 months), pregnancy and breastfeeding, significant immunosuppression, thymus disorder or thymectomy, severe egg allergy
Age >=60 is a precaution - higher risk of viscerotropic and neurotropic disease
One dose confers lifelong protection (IHR certificate valid for life)

Household contacts of an immunocompromised person SHOULD be vaccinated - herd protection outweighs the tiny transmission risk
- MMR and rotavirus are not transmitted meaningfully (rotavirus - hand hygiene after nappies)
- Varicella vaccine transmits only if the vaccinee develops a vesicular rash (~1-3%) - avoid contact only if the rash appears; cover it. Do not withhold the vaccine.
Vaccinate ahead of planned immunosuppression - live vaccines >=4 weeks before, inactivated >=2 weeks before
Live vaccine spacing: give two live parenteral vaccines on the same day or >=4 weeks apart
Recent immunoglobulin or blood products blunt MMR/varicella - defer 3-11 months depending on product and dose
Egg allergy is no longer a contraindication to influenza or MMR - only to yellow fever (and Q fever)

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