Live vaccine contraindication in immunodeficiency — MRCPCH TAS MCQ

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ModerateImmunologyLive vaccine contraindication in immunodeficiencyMRCPCH TAS

A 13-month-old with suspected severe combined immunodeficiency is due routine immunisations. The team delays a vaccine containing live attenuated virus. Which vaccine is most relevant?

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Correct answer: B — MMR vaccine

MMR is a live attenuated vaccine and is contraindicated in severe T-cell immunodeficiency because uncontrolled replication can occur. Inactivated and conjugate vaccines do not replicate and are generally safer, although responses may be poor. The pearl is to consider immunodeficiency before administering live vaccines to infants with severe recurrent infections.

Reference: UKHSA Green Book; Nelson Textbook of Pediatrics; RCPCH Theory examination syllabi